US2496710A - Fuel controlling apparatus for longitudinally movable combustion chambers - Google Patents

Description

1950 R. H. GODDARD 2,496,710

FUEL CONTROLLING APPARATUS FOR LONGITUDINALLY MOVABLE COMBUSTION CHAMBERS Original Filed March 9, 1942 2 Sheets-Sheet l Feb. 7, 1950 R. H. GODDARD 2,496,710

FUEL CONTROLLING APPARATUS FOR LQNGITUDINALLY MOVABLE COMBUSTION CHAMBERS Original Filed March 9, 1942 2 Sheets-Sheet 2 Patented Feb. 1,1950 I UNITED sTAra FUEL CONTROLLING APPARATUS FOR LONGIIUDINALLY MOVABLE COM- BUSTION enemas 1mm 11. Goddard, deceased, late oi Annapolis,

Mil, by Either C. Goddardyexecutrix, Paxtomf Mam, auignor oi one-half to The Daniel and Florence Guggenheim Foundation, New York,

v N. Y., a corporation at New York.

application, March 9, 1942, Serial No.

ririnal 433,963, now Patent Nd. 2,397,658, dated April 2, i946. Divided and this application February 2 Claims. (CL 60 35.6)

This application'is a division of original applia conical discharge portion 21, and a discharge.

. cation Serial No. 433,963, filed by Robert H. Goddard March 9, 1942 and issued April 2, 1946' as Patent No. 2,397,658. "This divisional application relates more particularly to the mounting of the combustion chamber for longitudinal reaction and to the variation of the fuel feed-in response to such axial movement.

This-invention relates to a combustion chamber in which mixed oxidizing and combustible gases or vapors may be continuously burned.

While capable of general application, this im-' proved combustion chamber is particularly de-" signed and adapted for use in the propulsion of rockets or rocket crait.

An important object of thi'sinvention is to provide improved regulation of the fuel feed in a combustion chamber. In the preferred -form, fuel feed is maintained in a definite relation to the axial displacement of the combustion chamber in its supporting structure, which displacement is related to changes in axial thrust produced by the combustion gases in said chamber.

This invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

Preferred forms of the invention are shown in the drawings, in which Fig. 1 is a sectional front elevation of this improved combustion chamber: 7

Fig. 2 is an enlarged sectional front elevation of certain gasoline feed devices for said chamber;

Fig. 3 is, a sectional plan view, taken along the irregular line 3-3 in Fig. 2;

Fig. 4 is an enlarged detail sectional front elevation of an upper portion of the combustion chamber;

Fig. 4a is a slightly modified detail sectional plan view, taken along the line tar-4a in Fig. 4;

Fig. 4b is a fragmentary side elevation, looking in'the direction of the arrow 4b in Fig. 4a;

Fig. 5 is a detail sectional plan view of certain nozzle structure, taken along theline 5-5 in Fi 1;

Fig. 6 is a fragmentary sectional front elevation showing a braced construction; and

Fig. 7 is a front elevation of a brace or bracket.

Referring to Fig. 1, a combustion chamber is shown comprising an inner casing 20, an intermediate casing or jacket 2|, and an outer casing 22, said parts being held in spaced relation by tie rods or braces 23 (Fig. 4) secured to each of the casing members 20, 2i and 22.

.. 2 middle portion 25, a conical entrance portion 26,

nozzle 28. ,A liquid oxygen supply pipe to is connected into the space ll between the outer casing 22 and the intermediate casin or jacket 2! and adjacent the outer end of the nozzle 28. The space 3i is gradually reduced in cross sectional area upward asvlewed in Fig. l and is closed at its upper end. This gradual reduction. in cross sectional area facilitates the maintenance of uniform flow. The liquid oxygen is furnished from any suitable supply under pressure. and the flow-of liquid oxygen is controlled by a valve 32. I

The intermediate casing or jacket 2| isprovided with a multiplicity of-perforations 33 (Fig. 4) through which narrow streams or jets J of liquid oxygen are projected against the outer surface of the inner casing 20 to'cool said inner casing and to prevent melting or burning thereof by the extremely hot combustion gases developed within the chamber.

