VAPORIZING COMBUSTOR TUBE

Abstract: In prior art vaporizing combustors (18) having a chamber (30) having first (32) and second (34) end portions, fuel (42) and oxidizer (46) delivering structures for delivering fuel (44) and oxidizer (48) streams to the first end portion (32), the streams (44, 48) mixing to form a mixed stream (40) and a splash structure (38) which receives the mixed stream (40) and directs it (40) generally towards the second end portion (34), the fuel and oxidizer are generally mixed external of the chamber (30) and enter the chamber (30) via a single tube. The flame in the chamber (30) tends to produce hot spots on the tube, leading to thermal stress. Carbon deposits can form within the tube. Herein, these problems are solved by separate fuel (50) and oxidizer (56) delivery structures having respective delivery end portions (52 and 58) within the chamber (30) with the fuel stream (44) flowing towards the second end portion (34) and the oxidizer stream (48) flowing towards the first end portion (32) and aligned to impinge with the fuel stream (44).

Description: Description Vaporizing Combustor Tube Technical Field This invention relates generally to improved fuel delivery and oxidizer delivery means for use in a vaporizing combustor, and more particularly to use of such improved fuel and oxidizer delivery means in gas turbines. Background Art In prior art vaporizing combustors, the fuel and oxidizer have generally been added together through a single vapor tube. The flame which surrounds such a vapor tube is quite variable and tends to produce, hot spots on the vapor tube, which in turn leads to severe thermal stresses and incipient melting. Further, carbon deposits have tended to form within such vapor tubes, thus restricting the fuel and oxidizer flow and eventually rendering the system inoperable. Still further, because of the hot spots formed on the vapor tube by the variable flame which surrounds it, the lifetime of such a tube has been undesirably short. Because of the aforementioned severe thermal stresse.s, it is difficult to use materials such as ceramics which would have an adequate service life even when subjected to a variable flame and which would also be effective in preventing carbon deposits. Still further, lighting off of the fuel-oxidizer mixture is often relatively slow with prior art designs, thus resulting in slow engine starting. The present invention is directed to overcoming one or more of the problems as set forth above. BAD ORIGINA - ffK E t PI Disclosure of the Invention In one aspect of the present invention an improvement is set forth in a vaporizing combustor having a side wall construction defining a chamber having first and second end portions, fuel delivery means for delivering a fuel stream to the first end portion, oxidizer delivery means for delivering an oxidizer stream to the first end portion, the streams mixing to form a mixed stream, and a splash structure positioned to receive the mixed stream and adapted to direct the mixed stream generally towards the second end portion. The irrfprovement of the present invention is wherein the fuel delivery means includes a fuel delivery tube structure having a delivery end portion within the chamber and from which the fuel stream flows generally towards the second end portion and wherein the oxidizer delivery means includes an oxidizer delivery tube structure having an outlet end from which the oxidizer stream flows generally towards the first end portion, the tube structures being positioned to generally impinge the streams and form the mixed stream within the chamber. In another aspect of the present invention a rr.e hod of introducing a fuel and an oxidizer into a vaporizing combustor is disclosed. The method includes flowing a fuel stream at a fuel velocity into a combustion chamber defined by a side wall construction and having first and second end portions, the fuel stream being flowed into the first end portion, the direction of flow of the fuel stream being generally towards the second end portion. An oxidizer stream is flowed at an oxidizer velocity into the chamber, the direction of flow of the . I BAD ORIGINAL - VRE Yj oxidizer stream is generally opposed to that of the fuel stream. The oxidizer stream is flowed into impingement with the fuel stream to form a mixed stream, the oxidizer velocity being sufficiently greater than the fuel velocity to cause the mixed stream to flow generally towards the first end portion. The flow of the mixed stream is then redirected towards the second end portion. Through utilizing an improvement as set out above, oxidizer and fuel are never mixed within the separate oxidizer and fuel delivery tubes. This prevents the formation of carbon deposits with resulting restriction in fuel and oxidizer flow. Since the oxidizer delivery tube structure does not transport any relatively cool fuel, the thermal stress thereof is limited and it can be made of a ceramic material, thus giving it adequate service life at high temperatures. The oxidizer delivery tube structure can also be of simple geometry to minimize thermal and mechanical stress. Thus, the oxidizer deliver tube