PULSATING FLOW EFFECTS ON THE COMBUSTION CHARACTERISTICS

Abstract

An investigation was performed to increase the heat transfer rates from methane flames while simultaneously minimizing the soot and NOx emissions at extensive firing rates. The partially premixed flames responded favorably to the strain rate and the increase in temperature-soot interactions across the two reaction zones. Inverse flames with under-ventilation increased the temperature-soot interaction. Shifting the peak turbulent kinetic energy into the lean side in normal flames increased both the radiation and convection heat transfer rates respectively by13 and 9%. On the other hand, shifting the peak turbulent kinetic energy into the rich side reduced the NOx emissions. Exciting two concentric streams increased the turbulent kinetic energy and provided an innovative control of the pulsation effects. The soot growth and oxidation rates were thus controlled by setting the phase shift between the two streams at 20° and the corresponding frequency ratio at 4.0 such that the total