Exergy Analysis of Deflagration Wave Propagating in Autoignitive H2 Mixture for Constant Pressure Boundary Conditions

Exergy analysis has been performed on propagation of deflagration wave in autoignitive H2-air medium. Various one-dimensional (1D) direct numerical simulations (DNS) have been performed with constant pressure boundary conditions. The analysis is performed with multiple initial pressures and equivalence ratios. During autoignition in stratified mixture, flame like structure (deflagration wave) originates from thermal or compositional inhomogeneity inside the domain. In present study, the deflagration wave propagating from the hotspot is allowed to interact with the autoigniting mixture. Three major components are identified for the exergy loss from the system: heat conduction, mass diffusion, and chemical reactions. The results show that the 1D simulation shows larger ignition delays than the homogeneous simulations (0D). The irreversibilities associated with the reactions are found to be major contributors to entropy generated during combustion. During the interaction of deflagration wave and autoignition spot, the contribution of conduction and diffusion irreversibilities is observed to reduce. Whereas the contribution of reaction irreversibilities increases. For low-pressure combustion (10–20 bar), the ratio of exergy loss and heat release rate is observed to reduce during the interaction of deflagration wave and autoignition spot.