Study On Combustion Characteristics Of Dry Low Pollution Combustor

While improving combustion efficiency,reducing pollutant emissions has also become one of the directions of the development of gas turbines.Dry low-NOx（DLN）combustion technology has been generally used in gas turbines.The core is lean-burn premixing,that,the chemical equivalent ratio of the combustible mixture is close to the lean-burn flameout limit,which reduces the temperature of the main combustion zone and ultimately inhibits the formation of NOx.In this paper,the effects of equivalent ratio,duty fuel ratio,premix exit velocity,swirl vane inclination angle and flame barrel expansion angle on the combustion characteristics of DLN combustor are studied.The research results show that:The increase of equivalent ratio has little influence on the flow field structure.However,the increase in the amount of fuel promotes combustion,improving the temperature in the flame tube and upgrading the molar fraction of thermal NOx significantly,eventually leading to an increase in the concentration of NOx exported.With the increase in the fuel proportion of pilot,the range of the central recirculation zone decreases and the axial velocity value decreases.The flame propagates reversely,and the temperature distribution coefficient of outlet increases.The NOx mole fraction increases exponentially in the central reflux zone,which makes the outlet NOx concentration increase continuously.With the increase of premix exit velocity,the axis velocity of the main flow area increases greatly.The temperature distribution remains unchanged,and the outlet temperature distribution coefficient gradually drops.The reflux velocity of reflux zone increases,so that the residence time of high-temperature gas in the reflux zone is reduced,and the molar fraction of NOx in the reflux zone is greatly reduced,and the concentration of NOx at the outlet also decreases.With the decrease of blade inclination angle,the position of central backflow area was changed,and the backflow velocity increases.The outlet temperature distribution coefficient increases slightly.The increase in the axial velocity of the reflux zone reduces the mole fraction of NOx and the concentration of NOx at the outlet.With the increase of the expansion angle of the flame barrel,the distribution of high temperature is irregular.The flow rate of the reflux zone increases so that the production of NOx in the reflux zone decreases,and the concentration of NOx emission at the outlet also decreases.In scheme 3,the combination of 45° blade inclination angle and 30° blade expansion angle has relatively good effects on suppressing outlet NOx emissions.