US3136126A - Ignitor - Google Patents

Description

2 Sheets-Sheet l IGNITOR R. C. MILLIKAN m w m MP w/ ,MM f Am E Uma-Seconds /nvenor Roger C, Mf///fan,

by Ma/ fs Afforney.

June 9, 1964 Filed Feb. 1:5, 1961 F ue/ and r, 02I/a/ves Open June 9, 1964 R. c. MILLIKAN I 3,136,126

1GN1T0R Filed Feb. 13, 1961 2 sheets-sheet 2 Fig. 4

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Ooooooooooo /nvemon Roger C. M/'l/fkan,

3/ l by ma United States Patent O 3,136,126 IGNITR Roger C. Millikan, Schenectady, N.Y., assigner to General Electric Company, a corporation of New York Filed Feb. 13, 1961, Ser. No. 89,045 8 Claims. (Cl. 6t--39.82)

This invention relates to a high altitude repetitive detonator fuel ignitor and, more particularly, to a method and apparatus utilizing repetitive detonations to supply charges of high temperature gas as fuel ignition means, and is a continuation-impart of copending application Serial No. 666,727, filed June 19, 1957, now abandoned, and assigned to the same assignee as the present invention.

A repetitive detonator may best be described as an apparatus which burns fuel in a continual series of detonations to provide a definite supply of hot gases, and may be gainfully employed, for example, as an ignitor for initiating further combustion, as a tool for the study of combustion processes, or wherever a supply of hot gases may be required. One example of a particular application where the hot gases provided may be employed to aid or commence a combustion process, is a jet engine main or afterburner fuel system ignitor or the main fuel system ignitor.

The exhaust stream of a jet engine is generally described as a mass of turbulent high temperature gases moving through the exhaust at high velocity. Fuel may be introduced into this stream for further burning and increased thrust, a process which is referred to as afterburning. The turbulence and velocity of the exhaust gas stream is dependent on such variables as the rate of fuel consumption, the speed of the jet aircraft, and the altitude of the aircraft. With the stream velocity and turbulence reduced, and with the pressure in the gas stream near atmospheric, it is apparent that fuel introduced into the exhaust may be readily ignited by means of a simple spark ignition device such as the well-known spark plug, and the like. On the other hand, with a jet aircraft iiying at high altitudes and at increased velocity, the combined elements of the high gas velocity and turbulence, together with the low atmospheric pressures at such altitudes, lead not only to the loss of flame or flame blowout, but also to extreme difficulty in commencing a flame with a sparkling device such as a spark plug. The spark obtainable from a spark plug is generally of limited duration and of limited heat release, and the small volume ignition obtained is easily snuffed or dissipated in the turbulent gas stream. On the other hand, a repetitive detonator providing a series of charges or volumes of high temperature luminous reacting gas supplies the kind of volume or thermal reaction source necessary not only to initiate but to maintain and disperse the combustion process.

The main combustion chambers of a jet engine receive air from the compressor. After a high altitude iiame-out, the compressor, under windmilling conditions, supplies only low pressure, low temperature air to the combustors. These conditions present reignition problems and the repetitive detonator also serves electively as an ignitor for this system.

Accordingly, it is an object of this invention to provide an improved ignitor for jet engines, particularly at high altitudes.

It is another object of this invention to provide an improved jet engine ignitor in the form of a hot reacting gas generator.

It is yet another object of this invention to provide an afterburner ignitor wherein initial burning takes place in an enclosed area.

It is a still further object of this invention to provide an 3,136,126 Patented June 9, 1964 improved ignitor for fuel in jet apparatus under low pressure, high turbulence conditions.

Briefly described, my invention in one form includes the introduction at predetermined flows of detonable fuel and oxidizer into the closed end of a combustion tube or chamber having one closed end and one open end with a critical flow restricting opening forming the open end thereof, which tube is proportioned to promote detonations, and igniting the mixture formed thereof at a point removed from the closed end. In this manner, a first detonation wave is caused to move through the tube toward the open end of the tube to expel a charge of high temperature reacting gases from the open end into a turbulent high velocity and/.or low pressure gas stream containing a combustible mixture and a second detonation wave is caused to move through the tube toward the closed end temporarily restricting further admission of fuel and/or oxidant.

