Liquid film flow widely exists in various industrial processes. High-precision measurement of various parameters in the process of liquid film flow is crucial to understand relevant processes and heat transfer mechanisms. Diode laser absorption spectroscopy (DLAS) is used to determine liquid film thickness of the falling film outside horizontal tube. The heat transfer coefficient of the liquid film is calculated by using the tube-wall temperature and the liquid-film temperature. The relationships between liquid film thickness and heat transfer coefficient under different conditions, including spray density (0.16/0.24/0.32 kg (m·s)-1) and hot water temperature at the inlet of the tube (40/50/60℃), are analyzed. The results show that the average thickness of the liquid film increases with the spray density. The heat transfer coefficient of the liquid film increases with the spray density. When the spray density increases, the heat transfer coefficient of the liquid film increases with the increase of film thickness. When the temperature increases, the liquid film thickness remains constant while the heat transfer coefficient increases.
QIAO Wenyou
,
JIANG Yong
,
YANG Huinan
,
LI Ling
,
SU Mingxu
,
CAI Xiaoshu
. Investigation of the evaporation process of falling film outside a horizontal tube using diode laser absorption spectroscopy[J]. Journal of University of Chinese Academy of Sciences, 2020
, 37(2)
: 268
-273
.
DOI: 10.7523/j.issn.2095-6134.2020.02.018
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