US2569446A

US2569446A - Apparatus for the combustion of fuel, including a tubular walled combustion chamber

Info

Publication number: US2569446A
Application number: US506670A
Authority: US
Inventors: Claude A Bonvillian; Ralph C Brierly; Letvin Samuel
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-10-18
Filing date: 1943-10-18
Publication date: 1951-10-02
Anticipated expiration: 1968-10-02

Description

06L 1951 c. A. BONVILLIAN ETAL 2,569,446

APPARATUS FOR THE coususnou 0F FUEL, mcwnmc A TUBULAR WALLED COMBUSTION CHAMBER Filed Oct. 18, 1943 4 Sheets-Sheet 1 3o 2g 20 I 24 c1 2a 25 v 25 l9 FIG. 2

WITNESSES.

. c. A. BONVILLIAN ETAL APPARATUS FOR THE coususrrxou OF FUEL, INCLUDING Oct. 2; 1951 A TUBULAR HAL-LED COMBUSTION CHAMBER 4 Sheets-Sheet 2 Filed Oct. 18, 1943 WITBESSES -83&wnu9 /A w\ M44 1951 c. A. BONVILLIAN EI'AL 2,569,446

APPARATUS FOR THE COMBUSTION 0F FUEL, INCLUDING A TUBULAR WALLED COMBUSTION CHAMBER Filed Oct. 18, 1943 4 Sheets-Sheet 5 WIT NESSES. INVENTORS.

1951 c. A. BONVILLIAN EI'AL ,569,

APPARATUS FOR THE coususnon OF FUEL, mcwomc A TUBULAR WALL-ED COMBUSTION CHAMBER Filed on. 1a, 1943 4 Sheets-Sheet 4 FIG 7 INVENTORS. M I w I ,Patented Oct. .2, 1951 APPARATUS FOR THE COMBUSTION FUEL, INCLUDING A TUBULAR WALLED COMBUSTION CHAMBER Claude A. Bonvillian, Wynnewood, Ralph C.

Brierly, Narberth, and Samuel Letvin, Philadelphia, Pa.

Application October 18, 1943, Serial No. 506,870

4 Claims.

(Cl. Bil-39.32)

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) This invention relates to the combustion of fuels.

This application is related to our application Serial No. 479,010, flled March 13, 1943, issued March 21, 1950 as Patent No. 2,500,925, for Method and Apparatus for the Combustion of Fuel, in that this application discloses other forms of the inventions disclosed in that application.

The invention provides novel apparatus for the combustion of fuels, preferably at relatively high heat releases, which are applicable to a wide vari:- ety of uses, such as gas turbine systems, vapor generators, vapor superheaters, the heating of fluids, and the rocket or jet propulsion of aircraft. The apparatus of the present invention is characterized more particularly by the provision of a combustion chamber having a tubular wall of improved construction.

Furnaces embodying the invention preferably have an outer casing and means forming a combustion chamber within, and in spaced relationship to, the outer casing so arranged that secondary air may be supplied to the region surrounding the combustion chamber and delivered therefrom to the chamber to support combustion therein. The outer casing or the means forming the combustion chamber, or both, in the forms of the invention disclosed herein, include tubular members through which a suitable coolant is passed. Some or all of the coolant in the tubular members may be delivered into direct contact with the gases in the combustion chamber whereby vaporization or superheating, or both, of the coolant is efl'ected, or the coolant may be delivered to a place of use without direct contact with the gases. The tubular members forming the outer casing and the combustion chamber may be so constructed and arranged that the coolant flows through them separately, or in series, or in parallel, or in any combination of these types of flow.

It has been found entirely practicable to operate furnaces embodying the invention at heat releases on the order of ten million B. t. u. per cu. ft. per hour, and evidence is available that far higher releases are wholly practicable. Moreover, these furnaces possess wide flexibility, so that this heat liberation rate can be varied almost instantaneously through at least a ten to one range, for example, from one to ten million B. t. u. per cu. ft. per hour practically instantly. With furnaces embodying the invention and operating under constant firing conditions at the rates mentioned, it is possible to maintain temperatures of the gases flowing from the furnace within i25 F. of a given flgure, and to maintain CO2 percentages within 10.1%, with both substantially uniformly distributed across the exit end of the furnace. It is possible with this uniformity to operate continuously with furnace exit gas temperatures of at least 1800" F. The invention also permits the use of very high air preheats without jeopardizing the furnace or gas passages as evidenced by the fact that operations frequently have been conducted at air entrance temperatures of 600 F., and available data substantiate the fact that temperatures on the order of 1000 F. can be sustained advantageously. For these reasons, high power can be developed in furnaces of the invention which occupy no more than 2 or 3 cubic feet.

