出流孔对内流通道壁面换热影响的实验

根据相似理论放大的模型,实验研究了带有出流孔内流通道带孔—侧壁面的对流换热特性。实验采用加热钢带法,主要在主流雷诺数为2.5×104～10×104,出流比为1.0～4.0的范围内,测量了出流孔附近的换热系数分布,重点分析了主流雷诺数和出流比对壁面对流换热的影响规律。实验结果显示出流作用使出流孔下游区域内的换热得到强化。主流雷诺数一定时,随出流比的提高此区域换热强度提高,影响范围也扩大;出流比一定时,不同主流雷诺数下,带出流孔壁面换热强度与不带出流孔壁面换热强度的比值(Nu/Nu0)基本一致,换热被强化的程度无显著变化。

Effect of suction hole on heat transfer characteristic of internal passage

Experimental investigations of heat transfer characteristics near the entrance of a suction hole were carried out with proportionally enlarged model. The distributions of local heat transfer coefficients were measured with the heat-film method. Tests were performed with Reynolds numbers (based on average velocity of mainstream and hydraulic diameter of the internal passage) changing from 2.5 x 10 to 1 x 10 and suction ratios (SR) changing from 1.0 to 4.0. Influences of Reynolds number and suction ratio on heat transfer characteristic are studied. Results indicate that heat transfer coefficients are enhanced obviously in the downstream area of the suction hole by the suction effect. The increasing of suction ratio leads to higher heat transfer enhancement in this area; while the changing of Reynolds number contributes no remarkable effect on increase the value of Nul Nua , which representing the heat transfer enhancement's extent.