WO2017122141A1

WO2017122141A1 - Cooling device for a wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting

Info

Publication number: WO2017122141A1
Application number: PCT/IB2017/050143
Authority: WO
Inventors: Gianni MENGA
Original assignee: Extreme Flight Fze
Priority date: 2016-01-14
Filing date: 2017-01-12
Publication date: 2017-07-20
Also published as: ITUB20160133A1

Abstract

The cooling device for a wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting, comprises a deflector (20), for being placed in an air recirculation apparatus of the wind tunnel. The deflector (20) comprises: a plurality of wings (52), a support structure (54) for said wings (52), an inlet pipe (56), for receiving an air flow from an air cooling system, and at least one opening (58) to release the air coming from the inlet pipe (56) into the recirculation pipe.

Description

TITLE: "Cooling device for a wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting"

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DESCRIPTION

Technical field

The invention relates to a cooling device for a wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting, and to a wind tunnel provided with said cooling device. The invention also relates to method to implement an existing wind tunnel .

Technological background

In the field of wind tunnels with a recirculating air flow, among which there are also those used to perform simulations of free fall or parachuting, skilled people have to deal with the problem due to the overheating of the recirculating air. The heat is generated by the power introduced by the motors (generally electric motors) operating the valves and by the friction to which the air is subjected while flowing inside the conduits making up the wind tunnel. In order to reduce the temperature of the circulating air, different systems were developed.

Cooling systems are known, which are formed by condensers and evaporators, wherein the evaporators cool the air. The evaporators can be arranged inside the recirculation pipe and be entirely hit by the air flow, or they can be placed in a flow deflection pipe, so that only part of the air flow is cooled. This solutions are affected by some drawbacks, since they create high load losses, as they significantly obstacle the air flow.

Furthermore, the deflector means ("turning vanes") can be used as cooling batteries. This last solution allows cooling liquid (water or glycol or the like) to flow inside the turning vanes. This solution leads to some drawbacks, among which there are the need for said turning vanes to be waterproof and the necessity of a very expensive hydraulic circuit .

Furthermore, in wind tunnels used for aerospace research, liquid nitrogen injection nozzles are sometimes used, but this is not compatible with the health needs of the users of a wind tunnel for simulations of free fall or parachuting .

Summary of the invention

An object of the invention is to provide a cooling device for a wind tunnel with a recirculating air flow or for a closed circuit wind tunnel, in particular to perform simulations of free fall or parachuting, which is capable of solving this and other drawbacks of the prior art and which, at the same time, can be produced in a simple and economic fashion.

In particular, one of the objects of the invention is to provide a more efficient cooling device.

In particular, said cooling device comprises a deflector means having one or more openings capable of introducing cold air into a recirculation pipe of a wind tunnels .

A further object of the invention is to provide a wind tunnel with a recirculating air flow provided with said cooling device.

A further object of the invention is to provide a method to implement an existing wind tunnel with a recirculating air flow by means of the installation of said cooling device. According to the invention, this and other objects are reached by means of a cooling device having the features set forth in the appended independent claim.

The appended claims are an integral part of the technical teaches provided in the following detailed description concerning the invention. In particular, the appended dependent claims define some preferred embodiments of the invention and describe optional technical features thereof .

Brief description of the drawings

Further features and advantages of the invention will be best understood upon perusal of the following detailed description, which is provided by way of example and is not limiting, with reference, in particular, to the accompanying drawings, wherein:

- figures 1, 2, 4 are perspective views of a cooling device according to a preferred embodiment of the invention;

- figure 3 shows a cross section of a wing belonging to a deflector according to a preferred embodiment of the invention;

- figure 5 shows a schematic front view of a wind tunnel according to a preferred embodiment.

Detailed description of the invention

Figure 5 shows, by way of example, a wind tunnel according a preferred embodiment of the invention. In particular, it is a wind tunnel with a recirculating air flow .

The wind tunnel comprises:

- a flying chamber 10, which is designed to house a person who is going to float when hit by an air flow,

- a recirculation apparatus, which is in fluid communication with the flying chamber 10, thus defining a substantially closed path for said air flow; and

- a fan device 14, which is designed to produce said air flow, which is suited to circulate between the flying chamber 10 and the recirculation apparatus.

The recirculation apparatus usually is a recirculation pipe; a non-limiting example thereof is described below.

