US2869629A

US2869629A - Burner assembly

Info

Publication number: US2869629A
Application number: US551935A
Authority: US
Inventors: Anthony J Nerad
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1955-12-08
Filing date: 1955-12-08
Publication date: 1959-01-20
Anticipated expiration: 1976-01-20

Description

Jan. 20, 1959 A. J. NERAD 2,869,629

BURNER ASSEMBLY Filed Dec. 8, 1955 Inventor.-

A r7 thony d Ne rad,

/'-//'s Attorney.

BURNER ASSEMBLY Anthony Nerad, Alplaus, N. Y., assignor to General Electric Company, a corporation of New York This invention relates to burner assemblies and more particularly to burner assemblies which are used in gas turbine combustors, ramjets, afterburners, and household oil and gas burners.

.Flame extinguishment is a serious problem in gas turbine, jet,v propulsion, and domestic heating fields. A burner assembly which produces a stable flame is desirable to provide eflicient combustion and to prevent flame extinguishmentr Some present combustors use a rapidlyburning fuel or an increased amount of fuel in the fuel-air mixture 'to stabilize the flame. However, such additional fuel consumption creates a higher operating cost for the apparatus and requires excessive storage ispace for the fuel. The invention of the present application provides a burner assembly which has flame stabilization of a high order with normal requirements of a conventional liquid, gas or solid fuel.

Accordingly, it is an object of my invention to provide a new and improved burner assembly.

It is another object of the invention to provide an improved burner assembly which produces a stabilized flame without excessive fuel consumption.

It is another object of the invention to provide an improved burner assembly which can be used in gas turbine combustors, ramjets, afterburners, and household type oil and gas burners.

It is a further object of the invention to provide an improved burner assembly in which a portion of the flame stream is returned mechanically to the flame base to produce stable combustion.

In carrying out my invention in one form, a pair of inwardly curved numbers are positioned adjacent the outlet end of a fuel-air casing to produce a direct mechanical return of a portion of the flame from a zone of combustion to the flame base. Thus, thermal regeneration ofa highand controllable value is provided for high space rates of combustion.

These and various other objects, features and advantages of the invention will be better understood from the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a partial sectional view of a burner assembly which embodies my invention;

Fig. 2 is a front elevational view of the burner assembly shown in Fig. 1; and

Fig. 3 is a partial sectional view of a modified burne assembly.

In Figs. 1 and 2 of the drawing, a burner assembly is shown which comprises a fuel tube 11 spaced coaxially within an outer air inlet casing 12. Tube 11 which is shown in the form of a cylinder has a closed outlet end 13 with a central fuel aperture 14 therethrough. This arrangement is broadly descriptive of various forms of fuel nozzles. Casing 12 projects beyond closed end 13 to provide an air stream for atomization of fuel which is sprayed from aperture 14. Air and fuel are supplied to their respective casing and tube from any suitable sources (not shown). A pair of radial the burning stream of fuel air mixture.

c 1 2,869,629 Patented Jan. 20, 1959 ly and axially extending inwardly curved metallic members 15 with inturned lips 16 are positioned on opposite, outer surfaces of casing 12 adjacent the outlet end thereof or alternately may be formed from extensions of end portions of the casing 12. The inwardly curving may be defined in one sense as a hook member or a volute curve which commences in a direction substantially parallel to the longitudinal axis of the casing 12 and progresses in a general radial and axial direction away from the fuel outlet end 13 with the smooth volute curving inwardly toward the longitudinal axis of the casing and terminating in an inturned lip surface facing outlet end 13 to provide a stripping or peeling action of part of If it is desired, members 15 may be composed of a suitable refractory material. While a pair of members 15 are shown in Fig. 1 of the drawing, it should be understood that a single member or a plurality of members could be employed, and that such members may be axially extending without having an increase in the radial dimension. These members may be curved flat strips or have inner planar surfaces to peel a portion of the burning mixtureand guide or redirect this portion rearwardly to the fuel nozzle outlet end 13. I have found that a space should be provided between adjacent membersfor side air flow to support combustion.

In operation of burner assembly 10, a liquid, gas or solid fuel is provided from a source of supply (not shown) through tube 11 and sprayed from aperture14 into an air stream which is produced by tube 12.. The atomized fuel-air mixture is ignited within the confines of members 15 in any suitable manner to provide an initial flame stream which extends beyond members 15 as indicated by arrows 17 and engulfs lips 16. A portion of the flame is peeled off by lips 16 and returned directly to the base of the flame by members 15 .as indicated by arrows 18. This mechanical return of a portion of the flame stream from a zone of hot, rapid combustion to the flame base stabilizes the initial flame.

stream through a mixing of hot combustion products to provide eflicient combustion and to prevent flame extinguishment. I have discovered that a substantial portion of the initial stream can be returned to the flame base with an increased stabilization of high order.

