Mixed convection flow and heat transfer in entrance region of rectangular ducts rotating about a parallel axis
- Chung Cheng Inst. of Tech., Taoyuan (Taiwan, Province of China). Dept. of Aeronautical Engineering
- Hua Fan Coll. of Humanities and Technology, Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering
The objective of the present work is to investigate the laminar mixed convection flow and heat transfer in the entrance region of heated rectangular ducts rotating about a parallel axis. Heating conditions of isothermal and iso-flux are both considered. Boussinesq approximation is invoked to take into account buoyancy effect induced by centrifugal force. Navier-Stokes/Boussinesq system can be cast into a dimensionless form, in which five governing parameters, the Prandtl number Pr, rotational Reynolds number J, rotational Grashof number Gr{sub {Omega}}, aspect ratio {gamma} and the eccentricity E, are involved. Mechanisms of secondary vortex development in the ducts are explored by a theoretical analysis on vorticity transport equation. The values of Pr and E are fixed as 0.7 and 10, respectively. For various combinations of the other thee parameters, a vorticity-velocity method implemented with a marching technique is employed to solve the resultant three-dimensional system for simultaneously developing flow and temperature fields. The emphasis is placed on the rotational effects, including both coriolis force and centrifugal buoyancy; on the non-isothermal flow and the related heat transfer. The results reveal that the friction factors and heat transfer rates can be enhanced by Coriolis and rotation-induced buoyancy effects; and the variations of the local values are closely related to the evolution of the secondary vortices in ducts. The differences in flow behaviors and thermal characteristics for UWT and UHF are also investigated by the present theoretical analysis on secondary flow mechanism as well as the computational results.
- Sponsoring Organization:
- National Science Council, Taipei (Taiwan, Province of China)
- OSTI ID:
- 458431
- Report Number(s):
- CONF-951135-; ISBN 0-7918-1751-2; TRN: IM9717%%217
- Resource Relation:
- Conference: 1995 International mechanical engineering congress and exhibition, San Francisco, CA (United States), 12-17 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Proceedings of the ASME Heat Transfer Division. Volume 1: Benchmark problems of heat transfer analysis programs; High heat flux thermal management; Modeling of heat transfer in multi-phase systems; Natural and mixed convection; Numerical methods in heat exchanger design; HTD-Volume 317-1; Cochran, R.J.; Hogan, R.E. [eds.] [Sandia National Lab., Albuquerque, NM (United States). Engineering Sciences Center]; Khounsary, A.M. [ed.] [Argonne National Lab., IL (United States)] [and others]; PB: 484 p.
- Country of Publication:
- United States
- Language:
- English
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