Combined Buoyancy and Flow Direction Effects on Saturated Boiling Critical Heat Flux in Liquid Nitrogen

Abstract

It is well known that the maximum heat flux possible for a nucleate-boiling internal flow system may be markedly influenced by the various system parameters. A good analysis and literature review of this critical heat flux problem is presented by Tong [¹], with emphasis on the importance of each individual parameter. In his discussion, he includes flow direction with respect to the gravity force as a possible significant parameter but then reports this to be insignificant by referring to Barnett [²]. The latter conducted tests at pressures of 37.9 and 136.0 atm with a water flow system and reported no effect of flow direction on the boiling crisis. However, Macbeth [³] and Papell et al. [⁴] have reported the existence of gravity-directed effects.