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通过提高U型通道气体压力到500k Pa以上,将实验雷诺数Re和旋转数Ro范围分别扩展到10000~70000和0~2.0,从而匹配真实发动机转子叶片的工作条件。在此基础上实验研究了高旋转数下带直肋的、方形截面的U型通道的换热特性。研究结果表明:第一通道前缘面的努塞尔数比随旋转数的增大先下降后增强,该临界旋转数为定值Roc=0.26;随着旋转数的增大,第二通道前缘面的努塞尔数比一直高于后缘面,与光滑通道中的换热规律不同;随着旋转数的增大,第二通道内外侧面努塞尔数比的差异逐渐减小,在临近出口处几乎没有差异,与光滑通道相比正好相反。
The experimental Reynolds number Re and the number of revolutions Ro were extended to 10000-70000 and 0-2.0 respectively by increasing the gas pressure of the U-shaped channel to over 500kPa to match the working conditions of the real engine rotor blade. On this basis, the heat transfer characteristics of a U-shaped channel with a straight rib and a square cross section under high revolutions were experimentally studied. The results show that the Nusselt number ratio of the front face of the first channel decreases first and then increases with the increase of the number of revolutions, and the critical number of revolutions is Roc = 0.26. With the increase of the number of revolutions, The Nusselt number ratio of the edge surface is always higher than that of the trailing edge surface, which is different from that of the smooth passage. With the increase of the number of revolutions, the difference of Nusselt number ratio of the inner and outer sides of the second channel decreases gradually. There is almost no difference near the exit, as opposed to the smooth passage.