US2617254A

US2617254A - Explosion gas turbine plant

Info

Publication number: US2617254A
Application number: US5097A
Authority: US
Inventors: James H Anderson
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1948-01-29
Filing date: 1948-01-29
Publication date: 1952-11-11
Anticipated expiration: 1969-11-11

Description

Nov, 11, 11952 J. H. ANDERSON 2,617,254

EXPLOSION GAS TURBINE PLANT Filed Jan. 29, 1948 HIS ATTORNEY.

Patented Nov. 11, 1952 SAT NEFE

PENT OFFICE EXPLOSION GAS TURBINE PLANT Application January 29, 1948, Serial No. 5,097

4 Claims.

This invention relates to gas turbine plants, and more particularly to a resonant explosion unit for generating explosion gases to operate a turbine.

One object of the invention is to produce a maximum volume of turbine-operating gases with a minimum quantity of fuel by combining the explosion gases and separate volumes of air compressed by the pressure waves of the explosions.

Another object of the invention is to utilize pressure waves from the explosions in the explosion unit for compressing a supply of air which is in turn heated and then introduced into the explosion gases to cool said gases suitably for use in a turbine.

Another object is to utilize the gases discharged from the turbine for heating the air compressed in the explosion chamber.

A further object is to introduce a spray of water into the cooling air so that good heat transfer is obtained between the turbine discharge gases and said cooling air.

Other objects will be in part obvious and in part pointed out hereinafter.

In the accompanying drawing in which similar reference numerals refer to similar parts,

The figure is a side elevation, partly broken away, of a gas turbine plant constructed in accordance with the practice of the invention and showing the position of the controlling devices when at rest.

Referring more particularly to the drawing, a resonant explosion gas turbine plane, designated in general by 20, is shown as including a turbine 2|, a resonant explosion power unit 22 for providing the operating gases for the turbine, and a compressor 23 driven by the turbine for delivering compressed air to the power unit '22.

The compressor and the turbine are of the axial flow types having their

rotors

24 and 25 coaxially arranged with each other and the opposed ends of their

shafts

26 and 21 connected together by a coupling 28. On the other end of the shaft 21 is a power take-off coupling 29, and the outer end of the shaft 26 carries a clutch member 30 for engagement with a mating member on a shaft 32. For starting purposes, a motor 3| is adapted to impart rotary movement to the shaft 32 through a belt drive 33 causing the initial rotation of the

rotors

23 and 25. The clutch is operated by a lever 34 attached to one of the clutch members and pivoted on a stationary member I9.

The resonant explosion power unit 22 in this case comprises a casing 35 which forms an explosion chamber 36 having an explosion zone 3] and a compression zone 38, and a heat exchanger 39 for heating the compressed air discharged from the compression zone 38.

The air discharged from the compressor 23 is conveyed to the explosion zone 31 and the compression zone 38 by a conduit 40 which leads to ports 4| and 42 in the casing 35 located respectively adjacent the zones 3'! and 38. The flow of air through the ports 4| and 42 is controlled by pressure responsive valves 43 and 44, respectively. Both valves are shown as being of the poppet type and are normally held unseated by springs 45.

Fuel is injected into each charge of air entering the explosion zone 31 through the port 4| by a spray nozzle 46 in the casing adjacent the explosion zone, and the explosive mixtures thus formed are ignited by a spark plug 41 projecting into the casing in the transverse plane of the spray nozzle. The fuel is conveyed by a conduit 38 to the spray nozzle 43 from a fuel pump 49 which may itself receive fuel under pressure from an outside source (not shown). The piston 50 of the pump 49 is actuated by a rocker arm 5| operatively connected to the shaft of a motor 52, in a well known manner, for pumping fuel to the nozzle 46. An interrupter device 53 in an ignition circuit 54 for the spark plug 41 is also actuated by the rocker arm 5| to produce a spark in timed relation with the operation of the fuel pump 49.

