Numerical study on the flow characteristic of shell-side film flow of floating LNG spiral wound heat exchanger

Abstract

A mathematic-physical model was established to investigate the shell-side flow characteristic of film flow in spiral wound heat exchanger (SWHE), which was used for floating liquefied natural gas (FLNG). The numerical study was carried out based on CLSVOF model and dynamic contact angle model, and the numerical accuracy was validated by experimental data. According to the results under static conditions, the shell-side frictional pressure drop gradient increased with decreasing pressure and increasing mass flux and heat flux. Sloshing motion could significantly shorten the process of film flow in the heat exchanger, promote the early occurrence of flow pattern transition and lead to the remarkable change in frictional loss. Therefore, the effects of sloshing parameters and working parameters on shell-side frictional pressure drop gradient were investigated, where sloshing amplitude, sloshing period, pressure and mass flux respectively were 5 ∼15o, 5 ∼ 15 s, 0.2 ∼ 0.6 MPa and 60 ∼ 100 kg/(m2·s). As a result, in order to maintain the stable operation of FLNG SWHE, the heat exchanger should be placed near the gravity center of FLNG, and the shell-side pressure and mass flux should be respectively increased to 0.6 MPa and 80 kg/(m2·s), as far as possible. These results will provide some instructions in the design and operation for FLNG SWHE.