侧向冲击楔形通道旋转换热特性的实验研究

Experimental Heat Transfer Investigation in a Rotating Wedge-Shaped Channel with Lateral Impingement

关键词:  旋转换热  侧向冲击  楔形通道  实验研究  涡轮叶片

Key words:  Rotational heat transfer  Lateral impingement  Wedge-shaped channel  Experimental investigation  Turbine blade

摘要:

为研究侧向冲击入流对于涡轮转子叶片内部冷却结构的影响，针对带侧向冲击入流的叶片尾缘简化的楔形通道开展实验研究。实验采用铜块加热法，在Re=5×103～1×104和Ro=0～0.54内实验研究了通道内展向及流向的换热特性。结果表明，静止下的侧向入流冲击导致通道中部和内侧区域换热显著强于外侧区域，而旋转导致展向换热差异增大。通道中段局部换热随旋转数增大呈现典型的先减弱后增大的趋势，且对应最低换热水平的临界旋转数随着径向沿程的增大而减小。相比静止通道，旋转通道内的平均换热水平最大下降15%左右(Ro≈0.15)，最高相比强化20%左右(Ro≈0.55)。

Abstract:

In order to investigate the effects of lateral impingement on heat transfer in a turbine blade inner cooling structure， experimental tests were conducted in a lateral impingement wedge-shaped channel simplified from blade trailing edge. The test conditions were arranged at the Re of 5×103 to 1×104， and Ro of 0 to 0.54. The heated cooper plate technique is applied to obtain the span-wise and stream-wise heat transfer distributions. According to the experimental results， the lateral coolant impingement causes higher heat transfer at inner and mid regions than outer region. And the rotation enhances this span-wise heat transfer difference. As the Ro increases， the regional heat transfer of the channel middle part decreases first， and till to a critical rotation number which is corresponding for the lowest local heat transfer， and then increases again. The critical rotation number was found to decrease with increasing radial stream-wise locations. Compared to static channel， the averaged heat transfer level of rotational channel decrease till to 15% when Ro reaches 0.15， while increase up to 20% within the test range (Ro≈0.55).