Title: FLUID AND PARTICLE DYNAMICS IN AN AEROSOL VIRTUAL IMPACTOR
The collection and characterization of chemical and biological aerosols is crucial to several aspects of particle research for example toxicological studies, pollutant sampling, and biohazard analysis. This research presents the simulation of a low cutpoint, high volume aerosol sampling system called the virtual impactor….
Contents: Aerosol Virtual Impactor
1. Introduction
1.1 Problem Statement
1.2 Overview of Virtual Impactor
1.3 Contributions
1.4 Organization of the Thesis
2. Background and Related Work
2.1 Experimental Investigation of Virtual Impactors
2.2 Theoretical and Numerical Studies of Virtual Impactors
2.3 Approaches to Two Phase Turbulent Flows
3. Simulation Components
3.1 Compressibility
3.2 Device Geometry
3.3 Computational Meshes
3.4 Boundary and Operating Conditions
3.5 Discrete Phase Properties
4. Governing Equations
4.1 Fluid Flow
4.1.1 Reynolds Averaged Navier Stokes Equations
4.1.2 The Ҡ-∈ Closure
4.1.3 The RSM Closure
4.1.4 The Numerical Scheme
4.1.4a Discretization
4.1.4b Wall Functions
4.2 Particulate Flow
4.2.1 Particle Equation of Motion
4.2.2 The Drag Coefficient
4.2.3 Random Walk Model: Stochastic Tracking
4.2.4 Numerical Solution of the Particle Equation
4.2.4a FLUENT’S Implementation
4.2.4b AeroTrack: The Developed Code
4.2.4b.1 Trapezoidal Scheme
4.2.4b.2 Multi-Variate Scattered Interpolation
4.2.4b.2-i Motivation
4.2.4b.2-ii Theory
4.2.4b.2-iii Proposed Algorithm
4.2.4b.3 Adaptive Drag Coefficient
4.2.4b.4 AeroTrack Task Flow
5. Discussion of Numerical Approaches
5.1 Convergence of the Fluid Flow Solution
5.2 Accuracy of the Particle Tracking Algorithms
5.2.1 Time Stepping
5.2.2 Number of Particles
5.2.3 Interpolation Tests
5.2.3a Bi-Variate Functions
5.2.3b Tri-Variate Functions
5.2.3c Prescribed Velocity Field
5.2.3d Virtual Impactor Simulation Data
5.3 Summary
6. Simulation Results
6.1 Properties of the Fluid Flow Solution
6.1.1 Ҡ-∊ vs. RSM
6.1.2 Incompressible vs. Compressible Flow
6.1.3 Coarse vs. Fine Grid
6.1.4 1st
s. 2nd Order Discretization
6.1.5 Motion of Fluid Particles
6.1.6 Vorticity
6.1.7 Summary
6.2 The Discrete Phase Results
6.2.1 Incompressible Flow Field
6.2.2 Compressible Flow Field
6.2.3 The Drag Coefficient Revisited
6.2.3a More Realistic Models for the Drag Coefficient
6.2.4 Incompressible vs. Compressible Flow
6.2.5 Comparison with Experiment…..
Aerosol Virtual Impactor Downloads
Source: University of Maryland
Download URL 2: Visit Now