structure can operate very hot, but can be made of a suitable ceramic to give it long service life. Because of the thorough mixing of fuel and oxidizer, light off time for complete ignition is significantly reduced, thus providing quicker engine s υ rti . Brief Description of the Drawings Figure 1 illustrates, in a fragmentary elevational view, a portion of a vaporizing type gas turbine, partially broken away, and showing vaporizing combustor tubes and associated mechanism within an annular burner in accordance with an embodiment of the present invention; BAD ORIGINAL OMFI Figure 2 illustrates, in a fragmentary enlarged view, partially in section, a vaporizing combustor tube design and associated structure in accordance with an embodiment of the present invention; Figure 3' illustrates, in a fragmentary enlarged view, partially in section, a vaporizing • combustor tube design as in Figure 2 and taken generally along the line III-III; Figure 4 illustrates, in a fragmentary enlarged view, partially in section, a structure for mounting an oxidizer delivery tube structure to a side wall of an annular burner, all in accordance with an embodiment of the present invention; Figure 5 illustrates, in a view similar to Figure 2, an alternate embodiment of the present invention; and Figure 6 illustrates a view taken gensrally along the line VI-VI-of Figure 5. Best Mode For Carrying Out The Invention Embodiment of Figures 1-3 Adverting to Figure 1 , there is shown a gas turbine 10 which includes an outer case 12 and an inner case 14 which are substantially coaxial and which define therebetween an annular chamber or space iβ within which an annular burner or vaporizing combustor 18 is mounted. The vaporizing combustor 18 has a side wall construction 20, particularly an outer wall 22 and an inner wall or liner 24. A far more detailed description of a gas turbine of the nature shown in Figure 1 can be found in U.S. Patent 4.030,288 of Warren . Davis and David E. Keeley, issued June 21, 1977. Since the present invention is concerned solely with an improvement in the O RIGINA 1 vaporizing combustor 18, the gas turbine 10 will not be further described at this time. The side wall construction 20 defines an annular chamber 30 having a first end portion 32 and a second end portion 3 . An end wall 3β closes off the first end portion 32. A splash plate or structure 38 (Figure 2) is positioned in the first end portion 32 of the chamber 30. The splash plate 38 is positioned to receive a mixed stream, as indicated by arrows 40, and is adapted to direct the mixed stream generally towards the second end portion 34 of the chamber 30. In accordance with the present invention very particular fuel delivery means 42 are utilized for delivering a fuel stream as shown by arrows 44 to the first end portion 32 of the chamber 30. Further, very specific oxidizer delivery means 46 are utilized for delivering an oxidizer stream, as indicated by arrows 48, to the first end portion 32 of the chamber 30. The fuel delivery means 42 includes a fuel delivery tube structure 50 having a delivery end portion 5 within the chamber 30 and from which the fuel stream, symmetrical about a centerline 5^ and indicated by arrows 44, flows generally towards the second end portion 34 of the chamber 30. As is particularly apparent from Figure 2, the fuel delivery tube structure 50 enters the chamber 30 through the end wall 36 and continues through the splash plate 38. Turning next to the oxidizer delivery means 46, it will be seen that this includes an oxidizer delivery tube structure 6 having an outlet end 58 from which oxidizer stream (arrows 48) flows ~ BAD ORIGINA ■ JΕE l OMPI generally towards the first end portion 32 ' . The delivery end portion 52 of the delivery tube structure 50, and the outlet end 8 of the oxidizer delivery tube structure 6, are so positioned as to generally impinge the streams of fuel (arrows 44) and oxidizer (arrows 48) and to thereby form the mixed stream (arrows 40). The oxidizer stream (arrows 48) defines a centerline 60 and the tube structures 50 and 56 are preferably positioned to cause the centerlines and 60 to ntersect. It is particularly preferable to position the tube structures 50 and 56 so that the center lines 5 and 60 are coincident. Adverting now to Figure 3, the fuel delivery tube structure 50 is shown as entering the chamber 30 through the side wall construction 20, and more particularly through the outer wall 22. Figure 3 shows this * only generally. The tube structure is preferably formed of a high temperature resistant material e.g., ceramic material, which can stand the very hot temperatures of the flame which surround it within the vaporizing combustor 18. It should be noted that the fuel stream (arrows ^ and the oxidizer stream (arrows 48) ' generally have velocities which are selected to cause the mixed stream (arrows 40) to impinge on the splash structure 38. The velocities are chosen so that fuel will not enter the oxidizer delivery tube structure 6 and oxidizer will not enter the fuel delivery tube structure 50. Embodiment of Figure 4 Figure 4 shows the oxidizer tube 6 passing through the side wall construction 