涡轮试验准则数对流场相似性的影响

基于某高压涡轮模型,以各叶片排出口的气流角和马赫数径向分布为流场相似的评价标准,通过数值模拟的方法分析对比了几种常用的涡轮试验准则数对流场相似的影响,为涡轮试验提供参考。结果表明:未考虑比热比和考虑比热比的物理转速值相差15%以内,且流场差异很小；进口温度为450K时,保证比热比、折合转速、膨胀比相等可以很好地保证流场相似,而保证折合转速、膨胀比相等和保证折合转速、折合功率相等时，2级动叶出口马赫数与设计点差异最大,平均相对差异接近6%；温度越高,流场的相似性越好,且保证折合转速 折合功率要优于保证折合转速 膨胀比的方法；若无法保证比热比,进口温度至少需要800K才能使各叶片排马赫数相似差异在2.5%以内。 

Influence of turbine test criterion parameters on flow similarity

Based on a transonic high pressure turbine model, the angle and Mach number radial distribution on the outlet cross-section of each blade taken as the flow similarity evaluation criterion, several normal methods of turbine test dimensionless parameters were compared with the design point to provide some suggestions on the turbine test. Results indicated that, the physical speed relative difference between the methods with/without the specific heat ratio was less than 15%, and the simulation result difference was small enough to be ignored. At the inlet temperature of 450K, the method ensuring specific heat ratio, corrected speed and expansion ratio can obtain the best similarity with the design point; when using the method ensuring corrected speed and expansion ratio and method ensuring corrected speed and corrected power, the Mach number difference at the outlet cross section of the second blade was most visible and the average of relative difference can reach about 6%. The flow similarity turned better when the inlet temperature was higher, and the method ensuring corrected speed and corrected power was better than method ensuring corrected speed and expansion ratio at the same temperature. If the specific heat ratio cannot be ensured, the inlet temperature should be more than 800K to make the Mach number similarity difference of the every blade less than 25%.