Experimental study on chill-down process of horizontal exit-contracted pipe with smooth inner wall

Abstract

Different from cases of transfer pipes, when cryogenic fluid flows into an exit-contracted pipe, boiling pattern does not develop in a spatially non-sequential manner. This experimental study investigates the LOX chill-down process through a horizontal exit-contracted pipe with smooth inner wall with a wide condition of steady pressure ranging from 0.52 to 3.52 MPa and steady mass flow rate from 0.126 to 0.766 kg/s. The development of physical parameters and transition of the boiling patterns during the chill-down process are discussed respectively. The entire process of chill-down process is reconstructed through the inversed parameters, vapor film thickness and flow pattern diagrams comprehensively. The conclusion indicates that three QF modes are summarized and analysis is presented on the effect of pressure and mass flow rate.