20 at a different B^D ORIGINAL ^ ' , OMPI angle (90°) and shows means 62 for resiliently mounting the oxidizer delivery structure tube 56 to the side wall construction 20. Briefly, a sleeve 64 surrounds the tube structure 56 and is welded to the side wall consturction 20. A pin 66 fits within an appropriate generally radially extending bore in the sleeve 64 and also in. an ' appropriate bore in the tube structure 56. Embodiment of Figures 5 and 6 In the embodiment illustrated in Figures 5 and 6, primes have been added to the numbered parts which differ from those parts in the embodiment of Figures 1-4. In the embodiment of Figures 5 and 6, the delivery end portion 52 τ of the fuel delivery tube structure 50 f includes a pair of delivery ends 52a,52b through each of which a respective portion of the fuel stream (arrows 44') flows. The delivery ends 52a, 2b are positioned to direct the respective portions of the fuel stream 44' generally towards the second end portion 34 of the chamber 30 and generally outwardly towards the side wall construction 20, to define an included angle, A, between said respective portions. The oxidizer delivery tube structure 6 is positioned to deliver the oxidizer stream (arrows 48') generally along a bisector of the included angle, A. The splash structure 38' is noncircularly symmetrical, and has a pair of lobes 38 'a and 38 'b, each extending outwardly towards the side wall construction 20 and part way laterally about the annular chamber 30. The lobes 38'a and 38 'b are located between the end wall 36 and each respective one of the portions of the fuel stream (arrows 44'). The embodiment of Figures 5 and 6 thus provides a somewhat more controlled directing of the mixed BAD ϋRlC-lMA - l E t OMPI stream (arrows 40 ') than the embodiment of Figures 1- 4. Method A method of introducing a fuel and an oxidizer into a vaporizing combustor 18 also forms a part of the present invention. In accordance with the method, a fuel stream (arrows 44 or 44') travelling at a fuel velocity is flowed into a combustion chamber 30 defined by side wall construction 20 and having first 32 and second 34 end portions. The fuel stream (arrows 44,44') being flowed into the first end portion 32 are aligned so that direction of flow of the fuel stream (arrows 44,44') is generally towards the second end portion 34 of the chamber 30. Also in accordance with the method of the present invention, an oxidizer stream (arrows 48,48') moving at an oxidizer velocity is flowed into the chamber 30, the direction of flow of the oxidizer stream (arrows 48,48') is generally opposed to that of fuel stream (arrows 44,44'). The oxidizer stream (arrows 48,48') is flowed " into impingement with the fuel stream (arrows 44,44') to form a mixed stream (arrows 40,40'). The oxidizer velocity is sufficiently greater than the fuel velocity to cause the mixed stream (arrows 40,40') to flow generally - towards the first end portion 32. As a further step, the method of the invention includes redirecting the direction of flow of the mixed stream (arrows 40,40') towards the second end portion 34 of the chamber 30. Industrial Applicability Operationally, the invention includes a fuel delivery tube structure 50 which introduces SAD ORIGINAL MPI fuel with a velocity vector from a first end portion 32 towards a second end portion 34 of a combustion chamber 30. Oxidizer is supplied via an oxidizer delivery tube structure 46 with a velocity vector towards the. first end portion 32 of the combustion chamber 30. The fuel and oxidizer streams impinge upon one another and the relative velocities of the two streams are such that a mixed stream is formed with a velocity component towards the first end portion 32. A splash structure 38 or 38' is located between the outlet end 58 of the oxidizer delivery tube structure 56 and the end wall 36. The splash structure 38 ser.ves to redirect the mixed stream (arrows 40) towards the second end portion 34 of the combustion chamber 30. As a result of the use of the above structure and mode of operation, fuel is prevented from entering the oxidizer delivery" ube structure" 5 β while oxidizer is prevented from entering the fuel delivery tube structure 50. Thereby, carbon deposits cannot be formed within either the fuel delivery tube 50 or the oxidizer delivery tube structure 56. Since relatively cool fuel does not flow through the oxidizer tube structure 56, such structure can b-e formed of a ceramic material having a long service life at high temperatures. Faster ignition is also obtainable due to better fuel-oxidizer mixing. The present invention is particularly useful in gas turbines having an annular vaporizing combustor 18. Other aspects, objects, and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims. _ OMPI

