Numerical investigation on the effects of inlet air temperature on spray combustion in a wall jet can combustor using the k-ε turbulence model

A three-dimensional numerical study was performed to assess the effects of inlet temperature and equivalence ratio on the spray combustion and subsequent NOx emission in a wall jet can combustor (WJCC) installed with twin-fluid air-assisted fuel atomizers. The RNG k-ε turbulence model, eddy breakup (EBU) combustion model, and the Zeldovich model of NOx formation were utilized in the numerical study. The WJCC was implemented with a swirling air jet at the fuel nozzle exit and two other air jets, known as primary and dilute jets, at downstream locations. The inlet air temperature and overall equivalence ratio were varied from 373 to 1000 K and from 0.3 to 0.6, respectively. Our computational study showed that the inlet air of high temperature induced flow acceleration and sufficient jet penetration, which were desirable for achieving uniform temperature distribution at the combustor outlet but unfavorably yielded increased NOx emission. While the inlet air temperature had no prominent influence on the evaporation rate of the fuel drops in the upstream primary zone, its influence appeared to be prominent further downstream.