雷诺数和湍流度对叶片表面边界层转捩和换热特性的影响

为了深入了解涡轮叶片表面边界层转捩特性及其对换热系数的影响,在叶栅风洞中分别测量了进口雷诺数为5×10⁵、6×10⁵和7×10⁵时叶片表面压力分布,并将压力数据加载到边界层计算程序TEXSTAN中,计算了每个进口雷诺数在来流湍流度为3%、5%和7%时叶片表面换热系数分布。结果表明,进口雷诺数增大,压力面转捩点基本不变,吸力面转捩点前移3%~7%相对弧长,换热系数沿叶片型面减小的区域缩短。来流湍流度对压力面流动和换热的影响弱于吸力面,湍流度增大使压力面转捩点前移5%~10%,换热系数增加16%~34%,使吸力面转捩点前移17%~24%,换热系数增加19%~41%。

Effects of Reynolds Number and Turbulence Intensity on Boundary Layer Transition and Heat Transfer Characteristics of Blade Surface

In order to deeply understand the boundary layer transition characteristics of turbine blade surface and its effect on heat transfer coefficient, the pressure distribution on the blade surface was measured in a cascade wind tunnel at inlet Reynolds number of 5×10⁵, 6×10⁵ and 7×10⁵ respectively. The pressure data were loaded into the boundary layer calculation code TEXSTAN, and the heat transfer coefficient distribution of each inlet Reynolds number was calculated at the inflow turbulence intensity of 3%, 5% and 7% respectively. The results show that with the increase of inlet Reynolds number, the pressure side transition point is basically unchanged, and the suction side transition point moves forward by 3%~7% of the relative arc length, resulting in the area of heat transfer coefficient decreasing along the blade profile is shortened, thus enhancing the heat transfer. The effect of turbulence intensity on the flow and heat transfer on the pressure side is weaker than that on the suction side, with the increase of turbulence intensity, the transition point of the pressure side moves forward by 5%~10%, the heat transfer coefficient increases by 16%~34%, the transition point of suction side moves forward by 17%~24%, and the heat transfer coefficient increases by 19%~41%.