| Autor: |
Ravigururajan, T. S., Bergles, A. E. |
| Zdroj: |
Journal of Heat Transfer; May 1995, Vol. 117 Issue: 2 p276-282, 7p |
| Abstrakt: |
The paper presents the results of an experimental study that was carried out to determine the Prandtl number influence on the thermal-hydraulic performance of enhanced tubes. The enhanced tubes were identical in all aspects, except the roughness height. Emphasis was placed on turbulent flow, with water as the working fluid. Experiments were performed for Prandtl numbers from 10.2 to 5.8. Data for friction factor were obtained under both isothermal and heating conditions. The study confirmed the strong influence of rib roughness on heat transfer and pressure drop increase. In addition, the results of the investigation strongly suggest that the optimum roughness is application specific, because it is dependent on Reynolds and Prandtl numbers. The results show that the presence of entrance effects and the influence of temperature on the friction factor of enhanced tubes may be significant. The experiments show that a rib height-to-diameter ratio of 0.02 provides the best overall performance for water at Pr = 10; while at Pr = 6.0, the optimum e/d depends on the Reynolds number. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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