US2465525A - Reaction combustion chamber for unconfined charges or detonative fuel fed intermittently to the combustion chamber - Google Patents

Description

March 29, 1949. GODDARD 2,465,525 7 REACTION comaus'non CHAMBER FOR ,UNCONFINED CHARGES OF DETONATIVE FUEL FED INTERMITTENTLY TO THE COMBUSTION CHAMBER Filed D80. 15, 1943 2 Sheets-Sheet l R. H. GODDARD ,465,525 USTIQN CHAMBER FOR UNCONFINED CHARGES ON FUEL FED INTERMITTENTLY TO COMBUSTION CHAMBER March 29, 1949.

REACTION COMB OF DET ATIVE THE Filed Dec. 15, 1945 2 Sheets-Sheet 2 DE DE mwat l. Q3

Patented Mar. 29, 1949 UNITED STATES PATENT OFFICE REACTION COMBUSTION CHAMBER FOR UNCONFINED CHARGES OI DETONATIVE FUEL FED INTERMITTENTLY TO THE COMBUSTION CHAMBER Application December 15, 1943, Serial No. 514,411

14 Claims. 1

This invention relates to combustion chambers of the type in which a mixture of combustible and oxidizing liquids is consumed. More specifically, the invention relates to a combustion chamber of the general type shown in my prior application Serial No. 273,600, now Patent No. 2,396,566, issued March 12, 1946, in which the fuel charge is spaced from all supporting or confining surfaces at the instant of ignition and during combustion or detonation thereof.

It is the general object of my present invention to improve and simplify the construction shown in my prior application by presenting successive unconfined plugs or short columns of mixed combustible and oxidizing liquids to the combustion chamber, in place of using cartridges as in said prior application. I thus avoid provision of any cartridge magazine or of the multiplied feeding devices disclosed in said application.

A further object of the present invention is to provide improved and simplified devices for feeding the liquids to the combustion chamber in successive small amounts by utilizing the recoil of the combustion chamber caused by each detonation therein.

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

Preferred forms of the invention are shown in the drawings, in which Fig. 1 is a sectional front elevation of one form of my improved combustion chamber, the section being taken along the irregular line in Fig. la;

Fig. la is a diagrammatic plan view, showing the section on which Fig. 1 is taken;

Fig. 2 is an enlarged front elevation of an injector shown in Fig. l;

Fig. 3 is a partial sectional elevation of the injector, taken along the line 3-3 in Fig. 2;

Fig. 4 is a detail sectional view of a one-way control valve to be described;

Fig. 5 is a sectional side elevation of a pressure pump;

Fig. 6 is a view similar to Fig. 3 but showing a modified injector construction;

Fig. 7 is a perspective view of a perforated plug to be described;

Figs. 8, 9 and 10 are sectional front elevations of modified combustion chambers;

Fig. 11 is a partial sectional elevation of a further modification of the injector;

Fig. 12 is a sectional elevation of a combustion chamber modified for short and relatively thick fuel columns or plugs;

Fig. 13 is a sectional elevation of a modified combustion apparatus in which the stationary injector is replaced by a reciprocating post or piston, taken along the line |3|3 in Fig: 13a;

Fig. 13a is a diagrammatic plan view showing the section on which Fig. 13 is taken;

Fig. 13b is a plan view, partly in section, of certain parts shown in Figs. 13 and 17;

Fig. 14 is an enlarged sectional elevation of certain feeding devices to be described;

Fig. 15 is a partial sectional elevation of the reciprocated post;

Fig. 16 is a sectional elevation of a modification of the feeding devices shown in Fig. 14;

Fig. 16a is an enlarged sectional view of a portion of Fig. 16; and

Fig. 1'? is a detail view of certain disc-operating mechanism to be described.

Referring to Figs. 1 to 5, I have shown a combustion chamber 20 in the form of a cone, open at its lower end and having an upward extension providing a recess 2| and a hub or bear-' ing portion 22. The walls of the chamber 20 are preferably thickened upwardly for increased strength.

The hub or hearing 22 is a close sliding fit on a cylindrical injector 24 (Fig. 2) having a flange 25 secured to a stationary support or cross bar 26 by clamping screws 21. A cushioning ring 28 of rubber or some similar material provides a yielding mounting for the injector.

Liquid fuel such as methane or propane is fed to the injector tube 2 4 through a pipe 30 (Fig. 1), and a liquid oxidizing agent such as liquid oxygen is fed to the injector through a pipe 3| connected to the annular space between the pipe 30 and the wall of the injector. The liquids may be supplied to the pipes 30 and 3| through suitable connections from pressure tanks (not shown) or by pumping devices P to be described.

