旋转带肋回转通道换热实验研究

Experimental Investigation of Heat Transfer for Rotating

关键词:  涡轮叶片  带肋通道  对流传热  旋转数  瞬态液晶

Key words:  Turbine blade  Ribbed channel  Convective heat transfer  Rotation number  Transition liquid crystal

摘要:

为深入掌握高压涡轮叶片带肋回转通道在旋转状态下的换热分布，建立了旋转内通道实验系统，利用瞬态液晶测量方法研究了动叶回转内通道模型的换热机理，比较了三维数值模拟和实验的换热结果。通道入口雷诺数为5000~17000，旋转数为0～0.09，旋转半径与水力直径之比为46.4。结果表明:不同雷诺数下回转内通道的局部换热系数分布相似，局部、平均换热系数均随雷诺数增加而增大；沿程展向平均换热系数呈多波峰状分布，肋的扰动强化换热沿流向逐渐减弱；径向出流通道的努赛尔数随旋转数增加明显增大，径向入流通道的努赛尔数随旋转数的增加略有减小；哥氏力使转弯下游通道的局部换热系数改变，肋间的高换热区域由前肋的背风面附近向两肋之间偏移。

Abstract:

To deeply understand the heat transfer distribution in rotating ribbed serpentine cooling channel with high pressure turbine blade，the internal cooling channel experimental system has been set up. The heat transfer theory in cooling channel of rotor blade was researched by using transient liquid crystal measurement. The heat transfer results between experimental date and numerical simulation were compared. The range of Reynold numbers on channel inlet and Rotation numbers are from 5000 to 17000，0.0 to 0.09，respectively. The hydraulic diameter divided by radius of gyration is 46.4. The results show that local heat transfer distribution in serpentine channel is similar to different Reynold numbers. The local and average heat transfer coefficient increases with the augment of the Reynold number. The spanwise of averaged heat transfer coefficient distributes in multiple-peak form along the flow direction. The heat transfer enhancement by rib turbulators decreases along the flow direction. The radial outflow Nusselt number (Nu) increases and the radial inflow Nu decreases in trailing surface with the augment of the rotation number. The local heat transfer coefficient in downstream of turning area is changed by Coriolis force. The high heat transfer area of intercostal is shifted from downstream of the first rib to the middle of two ribs.