US2729062A

US2729062A - Power plant combustion chamber

Info

Publication number: US2729062A
Application number: US235432A
Authority: US
Inventors: Fritz O Hennig
Original assignee: Dresser Operations Inc
Current assignee: Dresser Operations Inc
Priority date: 1951-07-06
Filing date: 1951-07-06
Publication date: 1956-01-03
Anticipated expiration: 1973-01-03

Description

Jan. 3, 1956 F. o. HENNIG 2,729,052

- POWER PLANT COMBUSTION CHAMBER Filed July 6, 1951 llilHlHlllllIIIIIIHIIIHIHHII llllflllll llllliHIIHIHIHNIIII IHHIIHIIIHIIIHIIIIIIIHIIIIH INVENTOR azyelmg'g ATTO POWER PLANT COMBUSTION CHAMBER Fritz 0. Hennig, Olean, N. Y., assignor, by mesne assignments, to Dresser Operations, 1110., Whittier, Califi, a corporation of California Application July 6, 1951, Serial No. 235,432

4 Claims. (Cl. 60--39.65)

This invention relates to power plants of the gas turbine type and more particularly to the combustion apparatus therefor.

In the copending application of Ward J. Bloomer and Hyman R. Davis, Serial Number 201,415, filed December 18, 1950, now Patent No. 2,674,846, there is disclosed a novel form of burner particularly characterized by a hollow cylindrical tuyere the side wall of which is provided with tangentially disposed blades forming a plurality of tangentially disposed air inlets. By passing air under suitable pressure through these inlets, a rapidly rotating air column is formed within the tuyere. It has the characteristics of a vortex in that the centrifugal effect tends to compact the air against the tuyere side wall in the nature of a hollow column and thence to cause the air column to discharge as an annulus from the open end of the tuyere. A low-pressure central section is also formed which causes a central gas inflow. In a furnace or combustion gas chamber, this becomes a recycle of hot gases.

The fuel is introduced to this rapidly rotating air vortex to become very intimately mixed therewith. The air-fuel mixture is then burned in an adjacent combustion chamber of predetermined diameter and length, thus keeping the tuyere cool. When the combustion chamber, in diameter, does not exceed four times the tuyere outlet diameter, and, in length, is at least approximately as long as it is in diameter, the vortical mixture of air and fuel will continue to burn in a so-called closed flame pattern of a spiral nature so that high heat release is accomplished in a very short axial length.

My invention is based on a modification and adaptation of the foregoing type of combustion apparatus, the whole being generally described as a combustor. I have found that in gas turbine practice, it is indispensible that there be no refractory or other material which can spall, chip, or disintegrate and flow with the gas to the turbine wheel. It is essential with such high speed and high temperature devices that there be no impact of particles on the wheel and nothing to cause erosion or corrosion or out-ofbalance conditions.

My invention relates to the construction and operation of a combustion apparatus which is primarily intended to be used with a fuel-air mixing device of the vortical tuyere type wherein the combustion chamber may be made from readily formed sheet metal plates integrated, without permanent bonds, one to another, to form an enclosed combustion chamber, a substantial area of the plates being subject to direct cooling and thus controlled radiation whereby long life is obtainable even at the high tempera tures of operation.

A further object of my invention is to provide, in such a combustion chamber, a central cylinder of approximately maximum diameter mounted adjacent the inlet end to maintain a high temperature surface adjacent the points of impact of the air-fuel mixture discharged from the tuyere, such cylinder being normally maintained at a temperature approaching the maximum combustion ited States Patent chamber temperature whereby deposit and coalescence of Fig. 2 is a transverse cross-section taken substantially along the line 22 of Fig. 1.

Fig. 3 is a plan view of a combustion chamber plate.

As generally known, a gas turbine is normally provided with a blower or compressor for the combustion supporting gas, usually air, a burner or mixer for mixing the air and fuel, a combustion chamber and an air diluting device. In the present embodiment of my invention, the combustor including the fuel-air mixer, combustion chamber and diluting device are conveniently mounted in a casing 10. The air, under suitable pressure is supplied to this casing through inlet 12 and the desired products of combustion are discharged at 14 to the turbine. It is to be understood that the casing 10 may be vertical or horizontal or at any other desired angle.

