DE19808901A1 - Movable and / or deformable wall, in particular for a fluid channel section, and fluid channel section - Google Patents

Abstract

Optimal use can be made of fluid tunnels, e.g. wind tunnels, water tunnels, by adapting the size of the cross-sectional areas through which the fluid flows to the particular dimensions of the object being tested. The invention relates to a deformable wall (3) for at least locally altering the cross-sectional area of a fluid tunnel through which the fluid flows. Said deformable wall can be configured especially as a metal sheet with locally different flexural strengths to give the wall an advantageous shape in its deformed state, from the point of view of fluid dynamics. In a first position (3a), an inventive travelling wall (3) rests against an outer support structure (4a), especially an outer wall (4) of a section of fluid tunnel (1), said outer wall being turned away from the flow. In a second position (3b), said travelling wall is essentially at a distance from this outer support structure (4a) and on the incoming side, rests on another part of the flow-guiding surface. The inventive section of fluid tunnel (1) has an at least essentially rectangular cross section (9) and comprises at least one side wall (3) which can travel into the fluid tunnel section (1) and/or is deformable. In its repositioned and/or deformed state (3b), said side wall directly or indirectly annexes the base wall (7) of the fluid tunnel section (1) whilst the top wall (12) can travel into the fluid tunnel section (1) and/or is deformable. In its repositioned and/or deformed state (12b), the top wall lies at least partially on at least one repositioned and/or deformed side wall.

Description

The present invention relates to a deformable wall, in particular an at least egg deformable forming part of the flow guide surface of a fluid channel section Wall, according to the preamble of claim 1, a movable wall, which is part of the Forms flow guide surface of a fluid channel section and between at least two Positions is movable, according to the preamble of claim 12, a movable wall, which forms at least part of the flow guiding surface of a fluid channel section, according to the preamble of claim 14, a movable and deformable wall leading to forms at least a part of the flow guide surface of a fluid channel section the preamble of claim 27 and a fluid channel section with at least in the we substantial rectangular cross-section and at least locally changeable cross-flow Cutting surface according to the preamble of claim 29. The invention can in particular Nozzle sections of fluid channels, e.g. B. wind or water flow channels used become.

Vehicles and other objects are routed to great extent in fluid channels properties investigated. For example, automobiles and automotive parts in Wind tunnels subjected to numerous aerodynamic studies. The Automobiles or automotive parts tested at the original scale of 1: 1; to be prepared Smaller models are also used for investigations.

As is known, the cross-sectional area of a fluid channel to be examined is allowed Object in relation to the flow cross-sectional area of the fluid channel on the Position of the object should not be too large, otherwise the experimentally generated ones Flow conditions due to the presence of the flow-guiding Fluid channel wall boundaries too strong from the conditions with free flow deviate (so-called wall effect), which leads to errors in the experimentally measured Values. Experience has shown that the object to be examined is not  more than a quarter to a fifth of the flow cross-sectional area of the fluid channel should take the position of the object, otherwise the measurement results falsified inadmissible.

On the other hand, however, a large cross-sectional area through which the wind tunnel flows means that the wind tunnel must be built large and a correspondingly powerful and expensive circulation fan with a high energy consumption must be provided. From the cross-sectional area of the windka required at the position of the object nals and the performance of the circulation fan, the maxi male flow velocity of the object that can be realized in the wind tunnel.

In order to simulate high inflow speeds with relatively little effort, who which are widely used in fluid channel technology. However, the one set of models principle-related limits, since not all flow conditions and Have the measurement results transferred to the original object to scale. It is therefore on in any case, at least in addition, a measurement of the original object, e.g. B. an automobile bils or a 1: 1 scale automobile model, necessary in the wind tunnel.

With regard to the various object sizes to be examined in the wind tunnel, it is how has become apparent from the above, advantageous, the flowed cross-section to be able to change the area of the wind tunnel at least locally. This way, at given minimum ratio of the cross-sectional area at which the object flows and Cross-sectional area of the object and given the performance of the air blower the experi mentally achievable flow velocities are maximized: vehicles with smaller Cross-sectional area, e.g. B. fast passenger cars, typically higher Fahrge reach speeds as vehicles with a large cross-sectional area, e.g. B. Lastwa gen or buses, can then ge in a wind tunnel with the same fan power be tested. Alternatively, if the flow velocity achieved is sufficient, for smaller automobiles with a smaller cross-sectional area of the wind duct and, accordingly, lower blower output can be worked the blower's energy consumption is reduced and its lifespan is increased.  

The cross-sectional area through which the air flows has been tried in various ways to make a fluid channel changeable by the ones that delimit the fluid channel Walls forming the flow guide surface can be made movable and / or deformable.

The document US-PS 4,308,748 provides a fluid channel section with at least essentially Lichen rectangular cross-section and at least locally changeable cross-flow cut surface, which has side walls, a bottom wall and a top wall, the each form part of the flow guide surface of the fluid channel section. The at The side walls and the top wall are in the area that is to be examined Vehicle picks up, composed of individual, rectangular plates, the perpendicular to the plane of their extension on travel rods in the cross section of the fluid channels can be moved in and out. Between the individual plates are lower Right-facing panels are provided, which allow air to pass between the individual Prevent plates.

The document DE-OS 38 36 376 provides a simplified version of this principle before that there is only the ceiling wall made up of individual movable panels is set, which also extend across the entire width of the wind tunnel. The Adjustment of the ceiling wall is therefore only two-dimensional.

In the publication DE-PS 29 41 404 a wind tunnel section is described, the Wan is made of a material with a small modulus of elasticity and high yield strength. This stretchy wall is made on its outside by a multitude of lengths and crossways cut the wind tunnel of distributed, movable supports. The supports include in particular hydraulic cylinders, lifting spindles or the like, which individually or in Groups are adjustable.

From the document DE-U 87 02 336 is a device for generating a horizontal ten air flow known, in which the position of the exit surface of the freely emerging Airflow changes, but not the size of this cross-sectional area. To adjust the The outlet position of the air flow includes the device attached to a fan housing subsequent blow-out device with a rectangular flow channel through the most rigid existing side walls and is delimited by an upper and a lower baffle, the two baffles are pivotally mounted on their front and rear edges and the  front swivel axes in the vertical direction and the rear swivel axes in waa are displaceable in the right direction. This known device has the disadvantage that Achieving a horizontal direction of the freely emerging air flow in the air a rectifier grid is necessary, which leads to a disturbance of the flow and to a high pressure drop or loss of speed of the freely escaping air flow leads.

