US2555080A - Feeding and cooling means for continuously operated internal-combustion chambers - Google Patents

Description

May 29, 11951 R. H. GODDARD F'EEDING AND COOLING MEANS FOR CONTINUOUSLY OPERATED INTERNAL-COMBUSTION CHAMBERS 5 Sheets-Sheet 1 Filed July 16, 1945 L/ql//D FUEL Afl/"ali May 29, 1951 R. H. GODDARD 2,555,080 FEEDING AND COOLING MEANS FOR CONTINUoUsLY OPERATED INTERNAL-COMBUSTION CHAMBERS Filed July 16, 1945 3 Sheets-Sheet 2 /Q UID 40 Fuel.

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May 29, 1951 R. H, GODDARD 2,555,080 FEEDING AND COOL MEANS ,Fo ONTINUOU OPERATED INTER -COMBUSTI CHAMBER Filed July 16, 1945 3 Sheets-Sheet 3 7'8 BQ 75 74\ .9b I l 35 y 82, l l az R 61 8o l IN V EN TOR.

15g, 16. www 604mm.

Patented May 29, 1951 FEEDING AND COOLING MEANS FOR CON- TINUOUSLY OPERATED INTERNAL-COM- BUSTION CHAMBERS Robert H. Goddard, Annapolis, Md.; Esther C. Goddard, executrix of said Robert H. Goddard, deceased, assignor of one-half to The Daniel and Florence Guggenheim Foundation, New York, N. Y., a corporation of New York Application July 16, 1945, Serial No. 605,381

7. Claims.

This invention relates to apparatus particularly designed for combustion of an intimate mixture of two liquids such as gasoline and liquid oxygen. While certain features of the invention are capable of general application, the invention parf ticularly relates to the propulsion of rockets or rocket craft in which gases are continuously produced in a combustion chamber and are continuously discharged under pressure through a rearwardly open nozzle.

It is the general object of my present invention to provide a construction in which the thin walls of the combustion chamber are cooled and protected by films of both liquids, so that a larger part of the liquid material fed to the chamber may be utilized in cooling the chamber walls.

A further object is to provide apparatus which will produce a very intimate mixture of the ccmbustion liquids but With relatively low heat generation adjacent the chamber wall. I also provide a construction by which chemical action closely adjacent the chamber wall is substantially avoided.

My invention further relates to arrangements and ycombinations 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 side elevation of a combustion chamber embodying my improvements;

"Fig 2 is an enlarged detail sectional elevation' of a portion of the chamber Wall with certain modications;

w Fig. 3 is a detail sectional view of a portion of the inner Wall;

Fig. 4 is an enlarged detail plan view of a portion of the inner wall of the combustion chamber;

Fig. 4a is a detail sectional view taken along ythe line 4er- 4a in Fig. 4;

Fig. 5 is a partial sectional elevation showing a modified nozzle construction;

Fig. 6` is an enlarged sectional detail of a portion of the nozzle shown in Fig. 5;

Fig. 6a is a detail section through the feed opening 126 shown in Fig. 6;

Fig. '7 is a detail View of a portion of the inner surface of my improved combustion chamber;

Fig. '7a is a perspective view of a partition structure; i

Fig. 7b is a sectional view taken along the line 1b--1b in Fig. 7a;

Fig. 8 is a view similar to Fig. 1 but showing a modified construction;

n Fig'a is a perspective view of a portion of the inner surface of the combustion chamber shown in Fig. 8;

Fig. 9 is a sectional elevation of a spray device;

Fig. 9a is a similar view but showing reverse feeding;

Fig. 9b is a detail sectional View of a portion of a spray device;

Fig. 10 is an enlarged sectional elevation of parts of a spray device;

Fig. 11 is a sectional elevation of a modified spray device;

Figs. 12, 13 and 14 are diagrammatic views illustrating spray production and the mixing of the combustion liquids;

Fig. 15 is a sectional elevation of a further modified spray device;

Figs. 16 and 17 are side elevations of separated parts of the structure shown in Fig. 15; and

Fig. 18 is a diagrammatic view similar to Fig. l2 but relating to the structure shown in Fig. 15.

