Simulation of turbulent non-premixed and partially premixed flames using a look-up table

Abstract

In this paper, we present a simple combustion simulation technique based on a look-up table approach. In the proposed technique, a flow solver extracts the solutions of the ordinary differential equations (ODEs) of the chemical equations from the look-up table using the mixture fraction, mass fraction of products, and time scale of the reaction. The look-up table is constructed during combustion simulation. Thus, prior calculation is not needed in the proposed technique. The solutions of the ODEs are saved in the look-up table at points where the mixture fraction, mass fraction, and time scale are similar to those in the look-up table. Once the data are recorded, a direct integration to solve the chemical equations becomes unnecessary, and the time required to compute the reaction rates is shortened. The proposed technique is applied to an eddy dissipation concept (EDC) model and is validated through a simulation of a H2 turbulent non-premixed flame and a CH4 partially premixed flame. The results obtained through the proposed technique are then compared with experimental data and computational data obtained using the EDC model with direct integration. We found a good agreement between our method and the EDC model. Moreover, although the proposed technique is simple, the computation time for our technique is faster than the in situ tabulation method (ISAT) and is approximately 99% lower than that of the EDC model with direct integration.