US2684574A

US2684574A - Means for directing gaseous fluid flow to combustion apparatus

Info

Publication number: US2684574A
Application number: US200054A
Authority: US
Inventors: Walter G Marskell; Edwin C Mckenzie
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1949-12-12
Filing date: 1950-12-09
Publication date: 1954-07-27
Anticipated expiration: 1971-07-27
Also published as: GB700003A

Description

y 7, 1954 w. G. MARSKELL ETAL MEANS FOR DIRECTING GASEOUS FLUID FLOW TO COMBUSTION APPARATUS 3 Sheets-Sheet 1 Filed Dec. 9, 1950 1 Inventor: WALTEKGMARi/(EZZ i LI); v-llld y 27, 1954 w. ca. MARSKELL ETAL 2,684,574?

. MEANS FOR DIRECTING GASEOUS FLUID I FLOW TO COMBUSTION APPARATUS 7 3 Sheets-Sheet 2 Filed Dec. 9, 1950 In venior: W417i? 6. M416; K511 y ,EDW/A/ amkmz/i 01. Attorney y 7, 1954 w. G. MARSKELL ET AL 2,684,574

MEANS FOR DIRECTING GASEOUS FLUID FLOW T0 COMBUSTION APPARATUS Fi led Iiec. 9, 1950 5 Shets-Sheet 5 v f F G. 6

Inveriior: W41 TEE 6, MAASKHL By EDW/A c. MKEA/Z/E M Attorney Patented July 27, 1954 MEANS FOR DIRECTING GASEOUS FLUID FLOW T COMBUSTION APPARATUS Walter G. Marskell, Kilmacolm, and Edwin C. McKenzie, Inchinnan, Scotland, assignors to The Babcock & Wilcox Company, New York, N. Y., a corporation of New Jersey Application December 9, 1950, Serial No. 200,054

Claims priority, application Great Britain December 12, 1949 14 Claims. 1

This invention relates to combustion apparatus of the kind comprising an outer casing adapted to resist internal pressure, an inner wall arranged within the outer casing, surrounded by a gas flow passage and enclosing a combustion and mixing chamber arranged to receive fuel at one end thereof and provided with an outlet for combustion and tempering gases at the other end thereof, which inner wall is formed with tempering gas inlet means. Such apparatus is useful for providing gas under pressure and at moderate temperature for use, for example, in a gas turbine. An object of the invention is the provision of improved inner walls.

T e present invention includes an inner wall for combustion apparatus of the kind specified, wherein a port or row of ports extends circumferential of the wall and the wall is provided adjacent the port or row of ports at one side thereof with a flange which extends radially inwards and axially of the inner wall and is adapted to direct tempering gas along the inner surface of the wall.

The invention also includes an inner wall for combustion apparatus of the kind specified,

formed with at least one port associated with inner and outer flanges projecting from the wall at or adjacent one side of the port, the inner flange extending radially inwards and axially of the inner wall and being adapted to direct tempering gas along the inner surface of the wall and the outer flange lying in the path of radiant energy passing outwardly through the port.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is an elevation of a combustion apparatus in section on the axis of a combustion chamber thereof;

Figure 2 is an enlarged view of part of Figure 1; and

Figures 3, 4, and 6 illustrate respective modifications of the apparatus of Figures 1 and 2.

Referring to Figures 1 and 2 of the accompanying drawings, a combustion and mixing chamber l enclosed by a cylindrical metallic inner wall 2 is arranged with its axis upright and is surrounded by an outer casing 3 adapted to resist internal pressure and spaced from the combustion chamber so as to leave an air flow passage t between the wall and the casing. The top of the combustion chamber is closed by a flat-topped cowl 5 secured at the lower end of a depending cylindrical part 6 thereof to the upper end of the inner wall 2. At the axis of the combustion chamber near the plane of the upper wall of the cowl is an air atomising oil burner 1 arranged to direct a combustible spray of oil downwardly. Leading from the chamber at the lower end thereof is an outlet duct 8 having an upper sharply converging part 9 on which the inner wall 2 is suitably supported and a lower part I0 which extends through the lower wall of the outer casing 3 and, gradually diverges to a conduit i l leading to the gas turbine.

Combustion is supported, cooling of metal parts effected, and the gases for use tempered, by air which is introduced Within the outer casing near the top thereof by an air duct 12. The inner wall 2 is pierced by peripherally extending slots is arranged in five spaced annular rows. With each row is associated an internal deflecting ring it of frusto-conical form which is secured by welding its lower edge to the wall adjacent the level of the lower edges of the slots and whose upper edge is below the upper edges of the slots. The slots in the different rows are staggered, so that the wall parts l5 between the slots in each of the upper four rows are vertically above slots in the row next below.

