Natural convection heat transfer along a vertical flat plate with a projection in the turbulent region

✍ Scribed by Katsuo Komori; Shunsuke Kito; Terumi Inagaki; Norio Mizoguchi

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 290 KB
• Volume: 30
• Category: Article
• ISSN: 1099-2871
• DOI: 10.1002/htj.1012

✦ Synopsis

Abstract

In the present study, the heat transfer coefficients occurring with a projection in the turbulent region of a vertical flat plate were measured experimentally for various projection heights in the range of 0 to 20 mm. The wall temperature and fluid flow fields were also visualized using a liquid crystal sheet and nylon 12 powder, respectively. The average and local Nusselt numbers reach 1.07 to 1.22 and 1.2 to 1.7 times those for pure turbulent natural convection, respectively. The maximum enhancement rates of heat transfer are attained at a position of 2.3 to 3.3 times the projection height from the upper projection surface toward the downstream, and these positions are in good agreement with those of the reattachment of the fluid flow and with centers of dark red regions in the liquid crystal. On the other hand, the heat transfer coefficients in the just upstream and downstream regions of the projection are small compared with those for no projection. By introducing the nondimensional parameter R, the present experimental results are rearranged quantitatively and effectively. © 2001 Scripta Technica, Heat Trans Asian Res, 30(3): 222–233, 2001