The injector tube 24 is provided with a series of openings or feed orifices 33 (Figs. 2 and ,3) connecting through a recess 34 to the'fuel supply pipe 30, and with an additional series of feed orifices 36 connecting into the annular space between the pipe 30 and the injector tube 24. The combustion liquids are thus injected into the recess 2| (Fig. 1) at the upper end of the chamber 20 whenever the orifices 33 and 36 are uncovered by upward movement of the chamber 20 and its hub or bearing portion 22 relative to the injector. The chamber 20 is provided with a plurality of hollow posts 40 extending upwardly and tele and is compressed as the posts 40 are moved upward, thus providing an air cushion acting in conjunction with each compression spring 42.

As the cylinder 28 is forced upward by the recoil, the holes 33 and 3B are uncovered and the two liquids are sprayed into the recess 2| through the orifices 33 and 36 and are intimately mixed therein. The column of mixed liquids thus formed will then move downward out of the recess 2| to the position indicated at C in Fig. 1,

leaving a space S above the column which is substantially free of the detonating mixture.

This is desirable, as the mixture is thereby spaced from the upper end of the chamber wall and gases and vapors in the space S provide a cushion which protects the lower end of the projector 24 from the full force of the detonation.

While the liquids may be fed to the pipes 38 and3| by constant pressure from pressure tanks as above described, it is sometimes desirable to provide an intermittent or pulsating pressure, which pressure is applied when the feed orifices 33 and 36 are open but relieved when the orifices are closed.

For this. purpose, I provide pairs of pumps P and P' (Figs. 1 and 1a). consists of a hollow cylinder 44 (Fig. 5) having a piston 45 connected to the open outer end of the cylinder 44 by a bellows member 46. The piston rod 41 for the piston 45 is connected to a pair of toggle links 48 and 49 (Fig. 1). The link 48 is pivoted at its upper end to the fixed support 25 and the link 49 is pivoted at its lower end to the hub portion 22 of the combustion chamber 28. As the combustion chamber rises,

As the chamber 28 descends and the piston 45 moves to the right, one of the liquids, as liquid fuel, will bedrawn in from a supply pipe 50 past 'a=bobbin' -type check valve 5| slidable below a -seat portion 5|a of reduced diameter.

On the next upward or recoil movement of the chamber 20, movement of the piston 45 to the left will force the liquid fuel out past a check valve 52, slidable below a seat portion 52a of reduced diam- Each of these pumps eter to a pipe 53 which may be connected with the injector feed ipe 30. An oppositely positioned pump P will be similarly connected to a supply of the second liquid, as liquid oxygen, and t2 the other feed or supply tube 3| for the injector 2 The piston rod 54 (Fig. 1) for the pump P is preferably connected to the piston rod 41 for the associated pumpP by a yoke 54 spanning the injector 24 so that the pumps P and P of each so that pumping is substantially continuous except at the end of the return stroke when the links 48 and 49 are nearly in line and produce little piston movement. At this interval of lower arms 66. This construction has the advantage of end delivery from the injector instead of side delivery, which in turn permits the outer tube 6| to have a sliding fit in the recess 2| as well as in the hub portion 22 of the combustion chamber 28. The flow of the liquids to the combustion chamber is also more direct;

For igniting the charge C in the conical combustion chamber 20, I provide an annular casing 18 (Fig. 1) surrounding the larger and open' end of the chamber 28 and connected with the chamber by a plurality ofperforations I l spaced about the periphery of the chamber. A feed pipe 12 for liquid oxygenand a feed pipe 13 for liquid plies (not shown). of liquid oxygen and liquid fuel under constant pressure.

A spark-plug 16 is mounted on the casing 18 and is provided with a yielding contact arm 11 which engages a contact stud I8 as the combustion chamber 28 reaches its lowest position. The stud 18 may be mounted in fixed position on the casing 19 of a rocket craft or on' other fixed structure in which the combustion chamber is mounted.

In order to prevent the formation of an explosive mixture in the liquid fuel feed pipe, I preferably provide a plug 88 (Fig. 7) in the feed pipe 13 (Fig. 1). and form this plug with a plurality of small longitudinal perforations 8|. With this construction, flow of liquid fuel through the plug 88 may take place rapidly enough for ignition purposes, but reverse flow against pressure will be greatly retarded and substantially prevented.