Such narrow streams are superior to sprays for the reason that there is considerable friction tending to retard the motion of small drops, par- 'ticularly in a gas of high pressure and density,

.which would reduce the speed, and hencethe The inner casing 20' comprises a cylindrical 66 cooling effect, of sprays.

In order to prevent rebound and scattering of the liquid as it engages the casing 20, recessed portions or dents 35 are provided in the casing 20, which'recessedportions are convex inward and concave outward with respect to the casing 20. The recessed portions 35- are aligned with the jets J and as each jet strikes one of these recessed portions in substantial alignment therewith, the jet spreads out sidewise but develops enough centrifugal force to maintain the liquid in close engagement with the casing surface, -so that the inner casing is thus effectually cooled. The centrifugal force is strong because of the small radius of curvature of the dents. Cooling is further facilitated by the centrifugal force causing the liquid drops and cooler gas to make contact with the wall.

Such engagement, besides cooling the casing wall at, also evaporates the cold liquid oxygen. The oxygen vapor or gas thus produced passes upward along the annular space 36 betweenthe walls 20 and 2| and enters the combustion chamber as a conical sheet through an annular slot or opening 38 (Fig. 4) at the top of the cylin-' drical portion 25 and just below the conical entrance portion 26. It will be noted that the annular space 36 increases in cross section upwardly,

pinge from reverse directions, which causes very intimate mixture. The greater weight and volume of oxygen carries the gases well up in the entrance portion II, where mixing mainly takes place and where active combustion is initiated.

In the lower conical portion 21 of the combusseparate recessed portions or dents cannot be used, as they would break up the streamlined surfaces which are essential to prevent interference with the high velocity movement of the combustion gases as they approach the nozzle 28 and are discharged therethrough.

Consequently, in the portions 21 and 28 axially extending and outwardly concave ribbed portions are utilized, as shown at ll in Figs. 1 and 5. These ribbed portions develop the same centrifugal action in a circumferential direction as the dents 35 or "a but without interference with axial movement of the gases.

While it is necessary to cool the inner casing 20 to prevent destruction thereof, it is also desirable to prevent cooling of the gases in the combustion chamber as frr as possible, and for this reason a thin refractory lining 44 is provided within the parts 28 and 11 of the combustion chamber and within the discharge nozzle 28.

This lining is preferably formed in relatively small sections or shells andis of such thickness in relation to the thickness of the casing 20 that the inner surface of the casing 20 is heated just below its softening point and that the inner surface of the lining N is similarly heated just below its softening point. In this way, the casing 20 is protected, while at the same time the combustion gases are maintained at the highest permissible temperature.

Small shells a of refractory material are preferable because of the tendency of unequal expansion to produce cracks over large areas. In the form shown in Figs. 4a and 4b, the recessed portions or dents lib are quite close together and the shells of refractory material over the dents will be held in place by the arched or concave shape of the chamber wall.

A gasoline feed chamber ll (Fig. 2) is provided at the entrance end of the combustion chamber, to which gasoline may be supplied with valve openings 58. The second or inner sleeve 64 is connected by a spider as (Figs. 2 and 3) to a supporting rod 5'! which is connected to a plate 58 (Fig. l) which normally abuts the under side of a fixed frame member F. The upper end of the gasoline chamber 50 is connected by a bellows member I to the plate 58.

If the valve openings 53 and I! are aligned, in whole or in part, gasoline from the outer annular space 60 in the gasoline chamber 50 will pass through the valve openings 53 and 55 and thence downward through the inner casing 54 to a nozzle opening 62, provided with any usual device 83 for imparting a whirling motion to the gasoline as it is fed through the nozzle opening 62 to the upper portion 26 of the combustion chamber, which portion has a refractory lining N. Means for producing relative axial motion be- .1 tion chamber and in the discharge nozzle 28, the p tween the sleeves l2 and II will be hereinafter described.

