Effect of perforation on exhaust performance of a turbo pipe type muffler using methanol and gasoline blended fuel: A step to NOx control

Abstract

Abstract There is an extensive global effort to replace fossil fuel with blended fuel within existing engine configuration, yet conformed to available infrastructure. Though blended alcoholic fuel is able to reduce carbonated emissions (CO, CO2, unburnt HC), the NOx level increased significantly due to enhanced exhaust temperature resulted out of better combustion. At Green Engine Technology Center, new exhaust mufflers are fabricated with/without perforation to find out if new design of muffler develops less temperature. The main objective of this study is to investigate feasibility of using perforation in diminishing surface temperature. To achieve this, a computational fluid dynamics model is developed to study the effect of perforation on exhaust performance of a turbo pipe type straight and elliptic muffler, fitted to engine running on petrol-methanol blend. The CFD analysis is done through a pressure based solver to study the effect of perforation on back pressure, density, temperature. Prior to the result analysis, the model is validated with a fabricated chamber type prototype muffler fitted to a four stroke single cylinder petrol engine. The temperature thus measured is matching with the simulated temperature. The muffler performance parameters such as back pressure, temperature, density, velocity stream line are studied for different blends (5%, 10%, 15%) of petrol and methanol. Clear variations of these parameters are observed between non perforated and perforated type turbo pipe mufflers.