Large Eddy Simulation of Film Cooling with Forward Expansion Hole: Comparative Study with LES and RANS Simulations
Abstract
:1. Introduction
2. Geometry and Boundary Conditions
3. Validation of Numerical Methods
4. Results and Discussion
4.1. Contours of Time-Averaged η
4.2. Time-Averaged Film Cooling Effectiveness
4.3. Contours of Instantaneous Film Cooling Effectiveness on Wall
4.4. Contours of Velocity Fluctuation on Streamwise-Normal Plane
4.5. Contours of Temperature Fluctuations on Streamwise-Normal Plane
4.6. Time-Averaged Velocity Magnitude Contours in Hole
4.7. Mean Dimensionless Temperature Contours at Hole Exit
5. Conclusions
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
Nomenclature
D | diameter of lower hole |
L | hole length |
M | Blowing ratio = |
P | pitch between holes |
t | time |
Adiabatic wall temperature | |
Temperature of mainstream gas | |
U | Mean velocity |
injectant velocity | |
mainstream velocity | |
Greek Symbols | |
α | injection angle |
β = | compound angle (spanwise injection angle) |
Θ | dimensionless temperature |
adiabatic film cooling effectiveness | |
centerline film cooling effectiveness | |
lateral-averaged film cooling effectiveness | |
ρ | density |
injectant density | |
mainstream density | |
Subscripts | |
C | coolant |
aw | adiabatic wall |
m | lateral-averaged |
Abbreviations | |
LES | Large Eddy Simulation |
RANS | Reynolds-Averaged Navier–Stokes |
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Surface | Boundary Condition |
---|---|
Main inlet | Velocity inlet (u = constant) |
Plenum inlet | Velocity inlet (u = constant) |
Top | Symmetry () |
Test plate | Adiabatic wall (u = v = w = 0) |
Outflow | Pressure outlet |
Main sides | Periodic (u(x, y, z, t) = u(x, y, z + P, t), ΔP = 0) |
Sides of plenum | Wall (u = v = w = 0) |
Hole wall | Wall (u = v = w = 0) |
Grid | Number of Cells in x Direction | Number of Cells in y Direction | Number of Cells in z Direction | Number of Cells in Cross Flow Block (Million) | Total Cell Number (Million) |
---|---|---|---|---|---|
First | 320 | 70 | 70 | 1.89 | 4.49 |
Second | 502 | 75 | 76 | 3.18 | 5.78 |
Third | 552 | 80 | 82 | 3.94 | 6.53 |
Fourth | 602 | 85 | 86 | 4.72 | 7.31 |
Fifth | 682 | 90 | 90 | 5.85 | 8.45 |
Grid | Number of Cells in x Direction | Number of Cells in y Direction | Number of Cells in z Direction | Number of Cells in Cross Flow Block (Million) | Total Cell Number (Million) |
---|---|---|---|---|---|
First | 426 | 70 | 92 | 3.06 | 5.65 |
Second | 480 | 75 | 102 | 3.99 | 6.59 |
Third | 530 | 80 | 114 | 5.16 | 7.75 |
Fourth | 560 | 85 | 124 | 6.22 | 8.82 |
Fifth | 594 | 88 | 134 | 7.32 | 9.91 |
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Baek, S.I.; Ryu, J.; Ahn, J. Large Eddy Simulation of Film Cooling with Forward Expansion Hole: Comparative Study with LES and RANS Simulations. Energies 2021, 14, 2063. https://doi.org/10.3390/en14082063
Baek SI, Ryu J, Ahn J. Large Eddy Simulation of Film Cooling with Forward Expansion Hole: Comparative Study with LES and RANS Simulations. Energies. 2021; 14(8):2063. https://doi.org/10.3390/en14082063
Chicago/Turabian StyleBaek, Seung Il, Jaiyoung Ryu, and Joon Ahn. 2021. "Large Eddy Simulation of Film Cooling with Forward Expansion Hole: Comparative Study with LES and RANS Simulations" Energies 14, no. 8: 2063. https://doi.org/10.3390/en14082063