The term critical flow as employed in this specification refers to that set of conditions of mass iow of a gas through a flow resistor such that this How occurs at the sonic velocity of that gas. As will be fully explained below, a prerequisite to the practice of this invention is the provision, in combination with a combustion tube proportioned to promote detonation burning, of flowrestricting means located at the exit thereof and means for balancing the rate of inflow of gasses into the tube against the predetermined leakage rate through the flow-restricting means whereby this critical liow condition may be created.

These and various other objects, features, and advantages of thisinvention will be better understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a schematic representation of one basic form of this invention employed as an ignitor;

FIG. 2 is a modification of FIG. 1 adapted as a high altitude ignitor;

FIG. 2a is an enlarged View of the nozzle 22 of FIG. 2.

FIG. 3 is a diagrammatic representation of two cyclic operations of this invention;

FIG. 4 shows the basic ignitor of FIG. 2 when employed as a jet engine afterburner ignitor;

FIG. 5 shows the basic ignitor of FIG. 2 coaxially mounted in a fuel inlet of the main fuel system; and

FIG. 6 shows the basic ignitor of FIG. 2 in a combustion chamber separate from the fuel inlet.

Referring now to FIG. 1, there is illustrated a detonating device or ignitor 1 including a combustion tube or chamber 2 with a closed end mixing section 3 and an open end 4. While various types of fuels and methods of introduction may be employed, one preferred form of this invention is disclosed as utilizing C21-I4 (ethylene) as the fuel, and oxygen as the oxidizer, and introducing the ethylene and oxygen in gaseous form separately by means of inlet tubes or feed lines 5 and 6. Inlet tube 5 projects within section 3 and introduces oxygen into the closed end while inlet tube 6 introduces ethylene into the side of section 3 at a point below the projecting tube 5. The particular arrangement of fuel-oxidant delivery as disclosed has been found to give satisfactory mixing. However, other methods of fuel delivery such as parallel tubes connected to the bottom of section 3, or a single tube supplying a predetermined mixture of ethylene or oxygen or other fuels, may be utilized with good results.

As the ethylene and oxygen are introduced at a predetermined rate, the resulting mixture flows through combustion tube 2 toward the open end 4. In order to commence combustion of this mixture, an ignition device such as a spark plug 7 is positioned in the tube 2 adjacent the midpoint of the tube length. As the fuel mixture apoxidant'pair and the length and diameter of the combustion tube. In the iirst instance, it is desirable to employ a quick-burning, high heat release fuel-oxidant combination, characteristics particularly associated with detonable mixtures. Secondly, the combustion tube 2 diamete must be limited in order to restrict the expansion of the burning fuel within detonable limits. Finally, it should be noted that the initial burning of fuel generates what is commonly referred to as a combustion wave, which, while progressing through the tube, forms a build-up of a high pressure wave immediately preceding the combustion wave. The high pressure wave formed becomes closely associated with and a part of the combustion wave, and the combination is thereafter termed a rdetonation wave. It should be apparent, therefore, that the combustion tube E should be of a suiiicient length to permit formation ofa detonation wave after initial combustion. The combustion process as described is differentiated from the process generally associated with the well known pulse jet engine in that the pressure ratio across the combustion zone is on the order of :1, while in the pulse jet, this pressure ratio is approximately unity.

The voltage charge to the spark plug 7 is sequentially timed with respect to the fuel admission to generate a spark after the detonation wave in the inlet section has dissipated and a fresh charge of fuel is introduced to iiow beyond the spark plug 7 toward open end 4. The device then becomes repetitive in the detonation process until voltage to spark plug 7 'is stopped. Sequential timers such as that illustrated schematically in FIG. 1 (8) are well known in the prior art and merely comprise means for supplying voltage impulses at regulable intervals of time. Various other forms of ignition, such as flame and glow plug ignitors, as are well known in the art may be employed in place of spark plug 7. A study of this process as described for the detonator reveals that oncev each cycle a detonation or shock wave propagates a jet of hot luminous gas which extends two or more inches beyond the tube open end 4.

The detonation wave moving toward theVfuel-oxidant inlets may be employed as a shut-off means. Since neither ethylene nor oxygen will sustain combustion in their individual pure form, the detonation wave will dissolve in a pressure wave or pulse, moving into the inlets at a pressurew hich is higher than the fuel-oxidant inlet pressures and, accordingly, before dissipation, temporarily restricts further fuel-oxidant admission to the combustion tube 2. The detonation wave moving toward and out of open end 4 expels a charge of high temperature gas from the open end l of the combustion tube 2.

