Numerical Simulation of Single Droplet Combustion Characteristics in High Temperature Convection Environment

Abstract

In order to better study the combustion characteristics of small droplets during spray combustion, a mathematical model of single fuel droplet evaporation and combustion was established based on the numerical simulation method of VOF(Volume of Fluid). Numerical simulation was carried out using FLUENT. The combustion process and flame propagation characteristics of the small droplet in the convection environment under different pressures of 0.1 MPa, 0.2 MPa and 0.3 MPa, were studied respectively, and the influence of different ambient pressures on combustion was analyzed. The results show that due to the influence of air convection, the ignition position was located in the downstream area of the droplet, forming a wake flame. Then the flame gradually overcame the convection effect and developed upstream, and finally transformed into the enveloped flame. With the further development of combustion, the combination of fuel vapor diffusion and combustion promoted the development of the flame front in the direction of airflow. After reaching the balance each other, the position and temperature of the flame front would be relatively stable. The increase of ambient pressure promoted the combustion process, which increased the droplet burning rate and flame temperature. At the initial stage of ignition, the temperature rise rate of the average droplet temperature at 0.3 MPa was 1.18 K/ms, which was 32.6% higher than that 0.89 K/ms at 0.1 MPa.