管路截面突然扩大局部阻力计算的探讨

Discussion on the calculation of local resistance loss in case of the pipe section enlarging

流体在管道中流动的能量损失不仅有沿长度方向的沿程能量损失,而且还有主要由流体的相互碰撞和漩涡的形成等原因所造成的出现在局部的能量损失,这种损失成为局部能量损失或局部阻力。通常在计算局部阻力时没有考虑沿程阻力。但是在形成局部阻力损失的管段中,还会同时伴随产生由于液体的粘性力引起的漩程水头损失,这就造成了这项损失的计算误差。为了解决这个问题,笔者对管路截面突然扩大局部阻力测量原理进行讨论分析,从而得出计算这项损失的较为精确的表达式。

There are two types of enery losses when fluid flows in pipes: the friction head Loss over the length direction and Local resistance Loss caused by the collision of the fluid and formation of rotational flow.In general,the friction head is not concerned in the local resistance computation.However, For pipes with local resistance loss,the friction head loss caused by the viscosity of fluid does exist,which may lead to the calculation error.To cope with the pvoblem,the measurement principal of local resistance in case of the pipe section enlarging is analysed in the paper,and the accurate equation of calculating this loss is obtained.