The results of thermal interactions between a solid particle and a fluid have two folds: the motion of fluid affects the heat transfer and energy balance of a particle; and the heat transfer from particles influences the fluid motion. When the temperature of a particle and its surrounding fluid is not the same, heat is transferred between the particle and the fluid. The heat flux influences the properties of the surrounding fluid and changes the dynamics of the sedimentation of the particle. To study the effect of non-isothermal flows to the motion of a particle, we have developed a Direct Numerical Simulation (DNS) method that is capable of solving both the momentum equation and heat transfer equation for the computation of thermal interaction between particles and fluid. This numerical method makes use of a finite difference method in combination with the Immersed Boundary (IB) method for treating the particulate phase. In particular, the IB concept has been extended to treat thermal boundary condition at the particle surface. A regular Eulerian grid is used to solve the modified momentum and energy equations for the entire flow region simultaneously. In the region that is occupied by the solid particles, a second particle-based Lagrangian grid is used, which tracks particles, and a force density function or an energy density function is introduced to represent the momentum interaction or thermal interaction between particle and fluid. In this paper, the IB based DNS method has been applied to study the fluidization of 12,000 circular particles, the unsteady conduction of a sphere in a stagnant fluid, and the sedimentation of a non-isothermal sphere in a viscous fluid at different Grashof number. Our simulation results show that the sedimentation velocity of the particle depends strongly on the thermal interaction of particle and fluid due to the strong buoyancy force exerted on the particle.
- Fluids Engineering Division
An Immersed Boundary Based Method for Studying Thermal Interaction of Particles in a Viscous Fluid
Feng, Z, Paudel, BD, & Zhang, X. "An Immersed Boundary Based Method for Studying Thermal Interaction of Particles in a Viscous Fluid." Proceedings of the ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting: Volume 1, Symposia – Parts A, B, and C. Montreal, Quebec, Canada. August 1–5, 2010. pp. 2347-2351. ASME. https://doi.org/10.1115/FEDSM-ICNMM2010-30185
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