Numerical Prediction of Conjugate Heat Transfer in Fluid Network

Abstract

An unsteady finite volume procedure for conjugate heat transfer in flow network that takes into account the longitudinal conduction through the solid is presented. It uses a fully coupled approach in which the governing equations for solid and fluid are coupled through solid to fluid heat transfer that is expressed as a function of flow properties and temperature of solid. As an evaluation of the proposed technique, a chilldown problem for a cryogenic transfer line is formulated and solved. Test cases modeling transient flow of liquid hydrogen (LH2) and liquid nitrogen (LN2) under saturated and subcooled liquid conditions are presented. The effects of varying the inlet driving pressure on the chilldown time and flow rates have been evaluated. Increasing the driving pressure decreased the chilldown time and increased the flow rate. Subcooling the inlet cryogen further reduced the chilldown time. Numerical predictions are compared with available experimental data and are found to be in good agreement. The proposed model captures the essential features of conjugate heat transfer and provides an efficient and robust way for predicting chilldown of transfer line at a low computational cost.