CFD Modelling Case Studies

Cyclone Separator Design Evaluation

Multiphase CFD Simulation using Eulerian-Lagrangian Approach

Design evaluation of a cyclone separator was carried out. The objective was to evaluate the efficiency of this design in separating particles of different sizes and densities from a stream of particle-laden air flow.
Commercial CFD code was used for meshing and CFD modelling. Turbulence was modelled using Scale Adaptive Simulation (SAS) approach, considering transient flow assumption. Particles were tracked using Lagrangian approach with drag force computed using correlation by Morsi and Alexander (1972). The effect of turbulence on particle trajectories was accounted using Discrete Random Walk model. Due to lean concentration of particles in the inlet air stream, one-way coupling was considered.
The air flow profiles showed evidence of slight precessing of the vortex core. Trajectories of the particles are significantly influenced by its size and less influenced by its densities for the range of particle densities investigated.

Modelling of a Non-Premixed Burner

Design Evaluation using Single Phase Non-Isothermal Modelling

Performance of a non-premixed burner design was evaluated. It comprises four inlet air streams with centrally injected fuel stream comprising 25% methane and 75% hydrogen.
CFD modelling approach consisted of Reynold Stress Transport model for turbulence with P1 radiation model for considering radiation heat transfer and transient flow condition. Combustion calculations were incorporated in a commercial CFD code. Mixing of air and fuel streams and combustion characteristics in the chamber were analysed. Flame instability was predicted in the existing design leading to high NoX emissions. Changes were proposed in the design to improve the burner performance. This work resulted in improved burner performance which was not feasible with physical prototype testing due to cost and time constrains resulting in significant savings in time and costs.

Mixing Characteristics in a Stirred Tank

Multiphase CFD Simulation Case

Mixing characteristics in a non-baffled stirred tank containing suspended particles in water was analysed using Eulerian-Eulerian approach. RNG k-epsilon model was used for turbulence modelling with steady-state approach. Mixing of the stirrer was incorporated using rotating reference frame approach. The results showed good mixing characteristics in the tank.