From the publications DE-OS 196 37 348, DE-PS 38 37 970, EP 0 572 787 B1, SU-OS 587 448 A and SU-OS 657 707 A further methods are known, walls from fluid channels to make cuts movable and / or deformable.

It is also possible to increase the cross-sectional area of wind tunnel sections through which flow change by the wind tunnel cross-section partly with shaped elements, e.g. B. suitable cut polystyrene foam molded parts or suitably shaped sheet metal hollow bodies is filled. However, the changeover times for introducing the shaped elements are considerable Lich; In addition, when not in use, there must be an appropriate storage room nearby of the wind tunnel.

There is the task of a movable and / or deformable wall, especially for one Fluid channel, of the type mentioned and a fluid channel of the type mentioned to propose in a simple, fast and inexpensive way that to cross-flow area of a fluid channel at least locally to change. The too At least local change in the cross-sectional area through which flow is to take place should take as long as possible Changeover times can be carried out "at the push of a button".

The object is achieved by a deformable wall with the features of claim 1 movable wall with the features of claim 12, a movable wall with the Features of claim 14, a movable and / or deformable wall with the features of claim 27 and a fluid channel section with the features of claim 29 ge solves.

One of the main ideas of the invention provides that a fluid channel according to the invention cut has a movable wall that can be moved between at least two positions is, the wall in a first position facing away from the fluid channel flow  outer support structure, in particular a flow-facing outer wall, of the fluid channel section abuts while in a second position substantially from the outside Ren support structure is spaced apart and upstream on another part of the flow bears guide surface of the fluid channel section. In this way discontinuity ten in the course of the wall, as in the known prior art, as far as he individually Traversing bars provide movable individual plates, inevitably occur, at least far avoided.

Another key concept of the invention provides that a fluid channel according to the invention cut a movable wall, which by means of guide means, in particular guide rails and / or bars and / or levers, and separate from the guide means, separate traversing means, in particular traction ropes, can be guided. In contrast to the well-known plates that can be moved individually on travel rods and that are mosaic-like together men form one or more walls of a known wind tunnel is a movable Wall according to this key concept of the invention much easier to design, since only one or a few traversing devices must still be available while the task is being carried out wall of much simpler, passively working guide means can be taken over.

It is particularly preferred that the movable wall by means of the moving means, in particular their pulling ropes, at the same time is also deformable, to form a fluid-dynamic favorable shape exercise can be achieved. Of course, it is of course also possible that the wall by means of Travel means is movable and by means of separate, separate from the travel means Deforming agent is deformable.

Another key concept of the invention is that a deformable wall differs locally che bending stiffness to achieve a fluid dynamic favorable shape in one deformed state. The shape of the wall in the deformed state is then not ensured by a large number of individual deforming actuators as in the prior art, instead it is determined by appropriate dimensioning of the local bending stiffness aims. As a result, only one or a few deforming means are left to achieve the deformation of the Wall necessary, in contrast to the multitude of individually movable positioning devices such as in the state of the art.  

Another key concept of the invention provides that a fluid channel according to the invention section comprises at least one side wall which moves into the fluid channel section is bar and / or deformable, being in a moved and / or deformed state the bottom wall of the fluid channel section connects directly or indirectly, and that the The ceiling wall can be moved and / or deformed into the fluid channel section, whereby it in a moved and / or deformed state at least partially on the moved and / or deformed side wall. In this way, the process and / or shaping means and possibly the guide means are kept very simple and easy, since the bottom wall of the fluid channel section the position of the at least one moved and / or deformed side wall and this in turn a support for the procedure rene and / or deformed ceiling wall.

Wind tunnels, especially climate wind tunnels to simulate different environments conditions for the object to be examined and high-speed wind tunnels which are now practically exclusively designed as closed wind tunnels, in which the air flow generated by a powerful blower on a closed Way is led. In order to make the test conditions reproducible, it is necessary Lich that the air flow is even before entering the measuring section. This will u. a. thereby achieved that the air before or upon entering the measuring section is passed through a nozzle-shaped section. The invention is particularly suitable for this net to be used in such a nozzle section of a wind tunnel and the Size or position of the cross-sectional area through which flow passes at the end of this nozzle section to change. But it can also be used in other sections of fluid channels the, both with closed wind tunnels and with open wind tunnels.

A particular advantage of the invention is that an appropriately equipped wind tunnel not many complex, individually adjustable travel rods or hydraulic cylinders for one Large number of individual plates is required, but only relatively few simple traversing and / or deforming means, in particular pull ropes. Especially with climatic wind tunnels in which often extreme temperatures that deviate greatly from the surrounding environmental conditions and humidity are simulated, it is crucial that poss There are very few places where the external insulation of the climate wind tunnel is is interrupted over the environment to minimize heat and cold losses to keep. Dozens or even hundreds of hydraulically adjustable actuators  In practice, racks are not acceptable for climate wind tunnels because they become one corresponding unreasonable variety of cold bridges between the indoor climate and the reverse lead exercise air.

The invention is illustrated in more detail below using several exemplary embodiments, which are illustrated in the accompanying drawings. The attached drawings show:

FIG. 1a, 1b schematic vertical longitudinal sections through a first embodiment of a nozzle portion according to the invention a fluid channel;

FIG. 2 shows a schematic horizontal longitudinal section through the fluid channel nozzle section of FIGS . 1a, 1b;

FIG. 3 top view (partly in section) of the movable and deformable side wall of the nozzle section of FIGS . 1a, 1b;

Fig. 3a, 3b, 3c, 3d, 3e details of the side wall of Figure 3 to demonstrate the wall structure.

Fig. 4 side view of the movable and deformable side wall of Figure 3 of the nozzle portion of Figures 1a, 1b in the rest position, ie nestled against the fixed side outer wall .

Fig. 5 is cross-sectional view of the insulated outer wall of the fluid channel of the nozzle section 1a, 1b at the position BB of Fig. 4.

FIG. 5a cross-sectional view of Figure 5 of a modified variant of the first embodiment Fig.

Fig. 6 as shown in Figure 4, but the movable and deformable side wall is in the Ar beit position, ie moved into the fluid channel section and deformed.

