Ignition and combustion characteristics of aluminum particle in high-temperature turbulent environment

This study presents fundamental experiment and optical diagnostics on the ignition and combustion process of micron-sized aluminum particles in high-temperature turbulent environment. Firstly, the turbulent methane burner based on tangential swirl stabilization was developed to create a high-temperature turbulent exhaust for the ignition and combustion of aluminum particles. The particle image velocimetry (PIV) and hot-wire anemometer techniques were used to characterize the cold flow field of the turbulent burner, indicating that the pulsation intensity in the centerline exceeded 14%. In addition, the spectral temperature measurement method was employed to map the temperature field of turbulent hot exhaust. The results show that compared with the laminar flow environment with similar temperature and oxygen concentration, the turbulent exhaust with a bulk Reynolds number of approximately 2320 can shorten the ignition delay and combustion time of aluminum particles by more than 70%. Moreover, the promoting effect becomes more significant with the increase of turbulence intensity. To understand the interaction between turbulent flow and particle combustion, the high-speed microscopic imaging technology captured the dynamic process of mechanical stripping of aluminum particle oxide caps in the high-speed flow field, providing direct evidence of the aerodynamic shear effect of turbulence.