Laminar heat transfer in an externally finned circular tube
Abstract
An analysis has been carried out for laminar heat transfer in a circular tube subjected to an axially periodic variation of the external heat transfer coefficient. This thermal boundary condition serves to model flow in a tube fitted with a regularly spaced array of annular fins. It was found from numerical solutions that external finning yields substantial heat transfer enhancement compared with an unfinned tube, especially when the Biot number of the unfinned tube is low. The degree of enhancement is insensitive to the period of the Biot number variation provided that the overall proportions of the unfinned and finned surface are maintained and the Biot number level is also maintained. A constant-Biot-number model intended to approximate the heat transfer results for the periodic-Biot-number case was devised and tested; the predictions of this simplified model are especially accurate at low Biot numbers. The results of the laminar flow analysis have suggested ways of modeling turbulent heat transfer in externally finned tubes.
- Publication:
-
ASME Journal of Heat Transfer
- Pub Date:
- November 1980
- Bibcode:
- 1980ATJHT.102..605S
- Keywords:
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- Circular Tubes;
- Cooling Fins;
- Finned Bodies;
- Laminar Heat Transfer;
- Numerical Flow Visualization;
- Pipe Flow;
- Biot Method;
- Heat Transfer Coefficients;
- Periodic Variations;
- Temperature Distribution;
- Fluid Mechanics and Heat Transfer