A dynamic model for FLNG spiral wound heat exchanger with multiple phase-change streams based on moving boundary method

For predicting the dynamic performance of spiral wound heat exchangers (SWHEs) applied in floating liquefied natural gas (FLNG) offshore platforms, a dynamic model reflecting the heat transfer among multiple phase-change streams in SWHEs is presented. In the dynamic model, a two-dimensional partitioned matrix is proposed to describe the heat transfer relations among phase-change streams in a general form; a group of generic equations based on the partitioned matrix is developed to calculate the heat capacities of phase-change streams, suitable for all types of phase zones (i.e. vapor, two-phase and liquid zones). An implicit iterative algorithm is proposed to solve the equations. The reliability and capability of the model has been partly validated by comparing the calculated steady-state performance with experimental data, and the dynamic performance under sloshing conditions are investigated, indicating that the sloshing-induced reduction of SWHE overall performance is within 5% for most cases.