US1935659A

US1935659A - Pressureproof combustion chamber

Info

Publication number: US1935659A
Application number: US558261A
Authority: US
Inventors: Noack Walter Gustav
Original assignee: BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1930-09-01
Filing date: 1931-08-20
Publication date: 1933-11-21
Anticipated expiration: 1950-11-21

Description

Nov. 21, 1933. w. G. NOACK 1,935,659

PRES SUREPROOF COMBUSTION CHAMBER Filed Aug. 20, 1951 2 Sheets-Sheet 1 II I 10 a fig. 2

26 26 a 1 Z 14 a V INVEHTOR 22 By W G. lYoack S M FMQQQ HTTOITNEY NOV. 21, 1933. w NQAcK I PRESSUREPROOF COMBUSTION CHAMBER Filed Aug. 20, 1951 2 Sheets-Sheet 2 Patented Nov. 21, 1933 PATENT OFFICE PRESSUREPROOF COMBUSTION CHAMBER Walter Gustav Noack,

Baden, Switzerland, as-

signor to Aktiengesellschalt Brown Boveri 8; Cie., Baden, Switzerland, a joint-stock company of Switzerland Application August 20, and in Germany 12 Claims.

This invention relates to pressure-proof combustion chamber for subjecting combustible gases to combustion under high pressure, such as used in connection with gas turbines or steam generators, and it has among its objects simplified construction of such combustion chambers and reduction of their weight and costs.

The objects of the invention will be best understood from the following description of exemplifications thereof, reference being had to the accompanying drawings wherein Fig. 1 is a diagrammatic view of a steam generator with a combustion chamber made in accordance with the invention;

Figs. 2 and 3 are horizontal and vertical sectional views, respectively, of a section of the combustion chamber of Fig. 1;

Figs. 4 and 5 are horizontal sectional views of combustion chambers embodying modifications o! the invention;

Fig. 6 is a vertical sectional view of the chamber section of Fig. 5;

Fig. 7 is a horizontal sectional view of a combustion chamberstructure embodying a modification of the invention;

Fig. 8 is a vertical sectional view of a chamber section embodying a further form of the invention; and,

Fig. 9 is.a vertical sectional'view of a com-- bustion chamber structure embodying a modification of the invention. A

In my hopending application Serial No. 343,745, filed Marchl, 1929, I have disclosed a novel type of steam generator in which an extremely'high rate of steam generation is secured byperiodical- 1y subjecting a combustible mixture to explosiontype combustion in a pressure-proof chamber and utilizing the high pressure of the hot combustion gases formed in the chamber for imparting to said gases a very high velocity through a set of gas tubestraversed on the outside by a. steam generating fluid, such as water, thereby securing a very high rate of heat transference from the hot gases to the water and, as a consequence, very large steam generation within a relatively small structure.

The combustion chamber of such steam generator must be able to withstand the high pressure of the combustion gases, and it must be able to do it while it is exposed to the high temperature of such gases. To meet this double strain, of the pressure and of the heat, the walls of the combustion chamber must be cooled, and this is ordinarliy done by passing the steam generating fluid, such as-water, through cooling jackets sur- 1931, Serial No. 558,261,. September 1, 1930 rounding the chamber walls, the water taking up i the heat from the walls and converting it into steam, which is applied for the production of power. The cooling medium is then subjected to the full steam pressure, which may be considerably higher than the pressure in the combustion chamber. The cooling jacket must thus be able to withstand a higher pressure than the interior of the combustion chambenand the diameter of the cooling jacket will be considerably greater than the diameter of the chamber which is itself of considerable dimensions. Both conditions entail the provision of very thick walls for the combustion chamber and the cooling jacket, that is, heavy and costly bodies.

Since the heat must be led away through the walls of the chamber, it-must traverse the full wall thickness. There is accordingly a great temperature gradient in the wall and large internal strains appear in the wall material. Additional strains develop due to the large thermal expansion of the hot chamber walls relatively to the surrounding cool jacket walls giving further serious design difllculties.

