JP Journal of Heat and Mass Transfer
Volume 2, Issue 3, Pages 279 - 302
(October 2008)
|
|
NUMERICAL STUDY OF CONJUGATE HEAT TRANSFER IN A TUBE WITH TWISTED TAPE INSERT
Zhi-Min Lin (P. R. China), Shuai Teng (P. R. China) and Liang-Bi Wang (P. R. China)
|
Abstract: In the cases of reported analytical and numerical studies on heat transfer in a tube fitted with twisted tape, the thermal boundary condition on twisted tape surface is treated with some ideal and/or unrealistic assumptions resulting in the physical model an oversimplified situation. In this paper numerical studies on coupled conductive and convective heat transfer in a circular tube with twisted tape are performed, the fin contribution to heat transfer is analysed quantitatively. The numerical results are compared with available correlations obtained by experiments. The results reveal that the numerical method used in this paper can efficiently get the reliable results of fluid flow, but for heat transfer reliable results can be obtained only within certain Reynolds number region and with appropriate treatment of thermal boundary condition of the tape; thermal boundary condition treatment of the tape has very large effects on the numerical results, especially for isothermal and adiabatic treatments of thermal boundary of the tape, numerical results have very large difference from experimental ones; the fin contribution to heat transfer is mainly determined by fitness of the tape to tube, the fin contribution cannot be negligible even though the tape does not “perfectly” contact with the tube wall in the present studied cases; and the fin contribution does not increase with the increase of the tape thickness when the thickness reaches certain value. |
Keywords and phrases: conjugated heat transfer, heat transfer enhancement, secondary flow, twisted tape, numerical analysis. |
|
Number of Downloads: 239 | Number of Views: 680 |
|