Solidification in heat packs: II. Role of cavitation

✍ Scribed by Mansel A. Rogerson; Silvana S. S. Cardoso

• Publisher: American Institute of Chemical Engineers
• Year: 2003
• Tongue: English
• Weight: 111 KB
• Volume: 49
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690490221

✦ Synopsis

Abstract

When the metallic trigger in a commercial heat pack is flexed to initiate solidification, the acceleration of the liquid near the solid surface can cause cavitation and collapse of small vapor bubbles. It is investigated whether such cavitation is responsible for the operation of the metallic trigger in the subcooled sodium acetate solution in a heat pack. Using cavity collapse theory and the results in Part I for the nucleation pressure of a sodium acetate solution, it is shown that cavitation can generate pressures greater than the nucleation pressure of the solution. However, the period of time during which the solution is exposed to such high pressure is not sufficient to lead to nucleation, and hence the metallic trigger does not induce solidification as a result of cavitation. Experimental results, using sonication, tribonucleation, and shock waves, confirm the theoretical findings.