| As a fluid delivery machinery and mixing reaction equipment,the ejector pump not only has the advantages of simple structure,easy processing and easy maintenance,etc.More im-portantly,due to the device itself has no moving parts inside,so it can increase the pressure of the ejected fluid without rely on solid mechanical's compression action and has a high relia-bility working performance.At present,the ejector pump has been widely used in various production departments of national economy,including the aviation field.However,due to the turbulent effect of the jet,the two fluids at different pressure conditions are mixed with each other and thus causing the exchange of mass and momentum,this process is accompanied by a large energy loss.What's more,coupled with unreasonable structural design,all of these factors lead to a reduction in the overall efficiency of the ejector pump.At the same time,it also limits its application range to a certain extent.Based on the above reasons,numerical simulation and research on the internal flow field of the aviation fuel transfer ejector pump are carried out in this paper to reveal its inner flowing state and flowing law.Finally,the structure of the ejector pump is optimized by using the experimental design method,CFD parametric calculation and optimum design theory.The main research content is shown as follow:(1)Discussed the research status of ejector pump and its development trend,and the ex-isting problems in the current ejector pump is also introduced in detail such as the compre-hensive effect of multiple structural parameters on its working efficiency.Systematically de-scribed and deduced its internal flow theory and related physical phenomena,models and numerical methods involved in the flow field.(2)By comparing with the experimental data,the numerical calculation method based on pressure-coupling implicit algorithm to solve the Reynolds-averaged equation was validated in this paper.Study on the flow characteristics of the internal flow field under different work-ing conditions from the perspective of time-averaged and obtained comprehensive influence and mechanism of the pressure ratio,area ratio and other factors.The influence of key struc-tural design parameters on the flow characteristics and working characteristics of ejector pump were studied under different working conditions.(3)The approximate mathematical model of the performance evaluation index of the ejector pump were established by comprehensive use of the experimental design method,CFD parametric calculation and approximate model theory.After contrasted the sampling re-sults based on the different criterion,it adopted the Optimal Latin hypercube design which based on ?p criterion to conduct the experimental design.The accuracy of the established ap-proximate model is analyzed and results of random error shows that the approximate model established in this paper has high accuracy and reliability.(4)Based on the approximate mathematical model of the performance evaluation index of the ejector pump,the global optimization method is adopted to optimize its structural pa-rameters.Analysis the influence law of each design variable on the optimization objective by using approximate model.Using multiple regression method to conduct sensitivity analysis on the influencing factors of the optimization objective including linear main effects,sec-ond-order effects and interactive effects.Results shown that the interactive effects of each de-sign factors on the optimization objective are similar to the linear main effects and sec-ond-order effects,which has significant impact on the operating characteristics of the ejector pump.Through the MIGA global optimization design method,efficient optimization for the structural parameters of the ejector pump are carried out.The optimized ejector pump effi-ciency is more than 20 percent higher than the existing model. |
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