HEAT TRANSFER CHARACTERISTICS OF SLUSH NITROGEN IN TURBULENT PIPE FLOWS

• Published in: Advances in Cryogenic Engineering; Volume 53B 2008-01, Vol.53B (985), p.1141-1150
• Main Authors: Ohira, K, Ishimoto, J, Nozawa, M, Kura, T, Takahashi, N
• Format: Article
• Language: English
• ISSN: 0094-243X
• DOI: 10.1063/1.2908465

Slush fluids, such as slush hydrogen and slush nitrogen, are two-phase (solid-liquid) single-component cryogenic fluids containing solid particles in a liquid, and consequently their density and refrigerant capacity are greater than for liquid state fluid alone. This paper reports on the experimental results of the forced convection heat transfer characteristics of slush nitrogen flowing in a pipe. Heat was supplied to slush nitrogen by a heater wound around the copper pipe wall. The local heat transfer coefficient was measured in conjunction with changes in the velocity and the solid fraction. The differences in heat transfer characteristics between two-phase slush and single phase liquid nitrogen were obtained, and the decrease in heat transfer to slush nitrogen caused by the previously observed pressure drop reduction was confirmed by this study. Furthermore, for the purpose of establishing the thermal design criteria for slush nitrogen in the case of pressure drop reduction, the heat transfer correlation between the experimental results and the Sieder-Tate Equation was obtained.