A film boiling model for cryogenic chilldown at low mass flux inside a horizontal pipeline

A film boiling heat transfer model is developed for cryogenic chilldown at low mass flux inside a horizontal pipeline. It incorporates the stratified flow structure and is based on conservation principles of mass, momentum, and energy. Simplifying assumptions lead to an expression for the local film boiling heat transfer coefficient which varies with the azimuthal angle. The efficacy of the model is assessed by comparing the predicted wall temperature histories with those measured at several azimuthal positions and various mass fluxes. Good agreement is observed at low flux, G = 13–54 kg/m² s.