Numerical and Experimental Investigation of the Effect of Increasing Engine Load on Silencer Back Pressure in a Diesel Generator

Abstract

In this study, the exhaust back pressure (EBP) behavior resulting from the gradual increase in engine load of the exhaust muffler system used in a diesel engine generator was investigated numerically and experimentally. By examining the compatibility of numerical analysis and experimental test exhaust back pressure results with each other, the possibility of eliminating the need for experimental exhaust back pressure test is examined. Firstly, the exhaust gas temperature and flow rate of the selected diesel engine under five different engine loads were experimentally measured. A reactive muffler with perforated pipe, designed to be integrated into the selected engine, was subjected to computational fluid dynamics (CFD) analyzes using measured exhaust gas temperature and gas flow rate. Numerical EBP values were obtained with these numerical analysis studies, which were carried out using the finite volume method in the ANSYS-Fluent program. Finally, the exhaust silencer system, which was manufactured, was subjected to experimental EBP tests under five different engine loads that were gradually increased. According to the numerical and experimental EBP results obtained, it has been observed that the gradual engine load increase in a diesel generator increases the EBP as parabolic. It was understood that the numerical and experimental results of the EBP for different load conditions became more compatible as the engine load increased, and the numerical analysis error rate was found as 4.06% under the 110% engine load which is the critical load condition. In addition, it was concluded that the need for experimental EBP tests can be eliminated by using only numerical studies in the generator exhaust muffler design.