Numerical analysis of turbulent flow and heat transfer in a square sectioned U-bend duct by elliptic-blending second moment closure

2007 ◽  
Vol 21 (2) ◽  
pp. 360-371 ◽  
Author(s):  
Jong-Keun Shin ◽  
Young-Don Choi ◽  
Jeong-Soo An
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Turbulent Flow ◽  
Moment Closure ◽  
Second Moment ◽  
Flow And Heat Transfer ◽  
Second Moment Closure

Computation of Flow and Heat Transfer in Two-Pass Channels With 60 deg Ribs

2001 ◽  
Vol 123 (3) ◽  
pp. 563-575 ◽  
Author(s):  
Yong-Jun Jang ◽  
Hamn-Ching Chen ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Moment Closure ◽  
Closure Model ◽  
Second Moment ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Sharp Turn ◽  
Second Moment Closure ◽  
Near Wall

Numerical predictions of three-dimensional flow and heat transfer are presented for a two-pass square channel with and without 60 deg angled parallel ribs. Square sectioned ribs were employed along one side surface. The rib height-to-hydraulic diameter ratio e/Dh is 0.125 and the rib pitch-to-height ratio (P/e) is 10. The computation results were compared with the experimental data of Ekkad and Han [1] at a Reynolds number (Re) of 30,000. A multi-block numerical method was used with a chimera domain decomposition technique. The finite analytic method solved the Reynolds-Averaged Navier Stokes equation in conjunction with a near-wall second-order Reynolds stress (second-moment) closure model, and a two-layer k-ε isotropic eddy viscosity model. Comparing the second-moment and two-layer calculations with the experimental data clearly demonstrated that the angled rib turbulators and the 180 deg sharp turn of the channel produced strong non-isotropic turbulence and heat fluxes, which significantly affected the flow fields and heat transfer coefficients. The near-wall second-moment closure model provides an improved heat transfer prediction in comparison with the k-ε model.

scholarly journals Computation of Flow and Heat Transfer in Rotating Two-Pass Square Channels by a Reynolds Stress Model

1999 ◽  
Author(s):  
Hamn-Ching Chen ◽  
Yong-Jun Jang ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Reynolds Stress ◽  
Stokes Equations ◽  
Secondary Flows ◽  
Moment Closure ◽  
Closure Model ◽  
Second Moment ◽  
Flow And Heat Transfer ◽  
Second Moment Closure ◽  
Near Wall

A multiblock numerical method has been employed for the calculation of three-dimensional flow and heat transfer in rotating two-pass square channels with smooth walls. The finite-analytic method solves Reynolds-Averaged Navier-Stokes equations in conjunction with a near-wall second-order Reynolds stress (second-moment) closure model and a two-layer k–ε isotropic eddy viscosity model. Comparison of second-moment and two-layer calculations with experimental data clearly demonstrate that the secondary flows in rotating two-pass channels have been strongly influenced by the Reynolds stress anisotropy resulting from the Coriolis and centrifugal buoyancy forces as well as the 180° wall curvatures. The near-wall second-moment closure model provides the most reliable heat transfer predictions which agree well with measured data.

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