In one preferred form of this invention, a combustion tube 2 having a diameter of 1A inch, and a length of v36 inches, together with an ignition device positioned approximately 2/3 the length of the combustion tube from the open end 4 operates quite satisfactorily as above described with a mixture of oxygen and ethylene as fuel.

It has been discovered that such repetitive jets of hot reactant gas may serve as a useful ignition source for jet engines where conditions may be such that spark ignition of fuel mixtures is diflicult, for example, in the operation of jet engine combustion systems at high altitudes where the low ambient pressure and the high degree of turbulence make ordinary spark ignition ineffective. high altitude operation as a combustion system ignitor, the open end 4 of the combustion tube 2 is fitted With an orifice, iiow restrictor, or nozzle 9 to restrictthe exiting of the gases and thereby maintain at pressure in the combustion tube 2 greater than the ambient low pressures associated with high altitudes, and thus contribute tothe For Y 4 etiiciency of the spark plug operation. The exit area of nozzle 9 must be chosen in relation to the incoming gas low so as to cause an internal buildup of pressure in tube 2 prior to ignition. A more detailed description of the salient features and required operative principles of nozzle 9 in conjunction with fuel-oxidant inlet is described in relation to FlG. 2 When an orifice is described as being a critical iiow orifice, this means that the orifice is one through which gas liows at sonic velocity when the pressure on the upstream side thereof is at least two (2) times the pressure on the downstream side.

Referring now to FIG. 2, the ignitor assembly l0 includes the basic form of ignitor l as illustrated in FIG. l, together with a modilied form of fuel-oxidant and pressure control system. The fuel-oxidant system includes a fuel tank ll connected by a fuel delivery line S to the i. Line 5 also includes a pressure regulator l2 next adjacent tank Trl. and a critical flow orifice 13 next adjacent pressure regulator l2. Delivery of fuel to the ignitor l is controlled by a solenoid valve lid for on-off operation. Similarly, an oxidant tank 15 is connected to ignitor l by means of lineV 6. Line 6 also contains a pressure regulator le next adjacent oxidant tank l5, a critical iiow orifice 17 next adjacent pressure regulator le and a solenoid valve lf next adjacent critical flow orifice i7. It is thus understood that a predetermined flow'rate of fuel and oxidant is established'at a given pressure. Solenoid valves ltdand i8 may be interconnected in order to be simultaneously operated by interconnecting means broadly indicated as i9, and solenoid 2u. Solenod valves le and ld are actuated by any suitable timer control means 2l which provides timed operation of fueloxidant delivery together with a spark impulse to spark plug 7l. lt is understood that the timer and power supply 2l may also be employed to provide spark impulse to spark plug 7, or that a separate timer and power supply 3 (FIG. l) may be employed to provide the spark irnpulse to plug 7. The two timer and power supplies 2l and 8 are interconnected so as to supply the spark to spark plug 7 in detinite time relationship to the operation of valves le and ln order to maintain proper pressure conditions for high altitude operation, ignitor l is equipped with a nozzle 9, FlG. l, or more particularly, a flow restrictor or orifice 22. By means of orifice 22 in combination with critical flow orifices 13 and l', pressure in tube 2 isY maintained at a predetermined amount regardless of the ambient pressure in the combustion system at various altitudes. An enlarged View of oririce 22 is illustrated in FIG. 2a.

An orice type of control rather than an open-close type of valve is necessary because of the Very high temperature in the ignitor and the need to avoid quenching the reacting gas. Any blockage of the opening in the form of an open-closed type valve will not suice because the nozzle, in the first instance, must provide proper ilow of a fuel-oxidant mixture, must be capable of passing high temperature, high velocity gases resulting from detonation in the form of a luminous stream extending into a combustion chamber without quenching and, therefore, must be in effect out of the path of the hot gas stream or otherwise it will be rendered useless by burn out in a short period of operative time. In additiomin order to operate the ignitor of this invention as a high altitude fuel system ignitor, the pressure in tube Zis critical. The ignitor as described is effectively operated with a nozzle or orifice opening 22 in one end which will under various and varying altitude conditions provide the proper pressure rise for effective detonation while, at the same time, being also effectively out of the path of the emitting hot gas stream. Flow conditions must be and are balanced relative to fuel-oxidant introduction and predetermined leakage out of orifice 2,2.' Orifice 22 is referred to as an open orifice or flow restrictor indicating it is not of the open-closed type.

