Quench Pool Boiling with Temporary Crystalline Enhancers

Abstract

In some industrial activities, the use of permanent heat transfer enhancements such as metal coating, pins, and grooves in cryogenic treatment is quite problematic. Such permanent heat transfer enhancers were replaced with temporary enhancers made of different crystalline materials, here focusing on NaCl, MgSO 4 ·7H 2 O, CaCl 2 ·2H 2 O, and C 6 H 5 Na 3 O 7 ·2H 2 O, which were used during quenching of the sample in the cryogenic liquid, i.e., nitrogen. The time required for sample cooling until the liquid nitrogen saturation temperature is reached decreases significantly when a crystalline coating is applied. The dependence of the cooling time on temporary coating creation parameters such as solution concentration, initial temperature of the sample, and solution spreading time is discussed.

Modification of pool boiling regimes by sand deposition

“…Nonmetallic coatings include fibrous materials, corundum (Al 2 O 3 ), nichrome (NiCr), and tetrafluoroethylene . We have previously proposed several methods for creating temporary intensifying heat exchange coatings based on frost obtained from moist air and crystallization of salts, which significantly increased the rate of heat transfer during boiling. At the same time, this possibility is also available with the use of hybrid intensifying surfaces that combine both a heat‐insulating layer and a structure of powder particles, which are additional boiling points.…”