Influence of pressure on the circumferential diffusion characteristics of fuel vapor and combustion performance in a pressurized burner

To discuss the circumferential diffusion characteristics of the fuel vapor and combustion per-formance, a 15 kW pressurized burner fueled by diesel is first proposed in this research. And then, combustion experiments and cool-state numerical simulations are conducted at different pres-sures (P) and thermal loads (Q). The ratio (F) of the aerodynamic to buoyancy forces and the circumferential diffusion uniformity (sigma) of the fuel vapor are constructed through pollutant emissions, fuel vapor concentration distribution and velocity field. The results show that under a Q of 3.55 kW, the burner has a relatively low F, and the buoyancy force has a more obvious effect as P increases, further causing circumferential fuel vapor distribution uniformity to suffer. When the burner operates at a Q of 10.64 kW, the undesired circumferential diffusion uniformity of the fuel vapor is only found at 0.3 MPa. For a Q of 15.37 kW, the fuel vapor has a great circumfer-ential diffusion uniformity in the forward end of the liner at each P. A proper F of 89-278 and sigma of 0-3.6% are recommended for diesel vapor circumferential diffusion and pollutant emissions, in which the buoyancy force has a relatively lower effect than the aerodynamic force.

Automated summary

In this research, a 15 kW pressurized burner fueled by diesel was proposed to investigate the circumferential diffusion characteristics of fuel vapor and combustion performance. Combustion experiments and cool-state numerical simulations were conducted at different pressures and thermal loads. The ratio of aerodynamic to buoyancy forces and the circumferential diffusion uniformity of fuel vapor were analyzed through pollutant emissions, fuel vapor concentration distribution, and velocity field. The results showed that the burner had a relatively low aerodynamic to buoyancy force ratio at a thermal load of 3.55 kW, and the increase in pressure had a more significant effect on the buoyancy force, leading to a decrease in circumferential fuel vapor distribution uniformity. At a thermal load of 10.64 kW, undesired circumferential diffusion uniformity of fuel vapor was only observed at 0.3 MPa. For a thermal load of 15.37 kW, the fuel vapor exhibited a high circumferential diffusion uniformity at each pressure. A recommended aerodynamic to buoyancy force ratio of 89-278 and circumferential diffusion uniformity of 0-3.6% were suggested for diesel vapor circumferential diffusion and pollutant emissions, with a relatively lower effect of the buoyancy force.