A MULTIDIMENSIONAL RADIATION MODEL FOR DIESEL ENGINE SIMULATION WITH COMPARISON TO EXPERIMENT

Abstract

A radiation model based on the discrete ordinates method (DOM) was developed and integrated into the ERC version of KIVA-3V. The model was validated by comparison to an analytic solution and by comparison to previously published literature. In addition, the predicted radiative heat flux at a point on the head of a diesel engine was compared to experimentally measured values. The predicted radiative heat flux compared well with the experimental data both in phasing and peak intensity. Comparisons of the experimental radiative heat flux measurements to the predicted values using the mid-order (S4) DOM approximation with the radiation model showed good comparison to analytical solutions. For the other cases studied, a low-order (S2) DOM approximation was used since it required substantially fewer computer resources and was considered to be adequate. The low-order approximation results in a slight overprediction of the total heat loss between IVC and EVO (by about 1% compared to the mid-order approximation). It was shown that the low-order approximation gives sufficient accuracy for the volumetric heat flux provided that the local extinction coefficient is large, as is the case with even small quantities of soot.