Numerical Study Of The Flow Field On Non-Axisymmetric Endwall In An Annular Turbine Cascade

With the development of modem aircraft and gas turbine,the requitements of turbine load are also increasing.The increasing load of turbine leads to an increase in loss.Therefore,it is very important to understand the internal flow mechanism of the high-load turbine.In turbomachinery internal energy loss,secondary flow loss takes 30%to 50%of cascade total loss,many experts and scholars began the theoretical analysis and experimental study on the control of two secondary flow loss.The non axisymmetric endwall modeling technique has been proved to be an effective way to reduce the loss of the secondary flow in the blade passage.Numerical simulation had been carried out for the sector cascades of a high loaded turbine.The influences of outlet Mach number and inflow angle on turbine cascade are studied.The influences of outlet Mach number and inflow angle on turbine cascade are studied including inflow angles of-20°?-10°?20°?10°?0° and exit Mach numbers of 0.55?0.75?0.85?0.90.The influence of outlet Mach number and inflow angle on turbine cascade is studied by analyzing the static pressure of SS surface of blade,limiting streamline,vorticity and total pressure loss coefficient.The total loss,blade surface static pressure and vortex turbine structure vary with turbine outlet Mach number and inflow angle.At the same time,the non axisymmetric shape is applied to the sector cascades to find out the control mechanism of the non-axisymmetric endwall to the secondary flow in turbine with different outlet Mach numbers and inflow angles.Results show that the total pressure loss of the cascade increases with the increase of the exit Mach number,and the total pressure loss of the cascade is greater than that of the negative cascade under the positive flow angle.It is also found that in different outlet Mach numbers and flow angles non-axisymmetric endwall can effectively inhibit the tangential secondary flow and the development of the passage vortex,resulting in the decrease in the loss of total pressure in varying degrees.When the outlet Mach number is 0.85,the improvement is the best.When the Mach number is 0.55,0.75,0.85 and 0.90,the total loss of the cascade is reduced by 8.16%,10.44%,10.81%,and 9.85%,and the improvement of positive inflow angle is better than that of negative inflow angle,When the inflow angle is-200°?-100°?200°?100°,the total loss of the cascade is reduced by 10.28%?0.25%?10.53%?10.60%.