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Hydraulic Design And Numerical Simulation Of High Speed Centrifugal Pump With Ultra-low Specific Speed

Posted on:2018-05-11Degree:MasterType:Thesis
Country:ChinaCandidate:Q ZhuFull Text:PDF
GTID:2322330518969410Subject:Power engineering
Abstract/Summary:PDF Full Text Request
The low-specific-speed high-speed pumps are used widely in petrochemical industry and aerospace field because of little rate of flux,high water-head,compact structure features.But because of its high rotational speed,so there is a big difference between its internal flow state and.the common centrifugal pump,for instance:wake flow is easy in the suction surface of the blade,but the pressure surface is prone to jet flow and so on.The research on the internal and external characteristics of high speed pump is the key research topic in the field of fluid machinery.In the paper,the hydraulic design of compound impeller,volute,inducer of the high speed pump is combined with Qd = 10m3/h,H= 410m,n=8500r/min and ns = 18.Based on ANSYS CFX software platform,using three dimensional turbulent numerical simulation method,three dimensional steady and unsteady simulation of the whole flow passage of the well designed high speed pump is carried out.The velocity and pressure distribution characteristics of the impeller with splitter blades,volute and inducer are obtained,numerical simulation is used to predict the external characteristics of the pump and the pressure pulsation of the tongue.Main work is as follows:(1)The impeller with splitter blades,volute,equal pitch inducer of high speed pump with Qd = 10m3/h,H 410m,n=8500r/min and ns = 18 are designed,using velocity coefficient method means of enlarging flow rate.(2)Using PRO/E and Gambit software to carry on three dimensional modeling of pipe,impeller with splitter blades,volute and equal pitch inducer of the centrifugal pump,using unstructured grids to discrete the computational domain of the over flow component.(3)In order to explore the influence of speed change on the internal flow of centrifugal pump,based on Reynolds averaged N-S equation and standard k-? turbulence model,using ANSYS CFX software,numerical simulation of the flow state inside the pump with six different speeds in design flow working condition is carried out and influence of rotating speed on the distribution of static pressure and relative velocity is comparatively analyzed.(4)In the light of design velocity n=8500r/min,the internal and external characteristics of the centrifugal pump under the three conditions of little flux 0.4Qd,design flux 1.0Qd,and large flux 1.3Qd,the distribution of the pressure field,velocity field and the static pressure field in the volute tongue at different flow rates are obtained,energy characteristics of high speed pump are predicted in numerical simulation means.(5)Three dimensional steady turbulence numerical simulation of high speed pump with inducer is presented,the internal and external characteristics of three conditions of little flux condition 0.4Qd,design flux condition 1.0Qd and large flux condition 1.3Qd;Comparison of static pressure field and relative velocity field distribution of inducer and impeller with splitter blades is carried out;The influence of energy performance of pump with inducer is analyzed.(6)Numerical simulation of the coupled non-steady flow in the volute and impeller of high speed centrifugal pump with inducer is carried out,the pressure pulsation of three different monitoring points in the volute casing is obtained in three working conditions of little flux condition 0.4Qd,design flux condition 1.0Qd and large flux condition 1.3Qd,their time domain and frequency domain characteristics are compared and analyzed.(7)The cavitation of blades and meridian plane of impeller of centrifugal pump with inducer is numerically simulated,and the influence of inducer on NPSHr is predicted under the condition of deviation from design flow rate.
Keywords/Search Tags:High-speed pump, impeller with splitter blades, inducer, Cavitation, Numerical simulation
PDF Full Text Request
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