چكيده به لاتين
Nowadays, due to the reduction of oil reserves, the use of smaller engines with higher efficiency and lower fuel consumption has become one of the goals of the automotive industries, so turbocharger is considered as a highly efficient component in this regard. Among all the benefits of a turbocharger, the acoustic noise produced by a turbocharger compressor is one of its disadvantages. In this thesis, Turbocharger’s Compressor’s impeller has been analyzed by means of Ansys CFX software to check the amount of noise produced. For this purpose, three important parameters in the design of the compressor blade, namely the rake angle, the back sweep angle and blade thickness, have been investigated in order to explore the variations in the output noise associated with these parameters. First, STX71 compressor blade is selected as the primary blade and then tested. According to the results of the study of the produced noise changes associated with the mentioned blade parameters, noise and efficiency of the blade type with the least amount of noise produced were compared to initial blade. The results of this thesis show that by increasing the rake angle from 10 to 30 degrees the compressor output noise increases about 5.2 dB. Also increasing the back sweep angle from 40 to 60 degrees reduces the noise about 1.7 dB. This comparison shows that the rake angle has a greater effect on the compressor noise than the back sweep angle. Optimized compressor performance points in terms of output efficiency and noise level for primary and secondary blades calculated using Ansys multi-objective optimization which uses NSGA-II algorithm to optimize and then results compared to each other. Finally, it has been shown that by applying the results for the suggested blade’s optimum point and the thermodynamics and fuel consumption relationships, the brake specific fuel consumption at low engine speeds is reduced by 16%.
