Numerical study of the working mechanisms and influential factors affecting a compression ignition engine with a closed porous medium chamber

Abstract

This study simulated the working process of a porous medium (PM) engine, characterized as periodic contact type and fuelled with natural gas (methane (CH4)), by using an improved version of KIVA-3V to understand the working mechanism of the PM engine. The effects of the initial PM temperature, the PM structure and the valve opening timing on the compression ignition of the PM engine were also investigated. The improved version of KIVA-3V was validated by simulating the experiment made by Zhdanok et al. on the superadiabatic combustion of CH4—air mixtures under filtration in a packed bed. Computational results are in good agreement with experimental data for the speed of the combustion wave. Simulation results for the PM engine show that the initial PM temperature is the key factor in guaranteeing the onset compression ignition of the PM engine at a given compression ratio. The variation in PM structure affects the convective heat transfer between the gas and solid phase and the dispersion effect of the PM. The working of the PM engine does not allow later or earlier valve opening timing.