Abstract
In the process of gas granulation of blast furnace slag, a cyclone separator serves to cool slag particles and separate them from hot air. This study focuses on modelling the cooling of slag particles in a cyclone separator. Simulations revealed the airflow field, temperature field and particle trajectory distribution within the cyclone separator. Key parameters such as particle size, flow rate, and air velocity were examined for their influence on operational parameters. The findings indicate that air and particles in the cyclone move around the wall, with lower air velocities and temperatures in the central region and higher values near the wall. In the range of inlet air velocity of 15–20 m/s, particle size of 1–5 mm, and particle flow rate of 1–9 kg/s, increasing the inlet air velocity, reducing the particle size, and decreasing the particle flow rate prolongs the particle residence time in the separator by about 3 s, reducing the exit temperature and enhancing the waste heat recovery efficiency. The overall waste heat recovery efficiency of the particle population can reach more than 60%. An orthogonal parameter table was employed to analyse the influence of these factors. The hierarchy of effect on temperature reduction was found to be particle size > slag flow rate > inlet airflow velocity > initial temperature of the slag particles. Finally, the equation correlating the waste heat recovery efficiency with the dimensionless number was derived, with a maximum deviation of 5.41% from the simulation results.
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Abbreviations
- A :
-
Surface area, m2
- A cont :
-
Effective contact area of the particles, m2
- C :
-
Specific heat capacity, J kg−1 K−1
- C d :
-
Drag coefficient
- D :
-
Particle diameter, mm
- D ω :
-
Orthogonal dissipation term
- F drap :
-
Drag force, N
- g :
-
Gravitational acceleration, N s−2
- G k :
-
Generation of turbulent kinetic energy due to the mean velocity gradient
- G ω :
-
Generation of turbulence due to dissipation
- h :
-
Heat transfer coefficient, W m−2 K−1
- L w-p :
-
LW-p is the distance from the particle center to the wall, m
- L :
-
Latent heat of slag particles
- H :
-
Enthalpy, J
- m :
-
Mass, kg
- p :
-
Pressure, Pa
- Q pa :
-
Heat exchange term, J
- Q :
-
Flow rate of particles, kg s−1
- t :
-
Time, s
- T :
-
Temperature, K
- T s :
-
Initial temperature of particles, K
- T a :
-
Initial temperature of air, K
- T so :
-
Particle temperature at outlet, K
- u :
-
Velocity, m s−1
- Y ω :
-
Dissipation term in turbulence
- Y k :
-
Dissipation term in turbulence due to the mean velocity gradient
- μ :
-
Dynamic viscosity, Pa s
- ρ :
-
Density, kg m−3
- ε :
-
Emissivity
- k :
-
Turbulent kinetic energy, m2 s−2
- σ 0 :
-
Stefan-Boltzmann constant
- τ :
-
Shear stress tensor, Pa
- α :
-
Volume of fraction
- λ :
-
Thermal conductivity, W m−1 K−1
- σ k :
-
Effective Prandtl number for turbulent kinetic energy
- ω :
-
Specific dissipation rate
- η :
-
Waste heat recovery efficiency
- σ w :
-
Effective Prandtl number for turbulent energy dissipation
- SST:
-
Shear stress transport
- DDPM:
-
Dense discrete phase model
- Re :
-
Reynolds number
- Oh :
-
Ohnesorge number
- a:
-
Air
- p:
-
Particle
- w:
-
Wall
- surr:
-
Surrounding surfaces
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Acknowledgements
This work was supported by the National Natural Science Foundation of China (No.52306066), Fundamental Research Funds for the Central Universities (FRF-TP-22-077A1) and Major project of science and technology in Hebei Province (22373805D).
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Liu, X., Wen, Z., Su, F. et al. Simulation of Motion and Heat Transfer Characteristics of Blast-Furnace Slag Particles in a Cyclone Separator. Iran J Sci Technol Trans Mech Eng (2024). https://doi.org/10.1007/s40997-024-00768-9
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DOI: https://doi.org/10.1007/s40997-024-00768-9