US2602291A

US2602291A - Resonant explosion power unit with dilution air

Info

Publication number: US2602291A
Application number: US792071A
Authority: US
Inventors: Farnell George
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1947-12-16
Filing date: 1947-12-16
Publication date: 1952-07-08
Anticipated expiration: 1969-07-08

Description

G. FARNELL 2,502,291

RESONANT EXPLOSION POWER UNIT WITH DILUIION AIR July s, 1952 F1ed,.Dec 16, 1947 HIS ATTORNEY.

Patented July 8, 1952 REsoNANT EXPLOSION POWER UNIT WITH DILUTION Ara George Farnell, Phillipsburg, N. J., assigner to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey Application December 16, 1947, Serial No. 792,071

l cooling air into the explosion chamber of the unit between successive explosionain such a manner that the cooling air will thoroughly intermingle with the hot explosion gases in the chamber.'

Another object is to discharge explosion gases at practically constant pressure from the explosion chamber of a resonant power unit having a single explosion zone.

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

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

Figure 1 is a side elevationfofna gas turbine plant showing a resonant explosion chamber constructed in accordance withthe practice of the invention, l

Figure 2 is a transverse view of the resonant explosion power unit, somewhat enlarged, showing the position of the controlling devices when at rest, and

Figure 3 is an enlarged sectional view of a detail of Figure 2.

Referring more particularly to the y drawing and at first to Figure-1,` a resonant explosion gas turbine plant, designated in general by 20, is shown as including a turbine 2 I, a resonant explosion power unit 22 for providingoperating gases for the turbine, and a compressor 23 driven by the turbine for delivering vcompressed air to the power unit 22.

The compressor and turbine are shown as Vbeing 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 29 connected together by a coupling 36. [On the other end of the shaft 29 is a power take-olf coupling 3l and the outer end of the shaft Zllisy adapted to be connected with a clutch mechanism 32 which in turn is attached tothe operating shaft of a starting motor-33. Anoperating-leverarm 34 for the clutch mechanism 32 is pivoted on the base of the starting motor to make possi-ble the Y engagement and disengagement of the clutch mechanism.

The resonant explosion powerunit 22 comprises a tubular casing 35 which forms a chamber 36 having an explosion zone 31 located adjacent an end member 38 of the casing 35, and a housing 39 shown as being concentrically arranged around the casing 35 to form an air supply chamber 40 therebetween. Compressed air is conveyed from 2 Claims. (Cl. 60-39.65)

the compressor to the supply `chamber 40 by a conduit 4|, from whence a part of the air passes through a port 42 in the member 38 into the explosion zone 31.

The flow of air through the port 42 is controlled by a pressure responsive valve 43 shown as being of the poppet type and having its stem 44 extending through an L-shaped projection 45 attached to the end member 33 of the casing 35. The valve 43 is normally held unseated by a spring 46 encircling the valve stem and acting against the projection 45 and the valve.

Fuel is injected into the compressed air in the explosion zone 31 by a spray nozzle 41, and the resulting explosive mixture is ignited by a spark plug 4B projecting through the housing 39 and into the casing 35 in the transverse plane of the fuel spray nozzle. The fuel isconveyed to the spray nozzle by a conduit 49 from a fuel pump 50 which may'itself' receive' fuel,l under pressure, through a main fuel line 5 I from-an outside source (not shown).

Inorder to convey the exhaust gasesfrom'the explosion chamber 36 to the inlet of the turbine 2| a discharge conduit 52 is adapted to` extend through the housing 39 to an exhaustlopening 53 situated in the casing at the intermediate portion of the explosion chamber. Means, other than the main valve 43, are provided to introduce cooling air into the explosion chamber along the length thereof. To this vend, a plurality of ports 54 are arranged in the casing 35 between each end of the chamber 36 and the discharge conduit 52 to a'ord communication between the explosion chamber 36 and the supply chamber 40.

The flow of air through the ports 54 is controlled by pressure'responsive valves 55, preferably in the form of reeds. Eachvalve is essentially a resilient member normally held seated over the innerend 56v of its annular valve housing 51 by a boltf58 which clamps one 'end portion of the valve 55 between a washer v59 and the end 56 of the valve housing. Each-housing' 51 has a nice t in its port 54 and is held fixedly' therein by bolts 63. Thus, whenever a hgherpressure exists in the supply chamber 40 than in the explosion chamber 36 the valves 55 will bend inwardly in the direction of the explosion chamber and allow air to pass thereinto through the annular housing 51. To make the valves readily accessible for replacement or' repair, ports 6I are provided in the housing 39 opposite each of the ports 54 and said ports 6l are normally covered by plates 62.

