US 2990682 A
Description (OCR text may contain errors)
July 4, 1961 G. J. MuLLANl-:Y
FUEL CHARGE Filed Nov. '7, 1951 United States Patent O M 2,990,682 FUEL 'CHARGE George J. Mullaney, Burnt Hills, NY., assignor to General Electric Company, a corporation of New York Filed Nov. 7, 1951, Ser. No. 255,175 Claims. (Cl. 60-35.6)
This invention relates to a shaped charge of solid fuel for use in a rocket of the type which has a combustion support-ing agent separate and apart from the fuel itself. More particularly, the invention relates to a solid rocket fuel charge having a configuration to increase the turbulence of combustion gases in contact therewith, thereby increasing the efficiency of the combustion.
Many of the rockets presently being produced derive their thrust from the rapid combustion of -a liquid fuel such as alcohol with air oxidizer such as liquid oxygen. Rockets propelled in this manner require rather complicated apparatus to insure safe and efficient admixture of the liquid fuel with the oxygen. Solid fuels have also been used. Their use simplifies some of the control apparatus but makes more diicult the problem of obtaining etlicient combustion.
Accordingly, it is an object of this invention to provide a rocket having a solid fuel from which efficient combustion may be obtained.
It -is a further object of this invention to provide a rocket using solid fuel having a configuration to promote turbulence in the combustion gases making contact with the solid fuel whereby a more intimate admixture of the fuel with the combustion supporting agent takes place.
To this end, an important feature of the present invention comprises providing a rocket with a charge of solid fuel having a longitudinal passageway therethrough, the walls of said passageway having a plurality of spaced bal-'Iles composed of the fuel material which promote turbulence in fluids traversing the passageway.
Other objects and features will become apparent from a perusal of the following specification taken in conjunction with the attached drawing, wherein:
FIG. 1 is a sectional view of one embodiment of my invention; and
FIG. 2 is a sectional view of another embodiment of my invention.
Referring to either ligure, my invention may be seen to be comprised of a casing 10 having a front portion 11 and a back portion 12 separated by a central portion 13. Each of these three portions serves a different functional purpose, the front portion 11 being adapted for feeding a combustion supporting agent such as hydrogen peroxide through an opening 14. In operation the front portion 11 has `a container (not shown) for instruments and hydrogen peroxide or other combustion supporting agents attached thereto.
The back portion 12 of the casing 10 is equipped with a converging-diverging nozzle as shown in order to further aid in the eflcient combustion of the fuel and to accelerate the combustion gases to the optimum exit velocity. The converging-diverging nozzle is of the type normally used in the art.
The central section 13 of the casing 10 contains a solid fuel 15 which may preferably be polymerized ethyl` ene or a similar source of hydrogen yand carbon.
The casing 10 will normally have a cylindrical configuration but it need not necessarily be so. The cylindrical form is easy to fabricate and has a good contour for passage through air when the motor cylinder is used `as the outer surface of a missile. Whatever form the casing takes, the solid fuel 15 conforms on its exterior side to the interior walls of the casing 10. 'Ihe solid fuel 15 surrounds a longitudinal passageway 16 the walls of which Patented July 4, 1961 ICC are very irregular due to portions of the solid fuel 15 projecting into the passageway 16. While the solid fuel 1'5 could be machined in one piece to give it the appearance illustrated, it is preferable to fabricate it Ifrom several different sizes of stampings from sheet material.
The stamping technique above mentioned can best be applied to the embodiment illustrated in FIG. l. All stampings have the same outside dimensions but in one case the Wall thickness is not great as shown at 18 and in the other case the wall thickness is considerable as shown at 17, thereby enabling the alternate stampings to project some distance toward the center of the longitudinal passageway.
The front portion 11 of the casing 10 encloses a space wherein `decomposition of hydrogen peroxide takes place. This `decomposition reaction -is catalyzed by a series of screens 19 positioned in the decomposition space. Silver is a good agent for promoting the decomposition of hydrogen peroxide and the screen 19 may be fabricated either of pure sil-ver or of a base metal coated with silver. Copper, iridium land other metals are also satisfactory decomposition catalysts.
During operation, hydrogen peroxide, preferably of about purity, is passed through the opening 14 into contact with the screens `19. The silver at once decomposes the peroxide to produce a mixture of oxygen and steam at a temperature of about 700 C. This gaseous mixture then passes into the longitudinal passageway 16 where it comes into contact with the solid fuel 15. I have found that ignition of the fuel 15 commences very quickly and the gaseous reaction products build up a pressure within the passageway 16 which forces the products of combustion through the nozzle at the back end 12 of the casing 10. As pressure builds up within the passageway 16, the rate of combustion increases. The projecting portions 17 af the fuel charge promote turbulent flow of the gases supporting combustion and increase not only the frequency of contact between the gases and fuel 15 but also the contact area.
