2022 年 64 巻 209 号 p. 222-229
This paper describes the multi-dimensional flamelet modeling and the application to a combustion simulation by means of a large-eddy simulation (LES) on an oxy-fuel combustion system. The two-dimensional flamelet formulation for a three-feed combustion system can be simplified with the three types of the quasi-two-dimensional flamelet formulations (Q2DF) by post-processing of the conventional one-dimensional flamelet solutions. The Q2DF models are derived based on the treatments regarding the third stream; the diluent stream is mixed with the oxidizer stream and/or with the fuel stream, giving rise to the three models called Q2DF1, Q2DF2, and Q2DF3. LES with the three models were performed to analyze the characteristics of each model. It was found that the differences among the three models became apparent as the mixture fraction of the inactive third stream (Z3) evolved larger, otherwise the three models gave almost the same accuracy. In the larger Z3 region, its scalar dissipation rate played an important role and the mixing state (premixed or non-premixed) of the third stream with the other streams should be carefully considered. In addition, in the latter part of this paper, the three-dimensional flamelet modeling for coal-ammonia co-combustion is also described.