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 approximates one half a pressure Wave length or an odd multiple' thereof, Accordingly, in order to determine the proper frequency of explosions for any given length of the chamber :i5-the natural frequency of the chamber being dependent on the velocity at which the pressure wave travels in the chamber 36 and the length of the chamber SS-it is merely necessary to vary the timing of the ignition and, of course, the injection of the fuel so that firing occurs when the peak of a pressure Wave refiected from the opposite end of the chamber 35 reaches the explosion zone 43. When this timing relationship exists, the pressure at the explosion end will be at a maximum Whereas the pressure at the opposite end of the container will be substantially at a minimum and the frequency of explosions will then be equal to, or an odd multiple of, the natural frequency of the chamberV 36. Measurements of pressure at opposite ends of the container may be facilitated by any Well known means (not shown). In furtherance of this cycle of operation, an end plate 63 of the casing serves as a reflecting inember to reverse the direction of movement of the peak of the pressure waves in the chamber 35 on contact therewith. The timing of ignition of the explosive charges in the zone 31 by the spark plug 48 may be accomplished in any well known manner, such as illustrated in United States Patent 2,517,822.

At the beginning of an operating period of the plant, the starting motor 33 imparts rotary movement to the

rotors

24 and 25 causing compressed air to flow into the supply chamber 4Q and through the port 42/ into the explosion zone 31. If then the fuel pump is put into operation, fuel will be injected into the air in the explosion zone 31 through the nozzle 41' and the resulting explosive mixture will then be ignited by the ,A

spark Vplug 48. This initial explosion forces the valve 43 to its seat, thereby cutting off the further flow of compressed air through the port 42, and the pressure Wave of the explosion travels toward the opposite end of the chamber 3B caus- ,u

ing a low pressure area to exist in front of the valve 43 which permits the valve to open and admit a new charge of air into the explosion zone 31. As the trough of the wave passes over the valves 55 near 'the explosion zone 31, they are forced open consecutively, starting with those nearest the point of explosion, at the instant the pressure of the wave drops below that of the air in the supply chamber 49. Cooling air is thus admitted over a large area into the. explosion end of the chamber 36 to intermingle With the hot gasestherein. Y

When the peak of the pressure -vvave hits the end plate 63 'it is reflected back toward its point of origin but the trough of the original wave will continue to move along toward the reflecting end of the chamber 35 and will thus also pass over thel valves 55 located near the reflecting end of the chamber 35 causing them to open consecutively and admit additional cooling air from the supply chamber 40 into the explosion chamber 36. The. cooling air also intermingles With the explosion gases and reduces their temperature suitably for use in the turbine 2 l.

The peak of the reflected pressure Wave moving toward the explosion zone 31 compresses the new charge of air therein and, at the instant when the peak of the Wave reaches the explosion zone, fuel is injected through the nozzle 4l' into the compressed air and this explosive mixture is ignited by the plug 48. Thus, another Wave is started which continues through the same cycle as that just described but lags behind Ythe preceding Wave by approximately one wave length. n Y

ItV will be readily understood that the exhaust gases will pass from the middle of the explosion chamber through the opening 53 at practically Y a constant pressure since the original pressure wave and its reflected wave move simultaneously in opposite directions in the chamber and the reflected Wave originates at the instant the origi- Y the scope of the appended claims.

I claim: 1

1. A resonant explosion povverunit, comprising a casing forming an explosion chamber, means for forming successive charges of an explosive mixture in only one end of the chamber, means for igniting the charges of explosive mixture, .an -end member `on the casing approximately one-half of an explosion Wave length from the point of` explosion in the chamber for reversing the direction of movement of pressure Waves at the instant of contact therewith, a plurality of valves arranged in spaced relation along the length of the end portion of the explosion chamber adjacent the end member and acting responsively to the pressure waves therein for introducing cooling air into the explosion gases, a plurality of valves arranged in spaced relation along the opposite end portion of the explosion chamber for admitting cooling air thereinto, and an exhaust opening in the casing intermediate the end member' and the point oi' explosion. 2. A resonant explosion power unit, comprising a casing having anv` explosion chamber having an explosion zone in only one end thereof, a housmg arranged around the casing to form an air supply chamber therebetween, means for introducing the. air, 4and fuel constituents Y or",

successive charges of Yan explosive mixture into the explosion chamber, means for igniting Vthe charges of explosive mixture at .a frequency equal tothe natural frequency of the chamber, end members on the casing serving to 5 6 the exhaust gases at practically constant pres- FOREIGN" PATENTS sure from the explosion chamber. Number Country Date GEORGE FARNELL 1,329 Great Britain Jan. 24, 1905 27,724 Great Britain Dec. 16, 1907 REFERENCES CITED 176,838 Great Britain Mar. 6, 1922 The following references are of record inthe 188,642 vCirieatt Britain Nov. 29, 1923 le of this patent: 239,434 Great Britain Sept. 10, 1925 UNITED STATES PATENTS 274,554 Great Britain Jan. 10, 1346 Number Name Date m 76,836 Germany May 20, 1 33 332,313 Wilcox Dec. 15, 1885 2,480,626 Bodine Aug. 30, 1949 2,523,379 `Kollsman Sept. 26, 1950 2,546,966 Bodine Apr. 3, 1951 2,550,515 Anderson Apr. 24, 1951 15