Heat exchange with film boiling of nitrogen at the surface of solution droplets

• Published in: Chemical and petroleum engineering Vol. 44; no. 3-4; pp. 138 - 142
• Main Authors: Onopko, K. D., Platov, I. V., Trutnev, N. S.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.03.2008
• Subjects: Chemistry; Chemistry and Materials Science; Density; Droplets; Geotechnical Engineering & Applied Earth Sciences; Granular materials; Heat transfer coefficients; Industrial Chemistry/Chemical Engineering; Industrial Pollution Prevention; Liquids; Melts; Mineral Resources; Nanomaterials; Petroleum engineering; Cool Agent; Vapor Film; Heat Transfer Coefficient; Nanocrystalline Powder; Molten Droplet
• ISSN: 0009-2355; 1573-8329
• DOI: 10.1007/s10556-008-9025-7

A cryochemical method is considered for preparing nanomaterials, i.e., cryochemical synthesis of nanocrystalline powders, an important stage of which is rapid freezing of a solution droplet. A procedure is proposed for determining the heat transfer coefficient in a test unit during droplet solidification (in the period of forming a solid granule from a molten droplet or a melt with cryogenic liquid). It is noted that the central immersion angle for a droplet θ has a weak effect on heat transfer: within the limits from θ to π /2 to π the heat transfer coefficient does not change by more than 40%. It is also shown that there is no marked effect on the heat transfer coefficient of parameter β , i.e., the ratio of densities for the droplet and cooling agent (within the limits 1.24 ≤ β ≤ 2.0).