In order to cool the inner surface of the combustion chamber 28, I provide a plurality of annular casings 83, 84 and 85, mounted in axially spaced relation on the outer surface of the combustion chamber and connected with the interior thereof by perforations 86, 81 and 88. The perforations 81 and 88 are preferably approximately tangential to the cone in planes normal to its axis, and the perforations 86 are similarly tangential and also inclined upwardly as viewed in Fig. 1.

The casings 83, 84 and 85 have suitable flexible connections 89 to a. supply of water under pressure. The water is thus injected through the perforations 86, 81 and 88 to provide a liquid film on the inner surface of the combustion chamber and to thereby prevent overheating of the chamber wall.

A further modification of the injector is shown in Fig. 6, in which the inner tube 98 is slidably mounted in spaced guides 9| in the outer tube 92 and in which an end plate 93 is slidably mounted in a bearing 94 secured on spaced arms 85 in the tube 98. A flexible connection 88a is provided at the upper end of the tube 90 to permit slight endwise movement thereof.

With this construction, the combustion liquids are injected through closely adjacent annular slots in the outer cylindrical surface of the injector, and the slots are closed by upward movement of the plate 93 and inner tube 90 whenever a charge is detonated, thus preventing back pressure in the tubes 90 and 92.

In Figs. 8, 9 and 10 I have shown certain modifications in the cross-section of the combustion chamber and in the shape and size of the charge to be detonated. The section shown in Fig. 1 is desirable for a charge which detonates with great rapidity and which produces a large mass of combustion gases substantially instantaneously.

For a charge (Fig. 8) which detonates at a relatively slow rate, an elongated combustion chamber I00 having a narrow angle of expansion is desirable. For a charge C2 (Fig. 9) of mixed liquids which explode rather than detonate, a cylindrical combustion chamber I M having a discharge nozzle I02 is desirable.

A chamber I04 (Fig. of parabolic section may be. used for a relatively short and thick charge C3. Such a charge has the advantage of retaining its cylindrical form more perfectly and also has a reduced rate of evaporation. The force of the detonation, however, is more largely exerted against the upper part of the chamber, which necessitates further thickening of its side wall.

In Figs. 13 to 16, I have shown a modified construction in which a combustion chamber H0 is mounted to move vertically on telescoping supports III which may be of the same construction and operation as the corresponding parts shown' in Fig. 1.

Aplunger H2 is mounted to slide vertically in a hub or extension I I3 of the combustion chamber I I0. At its upper end the plunger I I2 has a cross head H4 to which is pivoted a pair of levers H5. Each lever H5 is pivoted at'its lower end H5a to a link I I6, the upper end of which is pivotally connected at H1 to an arm H8 pivoted at its lower end at H9 to a lug on the combustion chamber H0.

The upper end of each arm I I8 coacts with one of the levers H5. Each lever H5 is provided with an elongated slot I2I through which extends a pin I22 mounted in a fixed support I23. A tension spring I24 draws the arm H6 toward the axis of the combustion chamber. Exactly similar structure is provided at the left in Fig. 13 but is omitted for the sake of clearness, the section being taken on a line corresponding to the line I3I3 in Fig. 13a

An annular recess I30 (Fig. 14) is formed in the extension I I3 of the combustion chamber, and an oxygen feed pipe I3I is connected to said recess. A similar, closely adjacent recess I32 is also provided, connected with a liquid fuel feed pipe I33. These recesses are closed on the inside by annular rings or webs I34 and I35, having adjacent slotted openings I36 and I31, constituting intersecting delivery passages through which streams of the combustile liquids may enter the recess in the hub or extension H3 when the plunger H2 is raised. The provision for ignition of the charge and cooling of the chamber walls may be the same as previously described in connection with Fig. 1.

With this construction, upward movement of the chamber Hll on detonation of a charge not only carries the plunger head H4 bodily upward but also gives the levers H5 combined swinging and sliding movements about the fixed pins I 22. This results in moving the head H4 and plunger I I2 upward substantially faster than the cylinder H0 and hub H3. The supply pipes I3I and I32 are maintained under constant pressure,

or may be connected to intermittently acting pressure pumps as shown in Fig. 1.

Whenever the plunger H2 is thus raised at double speed, the annular port I34 is opened and the combustion liquids flow into the cylindrical recess in the hub I I3. As the chamber H0 thereafter moves downward and returns to initial position, the plunger I I2 simultaneously moves downward at twice the speed of the chamber and thus transfers the charge from the recess in the hub H3 to the operative position in the chamber H0.

indicated at C4.