The casing 35 comprises two cup-

shaped members

55 and 56 having their inner open ends spaced with respect to each other to provide therebetween an exhaust opening 51 for the exhaust gases from the explosions in the explosion zone 37. Surrounding this opening and attached to the casing is a housing ring 58 for conveying the explosion gases to an exhaust conduit 59 leading to the inlet of the turbine 2|.

In order to discharge the air from the compression zone 38 of the explosion chamber, a port 60 is provided in the casing at a point adjacent the compression zone, in this instance it is shown as being in the transverse plane of the port 22. A check valve 6|, normally held seated in the port 6|! by a spring 82, controls the flow of compressed air passing through the port 60 into a discharge conduit 63.

The compressed air from the compression zone 38 is conveyed, by the conduit 63, to the heat exchanger 39 which is provided with a tube nest 34 over which the air passes. An air conduit conveys the air from the heat exchanger to the exhaust conduit 59. The heating medium for the heat exchanger 39, in this case, consists of the gases discharged from the turbine 2| which 3 are conveyed to the exchanger 39 by a conduit 66. The discharge gases from the turbine pass through the tubes of the tube nest 64 and are discharged to the atmosphere through a pipe 87.

In order to cool the compressed air and to increase its mass flow before it enters the heat exchanger 39, a spray nozzle 68 is provided in the discharge conduit 63 and connected to a water supply (not shown) for intermittently or constantly spraying water into the air passing through the conduit 63. Since the mass flow of the turbine discharge gases is greater than the mass flow of the air discharged from the compression zone 38, the addition of water to the air raises its mass flow such that it will absorb a great amount of the heat contained in the turbine discharge gases passing through the exchanger 39. It will be readily understood, however, that a spray of water could be introduced into the air during its passage through the conduit 40 with corresponding desirable results.

The length of the chamber 36 is so chosen and the frequency of the explosions in the chamber is so timed that when a pressure wave from an explosion is at its peak in 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 36 approximates one half of a pressure Wave length or an odd multiple thereof. In other words, when the aforesaid pressure condition exists within the chamber 36, the frequency of explosions in the explosion zone 31 will be equal to, or a function of the natural frequency of the chamber 36,. It is apparent then, from the foregoing discussion, that in order to obtain the proper frequency of explosions such that the explosions occur at a time when the peak of the reflected pressure wave exists in the explosion zone 31, it is merely necessary to vary the frequency of the explosions-by controlling the speed of the motor 52 in any well-known manner, such as by varying the voltage impressed thereonuntil the aforesaid condition is obtained. As a guide for regulating the speed of the motor 52 the pressures at various points in the explosion chamber may be measured by any well known device (not shown).

For any given condition-that is, length of the chamber 36 and temperature and pressure of the gas within the chamber 36, there is a fixed frequency, or direct function of this frequency at which the power unit will operate most effectively. 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 from the explosion zone 31 to the compression zone 38 and return to its point of origin. This time is, of course, dependent on the distance travelled (twice the length of the chamber 36) and the speed at which the wave travels (depending on the temperature and pressure 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 explosion mixture during a period of maximum pressure at that endby maximum pressure it, is meant, of course, the maximum pressure at that end of the chamber prior to the explosion, or in other words, the maximum pressure caused by the refiected pressure wave, which maximum pressure would occur when the peak of the reflected pressure wave reached the explosion zone 31. An alternative method would be to measure the pressure at the exhaust opening 51 and varying the frequency of explosions until a relatively constant pressure is obtained at this point. An end plate 69 of the casing serves as a reflecting member to reverse the direction of movement of the peak of the pressure waves in the chamber 36 on contact therewith.

At the beginning of an operating period of the plant, the starting motor 3| imparts rotary movement to the

rotors

24 and 25 causing compressed air to flow through the conduit 40. Part of this air will pass through the port 4| into the explosion zone 31 while the remainder will pass through the port 42 into the compression zone 38. If then the fuel pump motor 52 is put into operation, fuel will be injected into the charge of air in the explosion zone 31, and the resulting explosive mixture will be ignited by the spark plug 41. This initial explosion forces the valve 43 to its seat, thereby cutting off further flow of air through the port 4|. The peak of the pressure wave from the explosion travels toward the compression zone 38 causing a low pressure area to exist therein which permits the valve 43 to open and admit a new charge of air into. the explosion zone. As the peak of the wave reaches the compression zone 38, it causes the valve 44 to seat, cutting off the flow of air through the port 42, and further compresses the charge of air in the compression zone 38 to such a pressure that the valve 6| is forced open to allow the compressed air to pass into the discharge conduit 63.

