An OpenFOAM solver incorporating detailed transport model for reacting flow simulations

Abstract

OpenFOAM (Open-source Field Operation and Manipulation) has become an important scientific tool for solving computational fluid dynamics due to its free and open-source nature, but its application in reacting flows may be restricted due to either the use of a simplified transport model or the requirement for pre-specified species (binary) mass diffusion coefficients as well as the use of Sutherland's formula. To fill this gap, a detailed transport model using a mixture-averaged formulation based on the standard kinetic theory of gases is newly incorporated into combustion solvers for dealing with reacting flow simulations in OpenFOAM. This is achieved by developing a new utility to input molecular transport parameters and a new library to calculate transport properties. All the codes are completely written under the code framework of OpenFOAM, making them very easy to read, use, maintain, enhance and extend. The developed utility and library are then coupled with a new reacting flow solver developed for the governing equations in terms of mass, momentum, species and energy by configurating an interface. In the present study, the function of the new utility is firstly examined and then a new solver (i.e., standardReactingFoam) is developed for solving reacting flows. A systematical validation and assessment in different flame configurations with detailed chemical kinetics is studied to evaluate the computational performance of these new solvers. A zero-dimensional auto ignition, one-dimensional premixed flame and two-dimensional non-premixed counterflow flame are selected to validate the solvers against Cantera and CHEMKIN, while a realistic combustion simulation of a two-dimensional partially premixed coflow flame is also verified. Numerical simulation results show that very good agreements with the benchmark data are obtained for all studied flames, which demonstrates the high computational accuracy of the developed combustion solvers incorporating a detailed transport model.

Program summary

Program title: standardReactingFoam.

CPC Library link to program files: https://doi.org/10.17632/rbm3cjk8rr.1.

Licensing provisions: GPLv3.

Programming language: C++.

Nature of problem: The performance of OpenFOAM solvers for reacting flow simulations is greatly limited by a simplified transport model or the requirement for pre-specified species (binary) mass diffusion coefficients as well as the use of Sutherland's formula, leading to incorrect numerical calculation of the critical transport properties. Developing an interface between OpenFOAM and Cantera can achieve the evaluation of transport properties, which makes it difficult to be widely used and conveniently maintained. Developing a separate package to obtain transport properties results in a very complicated operation when using.

Solution method: A detailed transport model using a mixture-averaged formulation based on the standard kinetic theory of gases is incorporated into combustion solvers for dealing with reacting flow simulations in OpenFOAM. This is achieved by developing a new utility to input molecular transport parameters and a new library to calculate transport properties. All the codes are completely written under the code framework of OpenFOAM, making them very easy to read, use, maintain, enhance and extend. The developed utility and library are then coupled with a new reacting flow solver developed for the governing equations in terms of mass, momentum, species and energy by configurating an interface.