Heat Transfer Research

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Film-Boiling Heat Transfer of Liquid Nitrogen and Hydrogen in Tubes at Large Liquid Subcoolings

G. A. Dreitser
Moscow Aviation Institute (Technical University), 4 Volokolamskoye shosse, Moscow, 1125993, Russia

V. P. Firsov
Moscow Aviation Institute (Technical University), Moscow, Russia

I. V. Antyukhov
Moscow Aviation Institute (Technical University), Moscow, Russia

A. A. Kurilenko
Moscow Aviation Institute (Technical University), Moscow, Russia

ABSTRACT

The results of experimental investigation of film boiling of liquid nitrogen in vertical tubes of a diameter of 9.7 mm and 20 mm and liquid hydrogen in tubes of a diameter of 70 mm are presented. The experiments were carried out under the conditions of unsteady cooling of the test section in the range of variation of mass flow velocity from 500 to 15,000 kg/(m²·sec), pressure form 5 to 20 bars, dimensionless liquid subcooling from 0.05 to 0.6, and wall temperature from 200 to 900 K. It is shown that under the conditions of large subcoolings of liquids the slug annular vapor–liquid regime is realized and the existence of two basic regimes of heat transfer is possible: self-similar and non-self-similar with respect to the temperature of a heat-transfer surface. The generalizing dependences on heat transfer in slug self-similar annular film boiling regime of liquid nitrogen and hydrogen are obtained.