Detached Eddy Simulation of Turbulent Flow and Heat Transfer in a Ribbed Duct

2005 ◽  
Vol 127 (5) ◽  
pp. 888-896 ◽  
Author(s):  
Aroon K. Viswanathan ◽  
Danesh K. Tafti
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Flow Direction ◽  
Main Flow ◽  
Detached Eddy Simulation ◽  
Heat Transfer Characteristics ◽  
Eddy Simulation ◽  
Flow And Heat Transfer ◽  
Main Flow Direction ◽  
Key Features

Detached Eddy Simulation (DES) of a hydrodynamic and thermally developed turbulent flow is presented for a stationary duct with square ribs aligned normal to the main flow direction. The rib height to channel hydraulic diameter (e∕Dh) is 0.1, the rib pitch to rib height (P∕e) is 10 and the calculations have been carried out for a bulk Reynolds number of 20,000. DES calculations are carried out on a 963 grid, a 643 grid, and a 483 grid to study the effect of grid resolution. Based on the agreement with earlier LES computations, the 643 grid is observed to be suitable for the DES computation. DES and RANS calculations carried out on the 643 grid are compared to LES calculations on 963∕1283 grids and experimental measurements. The flow and heat transfer characteristics for the DES cases compare well with the LES results and the experiments. The average friction and the augmentation ratios are consistent with experimental results, predicting values within 10% of the measured quantities, at a cost lower than the LES calculations. RANS fails to capture some key features of the flow.

Detached Eddy Simulation of Turbulent Flow and Heat Transfer in a Ribbed Duct

2004 ◽  
Author(s):  
Aroon K. Viswanathan ◽  
Danesh K. Tafti
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Flow Direction ◽  
Main Flow ◽  
Detached Eddy Simulation ◽  
Heat Transfer Characteristics ◽  
Eddy Simulation ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Main Flow Direction

Numerical predictions of a hydrodynamic and thermally developed turbulent flow are presented for a stationary duct with square ribs aligned normal to the main flow direction. The rib height to channel hydraulic diameter (e/Dh) is 0.1, the rib pitch to rib height (P/e) is 10 and the calculations have been carried out for a bulk Reynolds number of 20,000. Detached Eddy Simulation (DES) has been used to compute the flowfield and the heat transfer. DES calculations are carried out on a 963 grid, a 643 grid and a 483 grid to study the effect of grid resolution. Based on the agreement with earlier LES computations and experimental data the 643 grid is observed to be suitable for the DES computation. DES and RANS calculations carried out on the 643 grid are compared to LES calculations on 963/1283 grids and experimental measurements. The flow and heat transfer characteristics for the DES cases compare well with the LES results and the experiments. The average friction and the augmentation ratios are consistent with experimental results, predicting values within 15% of the measured quantities, at a cost lower than the LES calculations. RANS fails to capture some key features of the flow.

Constrained large-eddy simulation of turbulent flow and heat transfer in a stationary ribbed duct

2016 ◽  
Vol 26 (3/4) ◽  
pp. 1069-1091 ◽  
Author(s):  
Zhou Jiang ◽  
Zuoli Xiao ◽  
Yipeng Shi ◽  
Shiyi Chen
Keyword(s):  
Heat Transfer ◽  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Thermodynamic Quantities ◽  
Detached Eddy Simulation ◽  
Square Duct ◽  
Content Type ◽  
Eddy Simulation ◽  
Flow And Heat Transfer ◽  
Large Eddy

Purpose – The knowledge about the heat transfer and flow field in the ribbed internal passage is particularly important in industrial and engineering applications. The purpose of this paper is to identify and analyze the performance of the constrained large-eddy simulation (CLES) method in predicting the fully developed turbulent flow and heat transfer in a stationary periodic square duct with two-side ribbed walls. Design/methodology/approach – The rib height-to-duct hydraulic diameter ratio is 0.1 and the rib pitch-to-height ratio is 9. The bulk Reynolds number is set to 30,000, and the bulk Mach number of the flow is chosen as 0.1 in order to keep the flow almost incompressible. The CLES calculated results are thoroughly assessed in comparison with the detached-eddy simulation (DES) and traditional large-eddy simulation (LES) methods in the light of the experimentally measured data. Findings – It is manifested that the CLES approach can predict both aerodynamic and thermodynamic quantities more accurately than the DES and traditional LES methods. Originality/value – This is the first time for the CLES method to be applied to simulation of heat and fluid flow in this widely used geometry.

Large Eddy Simulation of the 7-7-7 Shaped Film Cooling Hole at Axial and Compound Angle Orientations

2020 ◽  
Author(s):  
Kevin Tracy ◽  
Stephen P. Lynch
Keyword(s):  
Large Eddy Simulation ◽  
Film Cooling ◽  
Flow Direction ◽  
Main Flow ◽  
Blowing Ratio ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Cooling Hole ◽  
Main Flow Direction ◽  
Compound Angle

Abstract Shaped film cooling holes are used extensively for film cooling in gas turbines due to their superior performance in keeping coolant attached to the surface, relative to cylindrical holes. However, fewer studies have examined the impact of the orientation of the shaped hole axis relative to the main flow direction, known as a compound angle. A compound angle can occur intentionally due to manufacturing, or unintentionally due to changes in the main flow direction at off-design conditions. In either case, the compound angle causes the film cooling jet to roll up into a strong streamwise vortex that changes the lateral distribution of coolant, relative to the pair of vortices that develop from an axially oriented film cooling hole. In this study, Large Eddy Simulation (LES) using the Wall-Adapting Local Eddy Viscosity (WALE) model was performed on the publicly available 7-7-7 shaped film cooling hole, at two orientations (0°, 30°) and two blowing ratios (M = 1, 3). Laterally-averaged film effectiveness was largely unchanged by a compound angle at a blowing ratio of 1, but improved at a blowing ratio of 3. For both blowing ratios, the lateral distribution of film was more uniform with the addition of a 30° compound angle. Both wall normal and lateral turbulent convective heat transfer was increased by the addition of a compound angle at both blowing ratios.

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