微尺度阵列射流冲击流动与换热特性研究

Study on Micro-scale Jet Array Impingement Flow and Heat Transfer Characteristics

针对微尺度阵列射流冲击结构的流动与换热特性，选取冲击孔为D=0．4mm、0．5mm、0．6ram，冲击距H／D=1．0、1．5、2．0，叉排和顺排结构的长圆形扰流柱，雷诺数Re范围为1000-10000，保证与真实燃气轮机工况相等的气动参数下，对微尺度列射流冲击结构的流动与换热情况进行分析比较，结果表明：在相同的雷诺数下，长圆形扰流柱的排列方式对冲击靶面平均换热影响很小，对局部换热分布影响很大，叉排方式的换热分布均匀、温度梯度小；随着孔径的增大，下游强换热面积覆盖区域增大，但是在相同的流量下，D=0．4mm的靶面平均换热系数是远高于D=0．6ram；靶面平均换热系数随着冲击距H／D的增大而减小。因此，在最小的冷气量下，尽可能减小涡轮叶片内冷结构的尺寸可大大增强内通道的换热效果。

To investigate the flow and heat transfer characteristics of micro-scale jet array impingement cooling configurations.The diameter of impingement holes are 0.4ram,0.5mm and 0.6mm,ratios of the impingement distance （H/D） are 1,1.5and 2.0, and the obround pin fins are in-line and staggered arrangements, the Reynolds number varies from 1000 to10000, the aerodynamics parameters need to keep equal with the real working condition of gas turbine, flow and heattransfer characteristics of the micro-scale jet array impingement cooling with different geometry are studied. The resultsshow us that the arrangements of obround pin fins have low influence to average heat transfer coefficient of the impingementtarget surface at the same Reynolds number, but impingement target local area distributions have big influences. Staggerarrangements have homogenous heat transfer distributions and small temperature gradient. Strong heat transfers areaincreases as the hole diameter decreases, but target average heat transfer of D = 0.4mm are higher than the D = 0.6ram atthe same flow, and the target average heat transfer coefficients decreases as the magnitude of H/D increases. So, decreasingthe scale of the turbine blade inner-cooling configuration can provide heat transfer at the minimum cooling flow.