Numerical investigation of turbulent heat transfer in channels with detached rib‐arrays

A numerical investigation is conducted to analyze the flow‐field and heat transfer characteristics in a rectangular passage of width‐to‐height ratio of 6:1 with detached ribs on one wall, where constant wall temperature condition is applied. The effect of detached‐rib geometry on heat transfer coefficient, friction factor, and thermal enhancement factor is investigated covering the range of the detached‐clearance ratios (c/a) of 0.1, 0.2, 0.3, and 0.4, the Reynolds number based on the channel hydraulic diameter ranges from 8000 to 24,000. The numerical results show that the flow‐field, temperature pattern, local Nusselt number distribution, average Nusselt number, and friction factor are strongly dependent on the detached‐clearance ratios. The thermal enhancement factor (TEF) under the same pumping power constraint is calculated in order to examine the overall effect of the detached‐clearance ratio. For the present range investigated, the maximum TEF of 1.22 is achieved by the use of the ribs with c/a of 0.1 at Reynolds number of 8000. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20357