Matching Design And Research Of Impeller Outlet And Diffuser Inlet In Stamping And Welding Centrifugal Pump

Stamping and welding centrifugal pump has the advantage of simple structure, high efficiency and energy saving, low leakage, low noise, longevity of service, low maintenance cost, etc. It is a perfect substitute for the small and medium-sized casting centrifugal pump, and is being used widely in various field of industrial and agricultural.However, the design methods and theory of stamping and welding centrifugal pump is still imperfect, so as to make the product can’t achieve ideal effect inpractice. This paper takes the DP32-4-8stamping and welding multistage centrifugal pump as the object of study, and the hydraulic model are simulated by CFD and tested in this paper. The influence of internal flow condition and performance, that due to the changes of impeller, diffuser and matching relationship of them, is analyzed. The results will develop the design theory and provide a reference basis for improving performance of stamping and welding centrifugal pump. The main work and achievements include:1. Based on a lot of technical literatures both abroad and domestic, the effect of centrifugal pump impeller and diffuser structure on performance is investigated. And according to the design feature of stamping and welding centrifugal pump, This optimized design method for impeller and diffuser in stamping and welding centrifugal pump.2. The parameters of stamping and welding centrifugal pump, such as clearance between impeller blade and shroud, angle between axis and outlet edge of impeller, impeller outlet to diffuser inlet area ratio, area of impeller to diffuser annulus inlet and interval between impeller and diffuser, are analyzed. In addition, the research programmes of them are established and the numerical computation are carried out.3. Based on the results of numerical calculation, the changes of internal flow distribution and performance in various models are analyzed. It could be mainly concluded that:(1) There is bigger influence of the clearance between impeller blade and shroud on pump performance, and the head and efficiency of pump will decline sharply if there is a larger clearance.(2) The angle between axis and outlet edge of impeller can improve pump efficiency, the stamping and welding centrifugal pump have good performance when θ=30°～40°.(3) As the impeller outlet to diffuser inlet area ratio increase, the head and efficiency of stamping and welding centrifugal pump will rise. When the area ratio increases from Y=1.48 to Y=3.49, the head will increase about3.0%and the efficiency increase about2.0%.(4) There is a good performanc of stamping and welding centrifugal pump when the area of impeller to diffuser annulus inlet is twice as for diffuser inlet area.(5) The smaller the interval between impeller and diffuser, the better performance of pump. The interval t=6mm compared wit t=lmm, the head drop about1.9%and the efficiency drop about1.4%.4. The experimental tests of two groups plan, one is the impeller with different angle between outlet edge and axis, another is the impeller outlet to diffuser inlet with different area ratio, are finished through cooperating with the enterprise. Comparing and analyzing the results of simulations and experiments, it indicate that the test results basically agree with the predictive result, and the reliability of the simulations was certificate.