Effect Of Diffuser Geometric Parameters On Its Internal Flow Characteristics And Performance Of Submersible Pumps

As an important underground water conveyance equipment,well-used submersible pumps are widely used in various fields of the national economy.At present,based on the needs of sustainable development and energy saving and emission reduction,this puts forward higher requirements on the hydraulic performance of submersible pumps.However,the efficiency of submersible pumps on the domestic market is generally not high.Research and development of submersible pumps with better performance have become green Problems that need to be solved urgently in low-carbon development.As an important hydraulic component of a well-used submersible pump,the diffuser directly determines whether the well-used submersible pump can operate efficiently and stably.This paper mainly studies the influence of the geometric parameters of the diffuser on its internal flow characteristics and the performance of the submersible pump.This subject takes the 200QJ50 two-stage submersible pump as the research object,and uses a combination of theoretical analysis,numerical calculation and experimental verification to carry out research on the optimization of the hydraulic performance of the submersible pump,and conducts a flow of the excellent performance of the diffuser Analysis of characteristics and energy characteristics,and the research results obtained are as follows:1.Theoretical analysis of the influence of the change of the geometric parameters of the diffuser inlet on the performance of the submersible pumpUsing the method of theoretical analysis,the characteristic equations of the impeller and the diffuser are respectively derived,and the change curve of the characteristic equation is drawn.It is proposed that the operating point of the submersible pump is the result of the combined effect of the diffuser characteristic curve and the impeller characteristic curve.For a given impeller,the determination of the operating point of the submersible pump is closely related to the geometric parameters of the diffuser inlet.It is also proposed that under the best working conditions,there is a certain relationship between the diffuser inlet width b₃and the inlet placement angleα₃.2.The influence of the change rule of the flow passage of the diffuser on the internal flow characteristics and the performance of the submersible pump.In order to improve the static pressure recovery capacity of the diffuser,reduce the hydraulic loss inside the diffuser,and to improve the hydraulic performance of the submersible pump as the research goal,on the basis of the diffuser channel of the model pump,keep the original guide vane following the flow path The geometric shape changes are broadened or reduced according to the trend,and three kinds of diffuser channels with different water passing areas are designed.Through numerical calculation,it is concluded that the flow area of the diffuser is S-shaped or linearly changing,and the performance of the pump has been improved.Compared with the original model,the flow path area is S-shaped and the head under linear change is increased by 0.56 m and 0.28 m,the efficiency has been increased by 1.9%and 1.1%respectively.Under different water passage areas,the changes in the velocity field inside the diffuser are emphatically studied,and the influence mechanism of the change in the water passage area of the diffuser on the energy conversion characteristics of the diffuser is explained in detail.Finally,an S type is proposed.The optimization method of the flow passage water area.3.Numerical analysis of the influence of the change of the geometrical parameters of the diffuser inlet on the performance of the submersible pumpUnder the theoretical analysis of the influence of the geometrical parameters of the diffuser inlet on the performance of the submersible pump,only the inlet width b₃and the inlet placement angleα₃of the diffuser of the model pump are changed,and the water passage area of the flow channel is changed to an S-shaped change.The cross-combination scheme of the inlet width b₃and the inlet placement angleα₃of the group diffuser.For a given impeller,the influence of the change of the diffuser inlet geometrical parameters on the performance of the submersible pump is studied by numerical calculation,and the maximum inlet geometrical parameters are obtained.Compared with the original model,the excellent combination scheme increases the head of the submersible pump by 1.19 m and the efficiency by 3.1%.In order to verify the relationship between the geometrical parameters of the inlet of the diffuser,the numerical calculation value of the optimal inlet placement angle under different inlet widths is compared with the theoretical value.The difference between the two is within 1°,indicating the most The characteristic equation of the diffuser under good working conditions has guiding significance for the optimization of the geometric parameters of the diffuser inlet.