Open rack vaporizers are basic load vaporizers that are widely used in LNG terminals. However

there are few experimental studies on the fluid flow and heat transfer behaviors of supercritical natural gas. In this study

nitrogen was used to replace natural gas

and the heat transfer characteristics of supercritical nitrogen in a heated vertical tube were investigated experimentally. The effects of various operating parameters

including nitrogen pressure

inlet temperature

and mass flow of water

on the heat transfer characteristics were investigated. The surface coefficient of heat transfer decreased with increasing pressure below the pseudocritical temperature

while the variation of the surface coefficient of heat transfer was opposite to that of the pseudocritical temperature. The outlet temperature of nitrogen was determined by the water temperature instead of the mass flow rate when the mass flow rate of water was sufficiently large. A new correlation was developed for the heat transfer of a supercritical cryogenic fluid based on the experimental data

and the mean absolute relative deviation between the predicted values and the experimental data was 8.42%. This new correlation can be used to accurately predict the surface coefficient of heat transfer of supercritical nitrogen in a vertical heating tube.