The cooling device comprises a deflector 20 or deflector means, which is designed to be placed in an air recirculation apparatus of the wind tunnel; the deflector 20 comprises :

- a plurality of wings 52,

- a support structure 54 for said wings 52,

- an inlet pipe 56, which is capable of receiving an air flow from an air cooling system,

- at least one opening 58 to release the air coming from said inlet pipe 56 into said recirculation pipe.

Therefore, said at least one opening 58 is in fluid communication with the inlet pipe 56.

In this way, the air circulating in the wind tunnel in operating conditions can be cooled. The term "cold air", which is used for merely descriptive purposes and not in a limiting manner, means air having a temperature below the temperature of the air circulating in the wind tunnel in operating conditions.

Preferably, the deflector 20 (also known as "turning vane") is provided with a plurality of opening 58 to emit air. The openings 58 can be, for example, holes, elongated slits, etc.

With reference to a particular embodiment, said at least one opening 58 is made in at least one of said wings 52, and said at least one wing 52 has a cavity 60, which is in fluid communication with the inlet pipe 56 and with said at least one opening 58. Preferably, at least one wing 52 has a plurality of openings 58, which are conveniently arranged in a substantially uniform manner on the length of said wing 52; more preferably, the openings 58 are equally spaced apart. In this way, we can ensure a better mixing of the cold air flowing out of the opening 58 with the hot air circulating in the wind tunnel. In particular, there are different internally hollow wings 52. The wings 52 are conveniently curved; though, it is possible to have straight or plan wings 52 as well as wings with any other known shape .

With reference to the detail shown in figure 3, the openings 58 (at least one opening 58) are arranged on the edge of the wing 52. Preferably, the openings 58 are arranged so as to emit a flow of (cold) air that substantially corresponds to the direction of the air flow hitting the deflector 20 in the recirculation pipe. In order to better understand the invention, if we consider the wing 52 as a wing immersed in an air flow, the openings 58 are placed in the area of the flap of said wing.

With reference to the embodiment shown herein, the inlet pipe 56 is in fluid communication with the cavity 60 of the wing 52 by means of a passage 62; in particular, the passage 62 is arranged at a lateral end of said wing 52. Preferably, each hollow wing 52 has at least one respective passage 62. Therefore, the wings 52 are substantially tubular elements defining the cavities 60.

Preferably, the inlet pipe 56 is in fluid communication with the cavity 60 through a pair of passages 62, arranged at the lateral ends of said wing 52. This solution ensures a better diffusion of the air inside the cavity 60 of the wing 52 and allows the openings 58 present on the wing 52 to deliver a similar quantity of air.

The cold air coming from the air cooling system flows through the inlet pipe 56, reaches the cavity 60 of the wing 52 passing through the passage 62, and finally flows out of the openings 58 in order to flow into the flow of hotter air circulating the recirculation apparatus.

The support structure 54 shown herein has a rectangular shape comprising four perimeter profiles 54a-d. The wings 52 are fixed, if necessary in a removable manner, to the support structure 54, in particular to the two lateral profiles 54b, d, where the passages 62 are located. Conveniently, the inlet pipe 56 is at least partly made up of said support structure 54. In particular, the inlet pipe 56 is made up of said support structure 54 and of a plate 64, fixed to said support structure 54. The plate 64 can be removable from the support structure 54, for example so as to make inspection and maintenance of the assembly easier. The lateral profile 54d of the support structure 54 cooperates with the respective plate 64 so as to form the inlet pipe 56 facing the passages 62, to channel the air into the wings 52. With particular reference to the preferred example, there are two inlet pipes 56 located on the side of the wings 52, each inlet pipe 56 being at least partially formed by a lateral profile 54b, d belonging to the support structure. According to further variants of the invention, the support structure 54 can have different shapes, such as a circular shape, an elliptic shape etc.

The support structure 54 optionally comprises further support elements 66, which are designed to support the wings 52. In particular, the further support element 66 is elongated, such as for example a bar or a rod or a plate, etc. Said further support element 66 comprises holes, each hole being crossed by the respective wing 52. Said hole corresponds to the cross section of the wing 52, so as to receive and hold said wing 52 in position.

According to a possible variant of the invention, said further support element 66 is internally hollow and acts as an inlet pipe (similarly to the lateral profiles) . The cavity 60 of the further support element 66 is in fluid communication with the cavity 60 of the wing 52 so as to convey the fluid towards said at least one opening 58 of the wing 52, conveniently by means of respective further passages. Therefore, the inlet pipe 56 can be at least partially made up of at least one between a perimeter profile 54a-d and a further support element 66 of the support structure 54.

According to a variant of the invention, the wings 52 are orientable and they can be controlled by an actuation means. For example, the wing 52 can be coupled to a support fitted with freedom of rotation in a housing of the support structure 54.

