Frosting performances of ambient air vaporizer in LNG for different fin numbers

This study modified a model based on the Euler-Euler model to describe the frosting performances of the AAV (Air Ambient Vaporizer) heat transfer process in the LNG (Liquefied Natural Gas) industry at ultra-low temperatures. The moisture and temperature contours were presented to illustrate the impacts of moisture and temperature fields on the frosting performances. The performances including the frost layer thickness, ice volume fraction, and thermal conductivity coefficient as affected by the fin number of AAV were compared and analyzed. Results showed that the fin number of 8 had the highest frost layer thickness (average of 3.44 mm at the frosting time of 300 s) and frost growth rate (average of 0.69 mm/min), whereas the fin number of 6 had the lowest frost layer thickness (average of 1.46 mm at the frosting time of 300 s) and frost growth rate (average of 0.29 mm/min). The average ice volume fraction was the highest (4.03 × 10-5) for the fin number of 8 and was the lowest (2.14 × 10-5) for the fin number of 6. The maximum thermal conductivity coefficient for the fin number of 8 increased from 0.15 W/(m·K) to 0.26 W/(m·K) with an average growth rate of 0.027 W/(m·K·min) when the frosting time changed from 50 s to 300 s. The study can provide a guide for the design and application of the AAV.