Referring particularly to Figs. 1 to 4, I have shown my improved combustion chamber as comprising a relatively heavy spherical outer casing 20, preferably formed in two parts and secured together by bolts 2l.V The two parts are clamped against a suitable gasket 22. The inner wall of the combustion chamber C comprises an inner layer of refractory material, and, a relative- 1y thicker layer 21 of some material having low heat conductivity. The inner Wall is spaced from the outer casing 20 by vanes or partition members (Fig. 4) and by annular partition members 33 (Fig. 3).

In the modified construction shown in Fig. 2, a thin metal layer 26 separates the wall layers 25 and 21 and a second thin metal layer 28 overlays the layer 21. Y The several parts of the combustion chamber Wall are shaped to provide peripheral distribution areas 3l and 32 (Figs. 1 and 2), which are concave on their inner surfaces.

These distributing areas are defined and separated by circumferential ridges 34 (Fig. 1) and by longitudinally extending ridges 34a.

The jacket space between the combustion chamber Wall and the outer casing is divided by inclined partitions 35 and 36 and upright partitions 31 (Figs, '7a. and 7b) into jacket zones which are supplied respectively with liquid fuel from a supply pipe 40 and branch pipes 4l, and with liquid oxygen from a supply pipe 44 and branch pipes 45. Liquid fuel is also suplied to the jacket space 46 of the nozzle N and enters the nozzle through small holes 41.

A spray nozzle device 48 or 49, to be explained in detail, is located in the center of each zone area. By means of one set of these devices 48 a liquid or fluid of one active type is ejected substantially tangential to one set of concave surfaceareas, and by means of another set of these devices i9 a liquid or fluid which is chemically active to effect combustion with the rst liquid is ejected substantially tangential to a second set of concave surface areas. An igniter of any convenient type is shown at 50, Fig. 1.

The surfaces of the concave areas are made rather sharply dished or concave and with a substantially shorter radius of curvature than that of the outer casing 20. This sharp curvature causes the liquid or iluid ejected by the nozzle devices 48 and 49 to be pressed closely against the concave surface areas by centrifugal force. This form of inner surface is of great advantage in large chambers using tangential cooling, for by its use a chamber of large radius can have a tangential flow exerting as strong centr1fugal force in each concave zone as would be obtained in a much smaller sphere of radius equal to the small radius of curvature of these zonal surfaces. The ridges which are formed between adjacent concave zones defiect the mingled liquids from the chamber wall surface and toward the center of the chamber C.

The inclined partitionsy 35 and 36 (Figs. 9 and 9a) coact with spray devices to bevdescribed to deliver fuel and oxidant to alternatey concave areas, so arranged that in general each concave area receiving one liquid adjacent its inner surface is bordered on all sides by concave areas receiving the other liquid adjacent their inner surfaces.

The outer wall 20 is made spherical in order to withstand high pressure and at the same time to be of light construction. The outside surface of this outer wall is preferably reinforced by wires 26a of high tensile strength, as described in my prior patent, No. 2,109,529, issued March 1, 1938.

It is important to employ as high a chamber pressure as possible, as this not only raises the chamber efficiency but also causes the fuel and oxidant to remain liquid at a higher temperature, thus producing greater cooling by centrifugal force, in the tangential flow along the concave areas, and also providing more intimate spray mixing by the impact of drops rather than the impact of large masses ofV gas, at the edges of these zones. The casing 20- preferably encloses the nozzle N, thus making possible the application of full feed pressure to reduce boil ing in the nozzle jacket and without using a special strong structure around the nozzle. Too large a liquid jacket space around the nozzle is avoided by the use of a hollow spacing member (Fig. l) made of some light material and filled with a light porous substance' 52.

The inner walls ofv the zones. 32 are of highly refractory oxide or other solid material that is not acted upon chemically by the liquid oxygen, whereas the walls of the zones 3| are of a high refractory carbide or other solid material that is not acted upon chemically by the liquid fuel, as propane or gasoline. Each wall may be strengthened against breakage and to prevent cracked pieces from dropping into the chamber C by a wire mesh or screen embedded near the outer surface of the refractory inner wall as shown at 52a (Fig. 2).

