Propagation of boiling fronts along horizontally arranged heated tubes

Citation
J. Mitrovic et J. Fauser, Propagation of boiling fronts along horizontally arranged heated tubes, CHEM ENG R, 79(A4), 2001, pp. 363-370
Citations number
23
Categorie Soggetti
Chemical Engineering
Journal title
CHEMICAL ENGINEERING RESEARCH & DESIGN
ISSN journal
02638762 → ACNP
Volume
79
Issue
A4
Year of publication
2001
Pages
363 - 370
Database
ISI
SICI code
0263-8762(200105)79:A4<363:POBFAH>2.0.ZU;2-G
Abstract
The behaviour of boiling fronts was studied experimentally, using pure liqu ids and their mixtures. The fronts are generated under isobaric conditions on the outer surface of a heated tube arranged horizontally in a liquid poo l. The tube surface was covered with different metallic coatings. Depending on wall superheat, slow or fast propagating fronts were observed. Slow fro nts, having Velocities up to 1 ms(-1), were established at low superheats. Their movement depends on liquid superheat, pressure and properties of the heating surface. Fast propagating fronts form above a particular superheat, independent of the characteristic of the heating surface. Their propagatio n velocity ranges up to 15 ms(-1). At the same superheat, boiling fronts ar e always slower in mixtures than in at least one of their components. Also, the minimum superheat required for generating fast fronts in mixtures is s hifted towards higher values. Both effects are mainly associated with mass transfer during phase transition.