The injected gasoline preferably forms a hollow cone of spray just inside the refractory lining 8|, this spray meeting the oxygen gas stream from the slot as at a substantial obtuse angle. The slot 3| is back of the refractory lining 64 and out of line with the gasoline spray, so that gasoline cannot enter the oxygen jacket 2| accidentally, in the absence of a high speed stream of oxygen gas, and thus produce an explosive mixture when the oxygen starts to flow.

It will be noted by reference to Fig. 1 that the gasoline enters the combustion chamber as a spray from the single nozzle opening 82. whereas 1 the oiwgen enters the chamber almost entirely in gaseous condition and through the extended circumferential entrance slot 38. In order to improve the mixture and to vaporize the gasoline as much as possible, special means are provided for heating the gasoline as it enters the portion It of the combustion chamber, such special means being necessary in order to break up the gasoline into veryflnedrops in the relatively short available distance of travel. For this purpose. an annular passage 65 is provided (Fig: 2) surrounding the discharge end of the gasoline chamber BI and connected by a bypass pipe 08 to the upper end of the annular oxygen space II. A shut-ofl valve I1 controls the flow through the pipe ll.

. For most efllcient operation, it is necessary that the proportions of oxy en and gasoline be correctly maintained, and as variations in the amount of oxygen supplied unavoidably occur, due to changes in the rate of evaporation of the oxygen and to other variable causes, provision is made to vary the gasoline feed with reference to variations in flow of oxygen gas or vapor to the combustion chamber.

To accomplish this regulation, advantage is taken of the reactive eifect of the combustion gases issuing from the nozzle 28 against the closed or upper end of the combustion chamber 45 20. The more complete and perfect the com? bustion, the stronger will be these reactive forces.

In order to utilize these forces in the regulation of the gasoline feed, the combustion chamber is mounted on an annular plate or ring I! 50 (Fig. l) and a plurality of supporting rods I3 are provided, each of which is secured to the ring I2 at its lower end. At its upper end, each of the supporting rods 13 is connected to a chambered piston ll, slidable in a ilxed sleeve I and 5s pressed downward by a relatively strong coil spring ll. Guide blocks 11 on the supporting rods I3 loosely engage the outer casing 22 of the combustion chamber and center the casing but without exerting pressure thereon. to with the chamber. thus supported, the casings 20, II and 22 areunder tension, rather than compression.- The reason for supporting the chamber and casings under tension rather than under compression is because all of these thin 68 structures will withstand tension but not compression, except when they are sustaining high internal gas pressure. Moreover, the thin refractory shells a cannot withstand the bending which would accompany compression. Tension, 70 on the other hand, merely opens slightly th spaces between the shells.

-. with this construction, any increase in the reactive forces from the name 28 will cause the chamber to move upward against the pressure is of the springs l0, carrying with it the gasoline chamber 50 and the outer valve sleeve 52. As the inner valve sleeve 54 normally remains fixed, the openings 53 and 55 will be more nearly aligned and the fiow of gasoline will correspondingly increase. The flexible bellows member 59 permits such relative upward movement of the gasoline chamber 50.

As the thrust increases. more gasoline will be admitted through the opening 55, and this will continue until the rate of gasoline flow is such as to produce the greatest thrust for the oxygen fiow that is taking place. This oxygen flow, although mainly dependent on the amount of opening of the valve 32 (Fig. 1), also depends largely on the temperature of the chamber and jacket walls. Further upward movement of the chamber 20 and gasoline chamber 50 will not increase the thrust, since the excess of gasoline over that required for best combustion will retard the oxygen fiow by creating extra chamber pressure. This retardation of the oxygen flow will reduce the combustion, and the velocity of the gases from the nozzle will fall.

