流動過冷却水および水溶液の管内凍結発生限界に及ぼす諸因子の影響

Supercooling characteristics of water and water solution in a forced flow were investigated both experimentally and analytically. The critical conditions of ice nucleation in a cooled circular tube were examined for five sets of tube dimensions under various Reynolds numbers. It was found that the critical degree of supercooling based on the inner wall temperature was independent of Reynolds number in a laminar flow region. However, in a turbulent flow region, it decreased with increasing Reynolds number. An ice nucleation model for the flowing supercooled liquid was developed to predict the critical conditions of ice formation, in which the effects of the flow and temperature conditions, tube dimensions and solute mass fraction were taken into consideration. Nondimensional correlation equations for the critical condition of ice formation were derived in laminar and turbulent flow regions as a function of some nondimensional parameters obtained by analyzing the ice nucleation model.

近年、製氷方法の多様性、輸送性の良さ、融解時の高い負荷追従性の観点から、スラリー状氷に対する関心が増大している。スラリー状氷の有効な形成方法の一つとして、前報において報告した水あるいは水溶液の過冷却状態を利用する方法は、製氷装置も比較的簡単で、将来有望なスラリー状氷の製造方法となる可能性を秘めているが、流動状態にある水あるいは水溶液の過冷却現象に関して、その過冷却安定性および管内での過冷却状態の解消に伴う管内凍結発生条件に影響を及ぼす諸因子の影響について検討するものである。

本文データは学協会の許諾に基づきCiNiiから複製したものである