In Fig. 3 of the drawing, a modified burner assembly 20 is shown which comprises a fuel tube 11 spaced c0- axially with an outer air inlet casing 12. Closed outlet end 13 of tube 11 has a central aperture 14 therethrough. A pair of hollow, inwardly curved members 21 with inturned lips 22 are positioned on opposite, outer surfaces of the outlet end of casing 12. The inner wall of each member 21 has a plurality of louvers 23 with associated apertures 24 which are directed toward the outlet end of casing 12 to provide an additional fluid stream, such as, air for combustion and cooling.

In the operation of burner assembly 21], the atomized fuel-air mixture from tube 11 and casing 12 is ignited to produce an initial flame stream which extends beyond members 21 as indicated by arrows 25. A portion of the flame is peeled off by lips 22 and returned to the flame base by members 21 as indicated by arrows 26. This mechanical return of a portion of the hot burning and burned combustion products to the flame base stabilizes the initial flame stream. An air stream flows through inlet 28 to each member 21 from a source of supply (not shown) as indicated by arrows 27 to cool the member during burner assembly operation. Air is discharged from members 21 through apertures 24 and directed by louvers 23 in a vortical stream toward the casing outlet to provide additional air for mixing with combustion products and the burning reactants.

As will be apparent to those skilled in the art, the

objects ofmy' invention are attained by" the use of a pair of inwardly curved members which are positioned adjacent the outlet end of a fuel-air casing to produce a direct mechanical return of a portion of the flame from a zone of combustion to the flame base to provide a highly stabilized flame.

1While other modifications of this invention and variations of apparatus which may be employed within the scope of the invention have not been described, the invention is intended to include all such as may be embraced within the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

l, A burner assembly comprising a hollow, substantially cylindrical casing having an inlet and an outlet, a fuel tube spaced coaxially within said cylindrical casing, a closed outlet end on said tube, said closed end having a central aperture therein and spaced inwardly from the outlet of said cylindrical casing whereby a fuel air stream is ejected from said outlet for ignition thereof, a hollow strip member positioned adjacent the outlet of said cylinder to extend therefrom in a general radial and axial direction and curving inwardly toward the longitudinal axis of said cylindrical casing to form a lip surface facing the outlet ofv said casing, said lip surface intercepting a portionof the burning fuel air mixture for redirection along the lip surface to the casing outlet, said hollow .strip members defining an air passage therein, and a plutially' cylindrical casing having an inlet and an outlet, a fuel tube spaced coaxially within said cylindrical casing,

a closed outlet end on said tube, said closed end having a central aperture therein and spaced inwardly from the outlet end of said cylindrical casing to provide a fuel air stream ejecting from said outlet for ignition thereof, a

plurality of hollow relatively flat strip members adjacent the outlet end on said cylindrical casing and positioned en the periphery thereof in opposite and species flit surface relation to eachother, the said members extending from the said outlet in a generally radial and that direction and curving inwardly toward each other and the longitudinal axis of said cylinder to provide a lip surface facing the casing outlet, said lip surface intercepting a portion of the burning fuel air mixture for redirection along the lip surface toward th e casing outlet, the said members defining an internal air passage therein, and a plurality of louvres on the said lip surface to provide a vortical air stream for the redirected portion of the burning fuel air mixture; j v

3. A burner assembly comprising in combination a fuel nozzle to emit a spray of fuel, means supplying combustion air for mixture with the fuel spray for burning thereof, a hollow strip member, means supporting the hollow strip member adjacent the periphery of the nozzle at the outlet thereof, said strip member extending from the outlet of said nozzle in a generally radial and axial direction and curving inwardly toward the longitudinal axis of said nozzle to form a lip surface'facing the outlet of said nozzle, said lip surface intercepting a portion of the burriing fuel air mixture for redirection along the lip surface to the nozzle outlet, said hollow strip member defining an inner air passage, and a plurality of louvres' 011 said lip surface to provide a vortical air stream for the redirected portion of the burning. fuel air mixture;

References Cited in the i116 of this atent,

UNITED STATE-S PATENTS