scholarly journals Numerical Simulation of Turbulent Fluid Flow and Heat Transfer in a Ribbed Rotating Two-Pass Square Duct

2005 ◽  
Vol 2005 (2) ◽  
pp. 152-160 ◽  
Author(s):  
Tong-Miin Liou ◽  
Shih-Hui Chen ◽  
Yi-Chen Li
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Hydraulic Diameter ◽  
Mean Velocity ◽  
Square Duct ◽  
Turbulent Fluid Flow ◽  
Turbulent Fluid ◽  
Flow And Heat Transfer ◽  
Number Ratio

The local turbulent fluid flow and heat transfer in a rotating two-pass square duct with 19 pairs of in-line90∘ribs have been investigated computationally. A Reynolds-averaged Navier-Stokes equation (RANS) with a two-layerk−εturbulence model was solved. The in-line90∘ribs were arranged on the leading and trailing walls with rib height-to-hydraulic diameter ratio and pitch-to-height ratio of0.136and 10, respectively. The Reynolds number, based on duct hydraulic diameter and bulk mean velocity, was fixed at1.0×104whereas the rotational number varied from 0 to0.2. Results are validated with previous measured velocity field and heat transfer coefficient distributions. The validation shows that the effect of rotation on the passage-averaged Nusselt number ratio can be predicted reasonably well; nevertheless, the transverse mean velocity and, in turn, the distribution of regional-averaged Nusselt number ratio are markedly underpredicted in the regions toward which the Coriolis force is directed. Further CFD studies are needed.

Computation of Spatially Periodic Turbulent Fluid Flow and Heat Transfer in a Channel With Various Rib Shapes

1995 ◽  
Author(s):  
Tong-Miin Liou ◽  
Shih-Hui Chen
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Cross Sections ◽  
Hydraulic Diameter ◽  
Wall Region ◽  
Mean Velocity ◽  
Turbulent Fluid Flow ◽  
Turbulent Fluid ◽  
Flow And Heat Transfer ◽  
Spatially Periodic

Periodic fully developed turbulent fluid flow and heat transfer in a channel with four shapes, namely, triangular, semicircular, semielliptic, and square cross sections, of rib pairs periodically mounted on two opposite walls has been investigated computationally with a curvilinear nonorthogonal body-fitted coordinate system. The Reynolds number based on the channel hydraulic diameter and bulk mean velocity, the rib pitch-to-height ratio, and the rib height-to-channel hydraulic diameter ratio are 1.3×104, 10, and 0.08, respectively. The standard k-ε turbulence model together with the two-layer wall region treatment was applied to solve the accelerating, decelerating, separating, recirculating, reattaching and redeveloping flows. The predicted fluid flow and heat transfer results were tested by previous laser-Doppler and holographic interferometry data, and reasonable agreement was achieved. The two layer treatment shows a superiority to the conventional wall function in predicting near wall mean velocity and peak turbulent kinetic energy. Triangular-shaped rib is favorable for a compromise between the thermal performance and possible presence of hot spots.

Fluid Flow and Heat Transfer in a Rotating Two-Pass Square Duct With In-Line 90-deg Ribs

2002 ◽  
Vol 124 (2) ◽  
pp. 260-268 ◽  
Author(s):  
Tong-Miin Liou ◽  
Meng-Yu Chen ◽  
Meng-Hsiun Tsai
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Secondary Flow ◽  
Separation Bubble ◽  
Hydraulic Diameter ◽  
Duct Flow ◽  
Mean Velocity ◽  
Number Ratio ◽  
Sharp Turn

Laser-doppler velocimetry and transient thermochromic liquid crystal measurements are presented to understand local fluid flow and surface heat transfer distributions in a rotating ribbed duct with a 180 deg sharp turn. The in-line 90-deg ribs were arranged on the leading and trailing walls with rib height-to-hydraulic diameter ratio and pitch-to-height ratio of 0.136 and 10, respectively. The Reynolds number, based on duct hydraulic diameter and bulk mean velocity, was fixed at 1.0×104 whereas the rotational number varied from 0 to 0.2. Results are compared with those of the rotating smooth duct flow in terms of maximum streamwise mean velocities Umax/Ub and turbulence intensities u′max/Ub, skewness of mean velocity profiles, secondary flow pattern, turn-induced separation bubble, and turbulence anisotropy. Nusselt number ratio mappings are also provided on the leading and trailing walls. The relationships between the fluid flow and local heat transfer enhancement are also documented. It is found that the rotating ribbed duct flow provides higher Umax/Ub,u′max/Ub, and stronger total averaged secondary flow and, hence heat transfer is enhanced. Comparisons with heat transfer data published by other research groups are also made. Furthermore, simple linear correlations between regional averaged Nusselt number ratio and rotation number are developed.

Fluid Flow and Heat Transfer in a Rotating Two-Pass Square Duct With In-Line 90° Ribs

2001 ◽  
Author(s):  
Tong-Miin Liou ◽  
Meng-Yu Chen ◽  
Meng-Hsiun Tsai
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Fluid Flow ◽  
Secondary Flow ◽  
Separation Bubble ◽  
Hydraulic Diameter ◽  
Duct Flow ◽  
Mean Velocity ◽  
Number Ratio ◽  
Sharp Turn

Laser-Doppler velocimetry and transient thermochromic liquid crystal measurements are presented to understand local fluid flow and surface heat transfer distributions in a rotating ribbed duct with a 180° sharp turn. The in-line 90° ribs were arranged on the leading and trailing walls with rib height-to-hydraulic diameter ratio and pitch-to-height ratio of 0.136 and 10, respectively. The Reynolds number, based on duct hydraulic diameter and bulk mean velocity, was fixed at 1.0×104 whereas the rotational number varied from 0 to 0.2. Results are compared with those of the rotating smooth duct flow in terms of maximum streamwise mean velocities (Umax/Ub) and turbulence intensities (u′max/Ub), skewness of mean velocity profiles, secondary flow pattern, turn-induced separation bubble, and turbulence anisotropy. Nusselt number ratio mappings are also provided on the leading and trailing walls. The relationships between the fluid flow and local heat transfer enhancement are also documented. It is found that the rotating ribbed duct flow provides higher Umax/Ub, u′max/Ub, and stronger total averaged secondary flow and, hence heat transfer is enhanced. Comparisons with heat transfer data published by other research groups are also made. Furthermore, simple linear correlations between regional averaged Nusselt number ratio and rotation number are developed.

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