Turbulent flow and heat transfer measurements on a curved surface with a fully developed round impinging jet

✍ Scribed by D.H. Lee; Y.S. Chung; D.S. Kim

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 804 KB
• Volume: 18
• Category: Article
• ISSN: 0142-727X
• DOI: 10.1016/s0142-727x(96)00136-1

✦ Synopsis

The effects of the convex surface curvature on the local heat transfer from an axisymmetric impinging jet were 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 dimensionless nozzle-to-surface distance (L/d) from 2 to 10, and the dimensionless surface curvature (d/D) from 0.034 to 0.089. The results show that the stagnation point Nusselt number (Nust) increases with increasing value of d/D. The maximum Nusselt number at the stagnation point occurs at Lid = 6 to 8 for all Res and d/Ds tested. Both the stagnation point and the average Nusselt number over the curved surface are well correlated with Re, L/d, and diD. For larger L/d, Nust dependency on Re is stronger because of 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_< 4 and Re=50,O00, the streamwise Nusselt number distributions exhibit secondary maxima at r/d ~-2.2.