Similar conditionsexist also in gas turbines where the combustion gases for driving the turbine blades are generated at high pressure in a pressure-proof combustion chamber and must be cooled to a lower temperature that will not burn the blades before discharge into the turbine; The chamber is therefore likewise ordinarily cooled by a jacket carrying water that takes up the heat and generates steam which is suitably utilized. The chamber as well as the jacket must both withstand high pressures, and their walls must be thick, giving, likewise, heavy and costly structures. e

In my prior application Serial ,No. 343,745, referred to above, I have shown that a much superior water-cooled high pressure combustion chamber may be obtained, by eliminating the water jacket around the chamber, and, instead, mounting a set of water tubes on the inner'side of the pressureresisting walls of the combustion chamber and in this way protecting the wall of the chamber fromexcessive heating. Asthe tubes are of relatively small diameter, their wall thickness is small even for high pressures of the cooling liquid. Since the cooling tubes lie on the inner side of the wall, the wall is protected against radiation from the combustion gases. The wall is only heated by the cooled gases collecting between the tubes and the wall, and by contact with the cooling tubes. The temperature of the walls cannot, therefore, be

' higher than the temperature on the rear side of the tubes. The temperature is accordingly low, and uniform within the wall, and there is substantially no flow of heat through the walls. The excessive stresses the chamber walls due to the temperature differences between the outer and inner-sides of the chamber walls and the jacket wall are thus eliminated. The only strain imposed on the chamber walls is that of the pressure of the gases in the chamber. The weight of the improved water-cooled pressure-proof combustion' chamber is thus considerably smaller and their construction much simpler than in case of chambers having an external jacket.

The present invention provides a further improvement in the construction of pressure-proof combustion chambers with interior tubular wall cooling. In accordance with the present'invention the interior wall of the combustion chamber is itself formed by the tubes through which the high pressure cooling medium flows, the tubes being welded together to constitute a smooth inner wall, and in some cases the welds between the tubes are made gas and pressure tight so as to hold the gas in the interior of the chamber without additional outer walls.

In Fig. 1 the invention is shown as applied to the combustion chamber of a steam generator of the type disclosed in my above referred to application Serial No. 343,745, Figs. 2 and 3 being detailed sectional views of the combustion chamber. The steam generator comprises a pressureproof combustion chamber having a main cylindrical section 2 with an inlet header 3 enclosing the bottom and an outlet header 4 enclosing the top of the chamber. Within the walls of the inlet header 3 is formed a water inlet chamber 5 and within the walls of the outlet header 4 is formed a water outlet chamber 6. A set of water tubes '1 is mounted along the periphery of the chamber 1 forming the inner walls thereof, the tubes being surrounded by a cylindrical outer wall 8, having at its ends flanges 9 within which the ends of the water tubes 7 are secured, as by welding. The tubes 7 are connected between the water inlet chamber 5 and the water outlet chamber 6 to pass water that is heated and vaporized while passing through the tubes, the mixture of hot water and admixed steam being discharged through a conduit 10 into a steam separator 11. The steam separates and collects in the upper part of the separator from where it is supplied to the load, and the water is collected in the lower .part of the separator, fresh feed water being supplied thereto through pipe 12. The water from the separator 11 is circulated through water tubes 7 by means of water pump 13 which is connected by pipes 14 between the separator 11 and inlet 15 of water chamber 5.