Apparatus embodying the invention requires no firebrick or refractory linings which customarily are employed in furnaces designed for operation at high heat releases in order to sustain combustion through the maintenance of high temperatures and radiant heat effects. In place thereof, heat resistant metal or equivalent material is employed and is cooled by the secondary air supplied to the furnace and by other fluids. The metallic members are so constructed and arranged that they serve to shape the flame in the desired manner, to promote attainment of the maximum heat release, the maximum combustion speed, and the maximum homogeneity of gases leaving the furnace, not only in regard to temperature but also with respect to constituents. This arrangement is particularly advantageous where lightness of weight is required, and it avoids the erosion that may occur with flrebrick or refractory linings with high velocities of air and gas, and which ordinarily results in the entrainment of particles which may have an abrasive action on turbine blading or cause deleterious results in portions of the system beyond the combustion chamber. Moreover, the ejection of incandescent particles of flrebrick or refractory would be disadvantageous with aircraft because of the resultant increase in the visibility of the aircraft. r vjI i The invention will be understood from the following description when considered in connection with the accompanying drawings forming a part thereof, and in which: i

Fig. 1 is a longitudinal sectional view of a furnace embodying the invention;

Fig. 1A, is front elevation partly in vertical cross section of the resilient means illustrated at 24' in Fig. 1

Fig. 2 is a transverse sectional view on line 2--2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1, showing another form of the invention;

Fig. 4 is a transverse and elevation on line 44 of Fig. 3 after removal of inner and outer burner (front) plates with the burner and its supporting plate omitted;

Fig. 5 is a longitudinal sectional view of a further form of the invention having tubular members associated only with the means forming the combustion chamber;

Fig. 6 is a transverse sectional view on line 6-6 of Fig.

Fig. 7 is a longitudinal sectional view of another form of the invention having tubular members associated only with the outer casing of the furnace, and

Fig. 8 is a sectional view on line 88 of Fig. '7.

Like characters of reference refer to the same or to similar parts throughout the several views.

Referring to Figs. 1 and 2 of the drawings, the furnace shown has an outer casing having cylindrical end portions and II and a central portion consisting of a tubular member l2 of spiral form having an inlet l3 and an outlet I4. A corrugated Sylphonlike runner or strip I! of spiral form fills the space between adjacent loops of the tubular member l2 and is welded thereto. The terminal loops of the spiral tubular member l2 are welded to the inner ends of the cylindrical peripheral portions of the end portions ill and II.

The combustion chamber I6 of the furnace is bounded by a tubular member If, preferably of resilient material, formed into a spiral with the individual loops thereof disposed in spaced relation'ship, and a spiral metallic band i8 which is secured to the tube I1. Fluid is introduced into the spiral tubular member I! through an inlet I 9 and is discharged through an outlet 20. As shown, the spiral band I8 is v-shaped in transverse cross-section, and the outer ends of the legs of the v are welded to the tubular member If so that the apex of the v will extend toward the outlet end of the furnace and the outer leg of the V will be spaced from the adjacent loop of the tubular member I1, thereby providing a spiral passage 2| which connects the combustion chamber IS with the annular passage 22 defined by the spiral tubular members l2 and I! and the metallic members secured thereto.

The terminal loop of the member I! at the inlet end of the combustion chamber abuts, or is secured to, an annulus 23 which is fixed to a member 24 having a plurality of radially extending arms 25' which are spaced from one another to form spaces 25" therebetween. The member 24 is carried by, and movable longitudinally in, the end member ID in spaced relationship to the outer end 25 of the end member. The terminal loop of the spiral band l8 at the outlet end of the combustion chamber, is in engagement with, or is secured to, an annulus 26 which is fixed to the outer end 21 of the end member ll. Expansion and contraction of the tubular member I1 is provided for by the movement of member 24 in the end member ID. Suitable resilient means'may be employed to urge member 24 toward the tubular member I! and to permit outward movement of member 24 upon expansion of the tubular member. One such means is shown in Fig. 1A wherein cushioning cylinder 24 is mounted on housing In by means of bracket 248 and cylinder plate 241 so that rod 242 of piston 243 engages chamber plate 24. Piston 243 travels in cylinder 24 in response to the urging of spring 244 or the rearward movement of plate 24. The tension on spring 244 is adjusted by movement of disk 249 in response to hand adjustment by knob 245 which causes threaded shaft 246 to travel inwardly or outwardly in plate 241. A plurality of cushioning cylinders 24' are preferably installed at intervals around the peripheral portion of plate 24 as shown in Fig. 2.