When the peak of the pressure wave hits the end plate 69, it is reflected thereby and will return back to its point of origin, thus permitting the valve 6| to be returned to its seat by the spring 62 and the valve 44 to open to admit a new charge of air into the compression zone 38. The peak of the reflected pressure wave moving toward the explosion zone 31 compresses a new charge of air therein, and at the instant of peak compression, fuel is injected through the nozzle 46 into the compressed air and this mixture is ignited by the spark plug 41 Thus, another wave is started which continues through the same cycle as that just described.

It is to be noted that due to the location of the valves 44 and 6.! and. the manner in which they are operated, the air passing from the compression zone 38. through, the discharge conduit 63 is substantially free of any of the products of combustion from the explosion zone 31. The reason for this is that the valve 44 isheld in the open position by the spring 45 except during a relatively short period in the explosion cycle when the peak of an explosion waye approaches the explosion zone 38- and is reflected therefrom,-

whereas the valve BI is held closed except during the aforesaid relatively short period of an explosion cycle during which time the valve, 44 is closed. Thus, a greater amount of air passes into the compression zone 38 from the conduit 40 than passesfrom this zone through the conduit63.

The excess of air valvedinto the compression zone 38 moves along the; explosion chamber 36 toward the exhaust conduit 59 thereby opposing any counter fiow of exhaust, or combustion, gas from the explosion zone 31, thereby effectively preventing the mixing of combustion gas with the air discharged through the conduit 63. The air moving; from the compression zone 38 mixes with the combustion gas at the exhaust conduit 59 thereby serving not only to increase the quantity of gas discharged at a relatively constant pressure through the conduit 59, but also to reduce the temperature of the fluid heated in the explosion zone 31 to a value at which the resulting mixture may be safely utilized in driving the turbine 2 I. In the form of the invention wherein the air valved from the compression zone 38 is subsequently mixed with the aforesaid mixture before use in the turbine for purposes of thermodynamic efiiciency, the quantity of cooling airwhich quantity may be controlled by the proper choice of the spring 45-mixed with the exhaust gases at the exhaust opening 57 is such that the temperature of the mixture exhausted through the opening 51 is not lowered to the most desirable value for use in the turbine 5|, rather, the temperature of this mixture is decreased further on mixing with the air exhausted from the compression zone 38 through the conduit 63.

Upon entering the discharge conduit 63, the compressed air is sprayed with the fluid issuing from the nozzle 68, thereby reducing the temperature of the air such that, as it passes around the tubes of the tube nest 64 in the heat exchanger 39, good heat transfer is eifected between said air and the heating medium in the exchanger. This air then passes out of the heat exchanger through the conduit 65 into the exhaust gas flowing from the explosion chamber 36 to intermingle therewith and reduce the temperature of such gas to a degree suitable for use in the turbine 2!. After this mixture is expanded through the turbine, it is conveyed by the conduit 55 to the heat exchanger 39 Where it passes through the tubes of the tube nest 64, giving up a portion of its heat to the compressed air flowing around the tubes, and subsequently is discharged through the pipe 61.

Ihe exhaust gases pass from the middle of the explosion chamber at practically a constant pressure. This is due to the facts that the original pressure wave and its reflected waves move simultaneously in opposite directions in the chamber and the reflected wave originates at the instant the original wave has moved one half wave length. Waves moving in this manner will have the effect of neutralizing each other at a distance of one quarter wave length from the points of origin and reflection, in this case, at the midportion of the explosion chamber 3 6.

From the foregoing it will be apparent that high thermal efficiencies may be attained in this unit by compressing the cooling air with the pressure wave in the explosion chamber and by reheating said air with the hot gases discharged from the turbine 2 I.

