Prediction of turbulent flow and heat transfer in channels with array of detached and alternative attached‐detached ribs

Abstract

Purpose

The purpose of this paper is to investigate turbulent fluid flow and heat transfer through passages with an array of either detached or alternative attached‐detached ribs of square cross‐section.

Design/methodology/approach

The finite‐volume method in a partially staggered grid system has been applied. For the modeling of turbulence, the zonal as well as the linear and non‐linear low‐Reynolds number k  −  ε models have been employed.

Findings

The numerical results show that the presence of the ribs produces a very complex flow in the channel. The mean flow predictions for the channel with detached ribs show that the low‐Re k  −  ε models are able to reproduce most of the experimentally observed flow features away from the ribbed wall, but return lower stream‐wise velocities close to the wall. Additionally, all low‐Re k  −  ε models underpredict the stream‐wise turbulence intensity whilst producing correct cross‐stream turbulence intensity levels close to the measured data. All three turbulence models fail to completely reproduce the distribution of Nusselt number. Among three turbulence models examined in this work, the zonal k  −  ε model produces the best heat transfer predictions.

Originality/value

The work contributes in understanding of the flow and thermal development in passages with detached ribs. The present set of 2D and steady heat and fluid flow comparisons establishes a base‐level for more realistic three‐dimensional and unsteady computations. The results of this study may be of interest to engineers attempting to re‐design the internal cooling system of gas turbine blades and to researchers interested in the turbulent flow‐modification aspects of heat transfer enhancement of forced convection in ribbed passages.

Citation

Raisee, M. and Rokhzadi, A. (2009), "Prediction of turbulent flow and heat transfer in channels with array of detached and alternative attached‐detached ribs", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 19 No. 3/4, pp. 266-284. https://doi.org/10.1108/09615530910938281