Design And Research On 3DG Electric High Pressure Boiler Feed Pump

As an indispensable key equipment in thermal power plant,a boiler feed water pumpconsumes thousands of kilowatt-hours of electricity per hour,so the energy saving benefits brought by improving the operation efficiency of feed water pump are very considerable.Therefore,we designed a 3DG electric high-pressure boiler feed water pump in this paper,which can improve the hydraulic efficiency to realize the purpose of energy saving through numerical simulation and optimization design,and verify the operation reliability and stability of the main parts by finite element analysis.In order to obtain the parameters of the optimal hydraulic model,we studied the cavitation performance of the first stage impeller,the efficiency of the secondary impeller and the efficiency of the radial guide vane by using CFD technology,carried out experiments and redesigned on the parameters having greater impact on efficiency,analyzed several different schemes by CAD,and then carried out optimized analysis by using "Minitab" analysis software.The strength and stiffness of key parts of 3DG boiler feed water pumpare checked by ANSYS Workbench so as to verify the reliability and stability of the whole pump.The main research work of this paper is as follows:1.Carried out simulation analysis on the cavitation performance of first-stage impeller,flow rate,head,efficiency and other parameters based on CFD technology to verify the rationality of the design.Made use of the CFX software to calculate the cavitation performance of the head impeller at the design flow rate and at the large flow rate.The performance analysis and numerical results show that the required cavitation allowance of the first-stage impeller at the rated flow rate was 8m,and the required cavitation allowance of the first-stage impeller at the large flow rate was 10 m,which are all meet the design requirements.2.For the sake of obtaining the optimal scheme of secondary impeller efficiency,carried out optimized design for the blade packing Angle and outlet packing Angle by orthogonal experimental design method to build the relation between blade packing Angle,outlet packing Angle and hydraulic efficiency and head.3.The result of research on the influence law of inlet Angle of radial guide vane on hydraulic efficiency shows that the impact Angle has no effect on the pressure distribution in the impeller passage while has a significant effect on the pressure distribution at the impeller outlet,and with the increase of the Angle of impact,a high-pressure zone appears at the outlet of the impeller,which is not evenly distributed;there is no significant effect on pump efficiency when the inlet Angle of positive guide vane is changed;when the Angle of impact is 0°,2°,4° and 6°,the hump appears in the flow-head curve;when the Angle of impact is 5°,the efficient point is at the design flow rate,and the flow-head curve has no hump.4.Calculated and checked the strength,stiffness and stability of the main parts after completing the structure design of the whole pump,the results show that the strength,stiffness and stability of the main parts are all meet the requirements.5.The finite element analysis results of the key parts of 3DG boiler feed water pump based on ANSYS software show that the maximum deformation of the pump shaft is 0.091184 mm,which is uniform and has no mutationphenomen on the strength check results of the key parts such as the impeller,the bar,the balance plate and the middle part show that the overall deformation is relatively gentle and there is no mutationphenomenon.