Experimental study on the effect of circulating liquid velocity on bubble size distribution and turbulence characteristic in an external loop airlift reactor
Xia Lu, Xiuqing Lu, Kai Yang, Xiaotao Zheng, Shixian Wang
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引用次数: 0
Abstract
The influence of circulating liquid velocity on bubble size distribution (BSD) and turbulence characteristics of an external loop airlift reactor was studied in this paper. The instantaneous and time-averaged velocity in the riser were studied using particle image velocimetry (PIV), and BSDs were measured by digital image analysis technique based on machine learning. Then turbulence kinetic energy (TKE) and energy dissipation rate (EDR) were calculated through the velocity field. The results indicate that as the circulating liquid velocity increased, the peak value of BSD rapidly decreased from nearly 6 mm to approximately 2 mm. The radial velocity of the liquid gradually decreased and changed direction, eventually increasing again. TKE first decreased and then increased. Compared with bubble flow with a BSD peak of 2–6 mm, bubble flow with a BSD peak of 2 mm had larger TKE. The radial movement of bubbles had great influence on the turbulence characteristics. This study demonstrates that selecting an appropriate circulating liquid velocity can reduce the diameter of bubbles while obtaining greater TKE, thereby improving the mass transfer and reaction efficiency in external loop airlift reactors (EL-ALR).
期刊介绍:
Asia-Pacific Journal of Chemical Engineering is aimed at capturing current developments and initiatives in chemical engineering related and specialised areas. Publishing six issues each year, the journal showcases innovative technological developments, providing an opportunity for technology transfer and collaboration.
Asia-Pacific Journal of Chemical Engineering will focus particular attention on the key areas of: Process Application (separation, polymer, catalysis, nanotechnology, electrochemistry, nuclear technology); Energy and Environmental Technology (materials for energy storage and conversion, coal gasification, gas liquefaction, air pollution control, water treatment, waste utilization and management, nuclear waste remediation); and Biochemical Engineering (including targeted drug delivery applications).