A plurality of fuel burners 28 having louvers 29 arranged in spaced relationship to each other and about the axis of the furnace, are supported by the member 24. Air is supplied to the burners 28 through a conduit 30 which discharges into a chamber 3| in the end member It. From the chamber 3|, the air flows through the burners and louvers and also flows through the openings in the outer peripheral portion of the member 24 into the annular space 22 for flow through the spiral passage 2| into the combustion chamber. The furnace is lighted off by any suitable means such as the devices disclosed in our previously mentioned application Serial No. 479,010, filed March 13, 1943, issued March 21, 1950, as Patent No. 2,500,925.

The form of furnace shown in Figs. 1 and 2 is particularly well adapted for use in a gas turbine system, with the air compressor located adjacent the left hand end of the furnace as viewed in Fig. 1, and with the gas turbine disposed adjacent the outlet end of the furnace at a the right hand end as viewed in Fig. 1. The turbine will drive a shaft 32 which passes axially through the furnace and drives the air compressor and any other devices requiring mechanical power. Drive shaft 32 is protected from the heat of the furnace by an outer metal shaft tube 33 and by an inner metal shaft tube 33' between which is installed suitable insulation 34. Any other suitable means may be employed for protection of the shaft 32.

In operation, fuel is introduced into the combustion chamber through the burners 28, and primary air is supplied tov the burners from the chamber 3| through the louvers 29. Secondary air is supplied to the periphery of the fuel and gas stream through the spiral opening 2| between the tubular member I! and the band it. The secondary air is directed obliquely into the combustion chamber with the result that the flame is compressed and assumes a conical shape, combustion is completed quickly and in a short path of flow of the fuel, the gases of combustion are diluted, a relatively high degree of homogeneity with respect to the temperature and constituents of the gas mixture is obtained, and the heat release per unit volume reaches the high figures previously mentioned. The coolant, which may be water, steam or chemicals, is passed through the spiral tubular member l1 and cools the boundary of the combustion chamber including the bands l8, and is also passed through the spiral tubular member l2 and serves to cool the outer casing of the furnace.

With this arrangement, the combustion chamber is a cooled, spiral-air-foil surface with the tubular member I! forming the air entering edge and the V-shaped band IS the leaving edge, and the outer casing of the furnace is a continuous spiral accordion-like member also cooled by the passage of suitable substances therethrough. The tubular members l2 and I! may be connected in parallel or in series to effect any desired result as far as the passage of coolant through the tubular members is concerned.

In the form of the invention shown in Figs. 3 and 4, the outer casing comprises a tubular member 35 in spiral form with adjacent loops of the spiral spaced apart slightly in overlapping relationship. As shown, the tubular member is flattened to provide a streamlined or airv foil cross-sectional configuration withthe larger coils of the tubular member. .chamber 31 is defined by a spiral tubular member 33 similar to the member 35, with the loops spaced apart and in overlapping relationship to provide a spiral passage 35 between adjacent loops. In the form disclosed, the inlet end of the member 38 is connected to the inlet end 45. Fig. 4, of the tubular member 35, and the outlet end is connected to the outlet end 4| of member 35. With this arrangement, the coolant, such as air, gas. water, steam or chemical, is passed in parallel through the

tubular members

35 and 33. Airfor the furnace is delivered through a suitable inlet to the chamber 42 and fiows therefrom into the annular passage 43 between the

tubular members

35 and 35; The inlet end of the furnace is closed by a circular plate 44 which isisecured to the end loop of the tubular member 35, and the annular space 43 at the outlet end of the furnace is closed by an annular plate 45 which is attached to the loop at the other end of the member 35 and to the end loop of the member 33 at the outlet end of the furnace. A single fuel burner 45 is mounted on a disc 44' which is secured to the end of the tubular member 35 which burner fires the furnace through an opening in the disc. More than one burner may be employed if desired. As shown, Jets 41 are disposed in those edges of the loops of the tubular member 35 which are nearer the exis of the combustion chamber, through which the coolant or other suitable substance may be discharged into direct contact with the gases in the combustion chamber 31. These jets may be omitted if desired, or they may be disposed in certain loops and not in others.

