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采用有限体积方法,研究了矩形截面微通道直角突缩弯道局部流场及压力损失机理,重点考虑了雷诺数和弯道进出口截面面积比对局部流场及压力损失的影响,雷诺数范围为1～200,特征尺寸为500μm.研究表明,低雷诺数时压力损失主要由壁面摩擦产生,弯道压力损失系数与具有相同中心线长度的直通道的压力损失系数变化趋势相同,但在数值上较小,突缩弯道会引起弯道内速度型发生变化,影响弯道压力损失;而高雷诺数时,压力损失主要由弯道内角位置的速度分离及漩涡产生,突缩弯道会抑制速度分离及漩涡产生,进而降低弯道压力损失.根据计算结果,拟合了弯道压力损失系数与雷诺数及进出口截面面积比的关系式.
The finite volume method is used to study the local flow field and pressure loss mechanism of rectangular microchannels at right angles to the curve. The influence of Reynolds number and the cross-sectional area ratio of inlet and outlet on the local flow field and pressure loss is mainly considered. The Reynolds number range The results show that the pressure loss at low Reynolds number is mainly caused by wall friction and the change tendency of pressure loss coefficient of straight channel with the same centerline length is the same, On the small, sudden turn curve will cause the speed curve within the curve changes, affecting the curve pressure loss; and high Reynolds number, the pressure loss is mainly caused by the corner angular position of the separation and vortex, the sudden curve will be inhibited Speed separation and vortex generation, and then reduce the pressure loss of the curve.According to the calculation results, the relationship between the pressure loss coefficient of the curve and the Reynolds number and the area ratio of the inlet and outlet sections is fitted.