Numerical Study of Cryogenic Transfer Line Under Conjugate Conditions

Conjugate heat transfer plays a vital role in a thermal system, which can alter the actual thermal condition at the solid–fluid interface. Thus, it can affect the thermal performance of a thermal system. Because of this, a three-dimensional numerical study of the cryogenic transfer line is undertaken where the transfer line is subjected to constant heat flux on the outer walls of the transfer line. The fluid and inner wall temperatures are evaluated at various axial positions of the model to monitor the chill down process by varying flow Reynolds number (Re ~ 200–1000). A comparative study is presented on the cold insulation materials with different grades of pipe materials for variable pipe wall to fluid thermal conductivity ratios (ksf ~ 88.95 – 2722.72) to determine whether a particular pipe material is suitable or not, as well as the existence of axial wall conduction. Based on the outcome of the study, the effectiveness of thermal stability is validated: When Re is increased, the temperature at the outflow ranges from 78 to 83 K. For a specific value of ksf, there is an excellent value of the average Nusselt number that reduces the presence of axial wall conduction. It is revealed that when working fluid flow Re increases, the average Nu increases due to longer thermal development length with varying thermal conductivity of materials.