A numerical investigation of heat transfer in a smooth bend part of a U-duct
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 1 January 2014
Abstract
Purpose
The aim of this paper is to study two-dimensional numerical simulations of the flow and temperature fields inside the bend (turn) part of a U-duct.
Design/methodology/approach
Several turbulence models based on two and five equations were used to solve the momentum and energy equations inside the bend (turn) part of the U-duct. For two-equation models, both the renormalization group and realizable k-ɛ turbulence models were implemented. The five-equation model used is a Reynolds stress model with different wall boundary conditions. Standard, non-equilibrium and enhanced wall functions were used in parallel with the two- and five-equation models to treat the turbulent flow near the duct walls.
Findings
Several turbulence models were used to simulate the flow and temperature fields along the bend part of a U-duct with different inlet and thermal boundary conditions. The numerical results indicate that the renormalization and realizable k-ɛ turbulence models with standard wall function treatment gave the best results when compared with experimental data obtained for similar conditions.
Research limitations/implications
For heat transfer analysis, two different thermal boundary conditions, i.e. constant wall temperature and constant heat flux at the wall are implemented. The results are calculated for Reynolds number equal 20,000.
Practical implications
The results can be used in designing heat exchangers, piping and duct systems, and internal passage cooling of gas turbine blades.
Originality/value
The numerical results obtained here concentrate on the detailed investigation of flow and temperature field at the outer wall of the bend part. Different boundary conditions at the inlet and the outer bend walls of the U-duct were applied to study how these boundary conditions affect the flow and temperature fields.
Keywords
Acknowledgements
Financial support has been received by the Erasmus Mundus Windows Programme and the Swedish Energy Agency.
Citation
Salameh, T. and Sunden, B. (2014), "A numerical investigation of heat transfer in a smooth bend part of a U-duct", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 24 No. 1, pp. 137-147. https://doi.org/10.1108/HFF-03-2012-0066
Publisher
:Emerald Group Publishing Limited
Copyright © 2014, Emerald Group Publishing Limited