Within the casing 10,.adjacent the air inlet end 12 is V mounted the fuel-air mixer which may be of the specific type described in the copending application of Bloomer heretofore mentioned. This device, generally indicated at 18, is a hollow, preferably cylindrical, tuyere, the side wall of which is provided with blades 20 which may be stamped out of the wall or otherwise formed to provide tangentially disposed air inlets.

The tuyere 18 is provided with an apertured face plate 21 having openings 21a, and 21b, such plate extending to the supporting and enclosing wind box 22. A shield 23 extends over the front of the face plate and by passing a small amount of air through the openings 21a and 21b the tuyere is kept relatively cool. The windbox 22 is supported from the casing 10 in a suitable manner as by guide 25. The windbox receives the air for combustion which is then directed through the tuyere 18 to establish the air vortex or hollow column heretofore mentioned.

Fuel may be introduced to this rotating air column in any desired manner. Preferably a light fuel such as a distillate or gas may be introduced through line 28 into the feed pan 30 as hereinafter described and thence into the air stream as it passes between the blades 20 into the tuyere Heavier fuels may be introduced through line 32 and the closed end 18a of the tuyere through one or more nozzles 34. These nozzles, if a plurality are used, are interconnected as by a suitable distributing ring.

A highly effective distribution of the fuel is established by the flow of air through the openings between the blades which picks up the fuel and carries it into th internal vortical air column. This fuel-air mixture discharges as an annular column adjacent to the tuyere wall and thus into the combustion chamber 36 in which combustion actually takes place.

In accordance with a preferred form of embodiment of my invention, the combustion chamber 36 is of a flexible or non-rigid all-metal construction consisting of a plurality of flat plates 38 as particularly shown in Fig. 3. These may effectively extend the full length of the combustion chamber 36 and have marginal portions 38a and 38b for attachment and a central portion 380 which, when assembled, will be out of contact with the products of combustion. As will be noted from Fig. 2, the marginal portion 38a is partially curved and integrally attached to the casing 10 as by welding, rivets, etc. It continues to the central portion 380 which ends at the row of openings 38d. The other marginal portion 38b extends from 3 the openings 38d to the end of the plate 38 including the tabs 38c.

As noted in Fig. 2, the tabs 38c on one plate act as an integrating portion and extend into the holes 38d on the adjacent plate thus forming an interconnected polygonal cross-section combustion chamber which is free to expand and contract with temperature changes. The portions 38c heretofore mentioned are outside of the combustion chamber and in the cooling air stream passing through the casing. These thus provide high cooling rates for the exposed marginal portions 38b which are subject to direct radiation from the flame.

In addition to the flexible combustion chamber, I find it desirable to use the hot ring or sleeve 40 at the inlet end of the combustion chamber. This piece is cylindrical and nearly as large as the inner diameter of the combustion chamber and of a very high quality of metal that will withstand continuous flame temperatures. It is not substantially cooled by the outside air although ports 42 controlled by a damper 43 may provide more or less air over the outer surface.

It has been found in the burning of fuels having Conradson carbon contents greater than distillate fuels that a cold wall causes premature coke deposit. While the reason for this is not fully understood, it may be due to a partial coalescence and sticking of the liquid droplets. This appears to accumulate at certain spots after which the coke particles may break off and carry into the turbine. With the central sleeve extending over the range of discharge of fuel, such deposits are avoided.

As described in the aforementioned Bloomer application, a closed flame pattern in the combustion chamber is accomplished when the air flow through the tuyere inlets is in the order of 50 to 150 feet per sec. By limiting the combustion chamber to a maximum of about four times the tuyere diameter, the flame creates both inner and outer eddies in the plane of the axis of the tuyere and combustion chamber. The flame rotation about this axis further emphasizes the formation of these whirls or eddies and gives unusual flame stabilization. Indeed, the greater the issuing velocity, the greater the vortical velocity so that the flame may be regarded as stabilizing itself. Substantially complete combustion is thus accomplished in a relatively short length of combustion chamber which is at least as long as it is in diameter.

