Research on the Formation Characteristics of Fog and Frost on Optical Windows of Unsealed Equipment Compartments in Aircrafts

In this study, a numerical method for the formation and dissipation of fog and frost is established using the Eulerian multiphase flow liquid film model. In this approach, the formation and dissipation of fogging and frosting layers is directly determined by the saturation of the water vapor surface...

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Main Authors: Chun Shen, Yuanyuan Liang, Bo Wei, Chengchun Zhang, Tian Zhao
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/2/437
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author Chun Shen
Yuanyuan Liang
Bo Wei
Chengchun Zhang
Tian Zhao
author_facet Chun Shen
Yuanyuan Liang
Bo Wei
Chengchun Zhang
Tian Zhao
author_sort Chun Shen
collection DOAJ
description In this study, a numerical method for the formation and dissipation of fog and frost is established using the Eulerian multiphase flow liquid film model. In this approach, the formation and dissipation of fogging and frosting layers is directly determined by the saturation of the water vapor surface, and it does not depend on any empirical coefficients. Additionally, Buck’s formula is used to determine the saturation vapor partial pressure, which is applicable for a relatively wide temperature range (−50 °C to 10 °C). This numerical method was validated by the existing experimental data about fogging and frosting, and afterwards the fogging and frosting processes on the optical observation window in the aircraft are further analyzed for three typical working conditions, namely the ground, the fixed-altitude, and the high-altitude descent. The calculation results show that, under the ground working condition, the maximum thickness of the fog layer on the outer surface of the optical window can completely reach the millimeter level within one hour, and the average thickness of the frost layer can reach the sub-millimeter level, which is one order of magnitude smaller compared to under the ground working condition. Under the high-altitude descent working condition, by setting the fixed wall temperature boundary condition on the outer surface of the glass, it is found that in extreme cases, the maximum thickness of the frost layer on the inner wall of the glass can reach the sub-millimeter level within one hour. The research conclusions provide effective basic data support for the subsequent design of anti-fogging and defrosting devices under flight conditions.
format Article
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institution Kabale University
issn 1996-1073
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series Energies
spelling doaj-art-37d96c8f658a415787ddb325253de0652025-01-24T13:31:29ZengMDPI AGEnergies1996-10732025-01-0118243710.3390/en18020437Research on the Formation Characteristics of Fog and Frost on Optical Windows of Unsealed Equipment Compartments in AircraftsChun Shen0Yuanyuan Liang1Bo Wei2Chengchun Zhang3Tian Zhao4National Key Laboratory of Automotive Chassis Integration and Bionics, Jilin University, Changchun 130022, ChinaNational Key Laboratory of Automotive Chassis Integration and Bionics, Jilin University, Changchun 130022, ChinaNational Key Laboratory of Automotive Chassis Integration and Bionics, Jilin University, Changchun 130022, ChinaNational Key Laboratory of Automotive Chassis Integration and Bionics, Jilin University, Changchun 130022, ChinaBeijing Laboratory of New Energy Storage Technology, School of Energy Storage Science and Engineering, North China University of Technology, Beijing 100144, ChinaIn this study, a numerical method for the formation and dissipation of fog and frost is established using the Eulerian multiphase flow liquid film model. In this approach, the formation and dissipation of fogging and frosting layers is directly determined by the saturation of the water vapor surface, and it does not depend on any empirical coefficients. Additionally, Buck’s formula is used to determine the saturation vapor partial pressure, which is applicable for a relatively wide temperature range (−50 °C to 10 °C). This numerical method was validated by the existing experimental data about fogging and frosting, and afterwards the fogging and frosting processes on the optical observation window in the aircraft are further analyzed for three typical working conditions, namely the ground, the fixed-altitude, and the high-altitude descent. The calculation results show that, under the ground working condition, the maximum thickness of the fog layer on the outer surface of the optical window can completely reach the millimeter level within one hour, and the average thickness of the frost layer can reach the sub-millimeter level, which is one order of magnitude smaller compared to under the ground working condition. Under the high-altitude descent working condition, by setting the fixed wall temperature boundary condition on the outer surface of the glass, it is found that in extreme cases, the maximum thickness of the frost layer on the inner wall of the glass can reach the sub-millimeter level within one hour. The research conclusions provide effective basic data support for the subsequent design of anti-fogging and defrosting devices under flight conditions.https://www.mdpi.com/1996-1073/18/2/437optical window glassfogging and frostinghigh altitudetemperature and humidityliquid film model
spellingShingle Chun Shen
Yuanyuan Liang
Bo Wei
Chengchun Zhang
Tian Zhao
Research on the Formation Characteristics of Fog and Frost on Optical Windows of Unsealed Equipment Compartments in Aircrafts
Energies
optical window glass
fogging and frosting
high altitude
temperature and humidity
liquid film model
title Research on the Formation Characteristics of Fog and Frost on Optical Windows of Unsealed Equipment Compartments in Aircrafts
title_full Research on the Formation Characteristics of Fog and Frost on Optical Windows of Unsealed Equipment Compartments in Aircrafts
title_fullStr Research on the Formation Characteristics of Fog and Frost on Optical Windows of Unsealed Equipment Compartments in Aircrafts
title_full_unstemmed Research on the Formation Characteristics of Fog and Frost on Optical Windows of Unsealed Equipment Compartments in Aircrafts
title_short Research on the Formation Characteristics of Fog and Frost on Optical Windows of Unsealed Equipment Compartments in Aircrafts
title_sort research on the formation characteristics of fog and frost on optical windows of unsealed equipment compartments in aircrafts
topic optical window glass
fogging and frosting
high altitude
temperature and humidity
liquid film model
url https://www.mdpi.com/1996-1073/18/2/437
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