US2881588A - Injector and method for fuel injection - Google Patents

Description

INJECTION 2 Sheets-Sheet 1 W. H. GOSS INJECTOR AND METHOD FOR FUEL Aprilv 14, 1959 Filed April 27, 1948 INVENTOR. WILBUR H. GOSS ATTORNEY Apli114., 1959 w. H. Goss l 2,881,588

INJECTOR AND METHODLFOR FUEL. INJECToN 2 Sheets-Sheet 2 Filed April 27, 1948 INVENToR.` wlLauR H. Goss Y ATTORNEY United States Patent() 2,881,588 INIECTOR AND METHOD FOR FUEL INJECTION Wilbur H. Goss, Silver Spring, Md., assigner to the United States of America as represented by the Secretary of the Navy Application April 27, 1948, Serial No. 23,478 3 Claims. (Cl. 6039.74)

The present invention relates generally to the art of guided missiles of the ram-jet type, and more particularly to an improved injector and method for fuel injection.

In down-stream and trans-stream fuel injection systems for ram-jets in use up to the time of the present invention, the maintenance of the desired rate of fuel injection is made difficult by variations in the back pressure against which the fuel is injected. Moreover, fuel injection lateral to the air stream or parallel thereto is subject to wide variations in static pressures. This is particularly disadvantageous, for example, when the burning etliciency in the combustion chamber of the missile momentarily decreases, immediately lowering the static pressure and thus introducing a transient pressure disturbance in the fuel system.

Another disadvantage for down-stream and transstream fuel injection systems is their requirement for high pressure atomizing nozzles which often clog with dirt and become inoperative.

One of the principal objects of the present invention, therefore, is to provide a fuel injector and method of fuel injection wherein, by utilizing the differential velocity between an air stream passing through the missile and a stream of fuel injected against said stream, substantially complete fuel atomization will be effected, so that optimum fuel burning in the combustion chamber will take place and maximum thrust by the missile therefore produced.

Another object of the invention resides in the provision, in a fuel injection method and apparatus for ramjet missiles, of simple orifices having relatively large exit areas opening against the air stream, with the result that the need for high pressure atomizing nozzles will -be obviated and that clogging by dirt or vother foreign matter will be eliminated.

And a further object of the invention is to provide a fuel injector and injection method for the purpose set forth wherein maximum area distribution of fuel (penetration of fuel lateral to the air stream) will be effected.

Other objects of the invention will appear from a reading of the following description.

In the drawings:

Fig. 1 is a side elevation, partly in section and partly broken away, showing a fuel injector according to the present invention as it would appear installed in a missile;

Fig. 2 is a perspective view of the injector, a portion of the missile being shown fragmentarily;

Fig. 3 is a front elevation of the injector;

Fig. 4 is an axial section on the line 4-4 of Fig. 3;

Fig. 5 is a detail section on the line 5--5 of Fig. 3;

Fig. 6 is a diagrammatic view showning the pattern of fuel discharged from a nozzle of the type in use up to the timel of the present invention; and

Fig. 7 is a diagrammatic view showing the improved pattern of fuel discharge in a ram-jet missile equipped according to the present invention.

Considered briefly, the fuel injection method, according to the present invention contemplates introducing fuel into a ram-jet missile, through simple,.relatively large orifices, against, rather than across or along,l the stream of air passing through the missile to mix therewith to form a substantially completely atomized combustible mixture. The apparatus consists of an injector which is placed in the ram jet missile near the mid portion thereof and with the windshield employed disposed toward the forward end of the missile. Fuel under pressure is led from an annular tank in the missile to a fuel -chamber formed in the windshield and led to orifices in radially disposed struts for discharge from the leading edges thereof. The combustible mixture produced by the admixture of the fuel and air is ignited by a burning iiare carried on and forming a part of the igniter;

Referring to the drawings in detail, the injector of the invention is indicated generally by the numeral 10. The injector 10 includes a ring 11, a windshield 12 and faired struts 13 connecting the windshield and ring. The ring, windshield and struts are interconnected by welding so as to provide a rigid, unitary structure, and said ring is clamped in place for mounting the injector in the combustion chamber of a ram jet missile. More specifically, the ring 11 is clamped between the adjacent ends of the inner body sections of the missile by cooperating flanges and tie bolts, as best seen in Fig. 1. The struts 13 are shown as being four in number but it should be understood that a greater or smaller number may be used, as desired.

As best seen in Fig. 4, the windshield 12 is formed with a chamber 14 which is closed at its rear end by "a wall 15, welded in place in an annular groove. The wall of the windshield is provided, rearwardly of the wall 15, with an enlarged, internally threaded socket 16 to receive the threaded neck of a flare holder 17 (see Fig. 2). Flare holder 17 houses a suitable llare for igniting the air-fuel mixture.