Claims: Claims 1. In a vaporizing combustor (18) having a side wall construction (20) defining a chamber (30) having first (32) and second (34) end portions, fuel • delivery means (42) for delivering a fuel stream (44) to said first end portion (32), oxidizer delivery means (46) for delivering an oxidizer stream. (48) to said first end portion (42), said streams (44,48) mixing to form a mixed stream (40), and a splash structure (38,38') positioned to receive said mixed stream (40,40') and adapted to direct said mixed stream (40,40') generally towards said second end portion (34), the improvement comprising wherein: said fuel delivery means (42) includes a fuel delivery tube structure (50) having a delivery end portion (52) within said chamber (30) and from which said fuel stream (44,44') flows .generally towards said second end portion (34); and said oxidizer delivery means (46) includes an oxidizer delivery tube structure (56,56') having an outlet end (58,58') from which said oxidizer stream (48,48') flows generally towards said first end portion (32), said tube structures (5.0,50', 5o,5δ ! ) being positioned to generally impinge said streams (44,44', 48,48') and form said nixed stream (40,40') within said chamber (30). OMPI 2. The combustor (18) as set forth in claim 1, wherein said fuel stream (44,44') defines a centerline (54,54'), said oxidizer stream (48,48') defines a centerline (6θ,6θ') and said tube structures (50,50', 56,56') are positioned to cause said centerlines (54,54', 60,60') to intersect. 3. The combustor (18) as set forth in claim 2, wherein said centerlines (54,60) are coincident. 4. The combustor (18) as set forth in claim 1, including: an end wall (36) closing off said first end portion (32); and wherein said fuel delivery tube structure (50,50') enters said chamber (30) through said end wall (36) and said oxidizer delivery tube structure (56,56') enters said chamber (30) through said side wall construction (20). 5. The combustor (18) as set forth in claim 4, further including: means (62) for resiliently mounting said oxidizer delivery tube structure (56,56') to said side wall construction (20). 6. The combustor (18) as set forth in claim 1, wherein said oxidizer delivery tube structure (56,56') is formed of a ceramic material. V" T~; Λ. OMPI 7. The combustor (18) as set forth in claim 1, wherein said fuel stream (44,44') has a fuel velocity, said oxidizer stream (48,48') has an oxidizer velocity, and said velocities are selected to cause said mixed stream (40,40') to impinge on said splash structure (38,38'). 8. The combustor (18) as set forth in claim 1, wherein: said delivery end portion (52') includes a pair of delivery ends (52a,52b) through each of which a respective portion of said fuel stream (44*) flows, said delivery ends (52a,52b) being positioned to direct said respective portions generally towards said second end portion (34) and outwardly towards said side wall construction (20), to define an included angle, A, between said portions. 9. The combustor (18) as set forth in claim 8, wherein: said splash structure (38') is non- circularly symmetrical and has a pair of lobes (38 'a and 38 ! b), each extending outwardly circumfere tially. "1 - ■ gUREA ' OMPI 10. A vaporizing combustor (18), comprising: a side wall construction (20) defining a chamber (30) having first (32) and second (34) end portions; a fuel delivery tube structure (50,50') having a delivery end portion (52,52') within said chamber (30) from which a fuel stream (44,44') flows, said delivery end portion (52,52') being positioned to aim said fuel stream (44,44') towards said second end portion (34) of said chamber (30); an oxidizer delivery tube structure (56,56') having an outlet end (58,58') in said chamber (30) between said delivery end portion (52,52') and said second end portion (34) and from which an oxidizer stream (48,48') flows, said outlet end (58,58') being positioned to aim said, oxidizer stream (48,48') towards said first end portion (32) and into impingement with said fuel stream (44,44') to form a mixed stream (4θ,4θ'); and a splash structure (38) intermediate said end wall (32) and said outlet end (58,58') of said oxidizer delivery tube (56,56'), said splash structure (38,38') being positioned to receive and adapted to redirect; said mixed stream (40,40') generally towards said second end portion (34) of said chamber (30). BAD ORIGINA URI 11. A method of introducing a fuel and an oxidizer into a vaporizing combustor (18), comprising: flowing a fuel stream (44,44') at a fuel velocity into a combustion chamber (30) defined by a side wall construction (20) and having first (32) and second (34) end portions, said fuel stream (44,44') being flowed into said first end portion (32), the direction of flow of said fuel stream (44,44') being generally towards said second end portion (34); flowing an oxidizer stream (48,48') at an oxidizer velocity, into said chamber (30), the direction of flow of said oxidizer stream (48,48') being generally toward said first end portion (32), said oxidizer stream (48,48') being flowed into impingement with said fuel stream (44,44') to form a mixed stream (40,40'), said oxidizer velocity being sufficiently greater than said fuel velocity to cause said mixed stream (40, 0') to flow generally towards said first end portion (32); and redirecting the direction of flow of said mixed stream (40, 0') towards said second end portion (34).

Inventors: BAILEY J
Applicants: BAILEY J, CATERPILLAR TRACTOR CO
Application year: 1980
Main classification: F23R3
IPC codes: F23R3