Application of ODT to constant volume autoignition problems

The One-Dimensional Turbulence (ODT) model is applied to a constant volume configuration by means of a periodic, one-dimensional domain subject to randomized ensemble members with initial inhomogeneous temperature fields and homogeneous mass fraction profiles. The multidimensional turbulent interactions in the flow are modeled by the separate implementation of turbulent advection and the diffusion-reaction processes, neglecting the mean advection of the system. On one hand, turbulent advection is modeled by means of the eddy events defined within the framework of ODT; on the other hand, the diffusion-reaction system is solved by means of the Zero-Mach limit conservation equations discretized with a 1D Finite Volume Method (FVM). The treatment is specialized in this work to constant volume systems. Due to the inherent stiffness of the diffusion-reaction system, an operator splitting approach is also included in the formulation. Results for n-Heptane chemistry comprising the temporal evolution of the heat release rate, pressure and normalized density-weighted displacement speed are shown and compared to DNS results from Yoo et al. Combust. Flame 158 (2011) 1727-1741], in terms of individual ensemble members and mean ensemble behavior. The results show that it is possible to obtain reasonably good results in comparison to the DNS if an appropriate set of initial conditions is used. Furthermore, it is shown that the model uncertainty is negligible in comparison to the ensemble standard deviation introduced by randomized initial conditions. Overall, this work introduces the framework for constant volume autoignition in ODT and shows its efficiency for complex chemistry simulations. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)