The windshield is formed with a tapered nose 18 hava relatively large, axially located fuel inlet 19, which communicates with the chamber 14. Asseen in-Fig. 1, a fuel inlet pipe 20 is fitted in the inlet 19 of the nose 18 and supplies fuel to the chamber 14 from a tank 21. Obliquely disposed orifices 22 are formed in the tapered nose 18, near its forward end, said orifices being arranged in an annularly spaced series, and communicating with the chamber 14. Pour of the orifices are shown but it should be understood that a greater or smaller number may be provided, as needed.

Openings 23 are formed in the side wall of the windshield 12 near the wall 15 and register with bores 24 in the struts 13 near and parallel to their leading edges. The bores 24 extend radially throughout substantially three-fourths of the lengths of the struts and terminate at their outer ends in forwardly (upstream) presented discharge orifices 26 which communicate with the interior of the projectile.

In operation, fuel is supplied to the chamber 14 through the pipe 20 from the tank 21. A pressure system, which includes a helical compressed gas storage tank 27, insures optimum fuel flow from the tank 21. The pressure system forms no part of the present invention. Fuel is discharged against the airstream flowing through the duct of the missile 25, through the orifices 22 and 26, .and is mixed with air in said stream to provide a combustible mixture for ignition by the flare holder 17.

Reference is now had to Figs. 6 and ,7. Fig. 6 discloses diagrammatically a fuel injection system as arranged prior to the present invention. Fuel is injected downstream by an injection nozzle, in a cone of relatively small diameter, with the result that sufficient fuel atomization and vaporization will not take place without thm-use of high pressure. atomizing nozzles. Moreover, transient pressure, disturbances. im the. fuel. system are. introduced, by momentary decreases in combustion eiciency in the combustion chamber, which lower the static; pressure;

even though there may be widevariations in. static pressures-.- Attentionis called tothe factthat area distribution of fuel (penetration of fuel lateral tothe air stream.) at. anyvpoint downstreamv of the injector is broader. with the.

arrangement shown iny Fig.. 7v than with that shown in.

Fig.6,Y and the need: for: high pressureinjection nozzles, withftheir need for frequent,` cleaning, is obviated. More over, the; need:y for. apparatus requiredto generate thepressures., necessaryv for. the operation ofl high pressure atomizing;- nozzles which. apparatus. is cumbersome and space consuming, willv be dispensed with.v

Whilefthere hasbeen` shown and described what is at presentconsidered tobe a preferred embodiment of the' presentinventiomitwill be obvious to those skilled in the artthatvarious changes. and modiiications may be madethereinwithout departing from the true scope there of, and it is, accordingly, intended in the appended claims;4 to.- cover all such changes and modiiications as fall withinA the true scope. of. the. invention and without the proper scope of the prior art.

What is.c:laimedis:

1.. In. aguided missileof theram-jet ytype having anair stream owing therethrough when, ini flight; inv combination, azfuel injector having, a chambered windshield and at least-one.aperturedstrut,.means.for conducting fuel toxthe windshieldfor dischargetherefrom and from the strutin a direction contra to said streamflow, and

means for mounting the. windshield, the leading edge of said. strut. confronting, said. air stream. ow whereby fuel discharging from said windshield and strut contra to said air stream flow will entirely mix with said air stream to produce a uniform combustible mixture.

2. A fuel injector for a ram-jet aerial missile having air ow therethrough when in. ight, comprising a frame having a are holder, a Windshield connected to said flare. holder, a supporting ring, struts connecting? said windshield and are holder to said ring, said windshield and said struts havingV fuel dischargeY jets for injecting liquid fuell in a direction contra to said air ow in said missile, and means for conducting fuel to said jets' for discharge therefrom. into andV against said air flow through said missile.

3. A fuel injector for a ram-jet aerial missile having an air stream flowing therethrough when in ight, comprising, a body having a frame comprising a ring, a hollow Windshield, hollowstruts connectingl said. ring,A with said windshield. and having fuel discharge jets: disposed toward the air stream inlet end of said missile, and af manifold for leading fuel to said. struts and. windshield, whereby said fuel isinjected into said. air. stream in a: direction contrato the direction ofiiowofsaidrair stream;

References Cited in the iile of this patent;

UNITED STATES PATENTS 799,856 Lemalez.. Sept. 19, 1905 1,678,086 Schrader July 24, 1.928 2,221,995 Parrigin Nov. 19, 1940 2,404,1134- Whittle.. luly 16,. 1946V FOREIGN PATENTS' 331,292 France. Iuly 24, 1903. 439,805 Greatv Britain Dec. 6,` 1935 y 920,910 France Jan. 8,. 1947

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