With each row of slots is associated a masking ring it extending around the inner wall 2, which is of sufiiciently larger diameter than the wall 2 to allow of easy movement axially thereof under all conditions but is sufficiently close to the wall to be able effectively to mask the slots of the row. Each maskin ring :6 is positioned by three rods 1!! which extend upwardly from lugs at equidistantly spaced points on the ring through the pressure casing 3 through glands [8 (Figure 3) to nuts l9 mounted in brackets H9, by which nuts the rods are secured in desired position and by turning which the masking ring may be raised or lowered.

In operation, air flows over the outside of the cowl 5 and generally downwardly in the air flow passage 4 and assists in cooling the cowl and in passing over the outer surface of the wall 2 and the inner surface of the outer casing 3 assists in cooling the wall and the casing. The air then enters through the slots [3 into the combustion chamber I, where it supports combustion of the fuel, dilutes the products of combustion, and cools inner surfaces of the wall 2 and the cowl 5. In view of the substantial number of slots, the pressure difference between the air flow passage 4 and the combustion chamber I is small, and in view of the short distance between adjacentrows of slots the cooling of the wall 2 is effective. The air entering the combustion cham-' her through the slots [3 is supplied by the deflecting vanes with an upward component of motion which has the result of establishing or increasing turbulence within the combustion chamber. The air is so admitted to the combustion chamber that combustion therein is not adversely aiiected, and the turbulence hastens complete combustion and the production of a suitably tempered gas stream of substantially uniform temperature. Turbulence of air in contact with the inner surface of the wall 2 promotes cooling of that wall.

The outlet duct 8 of converging-diverging form assists in ensuring that the gases reaching the turbine are of substantially uniform temperature.

In the region of the oil spray from the burner 1 there is a downward movement of air for first establishing combustion of issuing oil which air has been deflected upwardly into parts of the space within the cowl laterally of the burner upon entering the combustion chamber. It will be observed that much of the metal of the cowl is remote from the flame, while the outer surface of the cowl is traversed by substantially all the air supplied to the combustion apparatus.

The masking rings 153 are suitably positioned with respect to the slots. Thus at high loads they may be all clear of the slots 43 as shown in Figure 1 and in full lines in Figure 2, while at low loads in order to achieve proper mixing between tempering air and tempering gases, and proper protection of the metal of the wall 2, it may be necessary to supply the appropriate air quantity in greater proportion near the top of the combustion chamber and lower rows of slots may be either substantially wholly masked or partly masked by adjustment of the masking ring It to a position such as that shown in dotted lines in Figure 2.

If instead of masking the slot from the top edge of the slot as shown in dotted lines in Figure 2 the masking ring is moved downwardly to a position in which the slot is masked to the same extent from the bottom edge of the slot, the air is deflected by the deflecting ring to a lesser extent in the upward direction.

In the modification illustrated in Figure 4, the deflecting ring I l associated with each row of slots it by which air passes through the inner wall 2 to the interior of the combustion chamber is replaced by inner guide vanes 29 associated with the respective slots, each of which vanes forms part of a channel-shaped member having a rounded bottom and providing an outer guide vane 2i adapted to direct air flowing downwardly in the air flow passage 4 through the slot. The vanes diverge from one another upwardly from the lower edge of the slot, to which they are welded and overlap the wall above the slot so that a convergent entry and a divergent outlet to the air passage through the slot are formed even when the slot is not masked and radiant energy from the combustion chamber is intercepted before it can reach the outer casing. A masking ring it, positioned by rods i1, is provided for reducing the air flow through the slot to a desired extent.

In the modification illustrated in Figure 5, the inner wall is constructed in cylindrical sections of which

adjacent sections

2a, 2b are shown in part. The inner and outer guide vanes 30 and 3! similar in cross-section and position to those of Figure 4 are constructed as a ring extending round the whole periphery of the inner wall. The ring is welded to the upper edge of the lower cylindrical wall section 2b and to parts of the lower edge of the upper cylindrical wall section 2a whose lower end is castellated. Welded-on webs 32 extend between the vanes and the wall parts [5 between adjacent slots in the same row.

In the modification illustrated in Figure 6, the inner wall 2 is constructed in cylindrical sections, of which sections 20. and 2b are shown in part, and inner and outer guide vanes 39 and 3| respectively, in the form of a ring similar in crosssection and position to that of Figure 5, and welded at their lower ends to the upper edge of a wall section, and adjacent wall sections are spaced from one another, the spaces between adjacent wall sections forming annular ports it for the entry of air into the combustion chamber l. The wall section above the port is supported from the wall section below the port through a. number of brackets a'i, distributed around the periphery, which are welded to the outer guide vanes BI and have grooves therein permitting a certain amount of differential diametrical expansion between the two adjacent wall sections.

One or more of the illustrated constructions may also embody inventions the subject of claim in one or more or" other U. applications by the same inventors namely, Serial Numbers 200,051; 200,052 and 209,053.