Fig. 7 is cross-sectional view of the insulated outer wall of the fluid channel of the nozzle section 1a, 1b at the position BB of Fig. 6.;

Fig. 7a cross-sectional view of FIG 7 of the modified variant according to FIG 5a of the first embodiment..;

Fig. 8 is schematic perspective view of another embodiment of a deformable top wall for a fluid channel nozzle portion;

Fig. 9 side view of the deformable top wall of Fig. 8;

Fig. 10 shows a schematic horizontal longitudinal section through a further embodiment of a nozzle portion of a fluid channel of the invention;

Fig. 11 shows a schematic vertical longitudinal section through the nozzle portion of the fluid channel Fig. 10.

FIGS. 1a, 1b each show schematically a vertical longitudinal section through the first embodiment of a nozzle portion 1 of the invention, which is used in an air conditioning wind tunnel. The nozzle section 1 is composed of two subsections, namely a first, larger subsection 1 a through which the wind tunnel flow flows first and a second, narrower subsection 1 b through which the wind tunnel flow subsequently flows. Referring to Fig. 1a, 1b flows through the wind tunnel flow of air in the direction of flow 1 c from left to right through the nozzle portion 1. Since it is a nozzle section 1 for a climate wind tunnel, the nozzle section 1 has an externally attached thermal insulation layer 2 , which can be designed in a manner known per se.

The nozzle section 1 contains two movable and deformable side walls 3 , which between a respective second position 3 b shown in FIGS . 1a, 1b, in which they are moved into the wind tunnel cross section, and a respective first position 3 a, in which they rest against the fixed side outer wall 4 of the nozzle section 1 , are movable and deformable. The first position 3 a of the respective side wall 3 , in which the fixed side outer wall 4 serves as the outer support structure 4 a facing away from the fluid channel flow for the side wall 3 , is shown in dashed lines in FIGS . 1a, 1b. (Compare also FIG. 2, which shows a schematic horizontal longitudinal section through the nozzle section 1 ).

The respective movable and deformable side wall 3 lies on the inflow side in both the first position 3 a and in the second position 3 b with its front edge 5 in a region 6 against another, non-movable part of the flow guide surface of the nozzle section 1 . In this way, the wind tunnel air flow cannot get between the respective movable and deformable side wall 3 and the respective side outer wall 4 neither in the first position 3 a nor in the second position 3 b.

The total maximum wind tunnel cross-sectional area 9 of the nozzle portion 1 having a rectangular cross section with two side outer walls 4, a bottom wall 7 and a top outer wall 8 is determined by this fixed outer walls 4, 4, 7,. 8 The cross-sectional area 10 that is actually flowed through by the wind tunnel flow can be reduced compared to this maximum wind tunnel cross-sectional area 9 in that on both sides of the nozzle section 1 the movable and deformable side wall 3 , which previously applied in the first position 3 a to the respective side outer wall 4 , is moved into the space of the fluid channel flow and a deformable ceiling wall 12 , which has previously placed against the ceiling outer wall 8 , is deformed into the space of the fluid channel flow.

FIG. 1a is used to illustrate the movement of the moveable and deformable side walls 3 (the deformable top wall 12 is therefore not shown). For this purpose, a side view of one of the two movable and deformable side walls 3 is drawn in the nozzle section 1 . In the first position 3 a, shown in broken lines, the side wall 3 nestles against the contour of the fixed side outer wall 4 , while the lower edge 13 of the side wall 3 keeps a distance from the bottom wall 7 . (See also FIG. 2). When moving the side wall 3 into its second position 3 b, the side wall 3 not only moves into the space of the fluid channel flow, but is also lowered until it has its lower edge 13 the fixed bottom wall 7 touches down.

FIG. 1b serves to illustrate the movement of the deformable top wall 12 (the moveable and deformable side walls 3 are therefore not shown). The lower support frame 9 a of the nozzle section 1 can be designed in a manner known per se and is therefore only shown schematically in FIGS. 1a, 1b.

Fig. 3 shows a plan (partly in section) of the movable and deformable side wall 3 and the associated fixed side wall 4 in the corresponding area of the Düsenab section 1 . FIGS. 4 and 6 respectively show a side view of the moveable and verformba ren side wall 3 is in its first, rest position 3 a (FIG. 4) position or in its second, labor 3 b in the maximum wind tunnel cross-section 9 (Fig. 6). FIGS. 5 and 7 respectively show a cross sectional view of this side wall 3 and by means of the heat insulating layer 2 side insulated outer wall 4 at the position BB in Fig. 4 or 6 individual.

The movable and deformable side wall 3 is essentially an elastically deformable metal sheet. The metal sheet 3 is suspended on guide rods 14 , which are articulated by means of swivel joints 15 , 16 on the fixed side outer wall 4 at one end and on the movable and deformable metal sheet side wall 3 at the other end. The swivel joints 15 , 16 and the guide rods 14 serve as guide means 26 for the movement of the sheet metal side wall 3 from its first position 3 a on the side outer wall 4 to its second position 3 b on the bottom wall 7 spaced from the side outer wall 4 . The guide rods 14 are spring-loaded by means of torsion springs accommodated in the swivel joints 15 , 16 , so that the side wall 3 in its rest position (ie without the action of external forces) in its first position 3 a is nestled against the side outer wall 4 . A attached to the front edge 5 of the side wall 3 sealing profile 17 then ensures that can pass as through-flow cross-sectional area 10 is no air flow between the side outer panel 4 and the conformal to this side wall 3 during operation of the wind tunnel with its entire, maximum cross-sectional area. 9 Alternatively or in addition, elastic straps could be provided, mounted at one end on the fixed side outer wall 4 and at the other on the moveable and deformable side wall 3, in order to apply the restoring force for growing the side wall 3 to the side outer wall 4 at rest.

If the movable and deformable side wall 3 is now to be pivoted into the wind tunnel cross-sectional area 9 in order to reduce the cross-sectional area 10 through which it flows, this is done by means of traction ropes 18 as a means of travel 18 a which are attached to the side 19 of the side wall 3 facing away from the flow. The pull cables 18 are guided via a cable pull system from a plurality of deflection rollers 21 to cable pull motors 22 attached outside the heat insulation layer 2 of the nozzle section 1 on the outside of the wind tunnel, by means of which the pull cables 18 can be put under tension. If this happens, the side wall 3 pivotably guided on the guide rods 14 pivots from its first position 3 a into the wind tunnel cross section into its second position 3 b. The order steering rollers 21 are partially attached to holding plates 23 which - similar to the guide rods 14 - are attached to further spring-loaded swivel joints 24 , 25 one end on the fixed side outer wall 4 and the other end on the side wall 3 . These foldable holding plates 23 thus not only serve to fasten the deflection rollers 21 , but at the same time act in addition to the guide rods 14 as further guide means 26 . In the first position 3a of the side wall 3, these retaining plates are folded to the side outer panel 4 23 (see. Figs. 4 and 5), while b in the second position 3 in the wind tunnel cross-section 9 protrude (see. Fig. 6 and 7) .

