摇摆条件窄缝矩形通道内层流充分发展流动

Fully Developed Laminar Flow in a Rolling Narrow Retangular Duct

为获得摇摆条件下窄缝矩形通道内充分发展层流流动规律,首先根据流体质点受力分析结果求解摇摆条件下的动量方程获得层流充分发展速度分布和摩擦系数的理论解;然后开展角振幅±15°、周期8 s摇摆条件下900≤Re≤2600范围内的层流等温流动实验。理论和实验研究结果表明,摇摆条件相对静止条件的最大不同在于各项质量力的周期性变化会引起压力梯度的周期性变化,流体动力结构关系进行重新调整。其中,流体所受剪切力不发生变化,各项质量力产生的压降波动会相应地引起总压降的波动,而摩擦压降和流量不发生变化;摇摆条件下层流摩擦系数也不发生变化,并且理论预测值相对实验值的偏差在-1.1%～+4.3%的范围,两者具有较好的一致性。

To obtain the fully developed laminar flow law in a rolling narrow rectangular duct, the forces on fluid particle within a moving coordinates frame was analyzed firstly, and the momentum equation under rolling condition was solved to get fully developed laminar velocity distribution and friction factor. Then, the isothermal laminar flow experiments with 900~〈Re~〈2600 under rolling condition with amplitude of ±15° and period of 8s were conducted. The research results show that the most difference between rolling and stationary conditions is that the pressure gradient varies periodically with each body force, thus hydro-dynamical structural relationship readjusts while the shear stress keeps constant; the pressure drop wave induced by each body force will results in the total pressure drop wave while the friction pressure drop and mass flow rate keep constant; the laminar friction factor under rolling condition also keep constant, and the theoretical prediction deviates from -1.1% to ＋4.3% in comparison with the experimental data, therefore both results are with a good agreement.