Modeling two-phase gas-solid flow in axisymmetric diffusers using cut cell technique: an Eulerian-Eulerian approach
Khaled M. Salem, Adel M. Elreafay, Ramzy M. Abumandour, A. S. Dawood
Abstract
Abstract Axisymmetric diffusers find wide applications in various industrial processes, including combustion systems, pneumatic conveying, and fluidized bed reactors. Understanding and accurately modeling the behavior of two-phase flows in these devices are critical for optimizing their performance and efficiency. Various aspects of the two-phase gas-solid flow, including particle-particle and particle-wall interactions, interphase momentum transfer, and phase segregation, are investigated. Our currently developed technique, which uses a cut-cell technique, is an established new method to handle the inclined wall of an axisymmetric diffuser. The near-wall cells are treated as five faces for the new grid; one is the inclined wall. This helps treat the boundary condition at the wall in an accurate physical way. The code FORTRAN, developed in-house, was used to solve the axisymmetric diffuser using a cut-cell technique. The results of this study will provide valuable insights into the behavior of gas-solid two-phase flows in axisymmetric diffuser. A parametric study of the impact of particles diameters ( $100,\ 200,\ \text{and} \ 300\mu m$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>100</mml:mn> <mml:mo>,</mml:mo> <mml:mspace/> <mml:mn>200</mml:mn> <mml:mo>,</mml:mo> <mml:mspace/> <mml:mtext>and</mml:mtext> <mml:mspace/> <mml:mn>300</mml:mn> <mml:mi>μ</mml:mi> <mml:mi>m</mml:mi> </mml:math> ), the solid volume loading ratios $(0.005,\ 0.008,\ 0.01)$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>(</mml:mo> <mml:mn>0.005</mml:mn> <mml:mo>,</mml:mo> <mml:mspace/> <mml:mn>0.008</mml:mn> <mml:mo>,</mml:mo> <mml:mspace/> <mml:mn>0.01</mml:mn> <mml:mo>)</mml:mo> </mml:math> , and cant angle $(4.5^{\circ},\ 7^{\circ},\ 9.5^{\circ}) $ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>(</mml:mo> <mml:msup> <mml:mn>4.5</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> <mml:mo>,</mml:mo> <mml:mspace/> <mml:msup> <mml:mn>7</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> <mml:mo>,</mml:mo> <mml:mspace/> <mml:msup> <mml:mn>9.5</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> <mml:mo>)</mml:mo> </mml:math> effect of axisymmetric diffuser on the local skin friction, pressure, velocity, turbulent kinetic energy, and separation zone.