Measurement of detailed heat transfer along rib-roughened surface under arrays of impinging elliptic jets

• Published in: International journal of heat and mass transfer 2006, Vol.49 (1), p.159-170
• Main Authors: Yan, W.M., Mei, S.C.
• Format: Article
• Language: English
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Heat transfer; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Jets; Physics; Theoretical studies. Data and constants. Metering; Thermal instruments, apparatus and techniques; Thermometry; Turbulent flows, convection, and heat transfer
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2005.07.043

The objective of the present study is to examine the detailed heat transfer coefficient distributions over a ribbed-surface under impingement of elliptic jet arrays using a liquid crystal thermograph technique. Both continuous and broken V-shaped-rib configurations with different exit flow orientations were considered. To examine the angled rib effects, three angled ribs were discussed under jet-to-plate spacing Z = 3 for different Reynolds numbers. Measured results show that the local heat transfer rates over the ribbed-surface are characterized by obvious periodic-type variation of Nusselt number distributions. The downstream peaks are diminished for increasing crossflow effect. Compared to the results without ribs, the heat transfer over the ribbed-surface may be enhanced or retarded. Whereas, among the test angled-rib arrangements, the best heat transfer performance is obtained with a surface with 45° V-shape ribs. In addition, the surface with continuous ribs provides a better impingement heat transfer than that with broken ribs.