We present a new combustion simulation technique based on a lookup table approach. In the proposed technique, a flow solver extracts the reaction rates from the look-up table using the mixture fraction, progress variable, and reaction time. Look-up table building and combustion simulation are carried out simultaneously. The reaction rates of the chemical species are recorded in the look-up table according to the mixture fraction, progress variable, and time scale of the reaction. Once the reaction rates are recorded, a direct integration to solve the chemical equations becomes unnecessary; thus, the time for computing the reaction rates is shortened. The proposed technique is applied to an eddy dissipation concept (EDC) model and it is validated through a simulation of a CO-H2-air nonpremixed flame. The results obtained by using the proposed technique are compared with experimental and computational data obtained by using the EDC model with direct integration. Good agreement between our method and the EDC model and the experimental data was found. Moreover, the computation time for the proposed technique is approximately 99.2% lower than that of the EDC model with direct integration. 1. Introduction The growing availability of computational resources allows intensive use of numerical method to predict the chemical structure of flames and to design combustion equipment. However, simulation of turbulent combustion that includes detailed chemical mechanisms still remains elusive, although several techniques have been proposed to overcome this problem. For example, the intrinsic low dimensional manifolds (ILDM) [1, 2] is a method to automatically reduce the detailed chemical mechanisms. This method is based on a direct mathematical analysis of the dynamic behavior of the responses of nonlinear chemical equations. However, the ILDM is not well agreed in the low-temperature domain because the dimension and complexity of a lookup table increase tremendously in this domain. A flamelet-prolonged ILDM (FPI) [3] is developed to overcome this problem. Also, in the ILDM, diffusion is neglected in the construction of the lookup table, and therefore the results in the region where both chemistry and diffusion are significant are less accurate. To improve the accuracy in the region, the phase space ILDM [4] is proposed. Another alternative is the in-situ adaptive tabulation (ISAT) [5–7] method, which is based on in-situ generation of a lookup table that is constructed by solving for the time evolution of species concentrations directly. This method has been adopted in
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