Dynamic heat transfer analysis of liquefied natural gas ambient air vaporizer under frost conditions

Liquefied natural gas (LNG) ambient air vaporizer (AAV) is a cryogenic heat exchanger, which utilizes ambient air to evaporate LNG in gas terminal stations. The moist air around the AAV fin tube may freeze during the long-time operation, leading to a worse heat transfer performance. Study on the dynamic heat transfer performance of AAV is required for its optimal design and operation. This paper presents a coupled dynamic heat transfer model, which incorporates the cryogenic frost formation and flow boiling heat transfer of LNG. The model was demonstrated in the heat transfer analysis of a typical star-fin type AAV. The model results were validated by the test data of a commercial HAI848F type AAV. The dynamic heat transfer performance of AAV under frost conditions was also studied.