The shape of the sheet metal side wall 3 in its second position 3 b after pivoting into the wind tunnel is initially essentially the same as the shape of the side outer wall 4 to which the side wall 3 had nestled in the rest position 3 a. This leaves a wide entry gap for the air flow between the moved side wall 3 and the side outer wall 4 . In addition, the curvature of the displaced side wall 3 does not correspond to an aerodynamically favorable curvature of the nozzle contour for the second, working position 3 b of the side wall 3 of the nozzle section 1 .

To correct the curvature of the traversed side wall 3 , the tension of the traction cables 18 is therefore further increased even after the lower edge 13 of the side wall 3 has been placed on the bottom wall 7 . Since the pulling cables 18 attach on the inflow side to the side 19 of the side wall 3 facing away from the flow, the inflow-side front region of the side wall 3 bends elastically in the direction of the side outer wall 4 until the front edge 5 of the sheet metal side wall 3 with the sealing profile 17 attached thereto an area 6 of the side outer wall 4 comes into contact. The patch on the bottom wall 7 below Un terkante 13 of the side wall 3 is supported while the side wall 3 below, so that it can not be moved further, but must deform. In the rear, outflow area of the side wall 3 , the support by the guide rods 14 and the holding plates 23 prevents the side wall 3 from deforming to any appreciable extent there.

In order to achieve an aerodynamically favorable curvature contour of the moved and deformed side wall 3 in its second, working position 3 b, the side wall 3 must deform elastically in a very specific way. In order to ensure the desired contour in the deformed state, the side wall 3 in this exemplary embodiment cannot be designed as a multiple, homogeneous sheet metal part with a constant wall thickness, since the resultant curvature contour (namely corresponding to the elastic bending line) is aerodynamically unfavorable.

Rather, the bending stiffness of the side wall 3 should ideally vary over its length along the flow in a continuous function in order to exactly achieve an aerodynamically favorable shape of curvature. This can be accomplished, for example, by the fact that the wall thickness of the side wall 3 varies over its length along the flow in a continuous function. However, this is very complex in terms of production technology. As has been shown, it is sufficient if the side wall 3 consists of locally different numbers of sheet metal plates 27 attached to one another. The side wall 3 of the exemplary embodiment is thus constructed similarly to a leaf spring from layered plate-shaped elements 27 a. In FIGS. 3a to 3e are detail portions A to E of FIG. 3 shown enlarged in order to show this layered structure made of sheet metal plates 27. At the point A of Fig. 3, the sheet metal side wall 3 consists of five sheet metal plates 27 placed one on top of the other (see FIG. 3a; FIGS . 3a and 3e have a reduced scale in comparison to FIGS . 3b to 3d) point B is the transition from five to four sheet metal plates (see FIG. 3b), point C is the transition from four to three sheet metal plates (see FIG. 3c), point D is the transition from three to two sheet metal plates (cf. FIG. 3d) and finally at point E the transition from two to a sheet metal plate 27 . At this point E is also attached to the side 19 of the side wall 3 facing away from the flow, for. B. welded, towing eye 28 shown on which a pull rope 18 can attach.

On the flow-facing side 20 , the longest, continuous plate-shaped sheet metal element 27 a is arranged to achieve a smooth, the wind tunnel flow as little disturbing flow-facing side 20 of the side wall 3 . The material levels caused by the different numbers of sheet metal plates 27 stacked on top of one another are accordingly all arranged on the side 19 of the side wall 3 facing away from the flow. A flow-free cross-sectional area 11 is created there on the outflow side.

Experiments have shown that the transition on the inflow side, sealing the fixed side outer wall 4 in the region 6 into the side wall 3 which is moved and deformed into its second, working position 3 b, is often difficult. It is essential for the seal that in this area 6 along the front edge 5 of the side wall 3 there is a pressure force that is as equal as possible at each point. The sealing point itself on the front edge 5 of the side wall 3 is compensated for by the sealing profile 17 attached there. Short-range unevenness in this transition area 6 are closed by this elastic sealing profile 17 . Long-range bumps of a larger type are closed by a corresponding elastic deformation of the side wall 3 .

For this purpose, it is desirable that the introduction of the side wall 3 deforms elastically deforming force takes place as evenly as possible over the height of the side wall. 3 For this purpose, on the one hand, several to many traction cables 18 can be used, but this requires a corresponding number of deflection rollers 21 , holding plates 23 , cable-pull motors 22 and openings 30 in the heat insulation layer 2 of the nozzle section 1 . Alternatively, in this embodiment of the invention, a pull tab 31 is used which is attached to the inflow-side 19 of the side wall 3 on the inflow side, for. B. welded, and in turn attach only two traction cables 18 for each side wall 3 . The shape of the Zugla cal 31 (see. Fig. 4) is calculated so that the punctually acting tensile forces of the two traction cables 18 are divided onto the mounting area 32 of the pull tab 31 on the side wall 3 in such a way that there is a uniform introduction of force along the mounting area 32 takes place.

Since the vertical expansion of the two side walls 3 is less than the vertical extension of the maximum cross-sectional area 9 of the nozzle section 1 , at least one of the two horizontal walls - namely the bottom wall 7 and / or the ceiling wall 12 - must be designed to be movable and / or deformable in order to to obtain a reduced flow-through cross-sectional area 10 of the nozzle section 1 with the best possible aerodynamic and possibly acoustic quality. For this purpose, a ceiling wall 12 is provided in the nozzle section, which - similar to the two side walls 3 - nestles in a first, the rest position 12 a, against the fixed ceiling outer wall 8 (cf. FIG. 1b). In a second, the working position 12 b, the ceiling wall 12 is lowered onto the two displaced and deformed side walls 3 , which are in their respective second, working position 3 b, and rests on the upper edges 33 of the two side walls 3 . The upstream front edge 34 of the ceiling wall 12 is attached to the fixed ceiling outer wall 8 and as a whole is elastically deformable. When lowering into its second, working position 12 b, the ceiling wall 12 is elastically deformed. The bottom wall 7 is not designed to be movable and / or deformable or otherwise movable.

