Теплова ефективність ребер різного типу за наявності покриттів на теплообмінній поверхні

Authors

  • В. Г. Горобець

Abstract

UDC 536.24

THERMAL EFFICIENCY OF FINS DIFFERENT TYPE WITH COATING ON HEAT TRANSFER SURFACES

V. Gorobets

In the operation of finned heat exchangers on the finned surface can form contaminating deposits which reduce of heat efficiency for heat exchangers. When heat exchangers are in exploitation for condition chemically aggressive environments heat exchange surface can be protected from destruction layer of protective coating. Most of the contaminating deposits or protective coatings have low thermal conductivity.

The influence of deposits (coating) in engineering methods of thermal calculation into account as an additional thermal resistance for finned surface. This approach is generally based on operational studies and observations of heat and mass transfer process on the finned surface, accompanied by deteriorating thermal efficiency of heat exchangers. This approach allows take into account the influence of deposits in determining the total heat exchange surface area and size of heat exchanger during its construction, but makes it impossible to examine the influence of deposits on heat transfer conditions in the advanced surface coating and make the right choices the optimal size of fins.

Conducted several authors to study the conditions of heat transfer to the composite fins was  showed, that the presence of deposition or coating with low thermal conductivity on the developed surface leads to a significant adjustment of temperature fields which can vary substantially from temperature distributions for the surface of fins without coverage. For this reason, the optimal size of finned surfaces may differ from similar size calculated to "clean" fins.

In this work there are obtain two-dimensional solutions of heat transfer and thermal efficiency for longitudinal fins, circular fins and round ribs in the presence of uniform coating on their surface. The influence of shape of fins for thermal efficiency of fins with coating and compared the results to calculate for finned surfaces and the "clean" fins was performed.  In work been found that coating with low thermal conductivity ceteris paribus has the greatest effect on the thermal efficiency for circular fins, and the least - for the longitudinal fins.

References

Керн Д. Развитые поверхности теплообмена / Д. Керн, А. Краус. − М. : Энергия, 1977. − 452 с.

Barker J.J. The efficiency of the composite fins / J.J. Barker // Nucl. Sci. Eng. − 1958.− V. 3.− Р. 300−312.

Feijoo I. Heat transfer in the composite solids with heat generations / I. Feijoo, H.T. Davis, D. Ramkrishna // J. Heat Transfer. − 1979.− V. 101.− Р. 137−143.

Huang S.C. Heat conduction in unsteady, periodic, and steady state in laminated composites / S.C. Huang, Y.P. Chang // J. Heat Transfer. – 1980. − V. 102. − Р. 742−748.

Горобец В. Г. Влияние отложений прямоугольного профиля на тепловую эффективность продольного ребра / В. Г. Горобец, Н. В. Зозуля, В. С. Новиков // ?нженерно-физический журнал. – 1982. − Т. 42, № 6. − С. 820−824.

Chu H. Transient response of a composite straight fin / H. Chu, C. Weng, C. Chen // J. Heat Transfer. − 1983. − V. 105. − Р. 307−311.

Ghoshdastidar P.S. Transient heat transfer from a straight composite fin; f numerical solution by ADI / P.S. Ghoshdastidar, A. Mukhopadhyay // Int. Comm. Heat Mass Transfer. − 1989. − V. 19. − P. 257.

Mokheimer E.M.A. Analytical and numerical solution along with PC spread-sheets modeling for a composite fin / E/M/A/ Mokheimer, M.A. Antar, J. Farooqi, S.M. Zurair // Heat Mass Transfer. − 1997. − V. 32. − Р. 229−238.

Lalot S. Fin efficiency of annular fins made of two materials / S. Lalot, C. Tournier, V. Jensen // Int. Journ. Heat Mass Transfer. − 1999. − V. 42, N18. − P. 3461−3468.

Xia Y. An exact solution to steady heat condition in a two-dimensional slab on a one-dimensional fin: application to frosted heat exchangers / Y. Xia, A.M. Jacobi // Int. J. Heat Mass Transfer − 2004. − V. 47. − Р. 3317−3326.

Кошляков ?. С. Уравнения в частных производных математической физики / ?.С. Кошляков, Э. Б. Глинер, М. М. Смирнов − М. : Высшая школа, 1970. – 707 с.

Downloads

Published

2017-02-24

Issue

No. 242 (2016)

Section

Статті

License

Relationship between right holders and users shall be governed by the terms of the license Creative Commons  Attribution – non-commercial – Distribution On Same Conditions 4.0 international (CC BY-NC-SA 4.0):https://creativecommons.org/licenses/by-nc-sa/4.0/deed.uk

Authors who publish with this journal agree to the following terms:

  • Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
  • Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
  • Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).