The operation of the form of the invention illustrated in Figs. 3 and 4 is the same as that of Figs. 1 and 2 excepting when the jets 41 are employed. With the jets 41 in some or all of the loops of the tubular member 38, part at least of the coolant or other substance delivered to the tubular members will be introduced into the combustion chamber 31 into direct contact with the combustion gases, so that vaporization or superheating of the coolant or other substance will be effected.

The form of invention illustrated in Figs. and 6, has a cylindrical outer casing 55, and a combustion chamber 5| bounded in part by a plurality oi metallic bands 52, each of which has its annular wall surface inclined inwardly toward the outlet end of the furnace, all of the bands being disposed in spaced relationship to the inner wall of the casing and to each other, with the outlet end of each band except the last, disposed within the inlet end of the next band in the direction of flow of the gases through the furnace. The first furnace band 52 at the burner end of the furnace has a cylindrical extension 53 which is secured to, or is in engagement with, the radially extending member 24. The inlet end of each band 52 is welded or otherwise secured to the inner peripheral portion of an annular tubular member 54, the interior of which is connected to the interior of the adjacent member or members 54 by a plurality of spaced, short tubular members 55 of smaller diameter than the members 54 and which are curved outwardly, as shown, to take care of expansion readily. Coolant, such as water, gas, steam or chemical, is introduced into the members 54 through an inlet connection 55 and is withdrawn through an outlet connection 51.

The operation of the embodiment shown in Figs. 5 and 6 is substantially the same as the embodiments previously described, excepting that the outer casing 50 is cooled only by ambient air.

The arrangement shown in Figs. 7 and 8 is like the form shown in Figs. 5 and 6, excepting that the outer casing is formed principally of tubular members and the metallic bands forming the casing do not have tubular members associated with them. Referring to Figs. 7 and 8, the outer casing comprises a plurality of straight tubular members 50 extending parallel to the axis of the combustion chamber 5| and arranged in a circle with adjacent members in contact with each other, as shown in Fig. 8. Leakage between the tubes is prevented by means of a cylindrical plate 5| welded, or otherwise secured, to the members 50. The metallic bands 52 surrounding the combustion chamber, are in spaced relationship to the tubular members 50 to provide an annular space 62 through which secondary air fiows from the chamber 3| to the combustion chamber 5| through the spaces between the bands 52, as previously described. As shown, the ends of the tubular members 55 at the burner end of the furnace are in communication with the chamber 3|. so that air from the chamber 3| will enter each of the tubular members 60. The members 50 are constructed to supply air or other coolant to all of the annular spaces between the bands 52, or only to such spaces as may be desired. As illustrated, each tubular member 50 is provided with a slot 53, anda baflle member 54 within the tubular member and so positioned with respect to the slot 53 that air or other coolant is directed into the desired space between the bands 52. Air also will enter the tubular members 50 through the slots 53 from the annular space 62 and will flll the members 60 from the baflle members to the ends of the members at the outlet end of the furnace. With this arrangement, the coolant can be introduced into a region of the combustion chamber adjacent the outlet end thereof in a relatively cool condition because the coolant will not become highly heated in flowing through the tubular members 50., If it is desired to utilize a coolant other than air, such as steam, gas, water or a chemical, the inlet ends of the tubular members 50 may be connected to a suitable manifold to which such other coolant would be supplied.

From this description, the operation of the form of furnace shown in Figs. 7 and 8 will be apparent and will be substantially the same as the operation of the forms shown in Figs. 1 to 6.

The relative quantities of secondary air introduced between adjacent bands is dependent upon the angle, length and general configuration of the bands, and the flow area of the openings between bands. Preferably, the bands and the air passages between them are so proportioned that combustion is completed in the earliest practicable time and in the minimum length of furnace, irrespective of high velocities of air, fuel, or both, and so that maximum homogeneity of the gas mixture and maximum progressive heat releases are obtained prior to the passage of the mixture beyond the end of the last band.

Preferably, the furnace bands are made of high temperature resistant alloy, such for example, as an alloy having 25% chromium and 20% nickel, or an alloy having 60% cobalt, 30% chromium, and 10% molybdenum. The furnace outer casing,

including any tubular members therein, may be of suitable metal having a lower percentage of constituents providing high heat resistance which may require none of these alloying materials, but is constructed sufliciently heavily to withstand any pressure of the air delivered through them by a. compressor or other means.

Any suitable conbustible may be used for fuel for firing the furnace such as oil, pulverized coal, gasoline or gas.

