Supersonic compressor

Abstract

A supersonic compressor including a rotor to deliver a gas at supersonic conditions to a diffuser. The diffuser includes a plurality of aerodynamic ducts that have converging and diverging portions, for deceleration of gas to subsonic conditions and then for expansion of subsonic gas, to change kinetic energy of the gas to static pressure. The aerodynamic ducts include vortex generating structures for controlling boundary layer, and structures for changing the effective contraction ratio to enable starting even when the aerodynamic ducts are designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of in excess of two to one, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

We claim: 
     
         1 . A compressor, comprising:
 a rotor having an axis of rotation and a plurality of blades extending into a gas flow passage, said plurality of blades sized and shaped to act on a selected gas to provide a supersonic gas flow; and   a stator comprising a diffuser disposed around a longitudinal axis and comprising one or more aerodynamic ducts, said one or more aerodynamic ducts having an effective contraction ratio and comprising a radially converging portion and a radially diverging portion, said one or more aerodynamic ducts sized and shaped to decelerate said supersonic gas flow to subsonic conditions from a selected inlet Mach number, said diffuser comprising
 (a) at least one of (i) bypass gas passageways, or (ii) geometrically adjustable portions operable to adjust said effective contraction ratio; and 
 (b) boundary layer control structures comprising one or more vortex generators, said one or more vortex generators each comprising a base with a forward end and a leading edge extending outward and rearward from said forward end to an outward end, and wherein said leading edge comprises a first angular discontinuity at a height H 1  above said base, and a second angular discontinuity at a height H 2  above said base, for generating at least two (2) vortices. 
   
     
     
         2 . The compressor as set forth in  claim 1 , wherein said one or more of said aerodynamic ducts are helically arranged at a substantially constant helical angle about said longitudinal axis. 
     
     
         3 . The compressor as set forth in  claim 1 , wherein said leading edge further comprises a third angular discontinuity at a height H 3  above said base, for generating at least three (3) vortices. 
     
     
         4 . The compressor as set forth in  claim 1 , wherein a plurality of vortex generators are provided in each of said aerodynamic ducts. 
     
     
         5 . The compressor as set forth in  claim 1 , wherein said one or more vortex generators are located in said radially converging portion. 
     
     
         6 . The compressor as set forth in  claim 1 , wherein said one or more vortex generators are located in said radially diverging portion. 
     
     
         7 . The compressor as set forth in  claim 1 , further comprising outlet bleed ports for boundary layer removal, and bleed sub-chambers adjacent said one or more aerodynamic ducts, said bleed sub-chambers in fluid communication with said outlet bleed ports, said bleed sub-chambers configured for passage therethrough of said selected gas removed through said outlet bleed ports. 
     
     
         8 . The compressor as set forth in  claim 7 , wherein said rotor further comprises a shroud for said plurality of blades. 
     
     
         9 . The compressor as set forth in  claim 1 , wherein said rotor comprises a plurality of impulse blades. 
     
     
         10 . The compressor as set forth in  claim 9 , wherein said selected gas passing through said rotor is turned by an angle alpha (α) of at least ninety (90) degrees. 
     
     
         11 . The compressor as set forth in  claim 9 , wherein said selected gas passing through said rotor is turned by an angle alpha (α) of between ninety (90) degrees and one hundred sixty (160) degrees. 
     
     
         12 . The compressor as set forth in  claim 1 , wherein each of said plurality of blades has a hub end, a tip end, and a trailing edge, and said supersonic gas flow is provided at said trailing edge of each of said plurality of blades from said hub end to said tip end. 
     
     
         13 . The compressor as set forth in  claim 1 , wherein said bypass gas passageways are positionable between an open, startup condition wherein discharge gas is passed therethrough, and a closed, operating condition which minimizes or stops passage of said discharge gas therethrough. 
     
     
         14 . The compressor as set forth in  claim 13 , wherein said bypass gas passageways comprise external passageways fluidly connected with said one or more aerodynamic ducts. 
     
     
         15 . The compressor as set forth in  claim 1 , wherein said geometrically adjustable portions are positionable between an open, startup condition wherein said radially converging portion allows sufficient flow of said selected gas through said one or more aerodynamic ducts to establish and position a normal shock within said one or more aerodynamic ducts, and a closed, operating condition in which said radially converging portion is set to a selected operating position. 
     
     
         16 . The compressor as set forth in  claim 1 , wherein said geometrically adjustable portions, by change in position, change the contraction ratio of one or more of said one or more aerodynamic ducts. 
     
     
         17 . The compressor as set forth in  claim 16 , wherein said geometrically adjustable portions further comprise pivotable members and actuators, said pivotable members driven by said actuators, and wherein said geometrically adjustable portions are sized and shaped to change the shape of said radially converging portion of said one or more of said one or more aerodynamic ducts when said geometrically adjustable portions are moved with said actuators. 
     
     
         18 . A supersonic gas compressor for compressing a selected gas, comprising:
 a casing comprising a low pressure gas inlet and a high pressure gas exit;   a rotor comprising a plurality of blades and configured to act on a selected gas to impart axial and tangential velocity thereto to provide a supersonic gas flow;   a stator comprising a diffuser including one or more aerodynamic ducts configured for diffusing a gas received therein, said one or more aerodynamic ducts each having a radially converging portion, a radially diverging portion, and an effective contraction ratio, such that, with input of a supersonic gas flow, each aerodynamic duct generates a plurality of shock waves (S 1  to S x ) in said selected gas as said selected gas passes therethrough, said one or more aerodynamic ducts having an inlet relative Mach number for operation associated with a design operating point selected within a design operating envelope for a selected gas composition, gas quantity, and gas compression ratio, wherein said one or more of said aerodynamic ducts are helically arranged at a substantially constant helical angle about said longitudinal axis, said one or more aerodynamic ducts comprising   (a) bypass gas passageways or a geometrically adjustable portion, or both, operable to adjust said effective contraction ratio, and   (b) boundary layer control structures, said boundary layer control structures comprising one or more vortex generators, said one or more vortex generators each comprising a base with a forward end and a leading edge extending outward and rearward from said forward end to an outward end, wherein said leading edge comprises a first angular discontinuity at a height H 1  above said base, and a second angular discontinuity at a height H 2  above said base, for generating at least two (2) vortices.   
     
     
         19 . The compressor as set forth in  claim 18 , wherein each of said one or more aerodynamic ducts has a centerline, and wherein orthogonal to said centerline, one or more of said one or more aerodynamic ducts have a generally parallelogram cross-sectional shape. 
     
     
         20 . The compressor as set forth in  claim 18 , wherein said inlet relative Mach number of said one or more aerodynamic ducts is in excess of 1.5.