侧式进/出水口水头损失系数多元线性回归分析

Multiple linear regression analysis on head loss coefficients of side inlets and outlets

进/出水口水头损失是抽水蓄能电站输水系统水头损失的重要组成部分,准确计算水头损失是评估电站运行经济效益的重要需求。本文通过数值模拟方法研究了14个实际侧式进/出水口的水头损失系数;利用多元线性回归方法,建立了基于侧式进/出水口体型参数计算水头损失系数的回归方程,分析了侧式进/出水口体型参数对其水头损失系数的影响规律。结果表明:侧式进/出水口体型参数对水头损失系数的影响程度,对出流工况较显著,而对进流工况不显著;出流工况,侧式进/出水口体型参数对水头损失系数的相关性,扩散段长度、扩散段分流墩中墩缩进距离、水平扩散角、垂向扩散角、分流墩墩头中边孔宽度比和反坡段坡比为正相关,调整段长度和防涡梁段长度为负相关;利用回归方程得到的水头损失系数与数值模拟方法的结果吻合较好。本文建立的回归方程为计算侧式进/出水口水头损失系数提供了新方法。

Flows past the inlets and outlets cause a significant part of the total head loss in the water transmission system of a pumped storage power plant,and its accurate calculation is needed in evaluation of the plant’s economic benefit.This paper uses numerical simulations to study the head loss coefficients of 14 types of side inlets and outlets.Using the multiple linear regression method,we formulate regression equations that can calculate the head loss coefficient,and examine its variations with the shape parameters of the inlets and outlets.The results show that the influence of these parameters on the loss coefficients is significant in the outflow condition while insignificant in the inflow condition.Under the outflow condition,a positive correlation occurs between the loss coefficient and the parameters-the length of the diffusion section,the distance between the middle pier retraction of the diffusion section,the horizontal diffusion angle,the vertical diffusion angle,and the ratio of the width of the side hole in the pier head of the diversion section,and the slope ratio of the reverse slope section-while a negative correlation occurs between the loss coefficient and the length of the adjustment section or the length of the anti-vortex beam section.The head loss coefficients calculated using the regression equations agree well with the calculations from numerical simulations.Application of our regression equations is a new way to calculate the head loss coefficients of side inlets and outlets.