Vaneless supersonic nozzle

Abstract

A converging-diverging nozzle unit for supersonic expansion in turbines is presented wherein a plurality of converging nozzle segments open into a common diverging chamber at or near the throat of the converging nozzles. Convergence and divergence may occur in different directions in the nozzle unit; with reference to a rotating turbine wheel, convergence occurs in a direction substantially tangential with respect thereto, and divergence occurs substantially radial with respect thereto.

What is claimed is: 
     
       1. A converging-diverging nozzle unit for a supersonic expansion of a motive fluid for delivery to a turbine wheel, the nozzle unit including: a plurality of nozzles in an array with converging flow passages between adjacent nozzles in the array;   an entrance and a throat in each of said flow passages, the throat being downstream of the entrance in the direction of flow of motive fluid through the passage; and   a common diverging expansion chamber connected to receive flow from said converging passages, said common diverging chamber extending from the vicinity of the throats of said converging passages downstream toward the turbine wheel.   
     
     
       2. A converging-diverging nozzle unit as in claim 1 wherein: said common diverging expansion chamber diverges in a direction generally radial with respect to the turbine wheel.   
     
     
       3. A converging-diverging nozzle unit as in claim 2 wherein: said converging flow passages converge at least partly in a direction at an angle with respect to the direction of divergence of said common diverging chamber.   
     
     
       4. A converging-diverging nozzle unit as in claim 3 wherein: said converging flow passages converge in a direction generally tangential with respect to the turbine wheel.   
     
     
       5. A converging-diverging nozzle unit as in claim 3 wherein: said angle between the direction of divergence of said diverging chamber and the direction of convergence of .[.said.]. .Iadd.a .Iaddend.converging .[.chamber.]. .Iadd.flow passage .Iaddend.is approximately 90°.   
     
     
       6. A converging-diverging nozzle unit as in claim 1 wherein: adjacent nozzles extend downstream of the throat defined therebetween and extend into said common diverging chamber.   
     
     
       7. A converging-diverging nozzle unit as in claim 1 including: at least one backup wall in said common expansion chamber.   
     
     
       8. A converging-diverging nozzle unit as in claim 7 wherein: said backup wall is inclined at an angle to reduce the angle between the flow axis of a discharge stream from a flow passage and the exit plane of the passage upon an increase in the pressure ratio across the nozzle unit.   
     
     
       9. A converging-diverging nozzle unit as in claim 8 including: a plurality of backup walls in said common expansion chamber, any two adjacent backup walls being spaced apart to include at least two flow passages therebetween.   
     
     
       10. A converging-diverging nozzle unit as in claim 1 wherein: said passages in said nozzle converge in a first direction with respect to the turbine wheel; and   said common diverging expansion chamber diverges in a second direction with respect to said turbine wheel and at an angle with respect to said first direction.   
     
     
       11. A converging-diverging nozzle unit as in claim 10 wherein: said second direction is at an angle of approximately 90° with respect to said first direction.   
     
     
       12. A converging-diverging nozzle unit for supersonic expansion of a motive fluid for delivery to a turbine wheel, the nozzle unit including: a plurality of nozzle means arranged in an arcuate array with converging flow passages defined between adjacent nozzle means for subsonic expansion of a motive fluid;   an entrance and a throat in each of said flow passages, the throat being downstream of the entrance in the direction of motive fluid flow through the passages; and   common expansion chamber means between said array of nozzle means and the turbine wheel for supersonic expansion of motive fluid from said nozzle means and delivery to the turbine wheel, said common expansion chamber means having inner and outer arcuate walls spaced apart in a direction substantially radial with respect to the turbine wheel, at least one of said inner and outer arcuate walls being inclined away from the other along at least part of its length whereby said common expansion chamber diverges between said array of nozzle means and said turbine wheel.   
     
     
       13. A converging-diverging nozzle unit as in claim 12 wherein: said converging flow passages converge at least partly in a direction at an angle with respect to the direction of divergence of said common diverging chamber.   
     
     
       14. A converging-diverging nozzle unit as in claim 13 wherein: said converging flow passages converge in a direction generally perpendicular with respect to a radius of the turbine wheel.   
     
     
       15. A converging-diverging nozzle unit as in claim 13 wherein: planes extending in the direction of divergence of said diverging chamber and the direction of convergence of .[.said.]. .Iadd.a .Iaddend.converging .[.chamber.]. .Iadd.flow passage .Iaddend.intersect at an angle of approximately 90°.   
     
     
       16. A converging-diverging nozzle unit as in claim 12 wherein: adjacent nozzles extend downstream of the throat defined therebetween and extend into said common diverging chamber.   
     
     
       17. A converging-diverging nozzle unit as in claim 12 including: at least one backup wall in said common expansion chamber.   
     
     
       18. A converging-diverging nozzle unit as in claim 17 wherein: said backup wall is inclined at an angle to reduce the angle between the flow axis of a discharge stream from a flow passage and the exit plane of the passage upon an increase in the pressure ratio across the nozzle unit.   
     
