US2689457A - Burner, particularly for gas turbines - Google Patents

Description

Sept. 21, 1954 KRUPPE 2,689,457

BURNER, PARTICULARLY FOR GAS TURBINES Filed March 7, 1950 3 Sheets-Sheet l 11s/VENTO@ TTORNEY H. KRUPPE BURNER, PARTICULARLY FOR GAS TURBINES sept. 21, 1954 3 Sheets-'Sheet 2 Filed March 7, 1950 Sept. 21, 1954 f1 TTRNE YS.

Patented Sept. 21, 1954 BURNER, PARTICULARLY FOR GAS TURBINES Herbert Kruppe, Decize, Nievre, France, assignor to Hermann Oestrich, Decize, Nievre, France Application March 7, 1950, Serial No. 148,175

Claims priority, application France March 15, 1949 8 Claims.

In conventional burners, particularly those designed for gas turbines, the mixture formation and combustion take place in the turbulent zone caused by a resistant body, for instance a cone or a frustum of a cone, arranged in the stream of air for supporting combustion.

Such burners which are called conical burners,

mainly comprise an outer sleeve and an inner one. in the shape of concentric frustums of a cone allowing passage of primary air therebetween for mixture further on with fuel injected through the centre.

It is quite obvious that the mixture formation is most intimate in the zone wherein direct contact occurs between air and fuel. It decreases in the outer layers of the stream which, owing to this fact, play a less active part in combustion. This causes a poor distribution of temperatures with a sharp peak on the axis of the burner.

It is an object of my invention to provide a burner which improves homogeneity of the mixture and ensures an even distribution of temperatures Within a wider space. For this purpose, the inner sleeve along the outlet edge of which the mixture formation starts, is widened by radial corrugations, and if need be, the outer sleeve is` similarly corrugated to have festoons projecting into the free space between the inner sleeve corrugations, in such a way that the passage for air for supporting combustion be reduced to a rel.

atively narrow slot along the outlet edgeof the corrugations. Instead of corrugations I may also provide appropriate shaped pieces arranged between the Outer sleeve and the inner one. The efcient length of the outlet edge is thus considerably increased and hence the zone wherein mixture formation takes place is widened. Combustion is therefore effected in that widened turbulent `zone whose cross-section depends upon the radial extent of the corrugations. The reduction in the annular space between the inner and outer sleeve does not cause a resistance to flow much greater than in the case of conventional conical burners provided the number of burners or the inlet crosssection for secondary air are correspondingly increased.

However, the improved homogeneity of the mixture thus obtained oiers the advantage of ensuring a higher combustion elciency which may reach 100%.

A further object of my invention is to provide a burner of the type just described which is so constructed that the temperature peak is shifted away from the burner axis. With that object in view, I may either draw the corrugatons nearer to each other in the portion of the burner which lies in the direction along which the temperature peak is to be displaced, or increase the crosssection of said corrugations relatively to the other ones. Thereby a greater amount of fuel and/or a smaller amount of primary air are swerved in thisl direction with a corresponding asymmetrical temperature distribution.

With burners as described it is possible, even at the highest iiow velocities, to provide ignition of the various burners according to a predetermined sequence in the case of arrangement in an annulal` combustion chamber. For this purpose, it is only necessary to arrange the burners in such a way that the hot gas jets from two successive burners meet.

Other objects and advantages of the :invention will be apparent during the course of the following description. In the accompanying drawingV forming a partof this application and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 is a plan view of a burner embodying my invention, as seen in the` direction opposite to the jet, y Y

` Fig. 2 is a section of the burner shown in Fig. 1 along line 2 2 of Fig. l, I

Fig. 2a is a section of the burner shown in Fig. 1 taken along the line 2a/-2a of Fig. 1,

Fig. 3 is a plan View of another burner according, to the invention, as seen in the direction oppositeto the jet,

Fig. 4 is a sectional perspective view taken along line 4 4 of Fig. 3, and

Figs. 5 and 6 show embodiments of a burner of the type shown in Figs. 3 and 4. seen in the direction opposite to the jet, and having an unsymmetrical temperature distribution.

In Figs. 1, 2 and 2a, the innersleeve I is secured, for instance by welding, to the outer sleeve 2 at the points of contact 3. The widening of the inner sleeve I and the corresponding reentrant portions of the outer sleeve 2 are clearly seen. Between these two sleeves are passages 4 for air for supporting combustion, corresponding to the six festoons or corrugations 5 arranged in star formation (Fig. 1). The corrugations may also be distributed otherwise, by selecting an arrangement comprising for instance eight or nine corrugations.

