Simulation of combustion by vortex method

In this paper, we present a simple and efficient technique that uses a vortex method to predict the quantities of the combustion products; however, this technique uses no chemical equations. This technique incorporates the concept of chemical equilibrium into a vortex method. By using this technique, the products of a chemical system are determined by minimizing the Gibbs free energy, which is subject to the conservation of the chemical elements involved in the combustion process. The amount of gas (a mixture of fuel and oxygen) that is used for the calculation of chemical equilibrium is estimated by the eddy-dissipation model. In order to avoid increasing the number of species of particles, a single particle is provided with five physical properties - vorticity, turbulent energy, dissipation rate, amount of fuel, and amount of oxygen. To meet this condition, the motion equations of these properties are modified. For the sake of simplicity and low computational load, the presented technique does not focus on achieving higher order accuracy in the solutions. Nevertheless, the simulated results for the temperature and the main products for the premixed methane/air jet turbulent flame are in good agreement with the experimental results. In some cases, the data from the simulation concerning the intermediate products disagree with that from the experiment due to the slow reaction speeds in actual combustion. The convergence of the algorithms is also examined.