US2627163A - One-half wave length resonant explosion gas unit - Google Patents

Description

Feb. 3, 1953 J. H. ANDERSON EI'AL 2,627,163

ONE-HALF WAVE LENGTH RESONANT EXPLOSION GAS UNIT Filed Dec. 16, 1947 2 Sl-iEE'IS-SPEET l THEIR ATTORNEY- Patented Feb. 3, 1953 ONEdiALF wave LENGTH RESONANT EXPLosmN GAS UNIT James H. Anderson, Easton, Pa., and George Farnell, Phillipsburg, N. .L, .assignors to IngersolbRand Company,'New York, N. 1., a cor-pprat on o w Jersey Application December 16, 1947, Serial No. 792,066

sions at either of the points for cooling thelexhaust gases and the casing of the explosion Qhamber.

A fur her bjec is tocon truct-a resonan esplosion chamber which explosions occur at point t t are a pr ximate on alf oi a explosion wav ength anst thus allowi p e ur wa o an x l ion i the h mb r t compress a succeeding charge of explosive mixture therein.

Oth r obje i l be in a ob o and in part pointed out hereinafter.

In the accompanying drawingsin which similar efe ence n me a s r e o similar par s! Figure fl s a side el vationo a gas turbine pla em d n a n nt xplos n power unit onstructed in c o danc with he p actice o the invention,

Figure 2 is alongitudinalview of the gas turbine plant, somewhat enlarged and partly'broken away,showing the positions of the controlling devices when at rest, iqFigure 3 is a side elevation of a gas turbine plant showing a modified "form of the invention, Figure 4 is a view taken through'l 'igures along the line 4-4 and showing the position of the controlling devices when the power unit is at rest; and

Figure 5 is a top view, partlybroken away, of

a gas turbine plant-showingstill another modified format the invention.

Referring more particularly to the drawings, andat -firstto Figure Laresonant explosion gas '-turbine plant, designated in general by 20, is shown as includinga turbine 21!, a resonant explosion power unit 22 for providing the operating .gasesgfor the turbine, and a compressor ZS-driven by the turbine for delivering compressed air to :the lpoweruunit 22.

The compressorland turbine are shown ias being of $118 axial flow types having their rotors 24 and '25 coaxiallyarranged with each other and the opposedends of thelrshafts 28 and -19 con- 0-33- 7 2 nected together by a coupling 30. On the other end of the shaft 29 is a coupling 3| which serves as a power takeeofi for the turbine, and. theouter end of the shaft 28 is adapted to be connected with a clutch mechanism 32 which in turn is i litached to the operating shaft of a Starting motor 33. An operating lever arm 34 for the clutch mechanism 32 is pivoted at a point on the base of the starting motor to make possible the en.- gagement and disengagement of the clutch mechanism.

The resonant explosion power unit 22 com? prises a casing 35 which forms alchamber 3J5 having relatively spaced explosion zones 31 and 38,

' two in the example shown, and located adjacent the ends of the casing 35. Compressed air is con.- vcyed from the compressor to theexplosion zones by a conduit 39 which leads to ports 40 and M in the end plates 26 and 21 of the casing 35.

The flow of air through the ports 4-0 and M is controlled by pressure responsive valves 42 and '43, respectively. The valves are shown as being Qf the poppet typ an th r st m 44 a hav n slidin f i rojecti s 4 and in he ondu ilho val e 2 n -3 ar held ota- 1y unsea ed by sp n s 46 a 41 ono ihs the valve stems and acting against the projectio 4 and 49 an the a e u s nj ct d to th cha be y spray no zles 50 and iaoent th explos on ones 31 and 38, respectively, and the explosive mixtures a gnited .by pe k plugs and 53 proi o nsint e c si n each i t t an verse plane of the-fuelspray nozzles. Fuel, under pressure, isconveyed from fuel pumps 54 and 55 to the spray nozzles by conduits 56 and 51. The pistons 59 and 60 of the pumps 54 and=55 are actuated by a crankshaft 6| and amotorqfl in a well known manner for pumping fuel from the main fuel line 58 alternately to the nozzles and 5|.

