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Study On Characteristics And Calculation Of Rotating Flow Field On Roto-Jet Pump

Posted on:2020-06-09Degree:MasterType:Thesis
Country:ChinaCandidate:H XuFull Text:PDF
GTID:2392330596478067Subject:Fluid Machinery and Engineering
Abstract/Summary:PDF Full Text Request
The roto-jet pump is a new type pump with especial structure.Its specific speed is extremely low,and the efficiency is about 10%-25%higher than that of the general centrifugal pump.The roto-jet pump has the advantages of small flow,high lift;simple structure,and economical and easy maintenance.It is mainly used in chemical oil,metal smelting,agricultural machinery,food scouring,paper inkjet and other fields.However,China's research on roto-jet pumps is still in its infancy,and there are many problems to be further explored,especially the lack of corresponding research on the liquid flow characteristics of the rotating flow field inside the roto-jet pump.In this paper,the research status of roto-jet pump at home and abroad is analyzed comprehensively.The numerical research on the velocity and pressure characteristics of the rotating flow field in the rotating shell and its calculation method are carried out.At the same time,in order to ensure the reliability of numerical simulation,this study made a performance test of the rotjet pump and a liquid pressure test in the spiral shell.The main work and conclusions are as follows:l.On the multi-functional test bench of the self-designed roto-jet pump,the performance test of the roto-jet pump and the measurement of the pressure of each pressure tapping hole in the radial direction of the rotor cavity under different flow conditions,comparative test and numerical simulation results,The numerical simulation results are slightly larger than the test results,but the two errors are within the allowable range,so that the research in this paper is credible.2.Through the numerical simulation of the rotating flow field of the roto-jet pump,under the design conditions,analysis the liquid velocity and pressure variation and vorticity distribution in the characteristic shaft cross-section and the characteristic circumferential direction,The liquid flow in the range of 7mm<z<17mm is mainly affected by the high-speed rotation of the front cover of the impeller.In the range of 17mm<z<50mm,it is mainly affected by the rotation effect of the rotating shell and the wake of the collector airfoil,at 50mm<z<55mm range is mainly affected by the rotation effect of the rotating shell and the flow around the double-row solid column of the inlet and outlet pipe sections.In addition,the tangential velocity of the liquid in the circumferential direction of each feature is roughly divided into three regions,that is,a large region of the tangential velocity gradient when r>110 mm,a small region of the tangential velocity gradient when r<60mm,and 60mm<r<110mm transition zone.3.By studying the cross-section of the inlet center of the collector,the flow of the liquid before the inlet of the collector is slightly higher,and it is proposed that the angular velocity of rotation of liquid is 0.517 times the angular velocity of rotation of the impeller.4.Take z=8.5mm,34mm,50mm shaft cross section,and analyze the liquid flow characteristics of the rotating flow field in the rotor cavity under different flow conditions in the circumferential direction 8=67,135,270.The performance is as follows:when the flow rate is small,that is,Q=1.26m3/h and 3.78m3/h,the liquid flow changes drastically,and the speed and pressure fluctuations occur after the collector airfoil,that is,0=135 and 270.Larger,before the inlet of the collecting pipe,that is,e=67,the liquid flow is stable under all flow conditions.5.In this paper,the impellers of three structural blades are designed.The influences of the impellers on the rotating flow field and pump performance of the three structural blades are compared and analyzed.The performance of the roto-jet pump with twisted blade impeller is optimized,and the rotating flow field is stable.
Keywords/Search Tags:roto-jet pump, collecting pipe, rotor cavity, rotating flow field, numerical simulation
PDF Full Text Request
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