水力光滑圆管临界雷诺数的确定

The Determination on the Critical Reynolds Number of the Smooth Pipe

根据由Prandtle紊流混合长理论推导出的光滑圆管中紊流的速度分布和Nikuratse测得的圆管中紊流的速度剖面图确定的层流边层的区域范围,推导出层流边层厚度的计算公式,提出一个新的水力光滑圆管临界雷诺数计算模型。经试验数据验证,新计算模型确定的临界雷诺数与试验点符合很好。

According to the velocity profile based on Prandtle mixing-length theory and the one measured by Nikuratse,the region of the viscous sub-layer in the smooth pipe is determined,and then the formula of the viscous sub-layer thickness is deduced. Then a new equation calculating the Critical Reynolds Number of the hydraulic smooth flow is obtained. It is proved that the new equation accords with the experimental data.