Effect of flow direction on the conjugate heat transfer performance of LNG ambient air vaporizer with U-bend

Ambient air vaporizers (AAVs) with multiple U-shaped finned tubes are preferred for liquefied natural gas (LNG) vaporization due to their low energy consumption and eco-friendly nature. The flow direction significantly impacts vaporization efficiency and must be clarified for optimal design. This st...

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Main Authors: Shanshan Liu, Wenling Jiao, Ping Zhang, Qi Li
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Case Studies in Thermal Engineering
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2214157X25002357
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author Shanshan Liu
Wenling Jiao
Ping Zhang
Qi Li
author_facet Shanshan Liu
Wenling Jiao
Ping Zhang
Qi Li
author_sort Shanshan Liu
collection DOAJ
description Ambient air vaporizers (AAVs) with multiple U-shaped finned tubes are preferred for liquefied natural gas (LNG) vaporization due to their low energy consumption and eco-friendly nature. The flow direction significantly impacts vaporization efficiency and must be clarified for optimal design. This study develops a conjugate heat transfer model of an AAV tube module with a U-bend (ATMU), considering internal LNG flow boiling and two-way fluid-solid coupling with ambient air. Experiments using liquid nitrogen (LN2) were conducted to provide boundary conditions and validate the numerical model. The relative error between measured and simulated wall temperatures was within ±5 % when relative humidity was below 30 %. Results indicate that wall temperature does not increase monotonically along the flow direction due to interference between adjacent tubes and the U-bend. Numerical analysis shows that the natural convective heat transfer coefficient on the air side is 20 % higher for top inflow than for bottom inflow in the first half of the tube, resulting in superior heat transfer performance for AAVs with an initial top inflow of LNG. The optimal AAV installation aligns the overall LNG flow direction perpendicular to the annual prevailing wind at gas terminals, maximizing vaporization efficiency.
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spelling doaj-art-c5b9c9a56f1642c4aa7d42b72b929c7c2025-08-20T03:18:16ZengElsevierCase Studies in Thermal Engineering2214-157X2025-05-016910597510.1016/j.csite.2025.105975Effect of flow direction on the conjugate heat transfer performance of LNG ambient air vaporizer with U-bendShanshan Liu0Wenling Jiao1Ping Zhang2Qi Li3Institute of Building Intelligence, Jiangsu Vocational Institute of Architectural Technology, Xuzhou, 221116, China; Corresponding author.School of Architecture and Design, Harbin Institute of Technology, Key Laboratory of Cold Region Urban and Rural Human Settlement Environment Science and Technology, Ministry of Industry and Information Technology, Harbin, 150090, ChinaLinyi Yage security technology Co., Ltd, ChinaGas Technology Research Institute of PetroChina Kunlun Gas Co., Ltd, ChinaAmbient air vaporizers (AAVs) with multiple U-shaped finned tubes are preferred for liquefied natural gas (LNG) vaporization due to their low energy consumption and eco-friendly nature. The flow direction significantly impacts vaporization efficiency and must be clarified for optimal design. This study develops a conjugate heat transfer model of an AAV tube module with a U-bend (ATMU), considering internal LNG flow boiling and two-way fluid-solid coupling with ambient air. Experiments using liquid nitrogen (LN2) were conducted to provide boundary conditions and validate the numerical model. The relative error between measured and simulated wall temperatures was within ±5 % when relative humidity was below 30 %. Results indicate that wall temperature does not increase monotonically along the flow direction due to interference between adjacent tubes and the U-bend. Numerical analysis shows that the natural convective heat transfer coefficient on the air side is 20 % higher for top inflow than for bottom inflow in the first half of the tube, resulting in superior heat transfer performance for AAVs with an initial top inflow of LNG. The optimal AAV installation aligns the overall LNG flow direction perpendicular to the annual prevailing wind at gas terminals, maximizing vaporization efficiency.http://www.sciencedirect.com/science/article/pii/S2214157X25002357Ambient air vaporizerConjugate heat transferFlow directionFlow boilingFluid-solid coupling
spellingShingle Shanshan Liu
Wenling Jiao
Ping Zhang
Qi Li
Effect of flow direction on the conjugate heat transfer performance of LNG ambient air vaporizer with U-bend
Case Studies in Thermal Engineering
Ambient air vaporizer
Conjugate heat transfer
Flow direction
Flow boiling
Fluid-solid coupling
title Effect of flow direction on the conjugate heat transfer performance of LNG ambient air vaporizer with U-bend
title_full Effect of flow direction on the conjugate heat transfer performance of LNG ambient air vaporizer with U-bend
title_fullStr Effect of flow direction on the conjugate heat transfer performance of LNG ambient air vaporizer with U-bend
title_full_unstemmed Effect of flow direction on the conjugate heat transfer performance of LNG ambient air vaporizer with U-bend
title_short Effect of flow direction on the conjugate heat transfer performance of LNG ambient air vaporizer with U-bend
title_sort effect of flow direction on the conjugate heat transfer performance of lng ambient air vaporizer with u bend
topic Ambient air vaporizer
Conjugate heat transfer
Flow direction
Flow boiling
Fluid-solid coupling
url http://www.sciencedirect.com/science/article/pii/S2214157X25002357
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