Development of Fast Solving Monolith Reactor Simulators: Computational Fluid Dynamics Studies of Methane Oxidation

Abstract

Abstract The optimisation of complex geometries such as that of monolith reactors can be supported by computation and simulation. However, complex boundaries such as those found in multi-channel monoliths where mass and heat transfer of characteristic of the reaction diffusion equation render such simulations of extremely high computational expense. In the first step toward developing a fast-solving hybrid simulation, a detailed CFD simulation was used to obtain the unsteady state, spatial temperature and concentration (and hence reaction rate) profiles for a range of input conditions. The results of the CFD simulation were then accepted as the benchmark to which faster-solving models were measured against to be considered as viable descriptions. The model evaluated here is a modified plug flow with effectiveness factor correction for wall mass-transfer. A close agreement between both temperature and species mole fraction profiles predicted from the modified plug flow model and a detailed CFD model was found with R2 values of 0.994 for temperature. The time needed to find a converged solution for plug flow model on an Intel(R) Core(TM) i5-5300U CPU @ 2.30 GHz workstation was found to be 53 seconds in comparison to 1.3 hours taken by a CFD model.