Modeling two-phase gas-solid flow in axisymmetric diffusers using cut cell technique: an Eulerian-Eulerian approach

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.