ITEMS

modern scholarly publishers in the finest tradition

Journals

	Search

Journal of Enhanced Heat Transfer

Theory and Application in High Performance Heat and Mass Transfer

ISSN for PRINT: 1065-5131

Institutional price:	$577.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2003, Volume10

126 pages

DOI: 10.1615/JEnhHeatTransf.v10.i2

Issue price - $138.00

Flow and Heat Transfer in a Rectangular Duct with Single Rib and Two Ribs Mounted on the Bottom Surface

Andallib Tariq
Department of Mechanical Engineering, IIT, Kanpur 208 016, India

Kamlesh Singh
Department of Mechanical Engineering, IIT, Kanpur 208 016, India

P. K. Panigrahi
Department of Mechanical Engineering, IIT, Kanpur 208 016, India

ABSTRACT

An experimental investigation of fluid flow and heat transfer for a single rib and two ribs mounted on the bottom surface of a rectangular channel at Re of 13,400, 22,600, and 32,100 has been carried out. The pitch-to-rib height ratio set during the experiment is equal to 10, and rib-height-to-hydraulic-diameter ratio is equal to 0.0624. The mean velocity and its fluctuations from hot-wire anemometry, mean temperature and its fluctuation from resistance thermometry and the surface Nusselt number from transient liquid crystal thermography are presented. The Nusselt number results obtained from the transient LCT analysis satisfy the energy balance check and correlate well with that from the law of the wall. No large-scale structures are observed in the spanwise direction near the reattachment region showing the overall two-dimensional nature of the flow. The temperature fluctuation has two peaks in the near-field region: one peak at similar cross-stream location to that of the velocity fluctuations and the other close to the wall. The velocity and temperature fluctuation have a flatter distribution in the far-field region than in the near-field region, indicating that turbulence production is important in the near-field region, while other mechanisms such as dissipation, convection, and diffusion predominate in the far-field region. The entropy generation calculation revealed that the two-rib case at Re = 32,100 is most advantageous from the thermodynamic point of view, with a 16% drop in entropy generation and a 47% heat transfer augmentation.