高旋转数下大宽高比矩形通道换热特性研究

Heat Transfer Investigation in a Large Aspect Ratio Rectangle Channel at High Rotation Numbers

关键词:  叶片冷却  高旋转数  大宽高比  实验研究

Key words:  Turbine blade cooling  High rotation number  Large aspect ratio  Experimental investigation

摘要:

针对大宽高比矩形通道，采用铜块加热法，在Re=1×104～2×104和Ro=0～1.23内实验研究了旋转通道内展向及流向的换热特性。结果表明，静止下的大宽高比通道表现出非常强的展向换热不均，而旋转的引入削弱了展向换热差异，对低半径区的外侧换热可提高50%～90%；同时，在通道中段的前缘面换热随着旋转数的增大先减弱后增强，存在一个对应最低局部换热的临界旋转数(Roc=0.2～0.5)；高旋转数下(Ro≥0.6)，除内侧区域前缘面外，通道其他位置处的前缘面和后缘面换热均受到强化和改善，最高可达静止的2倍水平。

Abstract:

Heat transfer characteristics in a large aspect ratio rectangle channel were investigated at the Re of 1×104 to 2×104， and Ro of 0 to 1.23. The heated cooper plate technique was applied to obtain the span-wise and stream-wise heat transfer distributions. According to the experimental results， the strong span-wise heat transfer differences were observed at static case. But rotation largely weakened this span-wise difference， which the outer section could be enhanced by 50%～90%. As the Ro increased， the heat transfer on the leading surface of the channel middle part decreased first， and till to a critical rotation number (Roc=0.2～0.5) which was corresponing for the lowest local heat transfer， and then increased again. At high rotation number (Ro≥0.6)， except for the leading surface of the inner section， both the leading and trailing surfaces experienced heat transfer enhancement due to the rotation， and the maximun could be reached up to 2 times of static cases.