It is desirable that the lower end of the recess in the hub H3 be closed during admission of the combustible liquids thereto, so that the liquids may be well mixed within the recess before being transferred to the chamber I I0.

I For this purpose, I provide a disc I40 (Figs. 13 and 13a) mounted toswing in a horizontal slot or opening I40a (Fig. 13) in the hub H3 and pivoted on a 'studI4I mounted in brackets I42 carried by the hub H3. A cam plate I45 (Figs. 13a and 17) is mounted on an outward extension of the disc I40 and is engageable by a stop I46 as the chamber H0 moves upward and by a stop I41 as the chamber thereafter moves downward. The stops I46 and I41 are yieldingly mounted on stationary parts of the mechanism, so that the stop I41 yields upwardly and is inoperative as v the stop I46 will swing the disc I40 to closed position and on the next downward movement the stop I41 will swing the disc to open position.

Ignition may take place as previously described in connection with Fig. 1, or the charge may be ignited at its upper end by extendinga rod I50 (Fig. 15) axially through the plunger H2 and insulating the rod by a bushing I5I. One wire I52 of an ignition circuit is secured to the upper end of the rod I50 and contact is made with the other spark terminal I53 through a spring contact I54 and fixed stud I55, thus completing the ignition circuit when the combustion chamber reache its lowest position.

In Fig. 16 I have shown a modified construction for feeding the liquids to a recess I60 in the hub H3a of a combustion chamber Hlla. In this construction, the recess I30 (Fig. 14) is replaced by the annular recess I60 in which wire mesh cloth or its equivalent is coiled in layers I6 I. With this construction, the liquids become intimately intermingled as they pass through the wire wesh layers I6I, and the screen also prevents burning gases from reaching the supply pipes I62 and I63. A downwardly projecting flange I65 (Fig. 16a) at the lower end of the hub I I3a helps to prevent upward leakage of the combustion gases past the piston or plunger H2a. The wire mesh layers may be replaced with perforated plates having their openings out of alignment.

In Fig. 12, I have shown a further modification in which an ignition ring I10 is mounted near 7 the upper end of the combustion chamber and the injection openings I12 are made perpendicular to the conical inner face of the combustion chamber and are directed toward the upper end of the charge C5, as indicated by the arrows. With the passages I12 thuspositioned, the ignition flames traverse the shortest distance to contact the charge and the charge is ignited at its upper end instead of at its lower end. The possibility of disturbance of the ignition flame by external air currents is reduced with this construction.

Provision for igniting the mixed liquids in the annularring I10 may be the same as shown for the ring 10 in Fig. 1 but these parts do not appear in the section on which Fig. 12 is taken.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. In an apparatus for producing a. propulsive force by the reaction obtained from the detonation of successive charges of fuel and an oxidizing agent, in combination, a combustion chamber permanently open at its lower discharge end, said chamber being supported for upward movement under recoil, means controlled by said movement and return, effective to place successive unconfined unitary detonating charges of previously intermingled combustion liquids in a firing position within said chamber, which position is spaced from the chamber walls, and means to ignite and instantaneously detonate each charge when thus positioned, the diameter of each charge being a minor fraction of the average effective diameter of the combustion chamber.

2. In an apparatus for producing propulsive force by the reaction obtained from the detonation of successive charges of fuel and an oxidizing agent, in combination, an injector for combustion liquids, a combustion chamber permanently open at its lower discharge end and mounted to slide axially on said injector and to be moved relative thereto by recoil following ignition of a charge therein, means to supply combustion liquids under pressure through feed openings in said injector to said combustion chamber, said openings being normally closed and being uncovered when the chamber recoils, said liquids intermingling in the upper part of said chamber to form a, detonating charge and being advanced as successive unconfined unitary and previously intermingled detonating charges to a firing position within said chamber, which position is spaced from the chamber walls, and means to ignite and instantaneously detonate each charge thus positioned, the diameter of each charge being a minor fraction of the average effective diameter of the combustion chamber.

3. In an apparatus for producing propulsive force by the reaction obtained from the detonation of successive charges of fuel and an oxidizing agent, in combination, an injector for combustion liquids, a combustion chamber, permanently open at its lower discharge end and mounted to slide axially on said injector and to be moved relative thereto by recoil following ignition of a charge therein, said injector having feed openings therein which are covered and closed by said chamber when in initial lower position and which are uncovered and opened by upward recoil displacement of said chamber, means to supply combustion liquids under pressure through said feed openings in said injector to said combustion chamber when the chamber recoils upward, said liquids intermingling in the upper part of said chamber to form a detonating charge and being advanced as successive unconfined unitary and previousl intermingled detonating charges to a firing position within said chamber, which position is spaced from the chamber walls, and means to ignite and instantaneously detonating each charge thus positioned as said chamber completes its return movement.