The thicknesses of they two kinds of refractory inner areas are directly as their thermal conductivities, in order that the poorly conducting layer 21 outside of these refractories may be heated evenly throughout and will not tend to melt at particular points. This layer 21 serves to reduce the temperature in the jacket spaces containing the oxidant and the fuel, and avoids overheated places where the liquids might produce gas bind by boiling, The thin metal wall 26 has a high melting-point.

The thickness of the layer 21 of poor heat conductivity is such that the two liquids in the outer jacket are not heated above a maximum permissible amount. The thickness of the layer 21 over each jacket space is thus inverse to the heat capacity of the flow in the jacket, as well as to the boiling point of the contained liquid. A light filler material 53 (Fig. 2) having considerable compressional rigidity may be inserted between the jacket spaces and the outer casing 20.

The metal wall 28 (Fig. 2) supports the outward chamber pressure on the inside, and the inward feed pressure in the jacket space on the outside. Since the feed pressure exceeds the chamber pressure by the amount necessary to force the liquids through spray devices to be described, the supporting varies or partition members 30 are required to prevent collapse of the wall 28 and the parts inside it.

The varies 36 are made in short sections and are set at such angles that they do not interfere with normal flow in the jacket spaces. as shown in Fig. 4.

The tangential flows across the areas 3| and 32, which are normally incandescent, are chiefly to protect these surfaces from chemical action by drops or small portions from the coacting liquid sprays. As these fiows constitute an appreciable fraction of the total propellant load, the mixing and burning of these liquids should be accomplished to the best advantage. For this purpose, the films of liquid near the boundaries of the zones are directed substantially parallel to the concave surfaces and move in opposite directions for adjacent zones, so that they impinge at an angle of closely and thereafter expand slowly toward the middle of the chamber but do not tend to escape prematurely through the nozzle.

To obtain these results-'`the` edges ofthe zones may be provided with curved grooves 51 (Fig. 7) and the impact along the edges of adjacent zones or wall surfaces 3| and 32 is between two different liquids or fluids. Also, the high temperature of the wall surfaces 3| and 32 isA conducive to good mixing and combustion, first, because the tangential speed along the surfaces will bev high, as the viscosity present when a liquid passes along a cold surface will be absent; and second, because the two liquid sheets will become at least in part high temperature gases which will ignite with ease.

An alternative construction is shown in Fig. 8, in which the zones are in the form of annular zones or surfaces of revolution 60, these zones being preferably of equal width and giving impact of opposite spray sheets at the zone boundaries. The zones 60 are concave and have a small radius of curvature compared with the radius of the chamber as a whole. Each annular zone BIJV (Fig. 8a) has a raised metal band 6|, 10W and streamlined and containing holes 62 which direct streams along meridians of the chamber C. Spray devices 64 (to be described) are located at intervals along the band 6|.

The outer casing 65 terminates at the'lower part of the chamber instead of at the open end of the nozzle, and may be reinforced by a ring or flange 66.

A preferred form of spray device is shown in Figs. 9 and 10. A convex deilector member I0 is threaded to a tube l| so that the edge of the member 'i0 is flush with the inner surface of the wall areas 3| or 32. This deflector member 1|] is provided on the inside with three or more arms 12 around the orifice opening, which arms serve to axially center a tube '|3 but leave it. freely spaced with respect to a circular opening 14. The deflector member 'EG may be tightened on the tube il by means of a spanner, the pins engaging small recesses ma (Fig. 9b) in the face of the deiiector lll.

Spray openings 'l5 in the member 1E] admit tangential streams of combustion liquids of one kind or the other, which form protective films over the wall areas 3| and 32.

