MODIFIED, DISCRETIZED-INTENSITY BASED, SPLIT-RADIATION CALCULATION PROCEDURE FOR USE IN FULL SIMULATION STUDIES OF COMBUSTION IN AXISYMMETRICAL PISTON ENGINES

A control volume based procedure has been developed that makes possible the materially meaningful inclusion of radiation heat transfer in full simulation calculations for the axisymmetric version of the "modified discretized-intensity method." Included in this procedure is an innovative technique that splits the radiation problem in two. Each subproblem, in turn, can be solved more effectively than if the problem had not been split, making the overall approach just as effective in optically thin absorbing-emitting media as it is in optically thick media. The mass absorption coefficients used in the formulation are based on a molecular band analysis and are computed at a finite number of discrete locations along each intensity ray. The model has applicability to any control volume energy balance formulation. A description of the incorporation of the model into a primitive variable approach is given. Application of the model is made to the solution of a portion of the combustion stroke of a four-stroke piston engine to demonstrate the utility of the model in moving boundary problems.