Simulated Research of Enhanced Heat Transfer Characteristics of LNG in Rectangular Small Channels with Circumference Micro-Grooves

In view of the technical development bottleneck of 3D printing manufacturing compact heat exchanger for supercritical LNG, a new passive enhanced heat transfer technology is proposed by developing circumferential micro-grooves on the top and bottom walls of rectangular small channels. Numerical simulation of heat transfer enhancement and flow resistance characteristics of LNG in the enhanced channels with micro-grooves is performed. The geometrical dimensions such as the groove depth, the groove width and the center distance between two adjacent micro-grooves were optimized, and then the heat transfer enhancement and flow of LNG within the range of 120 K—250 K which across the critical temperature after the use of the strengthening technology were discussed. Then, further effects of working fluid temperature, mass flow (Reynolds number), and inlet pressure on heat transfer coefficient (Nusselt number), friction factor, and comprehensive coefficient were investigated. In addition, by the analysis of local flow characteristics near the micro-grooves, the heat transfer mechanism is discussed.