Thermal performance analysis of SuperORV heat transfer tube at supercritical pressure

• A distributed parameter model for SuperORV heat transfer tube was proposed.
• Thermal performance of heat transfer tube at supercritical pressure is estimated.
• The effects of operating parameters on thermal performance are discussed.
• The effects of inner fin or twisted tape insert on thermal performance are studied.

Super open rack vaporizer (SuperORV) is a new-type of liquefied natural gas (LNG) vaporizer whose lower half of heat transfer tubes has double tube structure. A distributed parameter model based on energy balance is developed in the present paper with the aim to simulate the thermal performance of SuperORV heat transfer tube at supercritical pressure. Corresponding empirical correlations are used to evaluate the convection heat transfer of LNG and seawater, and the heat transfer enhancement effects of inner fin and twisted tape insert are considered in computation. Good agreement between calculated and experimental data implies the calculation model is reliable. On this basis, the temperature and ice thickness profiles along the heat transfer tube are obtained by numerical solution with or without ice layer presence, the thermal performance of heat transfer tube is analyzed, and the effects of operating parameters and heat transfer enhancement techniques on the thermal performance are discussed. The results indicate that both the operating parameters and the heat transfer enhancement techniques have great influence on the thermal performance, including required minimum tube length, ice thickness and length of formed ice layer. The heat transfer enhancement techniques can improve the heat transfer performance markedly, and the required tube length is reduced by 47.7% while both inner fin and twisted tape insert are applied.