Heat transfer from liquid nitrogen flows in smooth pipes

Proceedings of the 14th International Heat Transfer Conference IHTC14 August 8-13, 23010, Washington, DC, USA The two-phase flow of liquid nitrogen in a horizontal test section (13 mm inner diameter) is studied experimentally for total mass flow rates ranging from 20 g/s to 35 g/s. Local temperature fluctuations of the outer surface of the pipe are used to characterise the two-phase flow pattern inside. To investigate the effects of a heatin leak through the supports of a real pipeline, the effect of a local heat source placed on the bottom of the test section is also studied, for thermal powers in the range between 3 and 15 W. The results show that temperature measurements allow the automatic detection of flow patterns inside the pipe; furthermore, they can be used to find the position of heat-in leaks through supports in real pipelines, and deduce some dynamic features of liquid nitrogen boiling flow.