This tube 'i3 (Fig. 9) is threaded at 1S to a sleeve on the inclined partition 35 or 36 and has a constricted upper end portion ll, within which is a deflector 'i8 (Fig. 10) on an axial rod 19. This rod is threaded in a block Bil having arms 8| forming a spider in the tube 13, and is kept strictly axial at its upper end by three or more spacing arms 82, integral with the inner wall of the tube i3. Both sets of arms 8| and 82 are thin and streamlined. The deilector 'i8 is recessed or concaved on the upper or chamber side, so as to be of substantially uniform thickness and to conduct heat readily to liquid passing across its face.

The orifice edges where the conical sheets are formed are curved so as to be streamlined, and one of the combustion liquids leaves the spray device through the annular orice 84.

The outer edge of the inner tube i3 is expanded so as to throw a thin conical spray sheet of a second combination liquid, preferably having substantailly the same angle as the spray sheet produced by the inner deflector i8. For spray devices in adjacent zones, the compositions of the sprays will be reversed. The working edges of the parts 13 and 18 are grooved as shown in Fig. 1U, and these grooves are staggered in the two edges. Two at filament cones 86 and 8l (Fig. 12) are produced by this groove arrangement and by the angles of the deflectors. Fig. 12 also shows a section of the inner facing 25 of theA chamber, as well as a tangential film 88 of the second combustion liquid on this surface., The filaments 8l are slightly nearer the chamber wall than the laments 86.

This arrangement is important, as it ensures that the tangential lm S8 of combined liquids' of the second combustion liquid will be surrounded by vapor of the filaments 81 which are of the same chemical composition, thus preventing combustion and excessive heat along the chamber wall. Also, the filaments 86 and 81 are traveling in the same direction and do not mix to any great extent while thus traveling parallel, but nevertheless mix very thoroughly when adjacent sprays impinge.

The composite sprays, being liquids or cool fluids, take up latent heat more than they supply heat, and thereby protect the chamber wall. The mixture is thereafter forced away from the wall and toward the middle of the chamber. This cooling of the wall and simultaneous thorough and substantailly instantaneous mixing, is very important and the attainment thereof is a chief object of the present invention.

An alternative form of slots or grooves in the lips or edges 13a and 18a is shown in Fig. 13, the ports 13a' and '18a being relatively close together and the slots and 9| being rectangular and narrow. These may be used when very close grouping of the filament streams is required, so that very intimate mixing takes place when adjacent sheets impinge. The resultant lilaments travel in converging sheets which are relatively disposed generally as shown diagrammatically at 92 and 93 in Fig. 14.

The spray devices above described introduce into the combustion chamber all of the oxidant and fuel liquids. They provide a liquid film and thin, corneal sheets of liquids interposed between the intensely heated interior of the chamber and the wall surfaces of the areas 3| and 32, thus protecting the latter from excessive conduction,

convection and radiation. These liquids are not number of alternately arranged laments or stri- Y ations. When these conical sheets impinge, they immediately break up and mix very thoroughly by the simultaneous impact of a large number of these filaments.A VThe surface of each conical sheet or spray system which is adjacent to the wall area consists preponderantly of the same liquid as that in the thin tangential film which is in contact with the wall surface. These spray devices project but a short distance into the interior of the chamber and present a minimum of resistance to flow along the chamber wall.

In general, the oxidant and fuel liquids, up to the time they pass out of the spray devices, will Vbe at different temperatures, since most liquid oxidants and many liquid fuels of high energy are very cold at ordinary tank pressures. Hence the parts of the spray device structure -which are between two different liquids is preferably made with a thin but appreciable air space to reduce the heat conductivity. Such spaces are shown at 95, 96 and 91 in Fig.. l0. Small studs 9B are used at intervals on one of the adjacent walls to prevent collapse of the narrow low pressure space due to high outside pressure. A layer of air 0.001 thick has a substantial heat-insulating effect.

The partitions 35 between the different jacket spaces are preferably inclined in order to simplify the construction and installation of the spray devices, making it possible to use straight tube parts only in the construction of the deflector members. Fig. 9 shows one of the devices when the oxidant is introduced through a passage inside the fuel passage, and Fig. 9a shows the device when the oxidant is introduced through a passage outside of the fuel passage. partitions 3l (Fig. 7a) are used between the ends of adjacent sections of the partitions 35 and 36 in order-to keep the jacket spaces separated.

