尾缘厚度对低压涡轮气动性能影响的数值模拟

采用数值模拟的方法研究了尾缘厚度对Pak-B低压涡轮气动性能的影响.目的是通过增加尾缘厚度来控制边界层分离,降低损失,揭示增加尾缘厚度的流动控制机理.研究发现:适当增加尾缘厚度能减小低压涡轮损失,增大折转角.在雷诺数为25000,来流湍流度为1%时,适当增加尾缘厚度能使基于进口速度的能量损失系数降低10.4%,折转角增加1.73%.适当增加尾缘厚度和栅距同样可以使基于进口速度的能量损失系数减小,折转角增大.在雷诺数为25000,来流湍流度为1%时,尾缘厚度增加到4%s,栅距增加了2.2%,可以使基于进口速度的能量损失系数减小7.4%,折转角增加1.25%.通过增加尾缘厚度可以发展低稠度高负荷低压涡轮叶栅. 

Numerical simulation of the effects of trailing edge thickness on aerodynamic performance of low pressure turbine

Numerical simulation method was used to study the effects of trailing edge thickness on aerodynamic performance of Pak-B low pressure turbine. The trailing edge thickness was increased to control the boundary layer separation and reduce losses of low pressure turbine,and the flow control mechanism of increasing the trailing edge thickness was also revealed. It was shown that appropriate increasing trailing edge thickness could decrease the energy loss of low pressure turbine and increase the turning angle. Appropriate increasing trailing edge thickness could decrease the energy loss coefficient based on inlet velocity by 10.4%, increase the turning angle by 1.73% for Reynolds number of 25000 and free stream turbulence intensity of 1%. Appropriate increasing the trailing edge thickness and pitch also could reduce the energy loss coefficient based on inlet velocity, increase the turning angle. When the trailing edge thickness increased to 4%s and the pitch increased by 2.2%, the energy loss coefficient based on inlet velocity decreased by 7.4% and the turning angle increased by 1.25% for Reynolds number of 25000 and free stream turbulence intensity of 1%. Increasing the thickness of trailing edge can be used to develop low solidity and highly loaded low pressure turbine cascade.