Experimental study on the flow field distribution characteristics of an open-end swirl injector under ambient pressure

To investigate the influence of ambient pressure on the atomization characteristics of an open-end swirl injector, the spray morphology, droplet diameter distribution and velocity distribution were measured under ambient pressures of 0.1 MPa, 0.5 MPa, 1.0 MPa, 1.5 MPa and 2.0 MPa using a high-speed camera and Phase Doppler Interferometer (PDI). As the ambient pressure increased, the spray region and intact liquid film area decreased, and the spray angle, spray width and breakup length shortened. Increased ambient pressure made droplet SMD larger and the SMD curves flatter. The droplet Sauter Mean Diameter (SMD) at each measuring point along the radial direction increased gradually and then decreased slightly, but there was no significant difference between different measuring sections. Ambient pressure had a more significant influence on axial velocity than the tangential velocity. As the ambient pressure increased, the axial velocity decreased, and the region where droplets had negative axial velocity was compressed backward to the injector outlet. Additionally, the tangential velocity near the outlet fluctuated greatly along the radial distribution. As the axial distance increased, the velocity curves became much flatter. (C) 2020 Elsevier Masson SAS. All rights reserved.