Thermal-hydraulic characteristics of printed circuit heat exchanger used for floating natural gas liquefaction

Abstract

Printed circuit heat exchanger is considered a promising candidate for floating natural gas liquefaction because of its high compactness, high pressure resistance, and high efficiency. In this work, a numerical model is established to study the thermal-hydraulic characteristics of transcritical natural gas in the printed circuit heat exchanger in rolling conditions. The results show that the rolling condition has few effect on the total heat transfer rate, but significantly affects the local friction factor and heat transfer characteristics. The rolling condition enhances the local heat transfer performance of transcritical natural gas, but also increases the pressure drop, in which the influences of rolling are the greatest at 1/4 and 3/4 of the rolling period. The tangential force and Coriolis force caused by the rolling motion increase the heat transfer of the natural gas. In the subcritical zone, where the rolling condition has the greatest influence on the heat transfer of the natural gas, the maximum instantaneous Nusselt number is increased by 40%. The rolling condition shows minor effect on the pseudocritical zone, in which the maximum instantaneous Nusselt number is increased by 15%. The rolling condition has almost no effect on the heat transfer performance of natural gas in the supercritical zone. The effect of the rolling condition on the flow characteristics of natural gas is the greatest in the pseudocritical zone, where the friction factor and local pressure drop are increased by approximately 30% compared to those in the steady condition.