The generation of locally different wall stiffnesses - e.g. B. by layering sheet metal plates 27 as in the side walls 3 - is not necessary in the ceiling wall 12 because the shape of the ceiling wall 12 in its working position 12 b is determined by the shape of the upper edges 33 of the two side walls 3 pivoted into their respective working position 3 b becomes. It is therefore sufficient to design the ceiling wall 12 as a simple, elastically deformable sheet metal part. It is only necessary to design the top wall 12 with such a bending stiffness that in the areas of the top wall 12 which do not rest on the upper edges 33 of the side walls 3 , no kinks or excessive bulges occur.

Since the shape of the ceiling wall 12 is determined in its first, rest position 12 a by the fixed ceiling outer wall 8 and in the second, working position 12 b by the shape of the upper edge 33 of the side walls 3 , a quite simple mechanism for the desired deformation of the ceiling wall 12 sufficient. For this purpose, between the ceiling wall 12 and the ceiling outer wall 8, several inflatable hollow bodies 35 are arranged in the form of hoses running longitudinally with the wind tunnel flow direction 1 c, each of which is attached with a plurality of wall regions 36 on the side 38 of the ceiling wall facing away from the flow and with several other opposite wall regions 37 on the Ceiling outer wall 8 are attached. The hollow bodies 35 can be evacuated via feed lines 39 , so that the ceiling wall 12 is raised and clings to the fixed ceiling outer wall 8 . Conversely, if air is pressed under (excess pressure, if possible, the same for all hollow bodies 35 ) through the feed lines 39 into the hollow body 35 , the inflatable hollow bodies 35 expand, and the ceiling wall 12 is lowered onto the upper edges 33 of the two side walls 3 and pressed there .

By using the inflatable hollow body 35 for targeted deformation of the deformable top wall 12 not only a simple construction for deformation of the Dec kenwand 12 is achieved, but it is also achieved that the top wall 12 in its deformed working position 12 b with a along the top edge 33 of the side walls 3 constant force rests on this. This ensures on the one hand that along the entire upper edge 33 of the side walls 3 a constant sealing force between the side walls 3 and the ceiling wall 12 is given, so that a sufficient and uniform tightness is achieved at this point; In addition, another sealing profile can also be present at this point. On the other hand, it is prevented that the side walls 3 locally buckle or bulge due to otherwise possible local pressure.

Attaching a plurality of wall areas 36 and 37 of the hollow bodies 35 on the side 38 of the ceiling wall 12 or on the ceiling outer wall 8 facing away from the flow ensures that the hollow bodies 35 cannot contract completely in all three spatial directions during the evacuation: Ceiling wall 12 and the fixed ceiling outer wall 8 act as stiffening outer elements, which maintain the longitudinal expansion of the hollow body 35 along the wind tunnel flow direction 1 c. The contraction of the inflatable hollow bodies 35 during the evacuation takes place essentially vertically transversely to the wind tunnel flow direction 1 c until the ceiling wall 12 with the hollow bodies 35 lying therebetween comes into contact with the ceiling outer wall 8 (see also FIG. 5).

Alternatively, a single hollow body with longitudinally of the wind tunnel flow 1 c and horizontally transversely to the wind tunnel flow direction 1 c stiffening elements in its wall, or be provided in its interior, which prevent complete retraction of the inflatable hollow body during its evacuation. In both variants, it is ensured that a defined minimum contact surface of the hollow body (s) 35 on the side 38 of the ceiling wall 12 facing away from the flow is maintained, so that it is ensured that the force acting locally on the deformable ceiling wall 12 is at least substantially is proportional to the internal pressure of the inflatable hollow body (s) 35 and thus inadmissible local contact pressure peaks, which could lead to damage to the ceiling wall 12 and / or the side walls 3 , are avoided.

The illustrated core ideas of the invention allow numerous variations of the inven tion. Deviating from the first embodiment, in which the traction cables 18 act simultaneously as a traversing means 18 a and as a deforming means 29 , it is also possible, for example, to move the side walls 3 by means of actively moving traversing rods and to use traction ropes only for the targeted deformation of the side walls 3 . In this case, travel means 18 a and deformation means 29 would be separate.

Figs. 5a and 7a, which correspond to the views of Figs. 5 and 7 show a variant of the first embodiment of Figs. 1 to 7. In this variant the traversing means 18 a and the deforming means 29 separately. The variant largely corresponds to the first embodiment of FIGS. 1 to 7; therefore only the differences are dealt with. The same details have the same reference numerals.

In this variant of FIGS. 5a, 7a, the sheet metal side wall 3 is also deformed by means of traction cables 18 which act as deformation means 29 . The traction cables 18 are moved by pulley motors 22 via deflection rollers 21 .

However, the pull cables 18 do not simultaneously cause the side wall 3 to be moved ; rather, this is done by means of lifting ropes 18 b acting as a traversing means 18 a. The lifting ropes 18 b attach to the holding plates 23 on the side wall, which are articulated by means of swivel joints 24 , 25 on the one hand on the side outer wall 4 and on the other hand on the sheet metal side wall 3 . The hoisting ropes 18 b are moved over deflection rollers 21 a by hoisting rope motors 22 a which are arranged behind openings 30 a on the outside of the illustrated fluid channel nozzle section 1 .

In the second position 3 b of the side wall 3 shown in FIG. 7 a , ie in the working position moved into the cross section of the nozzle section 1 , the lower edge 13 of the side wall 3 is supported on the bottom wall 7 of the nozzle section 1 by its weight. In the in Fig. 5a illustrated first position 3a (the rest position) 22 is raised by a corresponding actuation of the Hubseilmotoren 3 the side wall. The control of the cable motors 22 and the lifting cable motors 22 a is coupled to one another in such a way that the pull cables 18 of the side wall 3 in the raised position 3 a of the side wall 3 shown in FIG. 5 a are not under tensile load, so that the sheet metal side wall 3 is tight can apply to the associated side outer wall 4 .