An alternative spray device to be used when the partitions between adjacent jacket spaces are in radial instead of oblique planes is shown in Fig. l1. This partition |10 is of somewhat simpler construction than the inclined form, but

an elbow IUI is required for each spray device.m

Cross are here everywhere close together, but the distribution is obviously less heterogeneous' than that shown in Fig. 11. rfhe chemical nature of the tangential nlm itil passing along theA surface of the wall 25 is the same as that of the sheet |63, as in the preferred form.

The spray device shown in Figs. to 17 comprises an outer tube iii nXed in an inner chamber wall a, an inner tube EH, inclined spacing arms H2, and a center deflector ||3 having inclined fins or arms i le. Concentric conical spray sheets are produced by centrifugal force by this device but with less intermingling across the section of the sprays than with the arrangement shown in Figs. 9 and 10. This construction is of advantage when the flow through the spray orices is small, so that the frictional resistance of a delector would be very appreciable. The protective film |84 (Fig. 18) adjacent the wall surface 25 is provided by spray openings H5 (Fig. 15).

n Figs. 5 and 6 I have shown a modified nozzle construction. The nozzle N projects beyond the casing |2 and comprises a thin inner layer |2| having a high melting point and backed by a layer IEE (Fig. G) of heat-insulating material, like asbestos paper, or magnesium oxide cement. Outside of this is a metal wall`l23 having as good thermal conductivity as possible. The wall |23 may have a comparatively low melting point, as n the temperature in the jacket sp-ace WeA is kept below the boiling point of the liquid. This wall |123 is held from collapse inwardly by varies |25 placed in the direction of flow in the jacket space. A jacket casing ia encloses the jacket space |24.

The tangential holes |255 which lead fuel into the chamber and nozzle spaces, close to the walls, here have side walls or sleeves |21 which are of the same metal as the nozzle and which are fastened to the outer metal wall |23. Additional small tangential holes Zla are made in the inner Wall |2|, which holes allow the pressure to be equal on both sides of the wall EEI without at the same time introducing resistance to tangential flow along the wall.

The advantages of this modified construction are as follows; The inner metal wall |2| maybe thin and may be at red heat or hotter, as it is not under stress because of the equality of pressure on the two sides owing to the holes i2?. temperature is of further advantage in not removing an excessive amount of heat from the combustion gases as they pass by the lower part of the chamber and out of the nozzle. If the holes |26 are sufficiently closely distributed, the inner face of thel wall lli will be protected by a film of fuel and fuel vapor, and a very high melting point inetal, as tungsten, may be used, because of this reducing atmosphere.

Further, the jacket wall |23, being protected against excessive heating by the heat insulator |22, will not tend to develop hot spots but will carry heat to the liquid in the jacket rapidly and can everywhere witl'istand safely the jacket pressure. Preferably the heat-insulating layer |22 is very thin, so that the heat flow to the jacket may be large. it may consist of a thin coating of .heat-proof enamel or of thin porcelain or carbon rings.

With the thin wall l2| capable of withstanding a high temperature and having considerable thermal resistance, with the heat insulating wall |22 thin, and with the wall E23 somewhatr thicker but still comparatively thin, the entire composite wall will be equivalent to a single metal wall of The high high melting point and high heat-resistance and of about the same thickness. The composite wall will have the advantage of permitting the inner surface to become red hot or incandescent without danger of weakening the jacket Wall or of boiling the jacket liquid, and it will also have the advantage that a major part of the wall consists of a metal |23 of comparatively good thermal conductivity.

With my improved construction, intimate mixing and high internal chamber temperatures are produced by the impact of liquid filaments of alternative composition, arranged in close order and causev to impinge and to then pass at moderate speed toward the center of the chamber. The chamber wall is everywhere shielded from internal heat by the screening effect of these filaments. Chemical action on the inner wall of the chamber and temperatures high enough to soften the surface are avoided by tangential flow and film formation at all points of the surface by a liquid that is inert 4with respect to the material of this surface. Heating of the surface is further avoided by having the liquid of the tangential flow of the same chemical nature as the preponderant liquid of the spray sheet next adjacent thereto.

