Abstract The second-order moment combustion model,proposed by the authors is validated using the direct numerical simulation(DNS)of incompressible turbulent reacting channel flows.The instantaneous DNS results show the near-wall strip structures of concentration and temperature fluctuations.The DNS statistical results give the budget of the terms in the correlation equations,showing that the production and dissipation terms are most important.The DNS statistical data are used to validate the closure model in RANS second-order moment(SOM) combustion model.It is found that the simulated diffusion and production terms are in agreement with the DNS data in most flow regions,except in the near-wall region,where the near-wall modification should be made,and the closure model for the dissipation term needs further improvement.The algebraic second-order moment(ASOM) combustion model is well validated by DNS.
1 Van Oijen, J.A., Bastiaans, R.J.M., Groot, G.R.A., De Goey, L.P.H., “Direct numerical simulations of premixed turbulent flames with reduced chemistry:Validation and flamelet analysis”, Flow, Turbulence and Combustion, 75 (1-4), 67-84 (2005). 2 Modest, M.F., “Multiscale modeling of turbulence, radiation, and combustion interactions in turbulent flames”, Int. J Multiscale Combustion, (1), 85-105 (2005). 3 Wang, Y., Trouve, A., “Direct numerical simulation of nonpremixed flame-wall interactions”, Combustion and Flame, 144 (3), 461-475 (2006). 4 Domingo, P., Vervisch, L., Payet, S., Hauguel, R., “DNS of a premixed turbulent V flame and LES of a ducted flame using a FSD-PDF subgrid scale closure with FPI-tabulated chemistry”, Combustion and Flame, 143 (4), 566-586 (2005). 5 Swaminathan, N., Bray, K.N.C., “Effect of dilatation on scalar dissipation in turbulent premixed flames”, Combustion and Flame, 143 (4), 549-565 (2005). 6 Hawkes, E.R., Chen, J.H., “Comparison of direct numerical simulation of lean premixed methane-air flames with strained laminar flame calculations”, Combustion and Flame, 144 (1/2), 112-125 (2006). 7 Yoo, C.S., Wang, Y., Trouve, A., Im, H.G., “Characteristic boundary conditions for direct simulations of turbulent counterflow flames”, Combustion, Theory and Modeling, 9 (4), 617-646 (2005). 8 Domingo, P., Vervisch, L., Reveillon, J., “DNS analysis of partially premixed combustion in spray and gaseous turbulent flame-bases stabilized in hot air”, Combustion and Flame, 140 (3), 172-195 (2005). 9 Freitag, M., Klein, M., “Direct numerical simulation of a recirculating, swirling flow”, Flow, Turbulence and Combustion, 75 (1-4), 51-66 (2005). 10 Sripakagorn, P., Mitarai, S., Kosaly, G., Pitsch, H., “Extinction and reignition in a diffusion flame:A direct numerical simulation study”, Journal of Fluid Mechanics, 518, 231-259 (2004). 11 Zhang, S.W., Rutland, C.J., “Premixed flame effects on turbulence and pressure-related terms”, Combustion and Flame, 102, 447-461 (1995). 12 Luo, K.H., “Combustion effects on turbulence in a partially premixed supersonic diffusion flame”, Combustion and Flame, 119, 417-435 (1999). 13 Overholt, M.R., Pope, S.B., “Direct numerical simulation of a statistically stationary, turbulent reacting flow”, Combustion Theory and Modeling, 3, 371-408 (1999). 14 Bedat, B., Egolfopoulos, F.N., Poinsot, T., “Direct numerical simulation of heat release and NO formation in turbulent non-premixed flames”, Combustion and Flame, 119, 69-83 (1999). 15 Sreedhara, S., Huh, K.Y., “Assessment of closure schemes in second-order conditional moment closure against DNS with extinction and ignition”, Combustion and Flame, 143, 386-401 (2005). 16 Hawkes, E.R., Chen, J.H., “Direct numerical simulation of hydrogen-enriched lean premixed methane-air flames”, Combustion and Flame, 138, 242-258 (2004). 17 Chong, C.M., Heinz, P., “Higher-order conditional moment closure modeling of local extinction and reignition in turbulent combustion”, Combustion Theory and Modeling, 6, 425-437 (2002). 18 Zhou, L.X., Qiao, L., Zhang, J., “A unified second-order moment turbulence-chemistry model for simulating turbulent combustion and NOx formation”, Fuel, 81, 1703-1709 (2002). 19 Zhou, L.X., Wang, F., Zhang, J., “Simulation of swirling combustion and NO formation using a USM turbulence-chemistry model”, Fuel, 82, 1579-1586 (2003). 20 Xu, C.X., Toonder, J.M.J., Nieuwstadt, F.T.M., Zhang, Z., “Origin of high kurtosis levels in the viscous sublayer. Direct numerical simulation and experiments”, Phys. Fluids, 8 (7), 1938-1944 (1996).