In the embodiment of Figs. 3 and 4, the inner sleeve generally designated by numeral I comprises a rearwardly flaring, front portion `II) fol- `lowed with a rearwardly tapering rear portion Projecting from the front into inner sleeve` formed with a forwardly flaring-*extension '13,

said extension and the rear portion of outer sleeve 2 having corresponding indentations to accommodate channel members or innersleeveextensions 6 which are frontwardly concave and provide radial baffles for theairflow supplied through passage il, so as to divide the air eiiluent into a plurality of separate jets. The channel extensions 6 are sheet metal strips, longitudinally bent and secured, for instance by welding; yto lthe outer sleeve 2 and extension I3 of inner sleeve I in `the corresponding indentations4 thereof.

Itfwill beiappreciated that owing to the shape of ya.do1'ible coneassumedby inner. sleeve I, the injector -'I vlies in a relatively quiescent, sheltered zone,and also that inview of the kconcave shape of channel .extensions 6, eddiesarefproduced in thechannels, i. e., on the rearside thereof,.pro moting mixture of air withthe `fuel-,spray from theinjector. v

Inv Figs.. 5 and 6, an unsymmetrical distribu tion of channel membersv and the provision -of channelfmernbersV 6 of different widthor peripheral extentv are respectively shown. In the former case, three' channelmembers 6 vhavezfbeenxmoved nearer I to'feach. other (top/.of Fig. 5) ,'while .the other ones are evenly distributedover thefremainderz'of.theiperiphery In Fig. 6,-distribu`tion is' symmetrical Ahowever it isnoted that the three top channelimembers 6- havebeen widened.

a greater proportion of fuel injectedv is directed towards the side thus alteredloffthe'burnerl and that fthe? temperature Ypeak is thereby displaced away from the'axisV ofthe burnerjnthe selected direction. This same result may take place owing to the smaller arn'ountiofA air passing through the reduced slots, or else to both elfects simultaneously.

It is to be understood that the forms'of the invention herewithshown rand described are to betaken as preferred examples ofthe same and that various changes in the shape; Isize and arrangementof'part's'may be resorted to without departing from the spirit of the invention orthe -scope ofthe subj'oined claims.

verge rearwardly and away from the sleeve axisiniistar. formation' to the rear periphery of said outer sleeve so as to provide a series of radial bafesaacross said annular space between-said inner and outer sleeves for'dividing the air efiluentinto-a plurality of separate jets.

2. The combination of claim 1, wherein the distribution of said fuel guiding, channel extensions is asymmetrical, said extensions being in closer proximity to one another over at least one sector of the rear periphery of said outer sleeve than overthe. remainder: of -rsaid periphery.

3. The combination of'claim' l, wherein the total peripheral extent of said fuel guiding, channel extensions over a sector of the rear periphery 'of-"said outersleeve is greater than over the diarnetrically opposite sector.

4.-. In a burner particularly for a gas turbine .plant,; the combination of an outer sleeve which generally' flares rearwardly, said sleeve having relatively shallow -corrugations provided in lengthwise direction, `the depth of which increases in rearwarddirection; with an inner sleeve, also varing rearwardly, formed with relatively deep corrugations which correspond with those of said outer sleeve and also have a depth increasing rearwardly,l ...said inner.v sleeve .-being. attached: to the .rearlfperiphery of` said outer.v sleeve solelyv in .the portions V.of maximum diameter.. thereof .so as .to..be v.supported `co-axially with Saidouter sleeve and to provide. between said inner sleeve and said outer sleeveagenerallyv annular air passage ending rearwardly in a. ring .series of V-.shaped intersp-aces. f

..5..The vcombinationof claim 4, wherein the corresponding. corrugations vin said-sleeves are fso designed and .arranged .that the various separate interspaces between said sleeves, providing.. the aiu-passages, are general-ly convergent rearwardly.

.6., In --awburnen .particular-ly. for-a gas turbine plant the. combination of.. an outer..sleeve which generally flares` rearwardly; an inner sleeve. of less cross .dimensions than said outer.sleeve,..lo

I catedI inthefrontportion of. said.. outer sleeve in coaxial..relationship therewithfto provide -an inner, sheltered, relatively quiescent zone for receiving `a rearwardly .directed stream-of fueland anfannular passage between .saidinner 4sleeve and said. outer Ysleeve for vsupply of air.v therethrough in, -rearward :direction and. va: plurality of separate, rearwardly concave, channel. members, `radiating.' instar-formation from and attached to the rear portion of. .the periphery. of .said .inner sleeve andcextending..andattached to the rear portionbf.. said louter sleeve, to .provide .baies adapted to divide Athe air .eliluentfrom said annularpas'sageinto aplurality of s eparatejets.

7. The combination. of claimn .6, whereinsaid channel members are-formed of bent sheet metal welded-.to said sleevesfor` bridging the4 same. and supporting said .inner y.sleeve .from said outer sleeve.'

.8.. The combination of claim 6, wherein. said inner sleeve. comprises a rearwardly haring front portion followed witha rearwardly tapering in-V termediatenportionfrom whichA said channel members radiate.

- References citeaun the fue of this patent .Unirse sTATEs PA'rENTs

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