A combustible mixture, such as a gas or air with fuel' admixed thereto, is compressed by compressor 20 and periodically delivered to combustion chamber 1 through conduit- 21 and suitably operated inlet valve 22. The admitted compressed combustible charge is subjected to explosive combustion in the chamber, for instance by ignition with spark plugs mounted on the interior wall of the chamber. The resulting high pressure is utilized to drive the hot combustion gases at a velocity of about 200 meters per second or above through a set of gas pipes 26 connected to the upper end of the chamber and leading through the interior of the water tubes '7, the gases being discharged into the gas outlet duct, and therefrom, through pipe 28 into a gas turbine where a part of the energy still remaining welded to the adjacent tube walls.

in the gases is applied to drive compressor 20 and thus serves to initially compress the cornbustible charge supplied to the chamber. Additional driving power may be supplied to the compressor by an auxiliary motor 30, such as'a Diesel engine, coupled to the gas turbine 29, the total power supplied by the motor and the turbine being proportioned to be suflicient to produce in the compressor the pressure head necessary for imparting to the combustion gases the high velocity and for driving the auxiliary gas turbine to supply a part or all of the initial charging pressure. This charging and explosion process is periodically repeated resulting in a continuous efficient generation of steam.

As pointed out before, the combustion chamber must be able to withstand the high pressure developed by the explosive combustion of the compressed charge while it is exposed to the high temperature of the gases. This is achieved in a way much superior to the prior practices. As seen in detail in Figs. 2 and 3, the main section of the combustion chamber is made by arranging the water tubes 7, which circulate the water that is to be heated and converted into steam, axially parallel close together to form the wall enclosing the interior of the chamber. The adjacent water tubes '7 are either directly welded to each other, or preferably have the interior grooves between each other filled by insertions 31 in the form of a round wire, or of a special form 32 conforming to the outer surfaces of the adjacent tubes asshown in Fig. 4, the insertions being The welding of the .tubes to each other forms tight joints between the tubes and produces a tight enclosure. It is important to have the internal cylindrical surface of the chamber smooth and without interstices so as to prevent trapping of remnant burned or burning gases that might prematurely ignite the next fresh charge. To this end the interstices and junctions between the inner tube sides and insertions are filled during the welding with filler material 33 and the welds then ground with an emery wheel, so that the interior of the chamber Wall shall have the character of a continuous unitary wall.

In combustion chambers with water tubes arranged parallel to the chamber axis as shown in Figs. 2 and. 3, the tubes are preferably surrounded by the cylindrical wall 8, of steel or similar material. In such constructions, the water tubes 7, before being welded to each other at their inner-sides, are'tacked, by welding, to the wall .8, at several places, as indicated in Fig.

2 at"34, to insure their bearing against the wall.

The outercylinder wall 7 takes up the longitudinal strain exercised by the bottom and

top headers

3 and 4 on the main chamber section 2, andvalso' the tangential forces acting in the direction of the circumference of the chamber section 2, although a part of the tangential pres sure may be taken up by the welding of the tubes. Since the water tubes 7 lie directly'on the inner side of the cylindrical wall 8, the

temperature of the wall cannot be higher thanconstruction of a combustion chamber that is much lighter than ordinary high pressure, high temperature combustion chambers, eliminating also the complicated construction problems arisingdue to the pressure and heat stresses in the chamber walls.

Instead of cyindrical water tubes 7, tubes of special cross section may be used for the chamber wall. Such arrangement is shown in Figs. 5 and 6, where the distance between the tubes is increased, and their number decreased by pressing the water tubes 36 throughout their length to an oval shape. Each tube occupies a larger part of the chamber periphery, and the adjacent tubes are welded to each other and joined to form a continuous smooth inner wall by welding and depositing a welding filler at the junctions. The tubes retain their cylindrical shape only at their ends 37 inside the flanges 9, to facilitate their mounting. The water tubes for the chamber wall may also be of trapezoidal form 38, as shown in Fig. 7, to facilitate the building up of the cylindrical chamber walls, the cross section of the tubes being well rounded or beveled at the corners to provide junction spaces for receiving sufficient quantities of welding material.

