圆管进口段层流一湍流边界层发展区的流动阻力

本文提供了一种计算模型，可以根据前文1]13]所提供的圆管进口段边界层单纯层流和单纯湍流时的近似分析解作为基础，计算3×10{sup}3≤ReD≤1×10{sup}5时进口平滑的圆管进口段内边界层先层流、然后过渡为湍流的任何区段不可压缩流体的流动阻力和壁面摩擦阻力。计算的流动阻力为文献6]所报导的实验原始资料所验证。

THE FLOW FRICTION FOR INCOMPRESSIBLE TURBULENT BOUNDARY LAYER FLOW THROUGH THE ENTRANCE REGION OF CIRCULAR TUBE

The friction behaviors for the completely laminar and turbulent boundary-layer flow of incompressible fluid in the bellmouth entrance region of a smooth circular tube had been treated respectively 1,13]. A simplified model (Fig.2) is suggested to determine the entrance effect on the flow friction for the complicated laminar-to-turbulent boundary-layer flow of incompressible fluid through circular tube. The analytical relations obtained previously1,13], eqs. (1)-(7), are used as the basis for calculation. With the apparent crihcal Reynolds number Rex1 taken as 5 x 105, 4]The predicted pressure drops are in good agreent with the experimental data reported6], (Fig.3).