Simulation-based Design Optimization Of Centrifugal Compressor Impeller Under Geometric Constraints

It has always been important to study the development and improvement of the design of turbomachines,owing to their numerous uses as well as their high energy consumption.Accordingly,optimizing turbomachine performance is crucial for sustainable development.The design of impellers significantly affects the performance of centrifugal compressors.Initially,the design process of the centrifugal compressor impeller was reviewed to compare its results with the designs available in the market and ensure that our model is complete.After evaluating the results of the 3D compressor model,the details of the flow field within the impeller were obtained.The results showed that the middle blades did not match the flow field,and there was a substantial drop in collisions at the leading edge.For this purpose,we sought to model and simulate the function of a centrifugal GT4082 compressor and evaluate the effects of losses in the impeller,volute,and diffuser.We also examined the mass parameter effect on the efficiency drop at different speeds.The total and static pressure drops are also examined in the volute and diffuser.The efficiency drops modeled at different mass parameters and speeds were discovered to be maximized in the volute and diffuser at a specific speed.A global minimum was observed in the overall pressure drop and a global maximum in the static pressure drop versus a mass parameter.The aerodynamic optimization of the impeller geometry was analyzed by modifying the splitter.The present study developed a hybrid optimization model based on genetic algorithms(GA)and a 3D simulation of compressors to examine specific parameters such as blade angle at leading and trailing edges and the starting point of splitter blades.The optimization was done in two different ways,using genetic algorithms and numerical simulations.The first method involved keeping the splitter profile constant and changing the position and shape of the leading edge.In the second method,the size of the splitter was consistent while its profile was altered.This method considers different designs for splitter blades.The location of the leading edge of the splitter blades at the hub and shroud was therefore modified.This modification leads to a splitter blade profile that is not the same as the main blades.The objective function in these optimizations was to increase efficiency across the compressor performance curve.new optimal impeller design in which the pressure ratio remained constant as that of the base design,and the efficiency was improved by 2%,while the stability of the compressor improved against surge by approximately 7%.The location of the leading edge of the splitter blades at the hub and shroud is therefore modified.The results revealed that,in one specific case,the efficiency of the compressor improved approximately about 1.5%.This finding proves that the previous design method was not the optimum one for compressors.In the final step,by using the mathematical analysis of the objective function,the optimization time and cost were developed.Initially,it was ensured that there was no change in the optimization results,as long as we assess the increase in the optimization speed.we studied three different functions,i.e.,linear function,exponential functions,and the triangular function.Subsequently,the results of improving the performance of the optimization model by the exponential function to replace in safety factor has a better result and it shows there is the shortest execution time for b=0.07.