Research On Characteristics Prediction Of Low Specific Speed Centrifugal Pumps And Software Development

The pump characteristics prediction can not only shorten the cycle of product research and development but also reduce the cost of the pump design and manufacture. The pump characteristics prediction has been a very important subject in pump field all the time. Low specific speed centrifugal pumps are widely applied in engineering because of small capacity and high head. But the characteristic prediction results for low specific speed centrifugal pumps are still not accurate enough to satisfy the need of engineering application, and there is still no practical software of the pump characteristics prediction. Therefore, it is necessary to have a serious study on the characteristics prediction of low specific speed centrifugal pumps. The main research contents of this paper are below:(1) The present situations and trend on characteristics prediction of centrifugal pumps are summarized. The advantages and disadvantages of several main methods on pump characteristics prediction, such as the hydraulic loss, the flow field analysis, the neural network and area ratio are compared. Also, the hydraulic design methods of low specific speed centrifugal pumps and the development trends are summarized.(2) The Stodola, Stechkin, Pfleiderer and Weisner slip coefficient formula are compared, and the research indicates that Weisner(ns<60) and Stechkin(ns>60) are more accurate for low specific speed centrifugal pumps. Based on practical calculation results of many excellent hydraulic model and experiment results, the two formulas are modified, and the coefficients are calculated by regression analysis method. On the base, the theory head formulas are modified.(3) The disk friction loss formulas are studied. The chosen formulas are modified and the coefficients are calculated by regression analysis method.(4) The hydraulic loss evaluation formula are analyzed,. The selected hydraulic loss formulas are revised and the coefficients are also calculated by regression analysis method. (5) Based ARX flat roof and using VC++6.0, the software of characteristics prediction of low specific speed centrifugal pumps with engineering practice has been successfully developed for the first time.