Direct numerical simulation of triple flames by using 2D reaction-diffusion manifold tabulation method

The characteristics of partially-premixed flames is investigated by simulating a series of triple flames with different variations of chemical equivalent ratio. A two-dimensional Reaction-Diffusion Manifold (REDIM) chemistry tabulation method is employed in the simulation and the results are compared with the methane-air 19-step chemical reaction mechanism. The performance of these two mechanisms is then assessed by using direct numerical simulations coupled with GRI3.0 detailed mechanism. It is shown that both 2D REDIM table and 19-step simplified mechanism can describe the temperature and main products accurately, however, for some minor intermediary products, predictions from 2D REDIM table is observed to be better than 19-step simplified mechanism. Compared with the 19-step mechanism, 2D REDIM table only needs to solve only the transport equations for CO2 and N2 species, which greatly simplifies the solution process of chemical reaction and provides a reliable solution for the numerical simulation of turbulence with higher accuracy. This work indicates that as a relatively advanced kinetic simplified method, the REDIM tabulation method can reduce the computational cost and at the same time retain the accuracy effectively.