Numerical investigation of embedding some hot obstacles in a low speed reacting flow of the moderate or intense low-oxygen dilution in a jet-in-hot-coflow

Abstract

Given the daily growth of pollutant emissions in this age of technology, every method that can increase the efficiency of the combustion as well as reduce the pollution is very important to consider. One way to reach this goal is moderate or intense low oxygen dilution. In the present work, this technology of turbulent nonpremixed CH4-H2 jet flames has investigated in various working conditions in Dally burner, numerically. In this regard, the finite volume method in OpenFOAM package has used with k-ε Re-Normalization Group as well as the discrete ordinates radiation model. Furthermore, the eddy dissipation concept for interaction between turbulence and chemistry in combination with the detailed reaction mechanism have been employed. At first, the results are compared with the experimental data and after validating the obtained results of the solution, the moderate or intense low-oxygen dilution combustion is investigated by putting some hot obstacles in the burner. The results show that the hot obstacle has a role similar to the hot spot and helps this condition of combustion to reduce the initial cost in order to preheat the hot oxidizer co-flow. This means that putting the hot obstacle in the burner causes to reduce the preheat temperature and the energy consumption per second up to 300 K and 17.9%, respectively, while it increases the turbulence intensity, reaction zone, outlet CO2 and H2O species while reduces NOx and CO emissions.