Wankel Pump Working Characteristics Research And Performance Prediction

In recent years,pump equipment has been developing in the direction of large-scale,wide and high-efficiency operation range,and ultra-high pressure and large flow,so it is necessary to continuously improve the design level of pumps to cope with the ever-increasing hydraulic performance requirements.As a new type of rotary positive displacement pump,the design of the small Wankel pump has been perfected day by day,but the design of the large Wankel pump is still in the theoretical stage.The research of Wankel pump performance conversion theory has great theoretical significance and practical application value for improving the design level of large pump and accurately predicting the working characteristics of pumps.However,the current theoretical research on the conversion of Wankel pump performance parameters is blank,and the optimal working range of the Wankel pump is unknown.The use of the pump under non-optimal working conditions can cause energy waste and unnecessary economic losses.Therefore,there is an urgent need to study the working characteristics of Wankel pump,propose a performance conversion theory suitable for Wankel pump,which can be used to realize the conversion of various Wankel pumps,predict the working characteristics of large Wankel pump,and apply them to their design.In view of the above problems,this paper takes the working characteristics andperformance prediction of Wankel pump as the main research points,adopts theoretical analysis,model tests and numerical simulation research methods,to study working characteristics of the Wankel pump under different working conditions.The influence law of the spindle speed and outlet pressure on the working characteristics of the pump has been summarized,and the optimal working range of the Wankel pump was pointed out.Based on the loss model of Wankel pump,both efficiency expression and conversion theory of Wankel pump were deduced.Using the genetic algorithm to fit each loss coefficient of the pump,predict the performance of the prototype pump through conversion theory,and then using experiment and numerical simulation to verifie the fitting results.The specific work results are as follows:(1)The basic equation of Wankel pump and the theory of pump performance conversion were deduced.According to the structural characteristics of the Wankel pump,the mechanical loss and its similar relationship,hydraulic loss and its similar relationship,volume loss and its similar relationship between the model pump and the prototype pump were analyzed respectively,and the loss coefficient of each loss was defined.Combined with the basic similarity relationship of Wankel pump,the conversion method of the loss coefficient was derived,and a unified expression of Wankel pump performance was obtained.(2)The performance test and pump performance conversion theory verification test of Wankel pump were carried out.The SDU-0.75-30 model and SDU-1.5-56 model high-precision Wankel pump hydrodynamic system were built,and multiple sets of test conditions were designed.Taking the SDU-0.75-30 model Wankel pump as an example,the influence law of spindle speed and outlet pressure on pump performance was studied,and the best working range of the pump under different working conditions was indicated.The performance parameters of the SDU-0.75-30 type pump were converted to the performance parameters of the SDU-1.5-56 type pump,and compared with the test data of the latter.It was found that the conversion parameters were greatly consistent with the test data,which verified the feasibility of Wankel pump conversion theory from the test aspect.(3)Based on the XFLOW numerical simulation software,the flow channel model of Wankel pump was established,the flow field in the Wankel pump was simulated,the distribution law of velocity field and pressure field in the pump were analyzed,and the output flow characteristic of the Wankel pump was analyzed.The working conditions of a variety of new sizes of Wankel pumps were simulated,and the volume loss of the simulated working conditions were calculated.The converted values were compared with the simulated values,and the errors were found to be small,which verified the feasibility of the theoretical conversion of Wankel pump from the numerical simulation aspect.