In most turbine practice it is necessary to reduce the temperature of the discharge gases to about 1000 F.- 2000" F. depending upon the duty and this is accomplished by by-passing a substantial part of the inlet air through the annular passageway 48 between the combustion chamber 36 and the casing 10. A damper may be used to control the amount which passes in this manner. This air then passes through the secondary tuyere arrangement shown at 44 and 46.

The secondary tuyere is of the same general construction as the burner tuyere 18 and is especially effective in accomplishing a uniform dilution of the products of cornbustion. As the secondary air from channel 48 passes into the tangential openings, it is uniformly diffused with the hot products of combustion to establish a uniform temperature of gas discharge. The secondary tuyere must be carefully formed to avoid the formation of a vortex which would form a core however and this may be accomplished by proportioning the air path openings so that there is about only one third the air velocity through the

tuyeres

44 and 46 that there is through tuyere 18.

It may also be found desirable to reverse the direction of certain of the

blades

44 and 46 in the secondary tuyere not only with respect to each other but also with respect to the blades in the burner. In a particularly successful operation, the two rows of blades 46 next to the combustion chamber were oppositely pitched with respect to the burner blades, and the next adjacent row of blades in tuyere 44 were in the same direction as the burner blades.

Temperatures at the gas discharge outlet 14 show extremely good distribution with average deviation from the mean of only about 10 F. to 20 P. where the mean was 1350 F. This is strikingly contrasted with other turbine combustion practice in which variations of about several hundred degrees from the mean temperature are often found.

While I have shown and described a preferred form of embodiment of my invention, I am aware that modifications may be made thereto which I consider within the scope and spirit of the description herein and the claims appended hereinafter.

I claim:

1. A power plant combustion chamber comprised of a plurality of plates, each plate extending along the central axis of the chamber and having a marginal portion attached to a support, a central portion normally out of the combustion zone and adapted to be air cooled, and a second marginal portion spaced from the first marginal portion by the central portion, said last mentioned marginal portion forming a part of the inner wall of the combustion chamber and means to secure the marginal edge of one plate to a central portion of another plate whereby expansion is provided.

2. A power plant combustion chamber as claimed in claim 1 which said plates form polygonal surface.

3. A combustion chamber having an air inlet end and a combustion products outlet end, comprised of a plurality of plates, each plate extending along the central axis of the chamber and having a marginal portion attached to a support, a central portion normally out of the combustion zone and adapted to be air cooled, and a second marginal portion spaced from the first marginal portion by the central portion, said last mentioned marginal portion forming a part of the inner wall of tie combustion chamber and means to secure the marginal edge of one plate to a central portion of another plate and a cylindrical imperforate sleeve concentrically mounted within the plurality of plates at the air inlet end.

4. In combustion with a fuel feeding device, a combustion chamber, having an air inlet end and a combustion products outlet end, comprised of a plurality of plates, each plate extending along the central axis of the chamber and having a marginal portion attached to a support, a central portion normally out of the combustion zone and adapted to be air cooled, and a second marginal portion spaced from the first marginal portion by the central portion, said last mentioned marginal portion forming a part of the inner wall of the combustion chamber and means to secure the marginal edge of one plate to a central portion of another plate, and an imperforate cylindrical sleeve concentrically mounted in spaced relation with the plurality of plates at the inlet end of said chamber, said sleeve extending a distance sufiicient to intercept the maximum range of discharge of fuel into said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,302,950 Muckle May 6, 1919 2,268,464 Seippel Dec. 30, 1941 2,299,154 Lair Oct. 20, 1942 2,420,135 Hennig May 6, 1947 2,555,965 Garber June 5, 1951 2,575,070 Reed et al. Nov. 13, 1951 2,581,999 Blatz Jan. 8, 1952 2,616,257 Mock Nov. 4, 1952