摘要
工程中普遍存在离心泵实际流量高于输水系统所需的情况,通过数值模拟研究平移叶轮前盖板对离心泵性能的影响,结合理论推导出平移前盖板改变离心泵扬程的换算公式,实现减小叶轮出口宽度及其工作流量达到泵站节能的目的.研究结果表明:切割叶轮外径与平移叶轮前盖板均会降低离心泵工作扬程,不同的是,前者使H-Q曲线整体向下移动且下降幅度较大,而后者H-Q下降幅度较小,能在小流量工况维持较高的扬程;平移叶轮前盖板后能抑制小流量工况下叶轮内回流旋涡的发展,离心泵效率有所上升,更适合多泵并联工作的场合,具有一定的工程价值;离心泵扬程随前盖板平移而变化的换算公式可以相对准确地预测较小叶轮前盖板移动量时中比转数离心泵0.8~1.0倍设计工况范围内H-Q曲线的变化.
It is common in the engineering practice that the working flow of the centrifugal pump is higher than that required by the water delivery system.The translation of the shroud to reduce the width of the impeller outlet can reduce the working flow to achieve the purpose of energy saving in the pumping station.Numerical simulation method is used to study the effect of axially shifting impeller shroud on the performance of centrifugal pump.Combined with the theory,the conversion formula of the front cover plate changing the head of the centrifugal pump is deduced.The results show that cutting the outer diameter of the impeller and translating the shroud of the impeller will reduce the working head of the centrifugal pump.The difference is that the former moves the head curve downward and the decline is greater,while the latter's head curve becomes steeper,but maintain a higher head in small flow conditions.Compared with cutting the outer diameter of the impeller,the hydraulic performance of the centrifugal pump is deteriorated.The translation of the shroud of the impeller suppress the development of the continuous vortex in the impeller under low flow conditions,and the efficiency of the centrifugal pump is increased,which is more suitable for the occasions where multiple pumps work in parallel.According to the basic equation of the pump,the conversion formula of shifting shroud to change centrifugal pump head is derived,and the error of the conversion formula is corrected by using multiple regression analysis.After the test of different centrifugal pump models,the results show that the conversion formula can relatively accurately predict the change of H-Q curve in the range of 0.8~1.0 times working conditions of the centrifugal pump when the moving amount of the shroud of the impeller is small.
作者
赵万勇
梁允昇
彭虎廷
马得东
ZHAO Wan-yong;LIANG Yun-sheng;PENG Hu-ting;MA De-dong(School of Energy and Power Engineering, Lanzhou Univ. of Tech., Lanzhou 730050, China)
出处
《兰州理工大学学报》
CAS
北大核心
2021年第6期31-37,共7页
Journal of Lanzhou University of Technology
基金
江苏大学国家水泵及系统工程技术研究中心开放基金(NRCP201605)。
关键词
双吸离心泵
叶轮切割
叶轮出口宽度
换算公式
double-suction centrifugal pump
impeller trim
impeller outlet width
Conversion formula
