Phase-relationships between scales in the perturbed turbulent boundary layer
The mixture-averaged thermal diffusion model originally proposed by Chapman and Cowling is validated using multiple flame configurations. Simulations using detailed hydrogen chemistry are done on one-, two-, and three-dimensional flames. The analysis spans flat and stretched, steady and unsteady, and laminar and turbulent flames. Quantitative and qualitative results using the thermal diffusion model compare very well with the more complex multicomponent diffusion model. Comparisons are made using flame speeds, surface areas, species profiles, and chemical source terms. Once validated, this model is applied to three-dimensional laminar and turbulent flames. For these cases, thermal diffusion causes an increase in the propagation speed of the flames as well as increased product chemical source terms in regions of high positive curvature. The results illustrate the necessity for including thermal diffusion, and the accuracy and computational efficiency of the mixture-averaged thermal diffusion model.
© 2017 Informa UK Limited, trading as Taylor & Francis Group. Received 07 Apr 2017, Accepted 20 Jul 2017, Published online: 14 Aug 2017. No potential conflict of interest was reported by the authors. This work was supported by the Air Force Office of Scientific Research [grant number FA9550-09-1-0701], [grant number FA9550-16-1-0361].