Of course, the ceiling wall 12 can also be deliberately deformed by other means. For example, it is possible to use an inflatable hollow body for applying the contact pressure of the deformable ceiling wall 12 to the upper edges 33 of the side walls 3 , which is not connected in wall areas 36 , 37 to the ceiling wall 12 and / or the ceiling outer wall 8 and also no stabilizing elements contains. The position of such a simplified inflatable hollow body relative to the Dec kenwand 12 and / or the ceiling outer wall 8 could, for. B. be determined in that it is attached to the outer wall 8 on the side facing away from the flow 38 near the front edge 34 of the ceiling 12 . The restoring force for lifting the ceiling wall 12 and nestling the ceiling wall 12 against the ceiling outer wall 8 could then be applied, for example, by elastic rubber cables which are connected at one end to the ceiling wall 12 and at the other end to the ceiling outer wall 8 .

FIGS. 8 and 9 show as schematic perspective view and a side view of another embodiment of a deformable top wall 12 c for a Fluidkanal- nozzle Section 1.

The adjustable ceiling wall 12 c is constructed from slats 80 which run horizontally and transversely to the fluid channel flow direction 1 c and are articulated to one another and are reinforced by struts 79 . The inflow-side ceiling wall end 12 d is articulated on the ceiling wall 8 (not shown). A rigid frame 57 is attached to the outlet-side ceiling wall end 12 e. Several mounting plates 56 are part of this frame 57 . Lower levers 59 are each articulated on the mounting plates 56 , and upper levers 60 are in each case articulated thereon. The upper levers 60 are in turn articulated in bearings 61 on a rail 58 which is part of the outer wall 8 of the ceiling (only shown in the cutout). The lower pivot points of the upper lever 60 are connected by a push rod 62 . All of the above-mentioned spherical bearings have a rotation axis oriented horizontally and transversely to the flow direction 1 c. The lever arrangement corresponds to two coupled four-bar parallelogram transmissions.

A lower cable 68 is attached to the mounting plates 56 and is guided over a cable pulley 73 and attached to a lower cable drum 69 . The lower cable drum 69 is torsionally rigidly connected to a lower shaft 70 , which is received in bearings 71 . The lower shaft 70 is driven by a lower motor 72 which is fastened to the rail 58 by means of a holder 74 . The bearings 71 are also attached to the rail 58 .

An upper cable 63 , which is attached to an upper cable drum 64 , is fastened to the upstream upper lever 60 . The upper rope drum 64 is torsionally rigidly connected to an upper shaft 65 , which is received in bearings 66 . The upper shaft 65 is driven by an upper motor 67 which is fastened to the rail 58 by means of a holder 75 . The bearings 66 are also attached to the rail 58 . The rope pulley 73 is mounted on the harmonic 65 .

An upper rotary encoder 76 is connected to the upper shaft 65 , and a lower rotary encoder 77 is connected to the lower shaft 70 in a torsionally rigid manner. The rotary encoders 76 , 77 and the motors 67 , 72 are in an electrically operative connection with an electrical control 78 .

By both of the lever assembly formed, coupled and individually controllable four-link parallelogram is the deformable top wall 12 c out at their adjustment so that the wall 12 c in a lessening of the upper cable 63 and lower cable 68 under its own weight from its upstream end 12 d beginning and then continuously vertically on the side walls 3 already retracted into the fluid channel cross section 9 . The upper rope 63 and the lower rope 68 are released by rotary movements of the motors 67 , 72 controlled by the electronic control 78 . In the lower, lowered position of the top wall 12 c placed on the side walls 3 moved into the fluid channel cross section 9 , the articulation points of the upper levers 60 and lower levers 59 do not lie one above the other in a vertical plane. In the upper, raised position of the ceiling wall 12 c, the levers 59 , 60 insert into the mounting plate 56 of the frame 57 so that only the height of the frame 57 is present as a vertical interference height in the fluid channel nozzle section 1 . The struts 79 prevent the lamellae 80 of the top wall 12 c from bulging and at the same time increase the counterforce to the vertical force component resulting from the fluid channel flow on the top wall 12 c due to their weight. Of course, it is also possible to construct the top wall 12 c from an elastically deformable sheet metal plate instead of from individual slats 80 which are connected to one another in an articulated manner.

Fig. 10 shows another embodiment of a fluid channel according to the invention the nozzle section 1 in a schematic representation. The same reference numerals again designate corresponding parts as in the first exemplary embodiment in FIGS . 1 to 7.

The illustrated movable and deformable side wall 50 is - similar to the movable and deformable side wall 3 of the first embodiment of FIGS. 1 to 7 - in its first position 50 a nestled against the contour of the fixed side outer wall 4 while it is in a second position 50 b is moved into the fluid channel cross section 9 . 1 different from the first embodiment of Figure 7 to - - the rest position of the side wall 50 but the second, into traversed position b in the fluid passage cross-section 9 50 without the action of external forces.. This is ensured by corresponding spacers 51 , which are under elastic prestress, two of which are indicated schematically in FIG. 10. These spacers 51 are - similar to the guide rods 14 of the first exemplary embodiment of FIGS . 1 to 7 - both ends in swivel joints provided with stops, so that the side wall 50 spring-loaded in the idle state assumes its well-defined second position 50 b. The side wall 50 is designed as an elastic sheet metal plate with un different wall thicknesses. The inflow end of the sheet metal side wall 50 is passed through a vertical slot 52 in the side outer wall 4 of the Düsenab section 1 and attached to an outside of the heat insulating layer 2 of the Düsenab section 1 arranged, motor-driven pull drum 53 . Now if the movable and deformable side wall 50 is brought into its working position, namely in its first position 50 a on the contour of the side outer wall 4 , the front region 54 of the side wall 50 is partially on the pull drum 53 by a motorized rotation of the same wound, so that the side wall 50 against the spring bias of the ver pivotable spacer 51 is moved to the side outer wall 4 and clings to it. As a result, the entire maximum wind tunnel cross-sectional area 9 is released as the cross-sectional area 10 through which flow flows.

The ceiling wall 12, in this further embodiment of FIGS. 10 and 11 be similar as in the first embodiment of Figs. 1 to 7. For reasons of symmetry the Figures 10 and 11 and the bottom wall as a deformable bottom wall 7 a, in this embodiment. Formed , wherein the deformation mechanism by means of a plurality of inflatable hollow bodies 35 corresponds essentially to that of the bottom wall 12 . The top wall 12 , the side walls 3 and / or the side wall 50 can, as described, consist of metal sheets, but also, for example, of plastic panels.