It will further be apparent to those skilled in the art that modifications and changes may be made without departing from the spirit of the invention or the scope of the claims.

I claim:

1. A resonant explosion power unit, comprising a casing having an explosion chamber whose length approximates an odd multiple of one half of an explosion wave length, means for introducing the air and fuel constituents of an explosive mixture into one end portion of the explosion chamber, means at said end portion for igniting the explosive mixture, an exhaust conduit for conveying the explosion gases from the explosion chamber, a valve at the other end portion of the explosion chamber acting responsively to a pressure wave of the explosion in the chamber for enabling a fluid to pass into the chamber, a conduit for conveying such fluid from the last. said portion of the explosion chamber to the exhaust conduit for cooling the hot gases therein, and means in the last said conduit for controlling the flow of fluid therethrough.

2. A resonant explosion power unit, comprising a casing, an explosion chamber in the casing whose length approximates an odd multiple of one half wave length and having an explosion zone and a compression zone, and means for introducing the air and fuel constituents of an explosive mixture into the explosion zone, means for igniting the explosive mixture, an exhaust conduit for conveying the explosion gases from an intermediate portion of the explosion chamber, a valve acting responsively to the pressure wave in the chamber for admitting charges of air into the compression zone for compression by the pressure wave in the chamber, a valve for valving the charges of air to be discharged from the compression zone at a predetermined pressure, a conduit for conveying the compressed air from the compression zone to the exhaust conduit, a heater in the last mentioned means for heating the compressed air passing therethrough, and a spray nozzle in the said last mentioned means upstream of said heater for introducing a cooling fluid into the compressed air flowing to the heater.

3. A gas turbine plant comprising a turbine, a compressor driven by the turbine, a casing having an explosion chamber whose length approximates an odd multiple of one half of an explosion wave length, an explosion zone in the explosion chamber adjacent one end thereof, a compression zone at the other end of the explosion chamber in which a supply of air is compressed by the explosion Wave, means for conveying air from the compressor to the explosion zones, means for introducing fuel into the explosion zone to form an explosive mixture therein, means at the explosion zone for igniting the explosive mixture, an exhaust conduit for conveying the explosion gases to the turbine, means for conveying air from the compressor to the compression zone, valve means in the casing acting responsively to a pressure wave in the chamber for allowing air to enter the compression zone and to be discharged after being compressed by the explosion wave in the chamber, means for conveying air compressed by said wave from the compression chamber, a heat exchanger in the last mentioned means for heating the compressed air, and a conduit for conveying the expanded gases from the turbine to the heat exchanger.

4. A gas turbine plant comprising a turbine, a compressor driven by the turbine, a casing having an explosion chamber whose length approximates one half of an explosion wave length, an explosion zone in the explosion chamber adjacent one end thereof, a compression zone in the explosion chamber in which a supply of air is compressed by the explosion wave, means for conveying air from the compressor to the explosion zone, means for introducing fuel into the explosion zone to form an explosive mixture therein, means at the explosion zone for igniting the explosive mixture, an exhaust conduit for conveying the explosion gases to the turbine, means for conveying air from the compressor to the compression zone, valve means in the casing acting responsively to a pressure wavein the chamber for enabling air to enter the compression zone and to be discharged after being compressed by the explosion wave in the chamber. a conduit for conveying the compressed air from the compression zone to the exhaust conduit for intermingling with and cooling the explosion gases passing into the turbine, a heat exchanger in the last mentioned conduit, and a conduit for conveying the expanded gases from the turbine to the heat exchanger for heating the air flowing through the exchanger.

JAMES H. ANDERSON.

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

Number Number UNITED STATES PATENTS Name Date Meininghaus May 25, 1937 Lysholm Apr. 26, 1938 Lysholm June 3, 1941 Ray July 18, 1944 Bodine Aug. 30, 1949 Kollsman Sept. 26, 1950 Bodine Apr. 3, 1951 FOREIGN PATENTS Country Date Great Britain Dec. 16, 1907 Great Britain Dec. 1, 1933 Great Britain May 3, 1938 France May 10, 1910