Speaker
Description
Effective sampling of airborne particles is essential for the environmental monitoring and is commonly achieved by using mechanical methods such as solid impactors, liquid impingers, and filters [1]. However, these methods often have limitations in capturing fine particles below PM2.5 or PM1. To overcome this challenge and enable efficient collection of fine particles, electrostatic precipitators have emerged as a promising solution. They offer high collection efficiency and lower collisional stress while reducing pressure drop through electrostatic attraction [2, 3]. One such precipitators, developed by Dixkens and Fissan, employs a jet flow to deliver particles to an electrode-embedded sample plate for the subsequent electrostatic capture [4]. This design has been successfully implemented in a commercial sampler known as model 3089 (TSI Inc., MN, USA). Previous studies attempted 3D simulations to assess particle collection within the device [1, 2], but these require relatively large computation resources for accurate calculation of the jet flow in 3D.
In this regard, we employed a 2D axisymmetric model using the commercial finite element method software COMSOL to simulate particle behavior accurately with a reduced computational cost. Instead of using 3D geometry, we employed a 2D domain with cylindrical coordinates by cutting the geometry along the axis of the axial sampler. Particle trajectories were determined using the Lagrangian discrete phase model, considering the effects of drag with slip correction, gravitational, electrostatic, and Brownian forces. Prior to the particle tracing, the flow field was obtained by solving the continuity and Navier-Stokes equations for steady and incompressible laminar flow, while the electric field was derived by solving the Poisson equation for the electrical potential. Subsequently, the flow and electric field solutions were coupled to the drag and electrostatic forces during the particle tracing, respectively. The numerical validation involves comparing the simulation results with experimental data by Dixkens and Fissan [4]. This study aims to establish a reliable numerical framework for assessing fine airborne particles in electrostatic aerosol samplers, with the advantage of relatively low computational cost by conducting 2D simulations. Furthermore, it contributes to the advancement of air quality assessment methodologies.
References
[1] Lee, J. W., Lee, S. H., Jang, J. Numerical analysis on the electrostatic capture of airborne nanoparticles and viruses in a homemade particle concentrator without a unipolar charger. J. Electrostat. 70, 192-200 (2012).
[2] Hong, S., Bhardwaj, J., Han, C.-H., Jang, J. Gentle Sampling of Submicronmeter Airborne Virus Particles using a Personal Electrostatic Particle Concentrator. Environ. Sci. Technol. 50, 12365-12372 (2016).
[3] Mainelis, G., Willeke, K., Adhikari, A., Reponen, T., Grinshpun, S. A. Design and collection efficiency of a new electrostatic precipitator for bioaerosol collection. Aerosol Sci. Technol. 36, 1073-1085 (2002).
[4] Dixkens, J., Fissan, H. Development of an Electrostatic Precipitator for Off-Line Particle Analysis. Aerosol Sci. Technol. 30, 438-453 (1999).
| Keywords | aerosol, electrostatic precipitator, finite element method, environmental monitoring, fluid mechanics |
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