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本文用六种冲击管对两种尺寸的铝质试验件进行冲击冷却实验。模拟叶片前缘的试验件予先加热,然后由不同的冲击管喷出的射流在不同的流量和距离下对它进行冲击冷却。采用集总热容法来确定铝块的冷却率从而算出冲击平均换热系数,并整理成准则形式。通过计算机的运算得出Nu数与R6数以及三种无因次几何参数的统一的准则关系式。用该式计算出来的Nu数同本文实验测得的Nu数进行了比较,取得比较满意的结果。最后用该式与美国亚利桑那州大学的梅茨格公式和辛辛那提大学的拉维利——塔巴戈夫公式同本文实验数据进行了比较,认为本文整理出来的公式是比较合理的。
In this paper, six kinds of impact tubes were used to impact cooling experiments on two kinds of aluminum test pieces. The test piece simulating the leading edge of the blade is preheated and the jets ejected by the different impact tubes are impact cooled at different flow rates and distances. Using lumped heat capacity method to determine the cooling rate of aluminum block to calculate the impact of the average heat transfer coefficient, and organized into a guideline form. Through the operation of the computer, we obtain the uniform criterion relation between Nu number and R6 number and three kinds of dimensionless geometric parameters. The number of Nu calculated by this formula is compared with the number of Nu measured in this paper, and the satisfactory result is obtained. Finally, this formula is compared with the Metzger formula of the University of Arizona and the Ravigne-Tabacoff formula of the University of Cincinnati to the experimental data in this paper. The conclusion is that the formulas formulated in this paper are reasonable.