Improving the performance of the turbocharger turbine by changing its blade inlet angle experimentally and numerically

Abstract

Due to the variety of engines in volume, number of cylinders and power, turbochargers on the market are often generally made for a specific range of engine power. This research shows one of the ways to improve the performance of a turbocharger with a wide range of performance in a specific engine. In this article, by changing the inlet angle of the turbocharger turbine blade compared to the turbine blade inlet angle of a selected turbocharger and three-dimensional flow simulation inside it, the goal is to improve turbine performance. A real model of a turbocharger turbine, including a volute and blades, has been photographed by precise devices and an image has been prepared in the form of a cloud of points. This image is modified by the software and a three-dimensional model is prepared from it and edited in different software environments, and finally the three-dimensional flow inside the turbine is simulated. For validation, the engine and turbocharger assembly placed on the test bench and the performance parameters of the turbocharger turbine has been measured at different engine speeds and compared with the simulation results. The results showed that changing the inlet blade angle of the turbine to the value of 4.7° compared to the initial entry angle of the blade in all engine speeds leads to the optimization of the values of the performance parameters of the turbine. This angle change, improves the pressure ratio of the turbine by about 11% and the efficiency and power by about 18%. At high speeds, due to the surge phenomenon in compressor, this pressure ratio may not be practical, but at low speeds, when the energy of exhaust gases from the engine is not enough for good turbine operation, this increase in power can be very beneficial.