Predictions of NO_x production have been tested for a series of premixed stagnation flames of the A2 fuel. NO_x productions in these flames range from pathways dominated by thermal to prompt NO. Because the NO_x production is not directly sensitive to the fuel composition (except for the fuel NO_x), the combined HyChem model with the NO_x submodel is expected to make reliable predictions for flames burning other fuels also.

Fig. 1. Experimental (open symbols) and computed (filled symbols with lines drawn to guide the eyes) NO_x mole fractions versus the experimental cold gas velocity for the premixed stagnation-flow A2 (Jet A) flames. Experimental data are taken from [1]. The flame conditions and parameters are listed in Table 1. The flames were simulated using the plug flow boundary condition for the cold flow boundary and the non-slip boundary condition at the stagnation surface. The distance measured between the flame and stagnation surface, L_s, is matched computationally by varying the distance between the burner nozzle to the stagnation surface. The error bars represent 2σ experimental data repeatability. The solid lines denote the total NO_x computed; the dashed lines represent the NO_x concentrations computed using reactions involved in the thermal NO pathway (Zeldovich mechanism [2]) only. Simulations are performed using a NO_x-enabled HyChem model for A2 (Jet A) which combines the HyChem A2 model [3,4] and Glaborg NO_x model [5]. The NO_x-enabled A2 HyChem model is available at the download page.

References

[1] C. Saggese, K. Wan, R. Xu, Y. Tao, C.T. Bowman, J. Park, T. Lu, H. Wang, A physics-based approach to modeling real-fuel combustion chemistry - V. NO_x formation from a typical Jet A, Combustion and Flame 212 (2020) 270-278.

[2] Y.B. Zeldovich, The oxidation of nitrogen in combustion and explosions, Acta Physicochim, URSS 21 (1946) 577-628.

[3] H. Wang, R. Xu, K. Wang, C.T. Bowman, D.F. Davidson, R.K. Hanson, K. Brezinsky, F.N. Egolfopoulos, A physics-based approach to modeling real-fuel combustion chemistry - I. Evidence from experiments, and thermodynamic, chemical kinetic and statistical considerations, Combustion and Flame 193 (2018) 502-519.

[4] R. Xu, K. Wang, S. Banerjee, J. Shao, T. Parise, Y. Zhu, S. Wang, A. Movaghar, D.J. Lee, R. Zhao, X. Han, Y. Gao, T. Lu, K. Brezinsky, F.N. Egolfopoulos, D.F. Davidson, R.K. Hanson, C.T. Bowman, H. Wang, A physics-based approach to modeling real-fuel combustion chemistry - II. Reaction kinetic models of jet and rocket fuels, Combustion and Flame 193 (2018) 520-537.

[5] P. Glarborg, J.A. Miller, B. Ruscic, S.J. Klippenstein, Modeling nitrogen chemisry in combustion, Progress in Energy and Combustion Science 67 (2018) 31–68.