Unsteady numerical simulations of a high-load transonic turbine stage have been carried out to study the influences of vane trailing edge outer-extending shockwave on rotor blade leading edge film cooling performance....Unsteady numerical simulations of a high-load transonic turbine stage have been carried out to study the influences of vane trailing edge outer-extending shockwave on rotor blade leading edge film cooling performance. The turbine stage used in this paper is composed of a vane section and a rotor one which are both near the root section of a transonic high-load turbine stage. The Mach number is 0.94 at vane outlet, and the relative Mach number is above 1.10 at rotor outlet. Various positions and oblique angles of film cooling holes were investigated in this research. Results show that the cooling efficiency on the blade surface of rotor near leading edge is significantly affected by vane trailing edge outer-extending shockwave in some cases. In the cases that film holes are close to leading edge, cooling performance suffers more from the sweeping vane trailing edge outer-extending shockwave.In addition, coolant flow ejected from oblique film holes is harder to separate from the blade surface of rotor, and can cover more blade area even under the effects of sweeping vane trailing edge shockwave. As a result, oblique film holes can provide better film cooling performance than vertical film holes do near the leading edge on turbine blade which is swept by shockwaves.展开更多
With the increase of blade loading, the loss prediction model used in the design process needs refinement and improvement to meet the high-performance design. For the turbine design, most of existing profile loss mode...With the increase of blade loading, the loss prediction model used in the design process needs refinement and improvement to meet the high-performance design. For the turbine design, most of existing profile loss models are developed for subsonic and transonic cases and their accuracy in high Mach number flow are limited. The primary research interest of this work is to study the flow mechanism of turbine cascade with high Mach number and the related profile loss. In this work, a transonic turbine cascade with strong shock wave is numerically studied with Reynolds Averaged Navier-Stokes(RANS). Also, to overcome the limitations of RANS modeling, Delayed Detached Eddy Simulation(DDES) type high-fidelity turbulence simulation is also conducted. Based on the numerical results, the primary loss sources, including the boundary layer loss, the trailing loss and the shock loss are analyzed and results from existing loss models are assessed. The results from current work may help to develop refinement profile loss model for the design of turbine cascade working in the high Mach number regime.展开更多
基金supported by National Natural Science Foundation of China,Grant No.51421063
文摘Unsteady numerical simulations of a high-load transonic turbine stage have been carried out to study the influences of vane trailing edge outer-extending shockwave on rotor blade leading edge film cooling performance. The turbine stage used in this paper is composed of a vane section and a rotor one which are both near the root section of a transonic high-load turbine stage. The Mach number is 0.94 at vane outlet, and the relative Mach number is above 1.10 at rotor outlet. Various positions and oblique angles of film cooling holes were investigated in this research. Results show that the cooling efficiency on the blade surface of rotor near leading edge is significantly affected by vane trailing edge outer-extending shockwave in some cases. In the cases that film holes are close to leading edge, cooling performance suffers more from the sweeping vane trailing edge outer-extending shockwave.In addition, coolant flow ejected from oblique film holes is harder to separate from the blade surface of rotor, and can cover more blade area even under the effects of sweeping vane trailing edge shockwave. As a result, oblique film holes can provide better film cooling performance than vertical film holes do near the leading edge on turbine blade which is swept by shockwaves.
基金National Natural Science Foundation of China(No.51506107,No.51476082)
文摘With the increase of blade loading, the loss prediction model used in the design process needs refinement and improvement to meet the high-performance design. For the turbine design, most of existing profile loss models are developed for subsonic and transonic cases and their accuracy in high Mach number flow are limited. The primary research interest of this work is to study the flow mechanism of turbine cascade with high Mach number and the related profile loss. In this work, a transonic turbine cascade with strong shock wave is numerically studied with Reynolds Averaged Navier-Stokes(RANS). Also, to overcome the limitations of RANS modeling, Delayed Detached Eddy Simulation(DDES) type high-fidelity turbulence simulation is also conducted. Based on the numerical results, the primary loss sources, including the boundary layer loss, the trailing loss and the shock loss are analyzed and results from existing loss models are assessed. The results from current work may help to develop refinement profile loss model for the design of turbine cascade working in the high Mach number regime.