In order to prevent undesirable oscillations or "hunting of the combustion chamber and particularly those produced by the coaction of the nozzle thrust acting on the valve 50 and the springs 85, perforated pistons 80 are provided in cylindrical openings 8| in the pistons 14. These perforated pistons 80 are mounted at the lower ends of rods 83 fixed in the frame F, so that a dash-pot effect is produced and oscillations of the combustion chamber are prevented. To permit upward movement of the oxygen feed pipe 30, a telescoping joint 84 (Fig. 1) is provided.

It is desirable that the nozzle opening 62 at the bottom of the gasoline chamber 50 be positively closed when the apparatus is not in use. For this purpose, the plate 58 (Fig. 1) is mounted at the lower end of a sleeve or plunger 86 slidable vertically in a bearing in the frame F and having a pin and slot connection 86a with a forked bell crank 81 and pull rod 88.

When combustion is to be discontinued, the rod Having thus described the invention and the advantages thereof, it will be understood that the invention is not to be limited to the details herein disclosed, otherwise than as set forth in the 5 claims, but that what is claimed is:

1. In a combustion apparatus, a fixed frame, a combustion chamber having an axial discharge opening at one end, a supporting structure in which said chamber is mounted for axial movement relative to said frame in response to changes in thrust produced by the flow of combustion gases from said chamber, means to yieldingly resist such movement, means to continuously supply an oxidizing liquid under constant pressure to said chamber, means to supply liquid fuel to said chamber, and valve means to vary the fuel flow in response to changes in the axial position of said chamber relative to said frame.

In a combustion apparatus, a fixed frame, a

combustion chamber having an axial discharge opening at one end, a supporting structure in which said chamber is mounted for axial movement relative to said frame in response to changes in thrust produced by the flow of combustion gases from said chamber, means to yieldingly resist such movement, means to continuously supply an oxidizing liquid under constant pressure to said chamber, a first valve member adapted for axial motion and radial flow and integral with said chamber, a second valve member attached to said fixed frame through a manually movable intermediate supporting device, said second valve member being freely slidable along said first valve member and with which it coacts, a bellows pack- ;;5 ing between said first valve member and said intermediate device, and a third valve member integral with said second valve member and with said intermediate supporting device and tightly closable by axial movement therewith.

-10 ESTHER C. GODDARD,

Emecutrix of the Last Will and Testament of Robert H. Goddard, Deceased.

REFERENCES CITED I8 is pulled, depressing the sleeve 86 and forcing a'valve member 89 at the lower end of the rod 51 against the lower end of the gasoline chamber 50, thereby closing the nozzle opening 62. The parts may be frictionally held in this position.

When active operation of the apparatus is to be resumed, the parts are manually restored to the position shown in Fig. 1, which position will be maintained during operation by friction and by the gaseous pressures developed in the apparatus.

As the parts adjacent the annular oxygen feed slot 88 are relatively unsupported, brackets or braces 90 (Figs. 6 and '7) are provided which are vertically disposed so that they do not interfere with the flow of oxygen gas but which nevertheless firmly support the upper edge of the inner casing 20.

It will thus appear that simple and effective apparatus has been provided for cooling and continuously operating'a combustion chamber and for automatically regulating the supply o fuel thereto.

The following references areofmord in the file of this patent:

UNITED STATES PATENTS Number Name Date 866,330 Calkins Sept. 17, 1907 1,291,032 Lesem Jan. 14, 1919 1,369,672 Koenig Feb. 22, 1921 1,820,154 Peets Aug. 25, 1931 1,842,446 Dabrasky Jan. 26, 1932 1,929,778 Goddard Oct. 10, 1933 2,103,274 Sanford Dec. 28, 1937 2,111,315 Damblanc Mar. 15, 1938 FOREIGN PATENTS Number Country Date 625,104 France Apr. 19, 1927 636,723 Germany Apr. 15, 1937 156,785 Switzerland Nov. 1, 1932'

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