A fuel charge shaped in accordance with my invention has given an impulse as high as of that which can be obtained theoretically. It might appear that the projections 17 would be consumed more rapidly than the surfaces of the fuel 15 which do not project. I have discovered that this is not the case but that the entire fuel charge is consumed at a fairly constant rate irrespective of the type of surface exposed to the combustion supporting gases although there is a tendency for the sharp angles to become rounded. This shows that the turbulence introduced by the portions 17 is a satisfactory way to insure even burning of the fuel 15. At the same time the rounding of the sharp angles during combustion tends to keep the surface area of the charge constant during combustion.
The structure of FIG. 2 operates in a manner similar to that shown in FIG. l except that the fuel projections extend toward the front end of the casing 10, This introduces a slightly different turbulent flow pattern which also asures intimate contact between the gases which support combustion and the fuel.
The dimensions of the various parts illustrated in the figures depend entirely upon design considerations. For a rocket 5 to 6 inches in diameter designed to operate at 400 to 500 lbs. pressure, I have found a high-strength steel of about 1A: inch thickness satisfactory for the casing 10. For this size of casing, the turbulator rings 17 and 18 are satisfactory if fabricated from ethylene polymer of about 1 -inch thickness. This size of rocket will give a Z50-lb. thrust when operating on a solid fuel of the configuration shown in FIG. 1.
While the present invention has been described by reference to two particular embodiments thereof, it will be understood that numerous modifications may be made by those skilled in the art without actually departing from the invention. I, therefore, aim in the appended claims to cover all such equivalent var-iations as come within the true spirit and scope of the foregoing disclosure.
What I claim as new and desire to secure by Letters Patent of the United States is:
1. In a rocket driven by a solid fuel having a separate source of oxygen, a fuel charge defined by a peripheral wall of fuel encompassing a combustion chamber, the outside of said wall being cylindrical in configuration, said wall including inwardly extending annular baffles to increase the turbulence of gases passing through said chamber during combustion.
2. A rocket fuel charge as claimed in claim 1 wherein the baffles are perpendicular to the yaxis of the cylinder.
the spaced annular constrictions extend inward at an angle 3. In a rocket driven by solid fuel having a separate source of oxygen for sup-porting the combustion of said fuel, a Afuel charge comprising a plurality of rings, the outside diameters of said rings being equal and the inside diameters being of a small dimension and a large dimension, a small inside diameter ring being alternately spaced with a large inside diameter ring whereby said rings create turbulence in any fluid flowing through the interior space defined by said rings. 1
4. A rocket fuel charge as claimedkin claim 3 wherein the rings have symmetrical spatial configuration along their axis from either side. y
5. In a rocket driven by a solid fuel having a separate source of oxygen for supporting the combustion of said fuel, a fuel charge of cylindrical configuration having an axial passageway therethrough, the interior walls of said cylinder having a plurality of spaced annular constructions to promote turbulence in fluids traversing said passageway.
6. A rocket fuel charge as claimed in claim 5 wherein normal to the walls of the cylinder.
7. In a rocket motor driven by a solid fuel having a separate source of oxygen for supporting the combustion of said fuel, a fuel charge composed of combustible material the walls of which define a longitudinal passageway, said walls including a plurality of straight-sided spaced inwardly extending bafiles to create turbulence in gases passing through the passageway during combustion of said fuel charge. e
8. A rocket comprising an elorlgelstegl'gzgngghayigxgg central section dening alwfuelmcwamwer, a lfront end and a back= end;meatiis'fifitroducinga combustion supporting substance through the front end of said casing, a goggle ositioned in the back endf'siils'iighhdwa solid iuel pos1t1'oned'1e centl'usection of said casing, said solid fuel having `a longitudinal passageway extending therethrough, spaced portions of which are -constricted by projections of said fuel extending into said passageway normal to the direction of flow therethrough.
9. A rocket motor as claimed in claim 8 wherein said elongated casing is of circular cross-sectional configuration.
l0. A rocket motor as claimed in claim 9 wherein the projections extending into the passageway are of annular configuration.
Referenc'es cited in the me of this patent UNITED STATES PATENTS 1,901,852 sioifa et a1 Mar. 14, 1933 2,406,560 Pope Aug. 27, 1946 2,434,652 Hickman Jan. 20, 1948 2,510,147 Skinner June 6, 1950 2,607,191v Lee Aug. 19, 1952 2,684,570 Nordfors July 27, 1954 FOREIGN PATENTS 570,210 Great Britain June 27, 1945