Pressure-, and temperature-proof combustion chambers for steam generators and gas turbines in accordance with the present invention may also be made by helically woundtubes, as shown in Fig. 8. The individual turns 40 of the water tubes lie one above the other, forming a cylindrical chamber, and the inner sides of the junctions of adjacent tubes are welded to each other and filled with welding inserts 41 and welding metal 42 to provide a smooth interior surface like in the construction shown in Figs. 2 and 3. The end turns of the water. tubes 40 are lightly welded to the flanges 44 to which the bottom and

top headers

3 and 4 are clamped. Water for absorbing the heat of the chamber gases is circulated under pressure through tubes 40, the water being admitted and led away by suitable ducts 49 joined to the ends of the coiled tubes. The tangential.

forces'in the circumference of the chamber pro-- duced by the internal pressure in the chamber are taken up by the tubes 40 themselves, and no external cylindrical wall is needed. The welding of the tube turns provides tight joints, and gives a tight pressure-proof chamber. The longitudinal stresses in the chamber wall, impressed by the bottom and

top headers

3 and 4 of the cham-- her, are taken up by tension bolts 45 which also serve to bolt the bottom and top headers to the main cylindrical section formed by the tubes 40.

A lagging 47 is provided around the chamber which case, however, there must be provided in addition to bolts 45 for taking up. longitudinal stresses, also several outer clamping rings surrounding the tubes and taking up the tangential stresses produced by the internal pressure in the chamber. v

,Instead of using cylindrical helically wound tubes for forming the combustion chamber in Fig. 8, tubes of special profile, such as the rectangular tubes shown in Fig. 9, may be employed, welded at the junctions like the tubes of Fig. 7. 3

The present application is directed only to the features of my invention disclosed herein'involving a pressure resisting combustion chamber, the walls of which are made of adjacently disposed tube elements held together tight and pressure proof condition.- The steam generator apparatus disclosed above in connection with the exemplification of the foregoing invention embodies many other novel features for causing high temperature compressed combustion gases to discharge at a high velocity over a small evaporator structure and generate steam at a high rate as described and claimed in my copending applications, Serial No. 333,453 filed January 18, 1929, Serial No. 343,745 filed March 1, 1929, Serial "No. 343,746 filed March 1, 1929, Serial No. 375,138 filed July 1, 1929, Serial No. 414,428 filed December 16, 1929, Serial No. 419,026 filed January 7, 1930, and Serial No. 558,260 filed August 20, 1931.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I'claim is 1. A pressure-resisting combustion chamber for steam generaors or gas turbines, comprising a chamber wall formed of adjacently disposed metallic tube elements, closure members joined to said tube wall and constituting therewith a combustion chamber, means for admitting a comb ustible charge into said chamber and subjecting said charge to combustion under great internal pressure substantially higher than the external pressure, and ducts connected to the opposite ends of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure,'the tube elements forming said chamber wall being weldedv to each other along their inner junction surfaces and being held together to maintain with said closure members said chamber in pressure-proof condition.

2. A pressure-resisting combus ion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed of adjacently disposed metallic tube elements, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means for admitting a combusiible charge into said chamber and subjecting said charge to combustion under great internal pressure substantially higher than the external pressure, and ducts connected to the opposite ends of said tube elements for passing thereihrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than'the external pressure, the tube elements forming said chamber wall being welded to' each other along their inner junction surfaces and being held together to maintain with said closure members said chamber in pressure-proof condition.

3. A pressure-resisting combustion chamber 143 for steam generators or gas turbines, comprising a tubular chamber wall formed of adjacently disposed metallic tube elements, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means for admitting a combustible. charge into said chamber and subjecting said charge to combustion under great internal pressure substantially higher than the external pressure, ducts connected to the opposite ends of said 150 tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure, the tube elements forming said chamber wall being welded to each other along their inner junction surfaces and being held together to maintain with said closure members said chamber in pressure-proof condition, and additional means extending longitudinally along said tubular chamber wall to take up the longitudinal wall stresses imposed by the pressure within said chamber.

4. A pressure-resisting combustion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed of adjacently disposed metallic tube elements, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means for admitting a combustible charge into said chamber and subjecting said charge to combustion under great internal pressure substantially higher than the external pressure, and ducts connected to the opposite ends 'of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure, the tube elements forming said chamber wallbeing welded to each other along their inner junction surfaces to form a smooth interior chamber surface and being held together to maintain with said closure members said chamber in tight and pressure-proof condition.

