具有离散出气孔的旋转盘平均换热特性

实际发动机涡轮盘腔结构中的冷气进入叶片的冷却通道被简化为旋转盘上离散的通孔,冷气从静盘的中心流入,然后从这些通孔和转静盘间隙流出.针对这样的转静系统进行换热实验,得到了旋转盘表面的平均换热系数和转盘上通孔内平均换热系数.分析了转速、冷却气体流量对换热特性的影响,并给出了无量纲经验关系式.结果显示进气流量系数和旋转雷诺数的增加将导致盘面平均努塞尔数和通孔内表面的平均努塞尔数的增加. 

Heat transfer measurements on a rotating disk with discrete receiver holes

Modern gas turbines are cooled using air diverted from the compressor. In a rotor stator system,the cooling air enters at the center of stator and flows radially outward,then leaves through the discrete receiver holes in the rotor and clearance between rotor and shroud.The rotor with 440 mm diameter has 60 blade-cooling holes with 6 mm diameter at a radius of 195 mm.The temperatures on rotor surface at a number of radial locations were measured by thermocouples.The average Nusselt numbers on the rotating disc Nu_(av,d) and on the surface of receiving holes Nu_(av,b) were determined by experiment results.The magnitude of them was governed by two nondimensional fluid-dynamic parameters: rotational Reynolds number,nondimensional mass flow rate.The experiments reveal that Nu_(av,d) and Nu_(av,b) are increasing as either of them increases.The Nusslet number Nu_(av,d) increases strongly with rotational Reynolds number and weekly with nondimensional mass flow rate compared to the rotating disk without receiver holes.