## 5 Conclusions  
A multi-point design process based on CFD and intelligent optimization method is proposed in this study to improve the energy transfer efficiency, taking the application of an automotive electronic pump as an example. Firstly, the three-dimensional CFD analysis of the prototype is carried out to understand the flow loss mechanism inside the pump and establish the numerical prediction model of pump performance. Secondly, an automatic optimization platform including fluid domain modeling, meshing, solving, post-processing, and design of experiment (DOE) is built based on the three-dimensional parametric design method. Then, orthogonal experimental design and the multi-island genetic algorithm (MIGA) were utilized to drive the platform for improving the efficiency of the pump at three flowrates. Finally, the optimal impeller geometries were obtained and manufactured into a prototype for verification. The conclusions are as follows.  
1. After orthogonal optimization, the heads of each working point are significantly improved. The weighted average efficiency of the optimization scheme 2 is improved by 3.29%. The number of impeller blades has the most important effects on pump performance improvement. After the intelligent optimization, the high-efficiency region of the automotive electronic water pump is further widened. The efficiency weighted average recorded 55.24% under three working conditions. The optimal efficiency at design flowrate is increased by 4.3% after optimization from the experiment test.
2. There is almost no obvious low-speed region under the optimal conditions and small flow conditions after orthogonal optimization. The flow loss is greatly reduced in the impeller and volume flow-path, the number of separation vortices and their area under a large flowrate are  
Figure 21: Comparison of the origin and optimal scheme. (**a**) Test rig; (**b**) Comparison pump performance results.  
smaller than the original model pump. The pressure distribution in the impeller flow-path of the optimized pump is more uniform, and the pressure gradient becomes smaller inside the impeller flow-path. the overall turbulence energy is significantly reduced after optimization. All of the above is the root cause of the efficiency improvement.
3. The automatic optimization platform built in this study combined with intelligent MIGA algorithm could obtain the global optimization scheme among the selected parameter range. The hydraulic performance of automotive electronic water pumps under three multiple operating conditions have significant improvement, realizing the integration of \"design-simulation-optimization\" in limited time, which means this method has great potential in the application of fluid machinery design.  
Methodology, Q.S. and J.Y.; simulation, G.S.; analyzed the data, R.L. and C.S.; writing--review and editing, Q.S.; funding acquisition and validation, S.X. All authors have read and agreed to the published version of the manuscript.  
This research was funded by National Key Research and Development Program of China (2018 YFB0606103), National Natural Foundation of China (51976079, 51779107) and China Postdoctoral Science Foundation (2019M661745).  
The authors gratefully acknowledge the financial support by National Key Research and Development Program of China (2018 YFB0606103), National Natural Foundation of China (51976079, 51779107) and China Postdoctoral Science Foundation (2019M661745).  
The authors declare no conflict of interest.