KAUST VSRP Research Project | Conducted at King Abdullah University of Science and Technology (KAUST), Saudi Arabia
Project Overview
This validation study focused on recreating a CFD simulation of acetylene combustion in Low-Velocity Oxy-Fuel (LVOF) flame spraying using CONVERGE CFD software. The goal was to replicate the multireactional model from Bandyopadhyay and Nylén (2003) to establish a validated baseline for future hydrogen-fueled flame spray research.
Motivation
Flame spraying is widely used in aerospace, automotive, and energy industries to improve surface properties like wear and corrosion resistance. While acetylene is the conventional fuel for LVOF systems, this project serves as groundwork for exploring hydrogen as a cleaner alternative due to its carbon-free combustion and high thermal conductivity.
Technical Approach
- Computational Domain: One-eighth wedge geometry exploiting system symmetry, including central argon carrier gas orifice, fuel inlets, and cooling air inlet
- Chemical Mechanism: GRI-Mech 3.0 with 53 species and 325 elementary reactions
- Equation of State: Redlich-Kwong for real-gas effects at high temperatures
- Combustion Model: SAGE detailed chemistry solver
- Turbulence Model: Standard k-ε RANS with wall functions
- Particle Phase: Composite NiCrAl/bentonite powder with Ranz-Marshall heat transfer and Haider-Levenspiel drag model
Key Process Parameters
| Gas Stream |
Inlet Velocity [m/s] |
Volume Flow [lpm] |
| Argon (carrier gas) |
12.6 |
6 |
| Acetylene (C₂H₂) |
117.4 |
22.9 |
| Oxygen (O₂) |
117.4 |
32 |
| Cooling air |
200 |
— |
Results & Findings
The simulated temperature fields showed good agreement with the reference study along the centerline up to 13 cm axial distance. Key observations include:
- Temperature Profiles: Good centerline agreement; off-axis profiles showed some deviation
- Velocity Fields: Simulation predicted 20-40 m/s higher velocities than reference, but with more physically plausible decay rates
- Species Concentrations: Qualitative reproduction of H₂O, CO₂, O₂, and CO mole fraction trends
- Combustion Extent: Higher residual O₂ and lower product concentrations suggest under-prediction of reaction progress, likely due to turbulence-chemistry interaction differences
Tools & Skills
- CONVERGE CFD Software
- Computational Fluid Dynamics (CFD)
- Chemical Kinetics & Reaction Mechanisms (GRI-Mech 3.0)
- Turbulence Modeling (k-ε RANS)
- Particle-Gas Two-Phase Flow
- Thermal Spray Process Simulation
Future Work
This validated acetylene-based model provides the foundation for extending the framework to hydrogen-fueled flame spray systems, enabling research into cleaner thermal spray coating processes.
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