涡轮叶片综合冷却效率实验研究

Experimental Investigation on Integrated Cooling Efficiency of Turbine Blade

关键词:  航空发动机  涡轮叶片  气膜冷却  综合冷却效率  红外修正

Key words:  Aero-engine  Turbine blade  Film cooling  Integrated cooling efficiency  Infrared calibration

摘要:

为了研究气冷涡轮叶片综合冷却效率及其影响因素，采用红外热像仪对叶片表面温度场进行了测量，同时在叶片中截面布置了15支热电偶用于校准红外热像仪的测量结果，获得了叶片表面温度场分布以及流量比、温比和落压比对叶片综合冷却效率的影响规律。实验结果表明：叶片温度场分布受内部冷却和外表面换热共同影响，叶片前缘与叶尖处于较高温度状态；在实验工况内，增加流量比可以有效提高叶片综合冷却效率，流量比从0.02增加到0.07时，平均综合冷却效率从0.426升高到0.645，提高了51.4%；温比对综合冷却效率影响不明显，但大温比可以降低叶片温度；落压比从1.3增加到1.5时，平均综合冷却效率由0.524上升至0.565，升高了7.8%。

Abstract:

In order to study the integrated cooling efficiency of air-cooled turbine blade and its influencing factors， the infrared thermal imager was adopted for the measurement of blade surface temperature field， and 15 thermocouples were set up in the middle section of the turbine blades for calibration， obtaining accurate surface temperature field distribution. The influences of flow ratio， temperature ratio and pressure ratio on the blades integrated cooling efficiency were thus deduced. The experimental results show that the temperature field distribution of the blade is affected by both internal cooling and external surface heat transfer， with the leading edge and the tip part of blade at a higher temperature state. Under experimental conditions， the integrated cooling efficiency of the blade is effectively improved by increasing the flow ratio. With the flow ratio increases from 0.02 to 0.07， the arc-averaged integrated cooling efficiency rises from 0.426 to 0.645， which means a growth of 51.4%. Although the large temperature ratio can reduce the blade temperature，the temperature ratio is found having no obvious effect on the integrated cooling efficiency. When the pressure ratio increases from 1.3 to 1.5， the arc-averaged integrated cooling efficiency goes up from 0.524 to 0.565， resulting in a 7.8% growth.