We claim:

1. Combustion apparatus comprising spaced inner and outer walls defining a gaseous tempering fluid flow passageway therebetween and enclosing a combustion chamber of circular cross section, fuel injection means positioned axially of and in one end of said combustion chamber, means defining ports in and extending circumferentially of said inner wall, at least one of said ports extending around the wall formed by a gap between adjacent wall sections, and a frusto-conical flange coaxial with said combustion chamber and positioned adjacent one side oi said ports extending radially inwardly and axially of the inner wall toward said fuel injection means and arranged to direct gaseous tempering iiuid flow from said ports along the inner surface oi said inner wall, said flange being welded throughout its length to one of the wall sections.

2. Combustion apparatus comprising spaced inner and outer walls defining an annular gaseous tempering fluid iiow passageway therebetween and enclosing a combustion chamber of circular cross-section, fuel injection mean positioned axially of and in one end of said combustion chamber, means defining a row of ports in said inner wall including a castellated end of an inner wall section fixed with respect to a plane end of an adjacent wall section, and a frusto-conical flange welded throughout its length to the plane end of said latter inner wall section.

3. Combustion apparatus comprising spaced inner and outer walls defining an annular gaseous tempering fiuid fiow passageway therebetween and enclosing a combustion chamber, fuel burner means positioned in one end of said combustion chamber, means defining at least one port in and extending circumferentially of said inner wall, inner and outer flanges associated with and projecting from the inner wall adjacent one side of the port, the inner flange extending radially inwards and axially of the inner wall toward said fuel burner and being adapted to direct tempering gas along the inner surface of the wall and the outer flange lying in the path of radiant energy passing outwardly through the port.

4. Combustion apparatus according to claim 3,

wherein the inner flange and the outer flange extend axially beyond the other side of the port.

5. Combustion apparatus according to claim 4, wherein the inner and outer flanges in cross-section are shaped as a U with divergent limbs.

6. Combustion apparatus according to claim 5, wherein the inner and outer flanges are formed in one piece.

7. Combustion apparatus according to claim 3, wherein a plurality of circumferential rows of ports are formed in said inner wall, said rows of ports being spaced axially of said combustion chamber, each port in each row being associated with inner and outer flanges.

8. Combustion apparatus comprising spaced inner and outer walls defining a gaseous tempering fluid flow passageway therebetween and enclosing a combustion chamber of circular crosssection, said inner wall being formed of annular Wall sections with adjacent sections spaced axially of said combustion chamber to define a circumferential gaseous fluid inlet port opening to said combustion chamber, and inner and outer frusto-conical flanges welded throughout their lengths to one of said wall sections adjacent one circumferential side of said port to diverge from said inner wall.

9. Combustion apparatus according to claim 8, wherein the outer flange is provided with brackets with which engage the wall section other than that to which the outer flange is welded.

10. Combustion apparatus comprising spaced inner and outer walls defining an annular space therebetween and enclosing a combustion chamber of circular cross-section, said inner wall being formed of a plurality of cylindrical wall sections spaced axially of said combustion chamber to define a plurality of annular ports, an inner frusto-conical flange welded to one of said wall sections adjacent one side of each of said annular ports, an outer inverted frusto-conical flange welded to each of said inner flanges at the same side of each of said annular ports with said flanges substantially masking each of said annular ports, and a plurality of brackets attached to the outer flange and the adjacent wall section on the opposite side of each of said annular ports.

11. Combustion apparatus comprising an outer casing adapted to resist internal pressure, an inner wall disposed within the outer casing surrounded by a tempering gas flow passage and enclosing a combustion and mixing chamber arranged to receive fuel at one end thereof and provided with an outlet for combustion and temporing gases at the other end thereof, means defining a circumferentially extending port in said inner wall, internal and external deflecting means inclined to the axis of the combustion chamber and associated with said port, and a movable ring arranged to partly close said port, said deflecting means overlapping said ring and defining therewith a converging. entry to and a diverging exit from the tempering gas flow passage through the port.

12. Combustion apparatus as claimed in claim 11, wherein the wall is formed with a plurality of said circumferentially extending ports spaced axially of said combustion chamber each of said ports being provided with a movable ring operable to change the cross-sectional area of a port.

13. Combustion apparatus as claimed in claim 12, wherein at least one ring is movable separately from the other rings.

14. Combustion apparatus as claimed in claim 12, wherein at least two rings are movable together and are adapted simultaneously to cover their respective ports to different amounts.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,225,775 Garrett Dec. 24, 1940 2,268,464 Seippel Dec. 30, 1941 2,459,709 Lysholm Jan. 18, 1949 2,470,184 Pfenninger May 17, 1949 2,485,207 Logan Oct. 18, 1949 2,531,810 Fyffe Nov. 28, 1950 2,541,171 McGarry Feb. 13, 1951 2,552,851 Gist May 15, 1951 2,555,965 Garber Jun 5, 1951 FOREIGN PATENTS Number Country Date 585,398 Great Britain Feb. 6, 1947