Prediction of Local Entropy Generation in Turbulent Combustion Systems

Analysis of local entropy generation or exergy destruction is an effective means to investigate sources of efficiency loss to optimize the performance of energy and combustion systems. The local entropy production is predicted using large eddy simulation of turbulent reacting flows. The unclosed entropy generation effects are accounted for by a novel methodology developed based on the filtered density function to embed the transport of entropy. Simulations are conducted of turbulent flames and predictions are validated via experimental data. Sources of irreversibility in turbulent combustion including viscous dissipation, heat conduction, mass diffusion and chemical reaction are predicted and analyzed. The influence of various operating parameters on local entropy generation and the exergetic efficiency of the combustion system is studied.