The particular constructive features and interrelation vof lk to 1, the orifice 5 of pressure rise together with orifice operation in this invention are best described in relation to a working embodiment thereof. Tank I1 contains CZH., as a fuel and tank 1S contains oxygen. Pressure regulator 12 limits the C2H4 fuel pressure to about 44 p.s.i.g. and regulator 16 limits the oxidant pressure at about 63 p.s.i.g. The diameter of the critical flow orifices 13 and 17 are .020 inch and .O32 inch, respectively. The diameter of the exit nozzle or orifice 22 is .090 inch. Under these conditions, (22H4 ows into line 5 at 450 cc. per second, and oxidant into line 6 at 150 cc. per second, to provide a stoichiometric mixture. The total flow of 600 cc. per second into the ignitor can only be passed out of orifice 22 when the internal pressure in tube 2 is or reaches about 14 p.s.i.a. Although the incoming mixture is continually leaking from orifice 22, it only does so at a much slower rate than the incoming mixture. Consequently, the pressure in tube 2 rises until the flow from the .090 orice (22) just equals or balances the incoming flow from orifices 13 and 17.

The time required to reach this steady pressure depends on the relative flow rates in and out of the ignitor and also upon volume of the tube. In this instance, the tube length was approximately 43 inches with a 3/8 inch O D. and .035 Wall thickness. Volume is 50 cc. With these dimensions, the time required for steady flow conditions is about .25 second.

The exit orifice 22 operates under critical flow conditions (i.e., the flow through it is independent of the pressure outside) for all outside pressures up to about 1/2 tube pressure. Thus, for the tube described, variation of the outside pressure from about 7 p.s.i.a. to approximately 0 can have no effect on its operation. This condition is required for a high altitude ignition source. For outside pressures of about 7 to 14 p.s.i.a., the only effect on the operation of the ignitor is that the tube 2 ills quicker` FIG. 3 is a schematic illustration of the operating cycles of this invention, indicating that the apparatus with the foregoing features operates at 2 cycles per second. In reference to FIG. 3, it is seen that once each cycle, valves 14 and 18, are opened and fuel and oxidant are delivered to tube 2, which is initially under ambient external pressure of less than 5 p.s.i.a., indicating very high altitude. Pressure is developed because of the balance of flow conditions as described to about 14 p.s.i.a. Valves 14 and 18 are closed. The mixture is suitably ignited, detonation occurs, and a luminous hot gas stream is ejected from nozzle 22. Thereafter follows the exhaust period to end one cycle. Variation in orifice sizes and pressures may be varied to provide, for example, 2 to l0 cycles per second and operation at various internal tube pressures. It is understood, however, that there may not be any independent lchange of orifice sizes between orifices 13, 1.7 and 22, because of the necessity of the balance of l flow conditions as described.

It is an important feature of this invention that the ignitor operates effectively only when detonation occurs and where the balance of flow out of orifice 22, together with iiow in, develops the required pressure. l It is quite obvious that under non-detonating combustion conditions, wherethe pressure ratio across the combustion zone is on the order of unity, very little ame Will be emitting from nozzle 22. lt will, in effect, be snufed out. With the pressure ratio across the combustion zone on the order 22 passes, by means of a detonation wave, a luminous hot gas stream.

When the repetitive detonator is employed as a jet engine afterburner ignitor, the tube 2 is not required to be axial but may be in curved form such as, for example, that shown in FIG. 4. Referring now to FIG. 4, there is shown a jet engine exhaust cone 25 having a repetitive detonator l mounted therein. Detonator l is preferably mounted adjacent or in combination with a flameholder 26 for increased performance, and is the detonator of FIG. 1 or 2 curved to include a first tube section 27 parallel to the exhaust cone, a second tube section 28 per- Vfunction of the distance along 6 pendicular to and entering the exhaust cone and a third tube section 29 directed axially into the gas stream. Fuel is supplied to detonator 1' in the same manner as described for FIGS. l and 2. The fuel to be ignited by the detonator 1 is introduced into the exhaust cone 25 by means of fuel nozzles 3i).

Other curved forms may be employed with good results and the particular location of the detonator in the exhaust cone may be varied for the desired operation. Such a detonator supplies charges of high temperature luminous gas to the exhaust stream for ignition of a combustible fuel mixture therein, and the high temperature gases are advantageously generated independently of the ambient conditions in the exhaust stream.