According to an alternative variant of the invention, said at least one opening 58 to introduce the air coming from the inlet pipe 56 into the recirculation pipe is made in the support structure 54. Furthermore, there can be a plurality of openings 58, wherein part of them is made in the wings 52 and part of the is made in the support structure 54.

According to further variants of the invention, the inlet pipe is separate from the support structure 54 and can be known per se, such as a conduit. For example, the inlet pipe directly feeds the cold air into the cavity 60 of the wing 52, for example by using a plurality of secondary conduits, each secondary conduit being connected to a respective cavity 60. According to a further variant of the invention, the deflector 20 comprises nozzles, which are suited to blow air coming from the inlet pipe into the recirculation pipe.

The subject-mater of the invention also comprises a wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting, comprising: a cooling device according to any of the aforesaid variants, which is placed in a recirculation apparatus of said wind gallery, and an air cooling system to introduce air into the inlet pipe 56 of the deflector 20.

The cooling system can be of any known type, such as for example an air conditioner.

Optionally, there is provided a temperature detector to detect the temperature of the air circulating in the wind tunnel. The cooling system is designed to activate itself depending on the data detected by the temperature detector. For example, the cooling system activates itself when the temperature circulating in the wind tunnel exceeds a threshold temperature. Furthermore, you can set a minimum intervention time for the cooling system, so as to avoid the "on/off" too frequently. Conveniently, the intervention of the cooling system can be coordinated by means of a control unit. Optionally, the cooling system also acts as a conditioning system to adjust the humidity of the air. According to a possible variant, in case of forced dehumidification of the air in the wind tunnel, you set the cooling/conditioning system at at least 90% of the cooling power, preferably at the maximum cooling power, and - at the same time - you make air circulate in the wind tunnel at the minimum speed. This allows you to obtain an advantageous dehumidifying effect.

The subject-matter of the invention also comprises a method to implement a wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting, comprising the step of installing a cooling device according to any of the aforesaid variants in an air recirculation apparatus of a wind tunnel.

Hereinafter you can find a description of further optional aspects of the invention, with reference to the preferred variant of wind tunnel shown by mere way of example .

The flying chamber 10 belongs to a substantially vertical conduit comprising:

- a cylindrical portion 11 with a circular section,

- a portion 12 with the shape of a truncated cone, which is connected, on the upper side, to the cylindrical portion 11 and has the shape of a truncated cone diverging towards the upper part .

Preferably, the flying chamber 10 comprises the cylindrical portion 11 and the portion 12 with the shape of a truncated cone. In particular, the flying chamber 10 also comprises the area indicated with number 22.

In particular, the portion 12 with the shape of a truncated cone is a right truncated cone, whose bases are parallel to one another.

The air flow in the vertical conduit and, hence, in the flying chamber 10 is ascending. The vertical conduit has a substantially straight vertical axis. The air flow flows through the flying chamber 10 in a substantially axial or vertical direction. The cylindrical portion 11 and the portion 12 with the shape of a truncated cone are aligned with the vertical axis. The cross sections of the cylindrical portion 11 and of the portion 12 with the shape of a truncated cone are circular.

One of the advantages of the special conformation of the cylindrical portion 11 and of the portion 12 with the shape of a truncated cone lies in the possibility of offering an adequate air flow rate needed for the free fall simulation, minimizing at the same time the consumption of energy used to maintain said air flow rate. As a matter of fact, the portion 12 with the shape of a truncated cone reduces the speed of the fluid and, as a consequence, also reduces the losses of load, thus decreasing the consumption of energy.

With reference to the variant shown herein, air circulates in the wind tunnel in a clockwise direction, as indicated by the broken-line arrow carrying number 7.

As you can see in the drawings, the recirculation apparatus comprises a firs conduit 16, which is in fluid communication with the portion 12 with the shape of a truncated cone by means of an angular connection 18, which comprises deflector means 20 (hereinafter also referred to as "deflectors" 20), which are interposed between a pair of angular portions 22, 24.

In particular, the first conduit 16 develops along a longitudinal axis and is inclined relative to the flying chamber 10 and, hence, relative to the vertical conduit.

Therefore, the angular connection 18 deflects the air flow flowing out of the flying chamber 10 towards the first conduit 16.

Thanks to the deflector means 20, the wind tunnel can become more efficient by allowing the air flow to more easily flow from the air conduit arranged downstream to the one arranged upstream of the deflector means 20.

