Large eddy simulation of aerosol particle dispersion mechanism in aircraft exhaust plume

Abstract

Aerosol Infrared Stealth Technology is a novel method to suppress the infrared by releasing aerosol particles around the hot exhaust plume. However, the Infrared Radiation (IR) suppression rate is much lower in flight tests, which is caused by the unclear particle dispersion mechanism in high-speed non-isothermal shear flow. Hence, the large eddy simulation (LES) and particle discrete phase model (DPM) are coupled to solve the turbulent shear flow and the aerosol particle motion. The effects of aircraft flight speed on the turbulent flow characteristics and particle motion behaviors are systematically studied. It is found that the Mach rings appear in flight conditions, and they are getting blurry when increasing the flight speed. Both γ-like vortex and horseshoe-like vortex are observed when Ma < 1, and the horse-like could disappear when Ma > 1. The aerosol particle distribution is closely related to the turbulent gas vortices. The particle lateral dispersion is obviously restricted with the rising flight speed. Besides, the drag force plays a dominant role, the Saffman force and the thermophoretic force are of the same order of magnitude, all of these three forces are much greater than the gravity.