Design And Software Development Of Pump System Flow Passage Based On Key Parameters

The inlet and outlet passages are an important part of the pump system.For the pump system with specific impellers and vanes,the inlet and outlet passages can determine the performance of the pump system.In actual engineering,the passage performance is often difficult to meet the design requirements.At this stage,the pump system flow passage is designed by professionals.The existing software of pump system flow passage design adopts one-dimensional design method.The input parameters are many and complicated.The parameter values need to be based on actual engineering experience,and the performance of the designed pump system cannot be guaranteed.The practicability of the software need to be improved.The engineering drawings drawn by the existing flow passage drawing software are still insuffient to meet the actual needs.This paper mainly studies the key parameters of the inlet and outlet passages of vertical axial flow pumping systems,and develops the flow passage design software based on key parameters.The key parameters of the inlet passage include the aspect ratio of the throat of the inlet passage,the ratio of the inlet and outlet area of the elbow and the area changes along the inlet elbow.The key parameters of the outlet passage include the elbow outlet height,the horizontal diffusion angle and the area changes along the outlet elbow.Through numerical simulation,the uniformity of velocity distribution,the average angle of the weighted velocity of the outlet section of the inlet passage,the hydraulic loss of the inlet and outlet passages,the recovery rate of the kinetic energy of the outlet passage,and the vorticity of the typical section in outlet passage are analyzed and compared.As well as the impact on the performance of the pump system,the recommended values for the key parameters are determined.It is determined that the aspect ratio of the throat of the inlet passage is between 0.4～0.6.If this value is too large,the water inflow angle of the impeller inlet will be larger.If the value is too small,the hydraulic loss will increase.The recommended value of the ratio of the inlet and outlet area of the elbow is about 1.8.Too large or too small will increase the hydraulic loss of the inlet passage.The area changes along the inlet elbow which meets concave function show better performance.It is recommended that the elbow outlet height values between(0.8～0.9)D0.If the value is too large,there will be a vortex zone at the junction between the elbow and the straight pipe.If the value is too small,the kinetic energy recovery capacity of the outlet passage will decrease,and average vorticity of the straight pipe will be enlarged.The recommended horizontal diffusion angle of the elbow is about 8°.When this value is taken,the hydraulic loss of the outlet passage is small,and the vorticity of the straight pipe is small.The law of the area along the elbow of the outlet passage shows better performance by the concave function.It is found that the straight pipe of the outlet passage diffuses in the longitudinal direction will easily lead to disorder of the flow state and increase the hydraulic loss.According to the results of the above research,using the computer programming language MATLAB and drawing software AutoCAD as the platform,with the interface function of MATLAB and AutoCAD,a pump system flow passage design software is developed,which has the function of passage design and engineering drawings output.It can effectively design high performance flow passage.The structure of the software is divided into an input module,a calculation module,a drawing module,and an output module.The numerical simulation calculation is applied to test and verify the pump system model designed by the software.Under the design condition,the pump system emciency reaches 78.39%,and the flow passage performance is guaranteed.It proves that the software can meet the requirements of engineering application.The flow passage design is beautiful and practical.The internal flow state is evenly distributed,so that the software can help the design of the actual pump system inlet and outlet passages.