Experimental Investigations of Spray Characteristics of a Pressure-Swirl Atomizer

Abstract

Spray characteristics of a pressure-swirl atomizer are investigated using high-speed shadowgraph technique under different pressure drops (Δ P) 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 Δ P, while the discharge coefficient ( Cd) decreases firstly and then climbs with the increase of Δ P. Δ P has larger effect on the cone angle relative to fuel temperature. With the increase of Δ P, 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 Δ P. The average breakup length climbs, then decreases to nearly a constant value with the increase of Δ P, 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 Δ P. Both the fuel temperature and Δ P 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 Δ P and fuel temperature. The results can further deepen the understanding of spray characteristics of pressure-swirl atomizer.

Experimental investigations on atomization characteristics of dual-orifice atomizers part I: Optimization method formation

“…Figure 2 shows the high-speed shadowgraph experiment system, which is the same with literature. 26 Figure 3 shows the droplet size measurement system. SMD is obtained by a Fraunhofer diffraction optical instrument.…”

“…Figure2. The high-speed shadowgraph experiment system 26. increase of main nozzle diameter, from 1.02 kg/min at d 1 ¼ 2.2 mm to 1.24 kg/min at d 1 ¼ 3.0 mm.…”

Experimental investigations on atomization characteristics of dual-orifice atomizers part II: Optimization method application

“…Figure 3 shows the high-speed shadowgraph experiment system, which is the same with literature. 2 Fuel distribution map in this paper is obtained by 1000 pictures taken by high-speed camera at 10000HZ. The fuel mass flow is measured by Coriolis mass flow meter with an uncertainty of AE0.1%.…”

Numerical and experimental analysis on spray characteristics of biodiesel (waste cooking oil) using pressure swirl atomizer

“…Pressure‐swirl atomizer is broadly used in various fields, such as aircraft air combustors, industrial furnaces, and DISI engine but liquid jet breakup process is crucial stage in combustion. The excellence of the liquid jet breakup process takes a leading role in overall performance, flame stability, and emissions, since it controls fuel distribution and droplet size 22,23 . Pressure swirl atomizers consist of spray devices that are designed to change heavier droplets in to fine droplets and then able to move in gaseous medium that results in spray formation.…”

“…The excellence of the liquid jet breakup process takes a leading role in overall performance, flame stability, and emissions, since it controls fuel distribution and droplet size. 22,23 Pressure swirl atomizers consist of spray devices that are designed to change heavier droplets in to fine droplets and then able to move in gaseous medium that results in spray formation.…”