带肋板尾缘开缝叶片内的流动传热性能研究

Investigations of Flow and Heat Transfer Performance in a Blade with Trailing-Edge Cutback and Lands

针对燃气透平带肋板的尾缘开缝叶片,采用RANS(Reynolds Averaged Navier-Stokes)方程求解结合SSTγ-Reθ转换模型数值方法,研究了3种来流湍流度、3种来流雷诺数和3种冷气质量流量比条件下叶片和尾缘开缝区域的流动传热性能,并与无肋板开缝叶片进行了对比,利用实验数据考核了数值方法的有效性。计算结果表明:随着来流湍流度的增大,带肋板的尾缘开缝叶片表面传热系数逐渐增大,开缝壁面的传热系数基本不变,能量损失系数和总压损失系数随之增加;在相同来流湍流度时,增加来流雷诺数可降低损失;增大冷气质量流量比对叶片表面的传热系数影响很小,但可显著提升开缝壁面的传热系数;与无肋板的开缝叶片相比,带肋板的尾缘开缝叶片表面的传热系数和压力系数更低,开缝壁面换热系数更高;当Re为2.0×106时,带肋板的开缝壁面平均换热系数比无肋板时的高14.46%,来流雷诺数分别为0.5×106、1.0×106、2.0×106时,相比无肋板开缝叶片,带肋板尾缘开缝叶片的能量损失系数分别增加了3.75%、5.91%、6.75%,总压损失系数分别降低了3.4%、3.37%、2.06%。

RANS(Reynolds-averaged Navier-Stokes)equations combined with transition model SSTγ-Reθare adopted to investigate the flow and heat transfer performance in a gas turbine blade with trailing edge cutback and lands.At three inflow turbulence intensities,three mainstream Reynolds numbers and three coolant ejection rates,heat transfer coefficient distributions and aerodynamic loss in blade with trailing-edge cutback and lands are compared with those in trailing-edge cutback blade without lands.With the existing experimental data,the reliability of numerical methods is validated at a range of operation conditions.The results show that,as the inflow turbulence intensity increases,heat transfer coefficients on blade surface for the blade with lands are gradually increased.However,the heat transfer coefficients on trailing edge cutback are not sensitive to the variations of inflow turbulence intensity.The energy loss coefficient and total pressure loss coefficient in blade with lands are both increased with increase of inflow turbulence intensity.With the same inflow turbulence intensity,the aerodynamic loss in blade is reduced with increasing the mainstream Reynolds number.For the blade with lands,increasing the ejection rate has little influence on the heat transfer coefficient distributions on blade surface,but it significantly increases the heat transfer coefficients on the trailing edge cutback.Compared with the blade without lands,heat transfer coefficients and pressure coefficients on blade surface are reduced,while the heat transfer coefficients on the cutback surface are increased in the blade with lands.Compared with the blade without lands,as the Reynolds number equals 0.5×106,1.0×106 and 2.0×106,the energy loss coefficient in blade with lands is increased by 3.75%,5.91%and 6.75%,respectively,whereas the total pressure loss coefficient in the blade with lands is decreased by 3.4%,3.37%,and 2.06%,respectively.