In FIG. 5, a repetitive detonator 1 is shown as a curved ignitor for the main fuel system of a jetl engine. A casing 31 houses a combustion chamber 32 which is adapted to receive air from a compressor, not shown. Fuel is introduced into the combustion chamber 32 by means of a fuel conduit 33. Detonator 1' is mounted concentrically Within fuel conduit 33 over a greater part of its length, and operates in the same manner as described for FIGS. l and 2 to provide a series of charges of high temperatures luminous gas adjacent the incoming fuel from conduit 33 for ignition thereof. In this embodiment, as in FIGS. l and 2, the high temperature gas is generated independently of conditions existing in the combustion chamber. This arrangement is further aclvantageous in permitting the detonator to be cooled by the incoming fuel and in turn aids in vaporizing the fuel. It should also be noted that various curved forms together 'with other configurations of position for the detonator inlet may be employed within the scope of this invention. FIG. 6 illustrates a conventional mounting of the ignitor l in a combustion chamber 34. lgnitor 1 is mounted in chamber 34 adjacent the fuel inlet 3S and arranged to direct the hot gases generated into the incoming fuel. lgnitor 1 may be directed at any desirable angle for optimum performance. In all cases, however, it is more advantageous to direct the hot gases into the chamber and away from the walls of the chamber in orderl to avoid quenching characteristics or wall effects on the gases.

When certain applications require the detonator to operate over long periods of time, the high temperatures 'involved may injure or destroy the materials used in combustion tube 2, or, particularly where the combustion tube is constructed of metal, the high temperatures involved may raise the Wall temperature to a point higher than that necessary to initiate combustion and, accordingly, the detonator will become inoperative. Under these conditions, combustion tube 2 may be cooled by various air or liquid cooling processes which are well known in the art and necessitate no further amplification.

The invention may also be employed as a tool for the study of combustion processes and particularly for the causes and effects of the transition of a combustion Wave to a detonation wave. The upper section of approximately 30 centimeters of the combustion tube 2 may be of glass or other transparent material, or have a transparent aperture therein for use with a camera. Alternatively, by observing the gas properties spectroscopically, as a v the tube, individual parts of the flame acceleration process can be observed. Accordingly, the detonator permits the integration of each measurement over many cycles, and thus sensitivity may be obtained many times that available in a single Wave process.

This invention thus provides an ignitor for jet engines, ram jet, and the like jet apparatus, which operates on a detonation wave principle to expel hot gases through a critical orice. When the invention is employed as a jet engine fuel system ignitor, the initiating combustion commences in an area sheltered from ambient conditions, such as turbulence, and under sufficient pressure for effective combustion. The stream of hot gases generated may be projected into a combustion chamber Well away from the surrounding walls and ignition of fuel may be commenced through purely thermal relationship with the high temperature gases or the hot stream of gases may contain certain additive reaction intermediates which may then serve as initiating means for further combustion reactions.

While other modifications of this invention and variations of apparatus that may be employed within the scope of the invention have not been described, the invention is intended to include all such as may be embraced within the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A repetitive hotreacting gas generator comprising in combination, a detonator chamber closed at one end and open at the other, means to introduce at a predetermined iiow rate a detonable fuel and an oxidant into said chamber adjacent the closed end thereof to provide a detonable mixture, critical, ow restrictingmeans at the open end of said chamber to control pressure rise of fueloxidant in said chamber to a predetermined amount Where said restrictor means operating at critical ow velocity passes all the fuel-oxidant flow entering the ignitor at the same iiow rate as the flow rate of the entering fueloxidant, and means in said chamber to ignite said mixture to generate detonation waves in said chamber to expel hot gases through said flow restricting means.

2. A repetitive hot reacting gas generator comprising in combination, a detonator chamber closed at one end and open at the other, critical flow orice entry means to introduce a detonable fuel and an oxidant into said chamber adjacent the closed end thereof at a predetermined rate to provide a detonable mixture, critical ow restricting exit means at the open end of said chamber to control pressure rise of fuel-oxidant in said chamber to about 30 Ap.s.i.a. under which conditions said restricting exit means passes all the fuel-oxidant flow entering the ignitor, and means in said chamber to ignite said mixture to generate detonation waves in said chamber to 'expel hot gases throughsaid restricting exit means.

