Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

V. G. Gorobets
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine

Influence of coatings (deposits) on thermal characteristics and the optimum sizes of fins of various type (longitudinal and circular fins, round pins) are investigated. Two dimensional and simplified decisions of problem heat transfer are received and heat efficiency of the longitudinal fins, circular fins and round pins is certain. Comparison of decisions of a problem heat transfer for circular fins with a uniform coating with application of the simplified procedure and two dimensional decisions is lead. The errors supposed at use of approached design procedures are obtained. It is studied influence of geometrical form of fins for them heat transmission. The optimum sizes of fins with coatings are found. It is shown, that the optimum sizes of fins with a coating depend on Biot number of a coating, grow with increase of this number and can considerably differ from the optimum sizes of "clean" fins considerably. Influence of non-uniformity of polluting deposits on heat transfer, thermal efficiency and the optimum sizes of longitudinal fins is studied. Correction factors which are taken into account by this influencing are certain. For tubes witch disposed in chess bunch with external longitudinal fins at presence uniform coatings with a low heat conductivity the problem conjugate heat transfer with application of integral methods is solved. It is carry out comparison of the decisions of conjugated heat transfer model and simplified models no considering influence non isothermal of a surface or using average heat transfer coefficient. Significant qualitative and qualitative differences for local heat transfer characteristics of fins finding in the conjugated and simplified models are received.

HTE-14 pages DOI: 10.1615/IHTC13.p17.140 Download article

Article price - $35.00

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