10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
CFD Analysis of Flow and Particle Behavior in the Performance Evaluation Chamber System for PM Sensor
SUNG-MIN SHIM, Jae-ho Cho, Hyeok Chung, Ki-tai Kang, Aerosol Research & Technology Plus
Abstract Number: 680 Working Group: Instrumentation
Abstract Recently, many studies on the risk of fine dust have been published. Particularly, it has been reported that fine dust particles having a particle diameter of less than 2.5 microns penetrate deeply into the lungs to cause serious respiration and heart-related diseases. As such fine dusts become a common concern worldwide, the World Health Organization, the US EPA, and the European Union are beginning to set up countermeasures. Measurement of fine dust is essential for the fine dust countermeasures. As a method of measuring fine dust, there is a measurement method using a light scattering method and a beta ray absorption method. Therefore, recently, light scattering type fine dust sensor has been actively developed all over the world, and the market related to the fine dust sensor is also growing rapidly. However, the method of evaluating the performance of the fine dust sensor as well as the performance of the fine dust sensor has not yet been clarified yet. Therefore, the fine dust sensor manufacturers evaluate and sell the performance of the fine dust sensor by their own methods. Therefore, a standard performance evaluation system is needed to evaluate the performance of the fine dust sensor in real time under the same test conditions. The fine dust sensor performance evaluation system is divided into a continuous flow type and a batch type according to the test air supply method. The batch type system used in this study has advantages in terms of ensuring uniformity of particle concentration and stabilizing flow since it is not forcibly generated airflow inside the chamber. On the other hand, in the batch system, disturbance of the internal airflow due to the flow generated during sampling of the sensor can affect the spatial uniformity of the particle concentration. Also, measurement device can affect to particle concentration. Therefore, it is necessary to analyze the distribution of the internal airflow and the trend of the particle concentration over time according to the ratio of the internal volume of the chamber and the sampling flow rate of the fine dust sensor. In this study, it is analyzed through computational fluid dynamics. The three - dimensional shape of the chamber and the fine dust sensor was modeled to analyze the flow and particle behavior inside the chamber. In order to simulate the initial flow and particle concentration in the chamber, steady - state analysis was performed under the condition that a constant test flow rate was supplied. The test particles were generated at the test air inlet side in the chamber using the flow analysis results. The particle concentration distribution inside the chamber was predicted. In order to analyze the flow and particle behavior in the chamber by gas sampling of the fine dust sensor, the unsteady flow and particle behavior are analyzed by using the steady state analysis results as initial conditions. The inlet and outlet of the test air in the chamber used the velocity-inlet and pressure outlet conditions, respectively, and the sampling inlet and outlet of the fine dust sensor formed the flow using the fan boundary condition. In order to simulate the decrease of the particle concentration due to the gas sampling of the fine dust sensor, analysis was performed by adding the sink term of the particle to the boundary condition so that the particles in the flow passing through the fan can be removed. The analysis results show that the tendency of airflow in the chamber due to the chamber internal volume and sampling flow rate and the tendency of decreasing the particle concentration by the fine dust sensor.