The details of construction of the jacketed nozzie are not claimed herein but form the subject matter of a divisional application Serial No. 137,111, led January 6,

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 a combustion apparatus, a combustion chamber having an inner surface subdivided into zonal areas separated by interposed raised portions, a first plurality of devices to feed a conical sheet of combustion liquid to each zonal area and adjacent its inner surface, a second plurality of devices to feed a second corneal sheet of combustlon liquid to each zonal .area adjacent but outside of said first sheet of liquid, means to supply one combustion liquid to certain of said first plurality of feeding devices and to certain of said second pluralityy of feeding devices, and means to supply a second and different combustion liquid to the remaining feeding devices, and the areas receiving one liquid adjacent their inner surfaces being alternated with the areas receiving the second liquid adjacent their inner surfaces.

2. fn a combustion apparatus, a combustion chamber having an inner surface subdivided into zonal areas separated by interposed raised portions, ineens to supply superposed conical sheets of liquid fuel and liquid oxidant to each area, with the conical sheet adjacent the inner surface formed of one liquid in one area and of the other liquid in an adjacent area, and means to provide a tangential film adjacent said inner surface which is alwaysv ofthe same composition as the conical sheet next adjacent thereto.

3. In a combustion apparatus, a combustion chamber having an inner surface subdivided into zonal areas separated by interposed raised portions, and means to supply superposed conical sheets ofliquid fuel and liquid oxidant to each area, and said supply means having grooved directing portions which subdivide said conical sheets into a great number of radiating liquid filaments which intermingle at the raised edges of' said arcas and flow toward the center of the combustion chamber.

4. In a combustion apparatus, a substantially spherical combustion chamber having ,a discharge nozzle and having its inner wall formed Iwith a plurality of adjacent internal zonal surface areas separated by interposed raised portions and each surface area being concave at a radius substantially less than the radius of said spherical chamber, the edge portions of .adjacent concave surface areas meeting to form inwardly-projecting ridges, the concave inner surface areas of said inner wall adjacent said ridges having grooves extending toward said ridges and substantially perpendicular thereto, and means to supply tangential films of different combustion liquids adjacent said different surface areas, the grooves adjacent the ridges and substantially perpendicular thereto facilitating flow of said liquids toward the center of the combustion chamber and retarding iiow toward said discharge nozzle.

5. In a combustion apparatus, a combustion chamber comprising annular concave inner surface areas, adjacent areas meeting in circumferential ridges, means to supply tangential lms for said surfaces from near the middle circumferential portion of each annular concave area, and means to supply superposed circumferential layers of combustion liquids adjacent said tangential films, with the layer next .adjacent the iilm having the same combustion characteristics.

6. In a combustion apparatus, a combustion chamber having an inner surface subdivided into two groups of zonal areas, the material of which one group is formed being inert to liquid fuel and the material of which the second group is formed being inert to liquid oxidant, and means to supply superposed sheets of liquid fuel and liquid oxidant to each area but with the sheets of liquid fuel positioned adjacent the inner surfaces which are inert to liquid fuel `and with the sheets of liquid oxidant positioned adjacent the inner surfaces which are inert to liquid oxidant.

7. The combination in combustion apparatus as set forth in claim 6, in which the thickness of the inert materials in said two groups of Zonal areas is proportionate to their thermal conductivity.

ROBERT H. GODDARD.

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

UNITED STATES PATENTS Number Name Date 1,754,603 Brown Apr. 15, 1930 2,012,171 MacDonald et al. Aug. 20, 1935 2,153,175 Duiy et al. Apr. 4, 1939 2,164,225 Walker June 27, 1939 2,217,649 Goddard Oct. 8, 1940 2,286,909 Goddard June 16, 1942 2,313,994 Grant Mar. 16, 1943 2,354,151 Skoglund July 18, 1944

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