Extension and Validation of a Constant Equivalence Ratio Multi-Zone Approach to DME Combustion in Vessels and CI Engines 2023-01-0193

This work has the objective to present the extension of a novel quasi-dimensional model, developed to simulate the combustion process in diesel Compression Ignition (CI) engines, to describe this process when Dimethyl ether (DME) is used as fuel. DME is a promising fuel in heavy-duty CI engines application thanks to its high Cetane Number (CN), volatility, high reactivity, almost smokeless combustion, lower CO2 emission and the possibility to be produced with renewable energy sources. In this paper, a brief description of the thermodynamic model will be presented, with particular attention to the implementation of the Tabulated Kinetic Ignition (TKI) model, and how the various models interact to simulate the combustion process. The model has been validated against experimental data derived from constant-volume DME combustion, in this case the most important parameters analyzed and compared were the Ignition Delay (ID) and Flame Lift Off Length (FLOL). Following this first validation process, the model has been tested against experimental values obtained from a heavy-duty DME-fueled CI engine in different operating conditions, representative of real engine applications. In this second comparison, the focus shifted on Heat Release Rate (HRR) and in-cylinder pressure trends and NO_x production during combustion. The results show good agreement between the experimental and computed values in all operating conditions, leading to the possibility of using the presented model to accurately predict the performance of engines with DME as fuel in a fast 1D- or quasi-dimensional simulation tool.