Abstract
The breakup processes and droplet characteristics of a liquid jet injected into a low-speed air crossflow in the finite space were experimentally investigated. The liquid jet breakup processes were recorded by high-speed photography, and phase-Doppler anemometry (PDA) was employed to measure the droplet sizes and droplet velocities. Through the instantaneous image observation, the liquid jet breakup mode could be divided into bump breakup, arcade breakup and bag breakup modes, and the experimental regime map of primary breakup processes was summarized. The transition boundaries between different breakup modes were found. The gas Weber number (Weg) could be considered as the most sensitive dimensionless parameter for the breakup mode. There was a Weg transition point, and droplet size distribution was able to change from the oblique-I-type to the C-type with an increase in Weg. The liquid jet Weber number (Wej) had little effect on droplet size distribution, and droplet size was in the range of 50–150 μm. If Weg > 7.55, the atomization efficiency would be very considerable. Droplet velocity increased significantly with an increase in Weg of the air crossflow, but the change in droplet velocity was not obvious with the increase in Wej. Weg had a decisive effect on the droplet velocity distribution in the outlet section of test tube.
Highlights
Atomizing the injected liquid through the air flow in a tube can significantly increase the gas–liquid contact surface area, and the atomized micron droplets are easier to disperse uniformly in the air flow, which can strengthen the gas–liquid contact mass transfer process
From the y-perspective, a stable liquid jet column can be observed near the nozzle when the liquid is injected into the air crossflow
The breakup process and atomization characteristics of liquid jets injected into a low-speed air
Summary
Atomizing the injected liquid through the air flow in a tube can significantly increase the gas–liquid contact surface area, and the atomized micron droplets are easier to disperse uniformly in the air flow, which can strengthen the gas–liquid contact mass transfer process. The liquid solvent is injected into the air flow through small holes in the tube wall and atomized by the gas–liquid interaction, which causes a low–pressure drop, but a highly efficient atomization. Such methods are commonly used in compact absorption devices. In order to optimize the structure and performance of Processes 2020, 8, 676; doi:10.3390/pr8060676 www.mdpi.com/journal/processes
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