Modelling of microwave heating of water in a monomode applicator – Influence of operating conditions

Robert Cherbański , Leszek Rudniak

Abstract

In this work, microwave induced natural convection in water was investigated experimentally and numerically. The modelling results showed that local overheatings (hot spots) are formed during microwave heating of water in a resonant microwave field. They are mainly localized in the axis of the heated liquid. As a result, natural convection develops which is chiefly induced in the strongest hot spot. The experimental and modelling approaches demonstrated that two characteristic periods can be distinguished in the time dependent temperature profiles of hot spots. While the microwave induced natural convection still develops in the first period of microwave heating, circulation of the liquid begins in the second. Moreover, it was shown that the deviation of only 5 MHz from the nominal frequency (2.45 GHz) changes the absorbed microwave power in water by about 20%. However, the simulated flow patterns at different microwave frequencies in the range between 2.4 and 2.5 GHz demonstrated that the primary circulation loop due to microwave induced convection has basically the same character – the upward direction in the axis of water and the downward direction near the PTFE cylinder wall. The obtained results also showed that the natural convection is not able to equalize the temperature over the entire volume of the liquid.
Author Robert Cherbański (FCPE / DPKT)
Robert Cherbański,,
- Department of Process Kinetics and Thermodynamics
, Leszek Rudniak (FCPE / DPKT)
Leszek Rudniak,,
- Department of Process Kinetics and Thermodynamics
Journal seriesInternational Journal of Thermal Sciences, ISSN 1290-0729
Issue year2013
Vol74
Pages214-229
Publication size in sheets0.75
Keywords in Englishmicrowave heating, maxwell’s equations, natural convection, modelling
ASJC Classification2200 General Engineering; 3104 Condensed Matter Physics
DOIDOI:10.1016/j.ijthermalsci.2013.07.001
URL http://www.sciencedirect.com/science/article/pii/S1290072913001579#
Languageen angielski
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Cherbański R., Rudniak L. - Modelling of microwave....pdf 4.46 MB
Score (nominal)45
Score sourcejournalList
ScoreMinisterial score = 45.0, 22-09-2020, ArticleFromJournal
Ministerial score (2013-2016) = 45.0, 22-09-2020, ArticleFromJournal
Publication indicators WoS Citations = 24; Scopus Citations = 24; GS Citations = 34.0; Scopus SNIP (Source Normalised Impact per Paper): 2013 = 2.254; WoS Impact Factor: 2013 = 2.563 (2) - 2013=2.732 (5)
Citation count*34 (2020-08-27)
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* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.
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