As has become clear from the above, the invention enables the cross-sectional area of a fluid channel actually flowed through, in particular one Nozzle section of a wind tunnel, in the shortest time "at the push of a button" without time-consuming To change renovations. The movable and / or deformable walls according to the Invention can be added to existing ones without substantial structural intervention Outside walls of a wind tunnel section are attached to this. Are the new ones movable and / or deformable walls to the contours of the existing outer walls nestled, the aerodynamic quality of the wind tunnel is practically not influenced, and it can be used as usual. In the moved and / or deformed In contrast, the condition of the walls results in a wind tunnel section with significantly reduced flowed through cross-sectional area, so that higher flow velocities at the outlet of the nozzle section can be achieved. The illustrated travel and / or deformable walls are therefore particularly suitable for retrofitting existing ones Wind tunnels, especially on climatic wind tunnels, since the further training according to the Embodiments of the invention with a small number of small openings or Slits in the thermal insulation layer of these climate wind tunnels get along.

Of course, the invention can also be used with new fluid channels to be built. Then the solid, additional outer walls - in the execution examples, the two side outer walls 4 and the outer ceiling wall 8 or the floor outer wall - do not necessarily have to be present as continuous walls, rather, for example, grid-like support structures are sufficient, to which the traversing and / or deformable actual fluid channel walls, which then form part of the flow guide surface of the fluid channel.

Reference list

1

Nozzle section

1

a first subsection

1

b second subsection

1

c flow direction

2nd

Thermal insulation layer

3rd

movable and deformable side wall

3rd

a first position (rest position)

3rd

b second position (working position)

4th

Side outer wall

4th

a outer support structure

5

Leading edge

6

Area

7

Floor outer wall

8th

Ceiling outer wall

9

Cross sectional area

9

a support frame

10th

Cross-sectional area with flow

11

flow-free cross-sectional area

12th

Ceiling wall

12th

a first position (rest position)

12th

b second position (working position)

12th

c ceiling wall

12th

d upstream ceiling wall end

12th

e end of the ceiling wall

13

Lower edge

14

Guide rods

15

,

16

Swivel joints

17th

Sealing profile

18th

Traction rope

18th

a travels

18th

b Hoist rope

19th

side facing away from the flow

20th

side facing the flow

21

Pulley

21

a pulley

22

Cable motor

22

a cable motor

23

Bracket

24th

,

25th

Swivel joint

26

Leadership resources

27

Sheet metal plate

28

Towing eye

29

Molding agent

30th

opening

30th

a opening

31

Pull tab

32

Mounting area

33

Top edge

34

Leading edge

35

Hollow body

36

Wall area

37

Wall area

38

side facing away from the flow

39

Supply

50

Side wall

51

Spacers

52

slot

53

Pull drum

54

Front area

56

Mounting plate

57

frame

58

rail

59

Lever

60

Upper lever

61

camp

62

Push rod

63

Top rope

64

Top rope drum

65

Harmonic

66

Depository

67

Top motor

68

Lower rope

69

Lower rope drum

70

Sub-wave

71

Depository

72

Lower motor

73

Rope pulley

74

holder

75

holder

76

Top encoder

77

Under encoder

78

control

79

strut

80

Slat

Claims (36)

