涡轮叶片斜肋通道冷态流场特性的实验研究

Experimental research on cold flow field characteristics of turbine blade oblique rib channel

为了探究涡轮叶片内部肋通道的流场特性与换热机理,设计不同角度的带肋通道实验模型.采用流动显示实验与粒子图像测速实验,对通道的典型截面流场进行统计平均特性分析与非定常分析.结果表明,当扰流肋与流向的夹角为60°~90°时,减小夹角能够降低扰流肋对流体的阻挡作用,增大扰流肋后方旋涡的纵向范围与强度.减小夹角使第1个肋区间的回流强度先增大后减小,第2个肋区间流体的纵向冲击强度增大.斜肋结构能够提高主流流体与肋间流体的雷诺应力峰值,增强肋间扰动强度,提升通道的换热特性.减小夹角可以提升流场的速度振荡幅值与振荡频率,提高通道的换热效率.减小夹角可以增大流体沿肋向流动的能量与能量波动频率,使得旋涡在向后脱落的过程中更易于与靶面进行能量交换.

The experimental models of ribbed channel with different angles were designed in order to analyze the flow field characteristics and heat transfer mechanism of the internal ribbed channel of turbine blade.The statistical average characteristics and unsteady flow field of typical section of the channel were analyzed by flow visualization experiment and particle image velocimetry experiment.Reducing angle can reduce the blocking effect of the rib on the fluid and increase the longitudinal range and strength of the vortex behind the rib when the angle between the spoiler and the flow direction is between 60°~90°.The reflux strength of the first rib increases first and then decreases with the decrease of angle,and the longitudinal impact strength of the second rib increases.The oblique rib structure can improve the peak Reynolds stress of the mainstream fluid and the intercostal fluid,enhance the intensity of intercostal disturbance and improve the heat transfer characteristics of the channel.Reducing angle can improve the amplitude and frequency of velocity oscillation,and improve the heat transfer efficiency of the channel.Reducing angle can increase the energy and energy fluctuation frequency of the fluid flow along the rib,and make the vortex easier to exchange energy with the target surface in the process of backward shedding.