Numerical investigation on local thermal characteristics of printed circuit heat exchanger for natural gas liquefication

PCHE (Printed Circuit Heat Exchanger) is deemed as the most promising candidate for cryogenic heat transfer process in Liquefied Natural Gas - Floating Production Storage and Offloading due to its high compactness and efficiency. In this paper, numerical study is conducted to investigate the thermal characteristics of natural gas with phase changing from supercritical state to liquid state in a PCHE with straight channels. Multi-phase model and single-phase model are both employed to predict the characteristics of trans-critical fluids and the comparison shows that two models provide comparable accuracy. The local thermal characteristics of PCHE are studied and the distributions of temperature, heat flux and heat transfer coefficient are presented. A valley point and a peak point in temperature difference distribution which representing the local positions of heat transfer deterioration and enhancement are found before and after pseudo critical point of natural gas, respectively. The specific heat and mass flow rate of both two fluids are revealed to have the most important impact on local thermal characteristics.