Faculty of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran
Shohadaye Hoveizeh Campus of Technology, Shahid Chamran University of Ahvaz, Ahvaz, Iran
In this research, an intercooler of three-stage centrifugal compressor is investigated in order to decrease energy consumption. Due to the lack of comprehensive studies about optimization of efficiency and cost for the finned shell and tube intercoolers, with using non-dominated sorting genetic algorithm (NSGA-II), the efficiency of shell and tube heat exchanger with radial fin (intercooler) is studied to improve the performance of multi-stage compressor. The total cost and efficiency of an intercooler are selected as two objective functions. Also, some main decision variables, such as tube arrangement, mass flow rate on the tube and shell sides, the diameter of tubes, rate of tube pitch as well as inlet temperatures of tube and shell are considered. The heat transfer coefficients and the pressure drop of the shell-side are calculated based on Delaware modified method. The variation of efficiency based on the tube length, tubes number, baffle spacing ratio and tube pitch rate are investigated. The results show that using NSGA-II, the efficiency improves up to 96 %. Also, the best fins number per inch length of the tube is 26 which leads to the highest efficiency value. Results show that the tube shape has no effect on the efficiency and by increasing tube pitch rate the total costs decreases. The optimization results with NSGA-II is compared with the PSO method and it shows the accuracy of the genetic algorithm. Also, the thermal modeling is validated with another study and the maximum difference is estimated about 2%.