With reference to the example shown herein, the first conduit 16 is substantially horizontal and the recirculation apparatus further comprises:

- a second substantially vertical conduit 26, which is in fluid communication with said first conduit 16;

- a lower substantially horizontal conduit 18, which is in fluid communication with said second substantially vertical conduit 26 and said flying chamber 10.

Starting from the flying chamber 10, the air flows through the angular connection 18 into the first horizontal conduit 16 and then it flows into the second vertical conduit 26, where it flows with a descending motion. After that, the air flows into the lower horizontal conduit 28 and it is finally led into the vertical conduit, where it reaches the flying chamber 10. Therefore, the conduits belonging to the special wind tunnel described above are arranged so as to substantially form a parallelepiped.

Preferably, the first conduit 16 is diverging relative to the air flow. By so doing, you can further reduce the losses of lead and, therefore, the energy needed. With special reference to figure 5, the second vertical conduit 26 is diverging relative to the air flow.

With reference to the preferred embodiment shown herein, starting from the portion 12 with the shape of a truncated cone up to the end of the second substantially vertical conduit 26, there is an increase in the cross section through which the air flow is going to flow, if necessary with short portions with a constant cross section. By so doing, you can reduce the losses of load and avoid sudden changes in the cross section, thus minimizing the consumption of energy. With reference to the preferred example shown herein, the vertical conduit comprises a tapered portion 30 in fluid communication with the lower part of the cylindrical portion 11; the inner surface of the tapered portion 30 has, in its longitudinal section, a concave part and a convex part. Said tapered portion 30 gets narrower, with special reference to the air flow, towards the cylindrical portion 11. The tapered portion 30 accelerates the speed of the air that is going to enter the flying chamber 10 on the lower side, in particular in the cylindrical portion 11, so as to allow the user to float when he/she is hit by an air flow. In particular, said tapered portion 30 is coaxial to the vertical axis. Conveniently, the cross section of the tapered portion 30 is substantially circular.

In the example shown herein, a first junction 32 establishes a fluid connection between the first conduit 16 and the second vertical conduit 26. A second junction 34 establishes a fluid communication between the second vertical conduit 26 and the lower horizontal conduit 28. A third junction 36 establishes a fluid communication between the lower horizontal conduit 28 and the vertical conduit, hence the flying chamber 10. The junctions 32, 34, 36 have an angular shape and deflect the flow. Preferably, said junctions 32, 34, 36 house, in their inner wall, respective deflector means 20, which are advantageously equal or similar to the ones used in the angular connection 18.

In the special example shown herein, the fan device 14 is placed in the second vertical conduit 26. However, it can also be placed in other parts of the wind tunnel. Furthermore, there can be a plurality of fan devices 14 located in different areas of the wind tunnel, in accordance with the requested aeraulic performances. For example, the fan device 14 can be a single fan; however, you can also use a plurality of fans as well as other known apparatuses .

If necessary, the fan device 14 can be controlled by a control system; by way of example, the control system is capable of controlling the activation/deactivation of the fan device 14 based on the actuation of an operator, who, for example, intervenes by means of a remote control panel. Optionally, the control system is capable of controlling the operation of the fan device 14 depending on the reading of parameters detected by sensor means associated with the wind tunnel .

According to a preferred variant of the invention, the flying chamber 10 comprises an air-permeable wall 40, which is capable of being flown through by an air flow. For example, the permeable wall 40 can be a grid, a net, a netlike wall, or a perforated wall having holes with any shape and size, depending on the different needs.

In the embodiment shown herein, the permeable wall 40 is arranged on a plane that is substantially transverse relative to the vertical axis of the flying chamber 10.

In the example shown herein, the permeable wall 40 also acts as a support surface, or as a floor, for the people standing inside the flying chamber 10 as well as for objects. The permeable wall 40 is arranged at the base of the cylindrical portion 11, in particular it is interposed between the cylindrical portion 11 and the tapered portion 30.

Optionally, there is, in the flying chamber 10, a second permeable wall, which is arranged in the upper part of the chamber 10 and is useful to hold the people - or the objects - floating in the air flow, thus preventing them from accidentally hitting other parts of the wind tunnel. Therefore, the second permeable wall minimizes the danger for people or objects of being pushed by the air flow towards parts of the wind tunnel, such as for example the recirculation apparatus or the fan device 14, thus preventing them from getting hurt and avoiding faults or jamming of the wind tunnel. For example, the second permeable wall can be made up of the deflector means 20. Alternatively, the second permeable wall can be placed between the portions indicated with numbers 12 and 22. Therefore, in these embodiments, the permeable wall 40 and the second permeable wall delimit the area of the flying chamber 10 where a user can float in a vertical or ascending air flow, thus experiencing a simulation of free fall or parachuting in total safety conditions.