4. In an apparatus for producing propulsive force by the reaction obtained from the detonation of successive charges of fuel and an, oxidizing agent, in combination, a tubular injector mounted in fixed position, a conical open-ended combustion chamber having a reduced entrance portion and mounted to slide axially on said injector by recoil of said chamber on detonation of a charge therein, springs to yieldingly resist such recoil movement and to effect return of said injector to initial position, said injector having feed openings uncovered by said reduced entrance portion of said chamber on recoil movement and covered by return movement thereof, means to supply combustion liquids through said feed openings to said reducedentrance portion of said chamber for intermingling therein to form a detonating charge when said openings are uncovered, and means to ignite and instantaneously detonate the previously intermingled liquids in said chamber on return of said chamber to initial position.

5. The combination in propulsion apparatus as set forth in claim 4, in which separate pressure pumps are provided for each liquid and in which said combination includes connections between said pumps and said chamber effective to operate said pumps in pairs by the recoil and return movements of said chamber.

-6. The combination in propulsion apparatus as set forth in claim 4, in which said chamber includes means to cool the inner conical surface of said combustion chamber in a plurality of axially-spaced Zones.

'7. The combination in propulsion apparatus as set forth in claim 4, in which separate pressure pumps are provided for each liquid and in which said combination includes connections between said pumps and said chamber effective to operate said pumps in pairs by the recoil and return movements of said chamber, certain of said pumps delivering liquid on recoil of said chamber and certain other pumps delivering liquid on return movement of said chamber.

8. The combination in propulsion apparatus as set forth in claim 4, in which said combination includes means to feed additional combustion liquids under pressure to an annular passage disposed about the discharge end of the conical combustion chamber, said passage being. connected to said chamber by relatively small spaced openings, and in which said combination includes means to periodically ignite said intermingled liquids.

9. The combinat on in pro ulsion apparatus as set forth in claim 4, in which said combination includes means to feed additional combustion liquids under pressure to an annular passage disposed about the discharge end of the conical combustion chamber, said passage being connected to said chamber by relatively small spaced openings, together with means to periodically ignite said intermingled liquids, and in which said combination includes a device to prevent backfire in the fuel connections to said annular passage.

10. In an apparatus for producing propulsive force by the reaction obtained from the detonation of successive charges of fuel and an oxidizing agent, in combination, a combustion chamber mounted for recoil and return movement and having an elongated hub portion, a post on which said hub is slidable, means to move said post on recoil of said chamber at greater speed than said chamber but simultaneously therewith in the same direction, thereby withdrawing said post on recoil, means to feed combustion liquids through said hub to said chamber when said feeding means is uncovered by withdrawing movement of said post on recoil of said chamber, said liquids intermingling in said chamber to form a detonating charge, and means to ignite and instantaneously detonate said intermingled liquids.

11. The combination in propulsion apparatus as set forth in claim 10, in which said combination includes multiplying linkage which connects said chamber to said post and which moves said post simultaneously with said chamber and substantially faster in the same direction.

12. The combination in propulsion apparatus as set forth in claim 10, in which said combination includes a disc in said elongated hub, together with means to close said disc as said post is withdrawn from said hub and to open said disc as said post moves into said hub.

13. The combination in propulsion apparatus as set forth in claim 10, in which the hub is provided with an annular recess to receive each of the combustion liquids, and in which said com- 10 bination includes means to make delivery from said recesses to the interior of said hub as said post is withdrawn and uncover said recesses.

14. The combination in propulsion apparatus as set forth in claim 10, in which the hub is provided with an annular recess to receive the combustion liquids, and in which said combination includes means to make delivery from said recess to the interior of said hub as said post is withdrawn and uncovers said recess, and in which said combination includes substantially concentric layers of perforated material in said annular recess to prevent back-fire and to assist intermingling of said liquids.

ROBERT H. GODDARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 502,168 Battey July 25, 1893 704,456 Gray July 8, 1902 1,156,846 Johnson Oct. 12, 1915 2,142,601 Bleecker Jan. 3, 1939 2,283,863 Achterman May 19, 1942 FOREIGN PATENTS Number Country Date 3,561 Great Britain Aug. 16, 1881 124,000 Germany Oct. 14, 1901

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