3. A repetitive hot reacting gas generator comprising in combination, an elongated combustion tube closed at one Vend fand open at the other, means to introduce a pair of separate fuel and oxidant components into said tube adjacent the closed end thereof at a predetermined iiow rate and to form a detonable mixture of said components, open critical iiow nozzle means the open end of said tube to provide a pressure rise in said tube above external pressures while at the same time passing all the fuel-oxidant ow at said flow rate, ignition means to ignite said mixture and generate detonation Waves in said tube to expel hot gases through said nozzle means and means to repetitively generate said detonation waves.

4. A repetitive hot reacting gas generator comprising in combination, an elongated combustion tube closed at one end and open at the other, means to introduce a pair of separate fuel and oxidant components into said tube adjacent the closed end thereof, critical flow entry orifice means connected to said means to introduce for regulating the rate of flow of said components into said tube, a critical flow exit orifice operatively related to said critical flow entry orifice means to pass all of the How out of said tube at an internal tube pressure of at least 2 times the pressure external to said tube and sequential timing means to stop the flow of fuel-oxidant into said tube and ignite Vsaid mixture to form detonation Waves in said tube to expel hot gases through said exit orice.

5. A jet engine combustion system including, a cornbustion chamber, means to introduce air into said combustion chamber, a fuel inlet tube to introduce fuel into said combustion chamber, and an ignitor for said fuel coaxially mounted in said fuel inlet tube, said ignitor comprising an elongated tube closed at one end and open at the other, means to yintroduce a detonable fuel mixture into the closed end of said tube to flow toward the open end at a pressure less than that developed by detonation in the tube, a critical flow restricting nozzle member at the open end of said ignition tube to maintain a pressure in said ignition tube greater than the pressure in said combustion chamber, ignition means adjacent the midpoint of said ignition tube, and means to energize said ignition means to generate a pair of oppositely moving detonation waves in said ignition tube, one of said detonation waves temporarily restricting further fuel mixture inlet in said ignition tube, and the other of said waves expelling a charge of high temperature gas from said ignition tube into said combustion chamber coaxially with the fuel from said fuel inlet tube for ignition thereof.

6. The invention as claimed in claim 5 wherein the detonable mixture is a mixture of ethylene and oxygen.

7. A method of igniting a combustible mixture in a combustion chamber wherein a first fuel introduced into a fast moving gas stream within said combustion chamber requires ignition and wherein the method of igniting is Vconducted in an apparatus comprising in combination an elongated chamber having a relatively small cross-sectional area and having one end thereof in flow communication with the fast moving gas stream through a flow-restricting opening, means connected to said chamber for the introduction therein of a detonable fuel and an oxidant in a manner promoting the mixing thereof and means connected to said chamber for igniting such mixture on demand, which method comprises:

(a) introducing a detonable fuel and an oxidant to said chamber,

. (b) balancing the total rate of fuel-oxidant introduction against the predetermined rate of leakage through theiflow-restricting opening to cause the pressure in said chamber to increase to a value at least twice the pressure outside said chamber whereupon the rate of fuel-oxidant introduction equals the flow of fuel-oxidant issuing from said orice independently of the pressure outside said chamber, and

(c) igniting the fuel-oxidant mixture to generate a detonation Wave to expel hot gases through the owrestricting opening yinto the fast-moving gasstream to ignite the first fuel therein. 8. A method of igniting a combustible mixture in a combustion chamber substantially as recited in claim 7 wherein the detonable fuel and oxidant are ethylene and oxygen, respectively.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. A REPETITIVE HOT REACTING GAS GENERATOR COMPRISING IN COMBINATION, A DETONATOR CHAMBER CLOSED AT ONE END AND OPEN AT THE OTHER, MEANS TO INTRODUCE AT A PREDETERMINED FLOW RATE A DETONABLE FUEL AND AN OXIDANT INTO SAID CHAMBER ADJACENT THE CLOSED END THEREOF TO PROVIDE A DETONABLE MIXTURE, CRITICAL, FLOW RESTRICTING MEANS AT THE OPEN END OF SAID CHAMBER TO A PREDETERMINED AMOUNT WHERE SAID RESTRICTOR MEANS OPERATING AT CRITICAL FLOW VELOCITY PASSES ALL THE FUEL-OXIDANT FLOW ENTERING THE IGNITOR AT THE SAME FLOW RATE AS THE FLOW RATE OF THE ENTERING FUELOXIDANT, AND MEANS INSAID CHAMBER TO IGNITE SAID MIXTURE TO GENERATE DETONATION WAVES IN SAID CHAMBER TO EXPEL HOT GASES THROUGH SAID FLOW RESTRICTING MEANS.

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