     
       19. A converging-diverging nozzle unit as in claim 18 including: a plurality of backup walls in said common expansion chamber, any two adjacent backup walls being spaced apart to include at least two flow passages therebetween. .Iadd. 20. A converging-diverging passage unit about an axis of a turbine wheel for supersonic expansion of a motive fluid, the passage unit including:   a plurality of passage defining elements in an array with converging flow passages between adjacent elements in the array;   an entrance and a throat in each of said flow passages, the throat being downstream of the entrance in the direction of flow of motive fluid through the passage; and   a common diverging expansion chamber connected to receive flow from said converging passages, said common diverging chamber extending from the vicinity of the throats of said converging passages downstream in the direction of flow through the passage unit. .Iaddend..Iadd. 21. A converging-diverging passage unit as in claim 20 wherein:   said common diverging expansion chamber diverges in a direction generally radial with respect to the turbine wheel. .Iadd. 22. A converging-diverging passage unit as in claim 21 wherein:   said converging flow passages converge at least partly in a direction at an angle with respect to the direction of divergence of said common diverging chamber. .Iaddend..Iadd. 23. A converging-diverging passage unit as in claim 22 wherein:   said converging flow passages converge in a direction generally tangential   
     
     
        with respect to the turbine wheel. .Iaddend. .Iadd. 24. A converging-diverging passage unit as in claim 22 wherein: said angle between the direction of divergence of said diverging chamber and the direction of convergence of a converging flow passage is approximately 90°. .Iaddend..Iadd. 25. A converging-diverging passage unit as in claim 26 wherein:   adjacent passage defining elements extend downstream of the throat defined therebetween and extend into said common diverging chamber. .Iaddend..Iadd. 26. A converging-diverging passage unit as in claim 20 including:   at least one backup wall in said common expansion chamber. .Iadd. 27. A converging-diverging passage unit as in claim 26 wherein:   said backup wall is inclined at an angle to reduce the angle between the flow axis of a discharge stream from a flow passage and the exit plane of the passage upon an increase in the pressure ratio across the passage unit. .Iaddend..Iadd. 28. A converging-diverging passage unit as in claim 27 including:   a plurality of backup walls in said common expansion chamber, any two adjacent backup walls being spaced apart to include at least two flow passages therebetween. .Iaddend. .Iadd. 29. A converging-diverging passage unit as in claim 20 wherein:   said passage converge in a first direction with respect to the turbine wheel; and   said common diverging expansion chamber diverges in a second direction with respect to said turbine wheel and at an angle with respect to said first direction. .Iaddend..Iadd. 30. A converging-diverging passage unit as in claim 29 wherein:   said second direction is at an angle of approximately 90° with respect to said first direction. .Iaddend. .Iadd. 31. A converging-diverging passage unit about an axis of a turbine wheel for supersonic expansion of a motive fluid, the passage unit including:   a plurality of passage defining means arranged in an arcuate array with converging flow passages defined between adjacent passage defining means for subsonic expansion of a motive fluid;   an entrance and a throat in each of said flow passages, the throat being downstream of the entrance in the direction of motive fluid flow through the passages; and   common expansion chamber means downstream of said array of passage defining means for supersonic expansion of motive fluid from said passage defining means, said common expansion chamber means having inner and outer arcuate walls spaced apart in a direction substantially radial with respect to the turbine wheel, at least one of said inner and outer arcuate walls being inclined away from the other along at least part of its length whereby said common expansion chamber diverges downstream of said array of passage defining means. .Iaddend..Iadd. 32. A converging-diverging passage unit as in claim 31 wherein:   said converging flow passages converge at least partly in a direction at an angle with respect to the direction of divergence of said common diverging chamber. .Iaddend..Iadd. 33. A converging-diverging passage unit as in claim 32 wherein:   said converging flow passages converge in a direction generally perpendicular with respect to a radius of the turbine wheel. .Iaddend. .Iadd. 34. A converging-diverging passage unit as in claim 32 wherein:   planes extending in the direction of divergence of said diverging chamber and the direction of convergence of a converging flow passage intersect at an angle of approximately 90°. .Iaddend..Iadd. 35. A converging-diverging passage unit as in claim 31 wherein:   adjacent passage defining means extend downstream of the throat defined therebetween and extend into said common diverging chamber. .Iaddend..Iadd. 36. A converging-diverging passage unit as in claim 31 including:   at least one backup wall in said common expansion chamber. .Iaddend..Iadd. 37. A converging-diverging passage unit as in claim 36 wherein:   said backup wall is inclined at an angle to reduce the angle between the flow axis of a discharge stream from a flow passage and the exit plane of the passage upon an increase in the pressure ratio across the passage unit. .Iaddend..Iadd. 38. A converging-diverging passage unit as in claim 37 including:   a plurality of backup walls in said common expansion chamber, any two adjacent backup walls being spaced apart to include at least two flow passages therebetween. .Iaddend.