The effect of biogas and dimethyl ether on the thermal characteristics of a dual‐fuel diesel engine: A numerical study

Abstract

This investigation used the Diesel‐RK simulation program to carry out a numerical analysis of the effects that dual‐fuel mixes have on the combustion, performance, and emissions of a dual‐fuel diesel engine. It applied the multizone combustion model, and the controlling equations were solved for each individual combustion region. The engine characteristics were examined under the following scenario: it was initially powered by single‐fuel regular diesel (DF), then it switched to dual‐fuel use with 20% biogas, and then it was changed again with the use of 30% dimethyl ether (DME). On this basis, the mentioned biogas and DME ratios were used. The results showed that combustion pressure for the operation of 30% DME and 20% biogas was reduced by 2.45% and 9.57%, respectively, with respect to diesel fuel alone. The Sauter mean diameter (SMD) of the droplets was reduced by 12.6% for 30% DME and 16.2% for 20% biogas. Heat release and brake thermal efficacy (BTE) were reduced slightly with the use of biogas or DME in comparison with DF. The brake‐specific fuel consumption (BSFC) increased by 15.27% and 8.34%, with 30% DME and 20% biogas respectively due to the difference in the energy content of the tested fuels. Nitrogen oxide emissions decreased by 2% and 28% for the operation of 30% DME and 20% biogas, respectively. The summary emission equation (SE), which describes the combination of NOx and PM emissions, decreased by 4.23% and 5.40% with 30% DME and 20% biogas respectively. Based on the results, this paper recommends the use of 20% biogas with diesel rather than 30% DME. The current findings matched well with other scientists' results.