Should the cooling of the furnace bands and casing and the related parts present any difflculty, such as may occur with high preheat or with recycling, it may be desirable to employ firing devices for the furnace, or combustibles, or both, which are capable of producing blue flames, thus minimizing radiation, particularly in the initial stages of combustion near the firing end of the furnace. If desired, the furnace bands whether cooled by air or any suitable fluid, may be plated with suitable metals such as cobalt, rhodium, ruthenium, or the like, and these plated surfaces may be polished on the inner or furnace sides to provide reflecting areas. Liners of similar materials may be employed in the event plating is impractical. By the use of such means, heat absorption of the furnace bands, casings and associated parts may be decreased materially.

The invention disclosed herein may be manufactured and used by or for the Government of the United States for Government purposes without the payment of any royalty thereon or therefor.

It will be understood that changes may be made in the form, location and relative arrangement of the several parts of the furnaces disclosed herein, and changes may be made in the steps or in the sequence of steps of the method disclosed. without departing from the principles of the invention. Accordingly, the invention is not to be limited excepting by the scope of the appended claims.

What is claimed is:

1. Apparatus for the combustion of fuel comprising means forming a casing, means within the casing forming a combustion chamber and spaced from the inner wall of the casing, means for projecting fuel and primary air into the chamber wherein the fuel is ignited and burns in a moving stream therein, the means forming the combustion chamber being constructed and arranged to provide an opening adjacent the burning fuel stream, means for supplying air to the space between the casing and the chamber for passage through said opening into the cha m' ber, the means forming the combustion chamber comprising a tubular member of spiral form with the loops thereof spaced apart, a spiral member V-shaped in transverse cross-sectional configuration having the ends of the legs thereof fixed to the tubular member in such manner that one leg extends between adjacent loops in spaced relationship to one of said adjacent loops and the other leg extends substantially longitudinally of the combustion chamber, and means for supplying a coolant to said tubular member.

2. Apparatus for producing high speeds of combustion of fuel and high heat releases therefrom; comprising in combination: an outer casing; means forming an elongated unobstructed combustion chamber positioned within said casing to provide an elongated annular space therebetween; an outer spiral tubular coil in said casing extending adjacent said space; inlet and out- 8 let means for circulating 'coolant through the interior of said coil; means for the high speed projection of fuel and primary air into said chamber wherein said fuel is ignited and burns therein in a stream; means for projecting secondary air into said space; said means forming said chamber comprising a spiral deflecting band surrounding said chamber and arranged to provide a spiral opening extending along said chamber adjacent said stream whereby said secondary air is deflected inwardly and forwardly in an oblique direction to compress said stream; an inner spiral tubular coil surrounding said chamber and positioned adjacent said spiral opening; and inlet and outlet means for circulating coolant through the interior of said inner coil.

3. The combination of claim 2 wherein said chamber includes a rearwardly disposed end plate mounted for limited longitudinal movement within said casing, and adapted to retain the rearward end of said band and said inner coil; resilient means mounted in cooperating relationship with said plate whereby said plate may be moved rearwardly by longitudinal expansion of said band and said inner coil and moved forwardly by said resilient means upon longitudinal retraction of said band and said inner coil.

4. Apparatus for the combustion of fuel including a casing comprisinga tubular member of spiral form with the loops thereof spaced apart and a spiral strip welded to the tubular member for closing the space between the loops, means within the casing forming a combustion chamber and spaced from the casing, said means comprising a tubular member of spiral form with the loops thereof spaced apart, a spiral member V-shaped in transverse cross-sectional configuration having the ends of the legs thereof fixed to the tubular member so that one leg extends between adjacent loops in spaced relationship to one of said adjacent loops and the other leg extends substantially longitudinally of the combustion chamber, the point of the V being directed towards the discharge end of the chamber, means for supplying a coolant to said tubular members, means for projecting fuel and primary air into the combustion chamber wherein the fuel is ignited and burns in a moving stream therein, and means for supplying air to the space between the casing and the chamber for passage into the chamber between the loops of the tubular member forming the chamber.

CLAUDE A. BONVILLIAN.

RALPH C. BRIERLY.

SAMUEL LETVIN.

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

UNITED STATES PATENTS Number Name Date 1,372,121 Davis Mar. 22, 1921 1,483,917 Tucker Feb. 19, 1924 1,531,475 Brandt Mar. 31, 1925 1,817,470 Adams Aug. 4, 1931 1,828,784 Perrin Oct. 27, 1931 2,268,464 Seippel Dec. 30, 1941 FOREIGN PATENTS Number Country 4 Date 127,287 Germany Jan. 9, 1902 368,263 Great Britain Feb. 26, 1932 376,974 Great Britain July 21, 1932