出口侧向扩张孔流量系数试验

采用试验研究的方法，探讨了不同结构参数出口侧向扩张孔的流量系数在不同工况下的变化规律。通过试验研究发现:出口侧向扩张孔圆柱段孔径为0.6 mm时的流量系数比孔径为0.8 mm时大3%；当孔倾角由30°减小至25°时，流量系数随之增大，当倾角继续减小至20°时，流量系数不变；当扩张角由20°增大至40°时，流量系数先增大后减小，且在扩张角为25°时最大；流量系数与次流通道雷诺数成正比，雷诺数越大，流量系数达到极限值所需的压降系数越小，且当压降系数大于0.9后，不同次流雷诺数下的流量系数差别在2%左右。 

Experiment on discharge coefficients for outlet lateral dilated hole

The experimental study on the discharge coefficient of outlet lateral dilated hole was conducted to investigate the trend of discharge coefficients with different structure parameters and aerodynamic parameters.Research showed that the diacharge coefficient of outlet lateral dilated hole cylindrical segment diameter 0.6 mm 3% larger than 0.8 mm.When the hole inclination angle was reduced from 30° to 25°，the discharge coefficient increased，and when the inclination decreased to 20°，the discharge coefficient remains unchanged.When the expansion angle grew from 20° to 40°，the discharge coefficient increased first and then decreased，and reached the maximum value when the expansion angle was 25°.Meanwhile the discharge coefficient was proportional to the secondary flow Reynolds number，and the larger secondary flow Reynolds number indicated the smaller pressure drop needed to reach the limit coefficient value.When the preesure drop was greater than 0.9，the difference of the discharge coefficient at different secondary flow Reynolds number was about 2%.