Number：

04095018

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Name：

林金標

Titles：

Lecturer

Author：

Sheng-Chung Tzeng , Tzer-Ming Jeng , Jing-Piao Lin , Yen-Chan Wang

Paper name：

Heat transfer Enhancement in the Annulus with an Inner Rotating Rib-Roughness Cylinder

Name of activity：

第五屆精密機械與製造技術研討會論文集

Keywords：heat transfer、rotating cylinder、rib-roughness、Taylor number

Abstract：This work experimentally investigates the heat transfer characteristics in the annulus with an inner rotating rib-roughness cylinder, whose flow and thermal behaviors are associated with Taylor number (Ta) and centrifugal buoyancy parameter (GrΩ). The operating range of Ta is from 1.47x103 to 5.80x105 , while the surface of the inner cylinder is heated up with several constant heat fluxes (279, 425 and 597 W/m2) to obtain various values of GrΩ.Besides, three modes of the inner cylinder without/with longitudinal ribs are considered. The end of the annular channel is connected to a side chamber to fit practical applications (such as in the rotary blade coupling of a four-wheel-drive vehicle). The experimental results show that the average Nusselt number (Nu) was almost constant at low Ta, but increased rapidly with Ta when Ta exceeded some critical value (3000~5200 for present study). Additionally, the GrΩ effect on the heat transfer was negligible herein. Furthermore, by comparing with the inner cylinder without longitudinal ribs, stalling ribs on the inner cylinder without longitudinal ribs, stalling ribs on the inner cylinder increases the transport of heat by a factor of 1.22 at 105<Ta<106 , and embedding cavities into the ribs increases the transport of heat by a factor of 1.16 at 105<Ta<106 . Finally, the relationships between the Nu and the Ta for various modes of test sections were proposed.

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