改进的特征线方法及过载对水锤效应影响分析

An improved MOC and impact analysis of overload on water hammer

传统特征线方法对过载作用下的水锤计算具有局限性,无法为水锤防护提供可靠性指导。本文在考虑过载效应和动态摩阻的基础上,提出了改进的特征线方法,该方法能准确模拟过载作用下水锤最大压力峰值及水锤波的衰减特性。基于该方法,建立了过载作用下水锤效应数学模型,通过分析结果与CFD数值仿真及实验数据对比,验证了改进特征线方法的正确性。分析结果表明,在恒定过载作用时,阀门位置的流体压力随过载量的增加而增大,且管轴向过载的影响大于横向过载;关阀过程受到瞬时过载作用时,过载效应对水锤最大压力峰值影响显著,而对关阀后水锤波的传播和衰减影响较小;同时,分析了过载效应下关阀特性和流体密度等参数对水锤效应的影响规律。

The traditional MOC is limited in the analysis of water hammer under overload,which cannot provide the reliable guidance for water hammer protection.Considering the overload effect and dynamic friction,an improved MOC that can accurately simulate the maximum pressure and wave attenuation of water hammer is proposed in this paper.The water hammer under overload is investigated,and the method was also verified by comparing the analysis data with CFD and experimental results.It is found that the pressure at the valve position rises with the increase of overload,and the influence of axial overload on water hammer is greater than that of lateral overload.The effect of instantaneous overload is significant on maximum pressure,but little on wave propagation and attenuation as valve closing.Moreover,the influence of parameters such as valve closing characteristics and fluid density on water hammer under overload was analyzed.