Optimal Design And Analysis Of Impeller Of Electric Submersible Pump

With the rapid development of modern industry,oil and gas resources as the "blood" of modern industry,their demand is also increasing day by day.The exploitation of land oil and gas resources has gradually been difficult to meet the needs of modern society.For strategic considerations,offshore oil and gas resources have been paid more and more attention by all sectors of society.Submersible electric pumps are the most important link in offshore oil and gas exploitation.For equipment,its application has become more and more extensive.Submersible electric pumps have attracted much attention in the field of artificial lifting due to their advantages of large discharge volume,simple operation and convenient maintenance and management.Because of the particularity of its actual working condition,its structure size and design form are also limited by the borehole size.At the same time,in order to make the pumped oil have enough lift,ESP also has the characteristics of small size and multi-series.Nevertheless,the essence of ESP still belongs to the category of multi-stage centrifugal pump.The two indexes of head and efficiency are also applicable to ESP.Impeller is the actual part of the whole submersible electric pump and the role of oil.Its structure and size have almost a decisive impact on the performance of the whole submersible electric pump.The blade is the core part of the impeller.The blade of the impeller twists in both radial and axial directions.The shape of the impeller is complex.Different blade shapes and parameters determine the different performance of the impeller of ESP.Therefore,the design and optimization analysis of impellers,including blades,play an important role in improving the performance of submersible electric pumps.However,there are more than a dozen structural parameters used to describe impellers,including blade shape,which have different effects on impeller performance.At the same time,many parameters are not completely independent,and so on.These factors pose great challenges to the design and optimization of impellers.In this subject,aiming at the complexity and particularity of submersible electric pump impeller design,by investigating a large number of domestic and foreign literatures,collecting relevant design information,studying and learning the relevant knowledge of impeller design theory,computational fluid dynamics,experimental design method and optimization calculation,and using relevant means,building a more systematic impeller structure design,performance analysis to.The method of optimization research.Its specific implementation process is as follows:(1)The main structural parameters of the impeller are preliminarily calculated based on the existing design parameters by the existing velocity coefficient method.The efficiency and head of the impeller are estimated to confirm that the design parameters are satisfied.The initial size of the impeller is determined according to the actual working conditions;(2)Based on the three-dimensional modeling software and CFD technology,the model is simulated and analyzed,and the important structural parameters of impeller are analyzed one by one by using sensitivity analysis method.The sensitivity degree of each parameter is determined,and the parameters that have significant influence on the head and efficiency of impeller are selected as optimization design variables;(3)Taking the selected structural parameters with high sensitivity and the inlet and outlet structural angles of impeller blades as design variables,the head and efficiency of submersible electric pump impeller as optimization objectives,the response surface model between optimization objectives and design variables was established by Box-Behnken response test method.The response surface model is evaluated according to variation coefficient,complex correlation coefficient,modified complex correlation coefficient,prediction-simulation distribution and residual normal probability distribution,and the feasibility of the model is verified;(4)The penalty function method is used to optimize the response surface model,obtain the optimal parameter combination,determine the optimized impeller model,and compare the hydraulic performance of the impeller before and after optimization.The results show that the hydraulic performance of the optimized impeller has been effectively improved,and the efficiency and head have been improved to a certain extent.Because the influence of the impeller’s size parameters on its hydraulic performance is very complicated,it is even more difficult to find the true physical relationship between various dimensional parameters and hydraulic characteristics.However,using this design idea to circumvent this problem,the combination of mathematical statistics has achieved the same effect.Therefore,the research work of this paper provides a new idea for the optimal design of submersible electric pump impeller.