高浓度固液两相球阀开启压差特性分析

利用雷诺应力模型和欧拉—欧拉方法对固液隔膜泵出口球阀的开启压差及压力分布特性进行了理论推导与仿真分析,以纯液相压力特征为基础,进一步研究了多参数下高浓度固液两相流进出口压差的变化规律并相应地建立了压差理论及回归数学模型。研究结果表明,球阀出口压力为1.0 MPa,阀球材质为氟橡胶包覆硬铝质芯时,理论分析所得球阀开启所需压差为3.99×105Pa,而球阀开启后,模拟得到进出口压差及轴向液动力迅速衰减,低压力区出现于阀座上下顶角间的10 mm环形阀隙中心区域,其轴向位置随阀口开度增大呈线性下降。当流动介质为高浓度液固两相流时,阀隙内部射流加速段上移至阀座上顶角z=30 mm处,球阀进出口压差达到了单相流压差的8倍以上,并且得到了各物性和操作参数(阀口开度、固相浓度、混合粘度、入口流量等)对压差影响的显著性程度排序。

Analysis of Differential Pressure Characteristics During the Opening Process in High-concentration Solid-liquid Ball Valve

Theoretical analysis and numerical simulation were employed to study the differential pressure characteristics of ball valve in U-diaphragm pump by using Reynolds Stress Model and Euler-Euler method.The single-phase pressure distributions in ball valve were investigated fundamentally.Furthermore,the changing rules of high-concentration two-phase differential pressure were studied and the corresponding theoretical model is established.The results show that when the outlet pressure is 1.0 MPa and the ball is made of aluminum core coated by hard fluorine rubber,the differential pressure needed for valve's opening is 3.99× 105 Pa by theoretical calculation.After the ball is pushed,the simulated differential pressure and axial steady flow force begin to decay rapidly,and the lowest pressure region is located in the 10 mm-width annular clearance which moves down linearly with the opening of ball valve.In case of high-concentration liquid-solid flow,the acceleration region moves up to the higher corner of valve seat(z = 30 mm),and the differential pressure reaches more than 8 times of single-phase differential pressure.It is found that two-phase differential pressure is affected by multiple factors,such as valve opening,solid concentration,viscosity and inlet flow rates,and the important degree of these various factors are obtained further for two-phase differential pressure in ball valve.