A simple three-component mixing problem for the evaluation of a new reaction rate model*

A simple computational mixing problem is presented which can be utilized to assess the behavior of Reynolds-averaged reaction rate models in a problem with temporally varying mixedness. In this problem, three mixing components are homogeneously distributed but initially separated in a triply periodic domain. These components are initialized within a Taylor-Green-like velocity field, which creates a mixing history evolving from the so-called ``no-mix limit'' to a well-mixed state. Large-eddy simulation results from this problem in configurations involving both premixed and non-premixed reactants are then compared with zero-dimensional Reynolds-averaged Navier-Stokes results utilizing a new model for multicomponent reacting mixtures. The new model is shown to appropriately respect the no-mix limit and outperforms an earlier model [Morgan, Phys. Rev. E 105, 045104 (2022)], particularly at early times when components are near the no-mix limit.