LAUSR

Spray characteristics of a pressure-swirl atomizer are investigated using high-speed shadowgraph technique under different pressure drops (ΔP) and fuel temperatures (T). An image processing method is developed using MATLAB. The results illustrate that the mass flow rate climbs with the increase of ΔP, while the discharge coefficient (Cd) decreases firstly and then climbs with the increase of ΔP. ΔP has larger effect on the cone angle relative to fuel temperature. With the increase of ΔP, the shape of liquid film changes from ‘onion’ to ‘tulip’ and finally be fully developed spray cone. Meanwhile, the surface of liquid film becomes smoother with the increase of ΔP. The average breakup length climbs, then decreases to nearly a constant value with the increase of ΔP, which is induced by the “Impact wave,” surface wave, and turbulent energy. There are little differences on the shape of the liquid film under different temperatures, and temperature has different influence on breakup length under different ΔP. Both the fuel temperature and ΔP have significant impact on the surface wavelength (λ) and velocities (U, V) of surface wave. The width of fuel stream becomes larger with the increase of ΔP and fuel temperature. The results can further deepen the understanding of spray characteristics of pressure-swirl atomizer.