低扬程泵装置起动虹吸驼峰压力分析

Analysis on the Hump Air-pressure in the Low-headSiphon Pumping Setting during Starting Transient Period

分析了低扬程泵装置流道内空气的动力学特性、管道内的非恒定流以及水泵的动力性能,结合实测的泵机组起动转速变化规律,提出了起动过渡过程中虹吸驼峰压力变化近似计算的数学模型,动态参数数值计算则通过构建数学模型的有限差分,组成非线性方程组,利用牛顿—莱福森法(Newton—Raphson)对泵流量、扬程、驼峰压力和下降段排出流量迭代求解。

Based on theoretical analysis of aerodynamic characteristics on the discharge pipeline, dynamiccharacteristics of pump setting and combined with rotating speed law through actual measure, the mathematicalcalculation model of transient hump air-pressure during starting period is put forward considering unsteadyflow, pump performance curve and similitude laws in low-head siphon pumping installation. The variation lawsabout dynamic parameters can be obtained through Newton-Raphson method by the way of Composingmathematical model finite difference and nonlinear equation. The integrated model can predict the hump air-pressure in the low-head siphon pumping setting during starting transient period.