I he casing 35 comprises two cup- shaped members 63 and 64 having their inner open ends spaced to provide adischai ge opening 65 for the exhaust gases. Surrounding this opening and lattachedto the casing is a housing ring .66 which is so timed that, when the pressure wave irom an explosion is at its peakin one end of the chamber, it will simultaneously be at its lowest value in the other end of the chamber and, to

this end, the length of the chamber approximates one-half of a pressure wave length, or an odd multiple thereof. In other words, it is to be noted, when this condition exists within the chamber 36 the frequency of explosions at the opposite ends of chamber 36 will be equal to or a function of the natural frequency of the easing which forms the chamber 36. It is apparent then, from the foregoing discussion, that in order to obtain the proper frequency of explosions and the proper timing relation of these explosions with respect to the reflected waves, discussed more fully hereinafter, it is merely necessary to vary the frequency of the explosionby controlling the speed of the motor 62 in any well known manner such as varying the voltage impressed on either the field or the armature, or both, of the motor 62 until the aforesaid condition is obtained. These pressures can, of course, be measured by any well known device (not shown).

For any given condition, that is, length of the casing 35and pressure and temperature of the gas within the chamber 36, there is a fixed frequency or direct function of this frequency at which the power unit 22 will operate most effectively. That is, under these given conditions the length of a pressure wave in the chamber 36 is determined by the length of time it takes for the peak of the wave to travel along the container and return to its point of origin. This time is, of course, dependent on the distance traveled (twice the length of the chamber 36) and the speed at which the wave travels (depending upon the pressure and the temperature within the chamber 36). Inasmuch as the pressure and temperature within the chamber 36 is dependent, in part, on the mixture and type of fuel used and the size of the chamber 36, a practical method for obtaining the proper timing relation is facilitated by the expedient of measuring the pressure at the explosion end of the chamber 36 and igniting the explosive mixture during a period of maximum pressure at that end. When this timing relation has been attained, the aforesaid condition will be closely approximatednamely, maximum pressure at one end of the chamber 36 and minimum pressure at the opposite end thereof. There will be a slight devia- -t'ion from this condition due to the difference in velocity in the peak of the pressure wave and the trough of the pressure wavedue to the difference in pressure-however, this variation is not of sufficient magnitude to materially effect the operationor the timing relation as herein set forth. 7

In furtherance of this cycle of operation or method of compressing a gas, the end plates 26 and 21 of the casing serve as reflecting members to reverse the pressure waves for return movement to their points of origin.

At the beginning of an operating period of theplant, and at which time the starting motor 33 is imparting rotary movement to the rotors 24 and 25, air discharged by the compressor will flow into the ends of the explosion chamber. If then, the fuel pump motor 62 is started fuel will be injected into the air charge in the explosion zone 31, for example, through the nozzle 50 and the resulting explosive mixture is ignited at the spark plug 52. This initial explosion forces the valve 42 to its seat, thus cutting off further flow of compressed air through the port 40, and the pressure wave of the explosion travels toward the opposite end of the chamber 36 cans ing a low pressure area to exist in front of the valve 42 which permits the valve to unseat and admit a new charge of air into the explosion zone 31. As the peak of the wave reaches the opposite end of the chamber 36 it further compresses the air in the explosion zone 33, thus causing the valve 43 to seat in the port 4|.

When the peak of the pressure wave hits the end plate 21 of the casing, it is reflected back toward its point of origin. As it moves back along the chamber a low pressure area is created in the zone 38, thus allowing another charge of air to be admitted thereinto. The peak of the reflected pressure wave hits the end plate 26 and is again reflected, this time toward the explosion zone 38 allowing a second charge of air to be admitted into the chamber through the port 40. The movement of the peak of the wave toward the explosion zone 38 compresses the new charge of air therein.

At the instant that the peak of the wave reaches the explosion zone 38, fuel is injected through the nozzle 5i into the compressed air, and this explosive mixture is ignited by a spark at the plug 55. A wave from this explosion moves toward the explosion zone 31 allowing the valve 43 to open and compressed air to be admitted into the chamber. When the peak of this wave hits the end member 26, it is reflected back toward its point of origin. As the wave next approaches the explosion zone 38, the valve 42 is again permitted to unseat and admit a third charge of air into the explosion zone 31. After again reversing direction when hitting the end member 21, the wave moves back toward the zone 31, compressing the air therein which is then impregnated with fuel, and the resulting mixture is ignited. Thus, from this explosion another Wave is started which continues through the same cycle of events. Timing of ignition of the explosive charges in the opposite ends of the chamber 36 may be accomplished in any well known manner, as for example the manner shown in U. S. Patent 2,517,- 822.