According to a convenient variant of the invention, the flying chamber 10 is at least partly made of a visually transparent material, such as glass, crystal, transparent plastic, polymethylmethacrylate (also known as Plexiglas™) , etc. The transparent material turns out to be convenient as it offers the possibility to see through the flying chamber 10, for example allowing a group of people standing outside the wind tunnel to see a user who is engaged in a simulation of free fall or parachuting on the inside of the wind tunnel.

In an especially convenient manner, an entire part of the flying chamber 10 can be made of a transparent material, thus enabling a 360° view from the inside of the chamber 10. For example, there can be a portion comprised between two sections orthogonal to the main vertical axis where the vertical conduit is made of a transparent material. For example, th cylindrical portion and, if necessary, the portion 12 with the shape of a truncated cone can be made of a transparent material. Alternatively, the portions 11 and/or 12 have a window-like surface made of a transparent material.

As already mentioned above, according to a preferred variant of the invention, the wind tunnel comprises an access, which is capable of allowing people or objects to enter and exit the flying chamber 10. For example, said access extends through the cylindrical portion 11 and/or the portion 12 with the shape of a truncated cone, especially according to a substantially radial or transverse direction. By mere way of example, the access only comprises a door; or it comprises a generic element to regulate the access and the exit of a person or an object to and from the flying chamber 10, such a sliding shutter or a sliding door. The door (or the doors) can be of a known type, such as a single-leaf door, a double-leaf door, a sliding shutter, etc. Conveniently, the access is also made of a transparent material.

Optionally, the part of wind tunnel comprised between the air-permeable walls (one of them is indicated with 40) is made of a transparent material. Furthermore, the access, which is also made of a transparent material, is preferably placed between the permeable walls.

In any case, the flying chamber 10, the angular connections 18, 32, 34, 36, and the conduits 16, 26, 28 can have any shape depending on the different needs, such as for example a shape with a circular section, a rectangular section, a square section, etc.

Naturally, the principle of the invention being set forth, embodiments and implementation details can be widely changed relative to what described above and shown in the drawings as a mere way of non-limiting example, without in this way going beyond the scope of protection provided by the accompanying claims.

Claims

1. Cooling device for a wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting, comprising a deflector (20), for being placed in an air recirculation apparatus of the wind tunnel; said deflector (20) comprising:

- a plurality of wings (52),

- a support structure (54) for said wings (52),

- an inlet pipe (56), for receiving an air flow from an air cooling system,

- at least one opening (58) to release the air coming from said inlet pipe (56) into said recirculation pipe.

2. Device according to claim 1, wherein said deflector (20) is provided with a plurality of openings (58) .

3. Device according to claim 1 or 2, wherein said at least one opening (58) is made in at least one of said wings (52), said at least one wing (52) having a cavity (60), which is in fluid communication with said inlet pipe (56) and with said at least one opening (58) .

4. Device according to claim 3, wherein said inlet pipe (56) is in fluid communication with said cavity (60) of said wing (52) through a passage (62), arranged at a lateral end of said wing (52) .

5. Device according to claim 4, wherein said inlet pipe (56) is in fluid communication with said cavity (60) through a pair of passages (62), arranged at the lateral ends of said wing (52) .

6. Device according to any of the previous claims, wherein said inlet pipe (56) is at least partly made up of said support structure (54) .

7. Device according to claim 6, wherein said inlet pipe (56) is made up of said support structure (54) and of a plate (64), fixed to said support structure (54) .

8. Device according to claim 3, wherein said at least one opening (58) is arranged on the edge of said wing (52) .

9. Device according to claim 8, wherein said at least opening (58) is arranged so as to emit an air flow that substantially corresponds to the direction of the air flow in the wind tunnel.

10. Wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting, comprising: a cooling device according to any of the previous claims, which is placed in a recirculation apparatus of said wind gallery, and an air cooling system to introduce air into the inlet pipe of the deflector.

11. Wind tunnel according to claim 10 comprising a temperature detector to detect the temperature of the air circulating in the wind tunnel; said cooling system being adapted to be activated based on the detection carried out by said temperature detector.

12. Method to implement a wind tunnel with a recirculating air flow, in particular to perform simulations of free fall or parachuting, comprising the step of installing a cooling device according to any of the claims from 1 to 9 in an air recirculation apparatus of said wind tunnel.