摘要
为了研究黏性介质下泵反转作透平的换算关系,选用5台不同比转速离心泵反转作透平,在5种不同的介质黏度下,对透平工况进行数值计算。为了验证数值计算的准确性,对离心泵反转作透平在清水介质下进行实验,实例表明数值模拟结果与实验结果吻合较好。通过引入以透平叶轮进口圆周速度为特征速度,进口半径为特征长度的叶轮雷诺数,得到某一比转速下泵作透平流量换算系数、压头/扬程换算系数随叶轮雷诺数变化的规律,以及流量换算系数、压头/扬程换算系数与叶轮雷诺数、比转速的关系。结果表明:对于同一比转速下泵反转作透平,流量、压头/扬程换算系数随叶轮雷诺数的增大而减小;随着黏度的增加,透平最优效率点向大流量工况偏移;基于泵和透平在最优效率点数据,采用拟合方式将流量、压头/扬程换算系数表示成仅与比转速、叶轮雷诺数有关的关系式。实例表明:在研究范围内,所得关系式可比较准确地计算任一比转速、任一黏度的流量、压头/扬程换算系数。
In order to study the conversion relation of pump reversing as turbine in viscous medium,the author selected 5 centrifugal pumps with different specific speed to reverse as the turbine and calculated the values of turbine condition in 5 different media viscosity.The experiment of centrifugal pump reversal as turbine was carried out in clear water medium to verify the accuracy of numerical calculation.It turned out that the numerical simulation results are identical to the test results.By introducing the Reynolds number of turbine with peripheral speed of turbine impeller inlet as reference speed and the radius of inlet as characteristic length,it's able to obtain the changing laws of the flow conversion coefficient of pump as turbine and the conversion coefficient of pressure head/pump lift in certain specific speed with Reynolds number of turbine,and the relation tween the flow conversion coefficient,the conversion coefficient of pressure head/pump lift and Reynolds number of turbine,the specific speed.The results show that,for pump reversal as turbine at the same specific speed,the conversion coefficient of flow and pressure head/pump lift decrease with the increasing Reynolds number of turbine;the point of the highest efficiency of turbine moves to condition with high flow,as the viscosity grows;based on the data of pump and turbine in;numerical the point with the highest efficiency,the conversion coefficient of flow and pressure head/pump lift is expressed as the correlation related to the specific speed and Reynolds number of turbine,by means of fit method.The examples indicate that,to the extent of research,the obtained equation can accurately calculate the conversion coefficient of flow and pressure head/pump lift at any specific speed and in any viscosity.
作者
杨军虎
罗钰铜
马琦航
林彬
姬亚亚
Yang Junhu;Luo Yutong;Ma Qihang;Lin Bin;Ji Yaya(College of Energy and Power Engineering,Lanzhou University of Technology,Lanzhou 730050,China)
出处
《甘肃科学学报》
2020年第3期84-89,100,共7页
Journal of Gansu Sciences
基金
国家自然科学基金(51569013)。
关键词
透平
黏性介质
数值计算
叶轮雷诺数
换算系数
Turbine
Viscous medium
Numerical calculation
Reynolds number of impeller
Conversion coefficient
作者简介
杨军虎(1962-),男,陕西蒲城人,教授,博导,研究方向为流体机械内流理论,E-mail:LZYangJh@lut.cn。