It will be readily understood that each wave will travel approximately one and one half wave lengths before another explosion takes place in the explosion chamber 36. Since successive explosions occur at opposite ends of the chamber, three separate charges of air will be drawn into one explosion zone in the interval between explosions in that particular zone. All three of the charges are advantageous in cooling the exhaust gas and the walls of the casing surrounding the explosion, and the third is impregnated with fuel to form an explosive mixture.

In the instance where materials capable of withstanding extremely high temperatures are used, the cycle could be so timed that the explosions would occur at time intervals of one half wave length. Thus, the speed of the fuel pump motor 62 would be increased so that fuel would be injected into each charge of air, and the speed of ignition would be increased accordingly to ignite the resulting explosive mixtures, consequently enabling a large volume output of high temperature exhaust gases. In such a cycle, -.a pressure wave would move from the explosion zone 31 through a distance of one half a wave length to the zone 38 of the chamber 36, compressing a charge of explosive mixture which is immediately ignited to set another wave in motion; toward the other zone;3'lof thechamber. i j. .3. hat; o insz char es; :Qfgair would'b'e admitted between I the charges 'ofexplosiveimixture. g

Another advantageous feature of .the invention is that the exhaust gases will pass from the middle of the chamber at practically a constant pressure and, therefore, without the pulsations which characterize the operation in the other parts of the chamber. Successive explosions in the explosion chamber produce pressure waves, which are 180 out of phase with respect to time and are moving in opposite directions; thus they will have the effect of constantly neutralizing each other at adistance of one quarter of a wave length from the point of explosion, or any odd multiple of one-quarter wave length. Since the length of the explosion chamber 36, in the form of the invention illustrated, is equal to one half of a wave length the exhaust gases are discharged from the middle portion of the chamber at a substantially constant pressure.

The modified form of the invention shown in Figures 3 and 4 comprises a tubular casing having a U-shaped explosion chamber 36 and an air supply chamber 69 which are separated by walls or reflecting members 10 and H therebetween. In the walls 10 and H are the air inlet ports 40 and 4|, respectively, having pressure responsive valves 42 and 43 adapted to seattherein to control the flow of air into the ends of the explosion chamber. The fuel injection and ignition devices are situated in the casing 35 near the ends of the explosion chamber, and a discharge opening 65 at the curve of the U allows the exhaust gases to pass from the chamber into the discharge conduit 68. This form of the invention is advantageous in that it reduces the space requirement of the unit and makes possible the use of shorter inlet and discharge conduits.

The modified form of the invention shown in Figure 5 differs from those previously described mainly in that the casing 35 and, therefore, the explosion chamber 36, is of circular shape in order to further minimize the overall length of the explosion unit. The mode of operation of this form of the invention and that disclosed in Figures 3 and 4 is identical with that described in connection with the form shown in Figures 1 and 2, and it is to be understood that, in both instances, the length of the explosion chamber approximates one half of a pressure wave length or an odd multiple of one half a wave length.

From the foregoing description, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the spirit of the invention or the scope of the claims.

We claim:

1. A resonant explosion power unit, comprising a casing forming an explosion chamber the longitudinal axis of which is U-shaped, reflecting members on the casing to reverse the direction of movement of pressure waves in the chamber and being approximately one half of an explosion wav length apart, air inlet ports situated in the reflecting members, valves to seat in the ports and acting responsively to the pressure waves in the chamber for admitting charges of air thereinto, fuel injection means so timed that fuel is introduced into every third charge of air entering the chamber through each inlet port, means for igniting the resulting explosive mixtures in the ends of the chamber in equally spaced intervals of time, and a discharge opening in the intermediate portion of the casing through which the exhaust gases are discharged.

' 2. A resonant explosion power unit, compris ing a casing having an explosion chamber wherein the longitudinal axis of which is arcuate in shape, reflecting members to reverse the movement of explosion pressure waves in the chamber and being approximately one half of an explosion wave length apart, said explosion chamber having explosion zones adjacent the reflecting members of the casing, air inlet ports in the reflecting members, valves to seat in the ports and acting responsively to the pressure waves in the chamber for admitting charges of air into the explosion zones, fuel injection means so timed that fuel is introduced into every third charge of air entering each explosion zone, means for igniting the resulting explosive mixtures'in the explosion zones in equally spaced intervals of time, and a discharge opening in the casing intermediate the two zones through which exhaust gases are discharged at practically constant pressure.

