Falling film flow and evaporation characteristics at shell-side of spiral wound heat exchanger under different conditions

摘要

Spiral wound heat exchanger (SWHE) is widely used as main cryogenic heat exchangers in LNG plants. For SWHEs in floating LNG plants, it undergoes complex sea conditions including sloshing. In the present study, the falling film flow and evaporation characteristics at shell-side of SWHE were investigated experimentally, and the flow pattern at shell side was also visualized. A model for simulating flow pattern, including the droplet flow, the column flow and the sheet flow, is developed by employing the Volume of Fluid - Continuous Surface Force method; the mass transfer model was developed for the liquid-gas interface and tube surface; the additional sloshing accelerated velocity was added in the model for reflecting the sloshing effect. The proposed model was verified by the obtained experimental heat transfer coefficients, and the mean deviations are within ±18.3%.