5. A pressure-resisting combustion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed of adjacently disposed metallic tube elements, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means for admitting a combustible charge into said chamber and subjecting said charge to combustion under great internal pressure substantially higher than the external pressure, and ducts connected to the opposite ends of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a higher pressure than the pressure inside said chamber, the tube elements forming said chamber wall being welded to each other along their inner junction surfaces to form a smooth interior chamber surface and being held together to maintain with said closure members said chamber in tight and pressure-proof condition.

6. A pressure-resisting combustion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed or adjacently disposed metallic tube elements, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means for admitting a combustible charge into said chamber and subjecting said charge to combustion under great internal pressure substantially higher than the external pressure, and ducts connected to the opposite ends of said tube elements for passing therethrougha cooling fluid absorbing heat from the hot jcombustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure, the tube elements forming said chamber wall being welded to each other along their inner junction surfaces and having the grooves between said junction surfaces filled with metal inserts weldedto said surfaces to form a smooth interior chamber surface and being held together. to maintain with said closure members said chamber in tight and pressure-proof condition.

7. A pressure-resisting combustion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed of adjacently disposed metallic tube elements, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means for admitting a combustible charge into said chamber and subjecting said charge to combustion under great internal pressure substantially higher than the external pressure, and ducts connected to the opposite ends of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure, the tube elements forming said chamber wall having flat side walls welded to each other to form a smooth interior chamber surface and being held together to maintain with said closure members said chamber in tight and pressure-proof condition. c

8. A pressure-resisting combustion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed of adjacently disposed metallic tube elements, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means for admitting a combustible charge into said chamber and subjecting said charge to mbustion under great internal pressure substanti ly higher than the external pressure, ducts conn ted to the opposite ends of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure, the tube elements forming said chamber wall being welded to each other along their inner junction surfaces and being held together to maintain with said closure members said chamber in pressure-proof condition, and tension bolts extending longitudinally along said tubular chambenwall to take up the longitudinal wall stresses imposed by the pressure within said ends of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure, the. tube elements forming said chamber wall being welded to each other along their inner junction surfaces and being held together to maintain with said closure members said chamber in pressure-proof condition, and a tubular wall extending between said closure member's around said tubular chamber wall in longitudinal direction to fake up the longitudinal and tangential wall stresses imposed by the pressure within said chamber.

10. A pressure-resisting combustion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed of metallic tube elements helically wound adjacent to each other,

closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, and means connected to the ends of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure, the tube elements forming said chamber wall being welded to each other along their inner junction surfaces and being held together to maintain with said closure members said chamber in pressure-proof condition. I

11. A pressure-resisting combustion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed of metallic tube elements helically wound adjacent to each other, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means connected to the ends of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a pressure substantially higher than the external pressure, the tube elements forming said chamber wall being welded to each other along their inner junction surfaces to form a smooth interior chamber surface and being held together to maintain with said closure members said chamber in tight and. pressureproof condition, and tension bolts extending longitudinally along said tubular chamber wall to take up the longitudinal wall stresses imposed by the pressure within said chamber.

12. A pressure-resisting combustion chamber for steam generators or gas turbines, comprising a tubular chamber wall formed of adjacently disposed metallic tube elements, closure members joined to the opposite ends of said tubular chamber wall and constituting therewith a combustion chamber, means for admitting a combustible charge into said chamber and subjecting said charge to combustion under great internal pressure substantially higher than the external pressure, ducts connected to the opposite ends of said tube elements for passing therethrough a cooling fluid absorbing heat from the hot combustion gases and maintaining within said tube elements a higher pressure than the pressure inside said chamber, and an additional tubular solid wall surrounding said tubular chamber wall and joined to said closure members to take up the chamber stresses and maintain with said closure members said chamber in tight and pressure-proof condition.

WALTER GUSTAV NOACK.