3. A resonant explosion power unit, comprising a casing having an explosion chamber and a discharge opening at the intermediate portion thereof, reflecting members on the casing serving to reverse the movement of explosion pressure waves in the chamber and being approximately one-half of a pressure wave length apart, said explosion chamber having explosion zones adjacent the reflecting members, means for introducing charges of air into the explosion zones, means for injecting fuel into every third charge of air introduced into each of said zones to form an explosive mixture, and means for igniting the explosive mixtures at equally spaced intervals of time.

4. A resonant explosion power unit comprising a casing with a chamber therein having a length substantially equal to an odd multiple of onehalf an explosion wave length, a discharge opening for the chamber located at substantially an odd multiple of one-quarter explosion wave length from an end of the chamber, end members on said chamber for reflecting explosion pressure waves in the chamber thereby causing periods of relatively high and low pressure at the ends of the chamber, a valve at each end of the chamber for admitting air thereinto in response to such variations in pressure, each of aid valves being arranged to admit a charge of air into the end of the chamber with which it is associated during each low pressure period at such end, fuel injection means at each end of the chamber for injecting fuel into one of a plurality of successive charges admitted into each end of the chamber between explosions, and means for igniting the explosive mixture resulting from such injection of fuel.

5. A resonant explosion gas unit comprising a casing with a chamber therein having a length substantially equal to one-half of an explosion wave length, a discharge opening in the chamber located at substantially the midpoint of the chamber, end members on said chamber for refleeting explosion waves in the chamber thereby causing periods of relatively high and low pressure at the ends of the chamber, valve means at each end of the chamber for admitting air thereinto in response to such variations in pressure, each of said valve means being rranged to admit a charge of air into the end of the chamber with which it is associated during each low pressure period at such end, fuel injection means at each end of the chamber for injecting fuel into every third charge admitted into each end of the aea'mea chamber, and means forigniting-the. explosive length from an endof the chamber; end members onsaid chamber for reflecting:explosive-waves in the-chamber: thereby causing periods of relatively high and low pressure. at; the: ends of: the" cham? ber, valvesa-t: the; ends. of the. chamber for. admitting: successive charges; of air thereinto in reg.-' sponserto: such variations inpressure, fuelinjection means: at. each end of the. chamber. for, injecting" fuel into the chamber to; form explosivecharges. of fuel and air therein, and. means t each; endof the chamber for ignitingthe explosive charges. andbeing timed to ignite: such charges I during successive third periods of relatively high pressure at each end. of the chamber.

7. A resonant explosion power unit comprising acasing with achamber therein having. a length substantially equal to an odd multiple. of onecharges. of" fuel and. airtherein. and; means-. at each end of the chamber for igni he 811ml;vexplosive. mixtures and being.- timed: relative to the end. of? the. chamber with: which it 2 8 0? ciated to ignite. such mixture; during" successive: third .periodszof relatively high ressurezandlbeing; timed relative to the. other end; ofthe, chambersuch; that: ignition, occurs. alternatively at; the. oppositeendsof the. chamber at equally; spaced intervalsi.

JAMES H; AN ERSON, GEORGE FARNELL.

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

UNITED STATES PATENTS Number Name. Date-- 1,036,288 Matricardi; Aug; 20,1912 1,415,780 Bowen May 9,..1922 1,726,491 Johnson l- Aug. 27,. 1929; 2,275,756. Hanson Mar. 10, 1942 2,396,068 Young ash Mar. 5,, 1946. 2,427,845 Forsyth Sept. 23,,1-947 2,480,626 Bodine: .Aug, 30, 1949 2,493,873 Hill- Jan. 10,1950 2,503,584 Lipkowski Apr. 11-, 19.50. 2,523,379 Kollsman Sept. 26, 19.50, 2,546,966 Bodine i Apr..3, 19,51 2,550,515 Anderson Apr. 24, 19.51

FOREIGN PATENTS Number Country Date 27,724. Great Britain Dec. 16,190.? 176,838 Great Britain Mar. 6; 1.922. 138,642. Great. Britain Nov... 29,1923

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