1. A deformable wall ( 3 , 50 ), in particular a deformable wall ( 3 , 50 ) forming at least part of the flow guiding surface of a fluid channel section ( 1 ), for influencing a flow, in particular for changing the cross-sectional area ( 10 ) through which the fluid channel section ( 1 ) flows, characterized in that the wall ( 3 , 50 ) has locally different bending stiffnesses in order to achieve a fluid dynamic favorable shape in a deformed state ( 3 b). 2. Deformable wall ( 3 , 50 ) according to claim 1, characterized in that the wall ( 3 , 50 ) is designed as a tabular element, in particular as a sheet metal plate. 3. Deformable wall ( 3 , 50 ) according to claim 1 or 2, characterized in that the locally different bending stiffnesses are formed by locally different wall thicknesses. 4. Deformable wall ( 3 , 50 ) according to claim 3, characterized in that the locally different wall thicknesses are formed by means of locally different numbers of stacked plate-shaped elements ( 27 a), in particular sheet metal plates ( 27 ). 5. Deformable wall ( 3 , 50 ) according to claim 4, characterized in that a continuous plate-shaped element ( 27 a) is arranged on the flow-facing side ( 20 ) of the wall ( 3 , 50 ). 6. Deformable wall ( 3 , 50 ) according to one of claims 3 to 5, characterized in that material levels caused by locally different wall thicknesses are arranged exclusively on the side of the wall ( 3 , 50 ) facing away from the flow ( 19 ). 7. Deformable wall ( 3 ) according to one of claims 1 to 6, characterized in that traction cables ( 18 ) serve as deformation means ( 29 ) for deforming the wall ( 3 ). 8. Deformable wall ( 3 ) according to claim 7, characterized in that the pull cables ( 18 ) on the side facing away from the flow ( 19 ) of the wall ( 3 ). 9. Deformable wall ( 3 , 50 ) according to claim 8, characterized in that on the side facing away from the flow ( 19 ) of the wall ( 3 ) on the inflow side at least one pull tab ( 31 ) is attached to which the pull cables ( 18 ) attach. 10. Deformable wall ( 3 ) according to one of claims 8 or 9, characterized in that the pulling direction of the pulling cables ( 18 ) is substantially parallel to the direction of flow ( 1 c). 11. Deformable wall ( 3 , 50 ) according to one of claims 1 to 10, characterized in that the wall ( 3 , 50 ) forms at least part of a fluid channel nozzle section ( 1 ). 12. Movable wall ( 3 , 50 ) which forms part of the flow guide surface of a fluid channel section ( 1 ) and can be moved between at least two positions ( 3 a, 3 b; 50 a, 50 b), characterized in that the wall ( 3 , 50 ) in a first position ( 3 a, 50 a) on an outer support structure ( 4 a) facing away from the fluid channel flow, in particular an outer wall ( 4 ) facing away from the flow, of the fluid channel section ( 1 ), while in a second position ( 3 b , 50 b) is essentially spaced from the outer support structure ( 4 a) and rests against another part of the flow guide surface of the fluid channel section ( 1 ) on the inflow side. 13. Movable wall ( 3 , 50 ) according to claim 12, characterized in that the wall ( 3 , 50 ) by means of guide means ( 26 ), in particular guide rails and / or rods ( 14 ) and / or levers ( 23 ), and separate travel means ( 18 a), in particular pull ropes ( 18 ) or hoist ropes ( 18 b), can be moved in a guided manner from the guide means ( 26 ). 14. Movable wall ( 3 , 50 ), which forms at least part of the flow guide surface of a fluid channel section ( 1 ), characterized in that the wall ( 3 , 50 ) by means of guide means ( 26 ), in particular guide rails and / or rods ( 14 ) and / or levers ( 23 ), and separate guide means ( 18 a), in particular pull ropes ( 18 ) or hoist ropes ( 18 b), which can be moved in a guided manner, separate from the guide means ( 26 ). 15. Movable wall ( 3 , 50 ) according to one of claims 12 to 14, characterized in that the wall ( 3 , 50 ) is designed as a plate-shaped element, in particular as a sheet metal plate. 16. Movable wall ( 3 , 50 ) according to one of claims 13 to 15, characterized in that the movable wall ( 3 , 50 ) by means of the simultaneously as a deforming means ( 29 ) serving as moving means ( 18 a), in particular the traction cables ( 18th ), is also deformable at the same time. 17. Movable wall ( 3 ) according to one of claims 13 to 16, characterized in that the traversing means ( 18 a) on the side facing away from the flow ( 19 ) of the movable wall ( 3 ) include traction cables ( 18 ). 18. Movable wall ( 3 ) according to claim 17, characterized in that on the side facing away from the flow ( 19 ) of the movable wall ( 3 ) on the inflow side at least one pull tab ( 31 ) is attached to which the pull cables ( 18 ) attach. 19. Movable wall ( 3 ) according to one of claims 17 or 18, characterized in that the pulling direction of the pulling cables ( 18 ) is substantially parallel to the direction of flow ( 1 c). 20. Movable wall ( 3 ) according to one of claims 13 to 15, characterized in that the wall ( 3 ) by means of traversing means ( 18 a), in particular lifting ropes ( 18 b) and / or traversing rods and / or levers, is movable and can be deformed by means of separate shaping means ( 29 ), in particular pulling ropes ( 18 ), which are separate from the traversing means ( 18 a). 21. Movable wall ( 3 , 50 ) according to any one of claims 16 to 20, characterized in that the wall ( 3 , 50 ) has locally different bending stiffness to achieve a fluid dynamic favorable shape in a deformed state. 22. Movable wall ( 3 , 50 ) according to claim 21, characterized in that the locally different bending stiffnesses are formed by locally different wall thicknesses. 23. Movable wall ( 3 , 50 ) according to claim 22, characterized in that the locally different wall thicknesses by means of locally different numbers of stacked plate-shaped elements ( 27 a), in particular sheet metal plates ( 27 ), are formed. 24. Movable wall ( 3 , 50 ) according to claim 23, characterized in that a continuous plate-shaped element ( 27 a) is arranged on the side facing the flow ( 20 ) of the wall ( 3 , 50 ). 25. Movable wall ( 3 , 50 ) according to one of claims 22 to 24, characterized in that material levels caused by locally different wall thicknesses are arranged exclusively on the side of the wall ( 3 , 50 ) facing away from the flow ( 19 ). 26. Movable wall ( 50 ) according to one of claims 12 to 16 or 21 to 25, characterized in that an inflow-side section ( 54 ) of the wall ( 50 ) through an opening (slot 52 ) in another part of the flow guide surface of the fluid channel section ( 1 ) is movable therethrough. 27. Movable wall ( 3 , 50 ) according to one of claims 12 to 26, characterized in that the wall forms at least part of a fluid channel nozzle section ( 1 ). 28. Movable and deformable wall which forms at least part of the flow guide surface of a fluid channel section, characterized in that the wall can be moved by means of travel means ( 18 a), in particular lifting ropes ( 18 b) and / or travel rods and / or levers, and by means of separate shaping means ( 29 ), in particular pulling ropes ( 18 ), which are separate from the traversing means ( 18 a), can be deformed. 29. Movable and deformable wall according to claim 28, characterized in that the wall forms at least part of a fluid channel nozzle section. 30. fluid channel section ( 1 ) with at least substantially rectangular cross-section ( 9 ) and at least locally variable flow-through cross-sectional area ( 10 ), with side walls ( 3 , 3 ), a bottom wall ( 7 ) and a top wall ( 12 , 12 c), each Form part of the flow guiding surface of the fluid channel nozzle section ( 1 ), characterized in that at least one side wall ( 3 ) can be moved and / or deformed into the fluid channel section ( 1 ), whereby it is in a moved and / or deformed state ( 3 b) the bottom wall ( 7 ) of the fluid channel section ( 1 ) connects directly or indirectly and that the top wall ( 12 , 12 c) can be moved and / or deformed into the fluid channel section ( 1 ), being in a moved and / or deformed state ( 12 b) at least partially rests on at least one displaced and / or deformed side wall ( 3 ). 31. Fluid channel section ( 1 ) according to claim 30, characterized in that the ceiling wall ( 12 ) is designed as a plate-shaped element, in particular as a sheet metal plate. 32. Fluid channel section ( 1 ) according to claim 30 or 31, characterized in that the ceiling wall ( 12 ) can be moved and / or deformed by means of one or more inflatable hollow bodies ( 35 ). 33. Fluid channel section ( 1 ) according to claim 32, characterized in that the or the hollow body ( 35 ) with at least one wall region ( 36 ) attached to the ceiling wall ( 12 ) or are integrally formed with it. 34. Fluid channel section ( 1 ) according to claim 30, characterized in that the ceiling wall ( 12 c) is constructed, at least in sections, from lamella strips which are articulated transversely to the direction of the fluid channel flow ( 1 c) and are at least partially articulated to one another. 35. fluid channel section ( 1 ) according to claim 30 or 31 or 34, characterized in that the ceiling wall ( 12 , 12 c) in its moved and / or deformed state ( 12 b) by means of ropes (upper rope 63 , lower rope 68 ) of the moved and / or deformed side wall ( 3 ) can be lifted off again. 36. Fluid channel section ( 1 ) according to one of claims 30 to 35, characterized in that the side walls ( 3 , 3 ), the bottom wall ( 7 ) and the top wall ( 12 , 12 c) form at least part of a fluid channel nozzle section ( 1 ).