Simulation of Solid Particles Behavior in a Heated Cavity at High Rayleigh Numbers

Abstract

Transport and deposition of solid particles in a differentially heated cavity at high Rayleigh numbers up to 10 8 was studied using an Eulerian-Lagrangian computational method. Two-dimensional Navier-Stokes and energy equations were solved and the motions of particles with diameters in the range of 10 nm to 10 µm were simulated. Effects of drag, lift, thermophoresis and Brownian forces on the particle trajectories were investigated. It was observed that the variation of Rayleigh number can significantly change the flow field and the corresponding particle deposition patterns. In particular, recirculation regions were formed near the corners as the Rayleigh number increased. Furthermore, the effects of changes in the Rayleigh numbers on transport and deposition of particles of different sizes were quite different. Increasing Rayleigh number from 10 7 to 10 8 caused a decrease in particles deposition except for 10 µm particles. Smaller particles had a higher probability to deposit on the cold wall as the thermophoresis effect becomes important. Increasing the Rayleigh number decreased the influencing zone of the thermophoresis in the vicinity of the walls.

Eulerian–Lagrangian analysis of solid particle distribution in an internally heated and cooled air-filled cavity

“…Bagheri et al [12] numerically simulated the deposition of solid particles with diameters between 10 nm and 10 lm in a differentially heated cavity filled with air. It was reported that the effects of thermophoretic and Brownian force are important on the distribution and deposition of sub-micron particles.…”

“…particle deposition on heat exchanger surfaces can reduce the heat transfer rate and adversely affect the energy efficiency of these equipment [8,9]. Therefore, several studies have been carried out to understand this problem using Eulerian-Lagrangian methods [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27].…”

Numerical investigation of deposition and dispersion of aerosols in a concentric annulus

“…As an example in the reference [8] the relationship and formula for C c , F D , F B and etc are described as below. Cunningham'sfactor is…”

“…H. Hassanzadehet al [7] investigated numerically dispersion and removal of microaerosol particles in a horizontal concentric annulus by Lattice Boltzmann Method and Lagrangian Runge-Kutta procedure with the assumption of one-way coupling. G. H. Bagheri et al [8] studied transport and deposition of solid particles in a differentially heated cavity at high Rayleigh numbers up to 10 8 using an Eulerian-Lagrangian computational method. T. H. Kuehn, R. J. Goldstein [9] investigated an experimental and theoretical study of natural convection in the annulus between horizontal concentric cylinders.…”

Numerical Simulation of Natural Convection of a Nanofluid in an Inclined Heated Enclosure Using Two-Phase Lattice Boltzmann Method: Accurate Effects of Thermophoresis and Brownian Forces

“…At Ra = 104, particles are more uniformly distributed than for the case with Ra = 106. Studies on micrometer-sized particle-laden flow usually show particle separation from the base fluid, e.g., [ 36].…”