Paper Title
Investigations On The Effect Of Helix Angle On The Transient Chill Down Of Helically Coiled Liquid Nitrogen Transfer Lines

Chill down in helical transfer lines were investigated using validated computational fluid dynamics code. Mass of fluid required and the time taken to completely chill down 4 helical transfer lines with different helix angles, at constant heat flux, were compared in this study. Important flow parameters for multiphase system such as volume fraction, liquid velocity, and temperature distribution were plotted and displayed. The measurement of two phase flow parameters like volume fraction of the fluid has given more insight into the much complicated chill down process. It was found that centrifugal forces due to shape of helical transfer lines play an important role in the phase, and temperature distribution in helical pipes. It was also observed that the mass of fluid used and time taken for complete chill down of helical transfer lines were much smaller as opposed to a straight transfer line. Among the various helix angled helical transfer lines, it was observed that as helix angle increases chill down time decreases. Keywords- Chill down, Liquid Nitrogen, CFD analysis, Cryogenics, Helical Transfer lines, Two Phase flow.