Ice formation prediction and heat transfer analysis of LNG in serpentine tube under supercritical pressure

Abstract

A numerical model employing the SST k-ω turbulent model and Shell Conduction model is established to predict the ice layer formation and thermal performance of serpentine tube in submerged combustion vaporizer (SCV) under supercritical pressure. The affecting factors on the heat transfer and ice layer formation such as pressure and heat flux are analyzed. A new semi-empirical heat transfer correlation is proposed taking account of the flow acceleration, thermophysical properties, buoyancy force and geometrical factor on the serpentine tube of supercritical LNG. The simulation results reveal that: (1) the interactive effect of centrifugal force, chaotic mixing fluid and buoyancy force are implied from the complicated flow structure and thermal performance of LNG in serpentine tube, and the centrifugal force dominates on heat transfer in the bend region resulting from the strengthening of cross flow and rotational flow; (2) the deviation of thermal performance between ice layer formation or not becomes slighter in the bend region than that in the straight sections due to the interaction of flow acceleration, reverse flow and secondary flow; (3) pressure and heat flux exhibit significant effects on thermal performance and ice layer formation; (4) the semi-empirical heat transfer correlation proposed in present paper can predict the heat transfer of LNG in serpentine tube under supercritical pressure accurately.