Enhanced heat transfer in ribbed ducts using vortex generators. Annual report, July 1991-June 1992
Local and average Nusselt number and overall pressure drop results were obtained experimentally for an air flow (Re = 3450) in a ribbed duct with vortex generators (circular rods) placed immediately above or just downstream of select rib elements. In virtually all cases, the presence of the generators led to increases in the average Nusselt number, Nu, and decreases in the entropy generation per unit duct length, S'. The largest generator-induced enhancement occurred for the largest dimensionless rib pitch (P/h = 38.4), where placing the largest diameter generators (d/h = 1.0) over every rib produced a 21-percent increase in Nu, and a 27-percent decrease in S'. For P/h = 19.2, the best performance corresponded to a 12-percent increase in Nu and a 9-percent decrease in S'. The local results demonstrated that the greatest generator-induced effect occurred behind the first generator, located at the entrance to the test section. Downstream, the generators typically had a minor impact on the local Nusselt number and frequently reduced the local Nusselt number.
- Research Organization:
- Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Mechanical Engineering
- OSTI ID:
- 7121718
- Report Number(s):
- PB-93-114320/XAB; CNN: GRI-5090-260-1961
- Resource Relation:
- Other Information: See also PB--92-190347
- Country of Publication:
- United States
- Language:
- English
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