Surface curvature effects on flow and heat transfer from a round impinging jet
- Inje Univ., Kyungnam (Korea, Republic of). Dept. of Mechanical Engineering
- Pusan National Univ. (Korea, Republic of). Research Inst. of Mechanical Technology
Effects of the hemispherically convex surface curvature on the local heat transfer from a round impinging jet were experimentally investigated. The flow at the nozzle exit has a fully developed velocity profile. The jet Reynolds number (Re) ranges from 11,000 to 50,000, the nozzle-to-surface distance (L/d) from 2 to 10, and the hemisphere-to-nozzle diameter ratio (D/d) from 11.2 to 29.3. The results show that the stagnation point Nusselt number (Nu{sub st}) increases with increasing curvature (i.e., decreasing value of D/d). The maximum Nusselt number at the stagnation point occurs at L/d {approx_equal} 6 to 8 for all Re`s and D/d`s tested. Nu{sub st} are well correlated with Re, L/d, and D/d. For larger L/d, Nu{sub st} dependency on Re is stronger due to an increase of turbulence in the approaching jet as a result of the more active exchange of momentum with a surrounding air. The local Nusselt number decreases monotonically from its maximum value at the stagnation point. However, for L/d = 2 and Re = 23,000, and for L/d {le} 4 and Re = 50,000, the streamwise Nusselt number distributions exhibit secondary maxima at r/d {approx_equal} 2.2.
- Sponsoring Organization:
- Korea Science and Engineering Foundation (Korea, Republic of)
- OSTI ID:
- 428137
- Report Number(s):
- CONF-960815--; ISBN 0-7918-1506-4
- Country of Publication:
- United States
- Language:
- English
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