Research On Cooperative Optimization Between The Impeller And Space Diffuser Of Diagonal Flow Pump

The diagonal flow pump is a kind of pump whose characteristic and structure is between the axial flow pump and the centrifugal pump,known as the guide vane mixed flow pump,with the advantages of small outer diameter structure,convenient maintenance and disassembly,strong cavitation resistance and high efficiency.The impeller and the space diffuser are the main flow parts of the diagonal flow pump.A systematic study of the matching of their key parameters can help the systematic collaborative design and improve the overall hydraulic performance of the diagonal flow pump.So far,many achievements have been made in the study of the main parameters of the impeller and the space diffuser,but less research on the coordinated design of the systematic matching.The article has made the collaborative matching design on the key parameters of the impeller and the space diffuser,analyzed the backflow and vortex in the diagonal flow pump,studied and ascertained the best matching design of the key parameters,and put forward the idea of collaborative matching design.First of all,the influence of impeller angle and wrap angle on the hydraulic characteristics of the mixed flow pump is analyzed,and the parameter selection range of the blade angle is determined.Then from the system level as the breakthrough point,the orthogonal experimental method is used to determine the 25 schemes of the guide of collaborative design of the impeller and the wrap angle,explore regularity of hydraulic characteristics with the change of wrap angle,select the representative of a total of 9 angle combination scheme,complete numerical simulation analysis combined model matching different cavitation conditions,to play a theoretical basis for further study of all the impeller and the guide vane space collaborative design.The conclusions are as follows:(1)With the increase of mixed flow pump impeller wrap angle value,impeller internal flow field region is smoother,the phenomenon of reflux vortex has gradually decreased,the phenomenon of flow separation on the surface of leaves has gradually reduced,the flow tends to be smoother,but when the angle is too large to increase to a certain value,between the fluid and the blade surface the friction loss will increase obviously.Under the condition of different space guide vane wrap angle,the change of blade envelope angle is similar,and the flow field flow inside the guide vane is similar to that of different impeller blades.There is an optimal value in both of them,which makes the hydraulic characteristics of the pump up to the best.(2)In the five groups with the standard of impeller wrap angle,the highest point of efficiency will skew when impeller wrap angle is too large or too small.In the five groups with the standard of space guide vane wrap angle,the curves of efficiency show saddle-type.The highest point is the same,but the highest efficiency is in a narrow region.At the same time,the change of the space guide vane wrap angle has great influence on the internal flow of space guide vane wrap,but the characteristics of the final efficiency and head are the result of synergy of the impeller and space guide vane.Take the changes of the impeller and the guide vane internal flow field into consideration comprehensively,when we analyze the internal factors.(3)Numerical analysis of different combination models of cavitation state conditions,small flow 0.6Qd,design condition and large flow rate condition of 1.4 Qd,The overall combination of plan B is more serious than the cavitation of the combination of plan C,basically the same distribution of vapor volume fraction distribution of inner product and small flow 0.6 Qd,conditions under design conditions.However at the same inlet pressure conditions under large flow condition,the overall cavitation situation the distribution of vapor phase in vivo is more serious than the cavitation in design conditions and large flow conditions in 1.4 Qd,the impeller and the guide vane wrap angle different matching on cavitation state influence,therefore should be a comprehensive assessment of the optimal design of mixed flow pump the system based on the analysis of the hydraulic characteristics.(4)In a certain angle range,the influence of impeller wrap angle on the diagonal flow pump is more pronounced than that of the space guide vane angle,so the two corners in the collaborative design process should be based on the impeller blade wrap angle optimum value.The analysis and selection based on the first selection of optimum vane inlet angle value,can reduce the workload greatly,and can easily select the best impeller and guide vane angle space optimal matching design.To sum up,a collaborative design concept,process and main idea of skew pump's key parameters and wrap angle is presented in this paper.It can quickly and accurately determine the best matching scheme and effectively improve the hydraulic performance of the diagonal flow pump.