NUMERICAL SIMULATION OF EFFECT OF INLET-AIR VELOCITY ON THE FORMATION OF OXIDES OF NITROGEN IN A NON-PREMIXED METHANE-AIR COMBUSTION

Анотація

A numerical simulation of none-premised methane-air combustion is performed. The purpose of this paper is to provide information concerning the effect of inlet-air velocity (dry air) on the exhaust gas emissions of oxides of nitrogen (NO), for a simple type of combustor. Effects of increased inlet-air velocity on NOx formation are examined. Numerical results show that NO formation mechanisms, decrease, with increasing inlet-air velocity. The simulation has been performed using the Computational Fluid Dynamics (CFD) commercial code ANSYS CFX release 15, including laminar flamelet model, for simulating the methane combustion mixing with air (none-premixed combustion) and predicting concentration of (CH- CH2- CH2O- CH3- CH4- CHO- CO- CO2- O- O2-H-H2-H2O-HO2-N2-H2O2- OH). k-model was also investigated to predict the turbulent combustion reaction, which indicated the simulation results of velocities, temperatures and concentrations of combustion productions. A thermal and prompt Nox formation is performed for predicting NO emission characteristics. A comparison between the various inlet-air velocity, and their effects on NO emission characteristics and temperature fields are presented.