Effect of vacuum environment on air side heat and mass transfer characters of plain fin-tube heat exchangers

•The heat and mass transfer performance are investigated under vacuum environment.•The air-side sensible heat transfer performance is insensitive to air inlet humidity.•The air-side mass transfer performance is closely related to air inlet humidity.•The total heat transfer performance is investigate...

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Bibliographic Details
Published in:International journal of heat and mass transfer 2022-06, Vol.188, p.122596, Article 122596
Main Authors: Huichen, Zhang, Jianhua, Liu, Xiaojin, Xu, Qingqing, Wu, Liang, Zhang, Jiawen, Zhang, Qi, Liu
Format: Article
Language:English
Subjects:
Air inlet humidity
Air intakes
Air-side heat transfer
Air-side mass transfer
Coefficient of variation
Enthalpy
Heat exchangers
Heat transfer
Heat transfer coefficients
Humidity
Latent heat
Mass transfer
Moisture content
Moisture effects
Noise control
Plain fin-tube heat exchangers
Regression analysis
Relative humidity
Tube heat exchangers
Vacuum environment
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Summary:•The heat and mass transfer performance are investigated under vacuum environment.•The air-side sensible heat transfer performance is insensitive to air inlet humidity.•The air-side mass transfer performance is closely related to air inlet humidity.•The total heat transfer performance is investigated under vacuum environment.•A simplified model is investigated under vacuum environment. Air-side heat and mass transfer performance of plain fin-tube heat exchangers at different vacuum degree have been experimentally investigated. In this experiment, influence of air inlet humidity on air-side heat and mass transfer under vacuum environment is studied by controlling vacuum degree and air inlet humidity. Results show that: variation trend of air-side sensible heat transfer coefficient (ha), heat transfer j-factor (jh), mass transfer coefficient (hm) and mass transfer j-factor (jm) are not all time remain the same. Variation trend of ha, jh are the same with increase of vacuum degree when air inlet humidity changes, ha is gradually decreased and jh is gradually increased. Variation trend of hm is opposite with the increase of vacuum degree when the air inlet humidity changes. Under constant air inlet relative humidity conditions, hm is gradually increased. Under constant air inlet moisture content conditions, hm is gradually decreased. However, variation trend of jm is the same with increase of vacuum degree when air inlet humidity changes, both are increased. But slope of jm is greater under constant air inlet relative humidity conditions. Overall heat transfer performance is greatly affected by air inlet humidity changes. Under constant air inlet relative humidity conditions, when air inlet relative humidity increases from 50% to 70% and then to 90%, proportion of latent heat transfer increases from 30.98%∼53.99% to 36.53%∼56.95% and then increases to 44.19%∼64.04% with vacuum degree increases. As proportion of latent heat transfer increases, air-side total heat transfer performance is not obviously reduced. Under constant air inlet moisture content conditions, when air inlet moisture content increases from 15 to 20 g/kg, proportion of latent heat transfer is basically unchanged with increase of vacuum degree, at about 36% and 37%, respectively. So, total heat transfer performance on air side decreases obviously. In order to model air-side heat and mass transfer performance of the complex structure fin-tube heat exchangers, a simplified model is investigated u
ISSN:0017-9310
1879-2189
DOI:10.1016/j.ijheatmasstransfer.2022.122596