Theoretical and Experimental Evaluation of a Compact Aerosol Wind Tunnel and its Application for Performance Investigation of Particulate Matter Instruments

• Published in: Aerosol and Air Quality Research Vol. 21; no. 7; pp. 1 - 20
• Main Authors: Patel, Prashant, Aggarwal, Shankar G.
• Format: Journal Article
• Language: English
• Published: Taoyuan City 社團法人台灣氣膠研究學會 01-07-2021; Taiwan Association of Aerosol Research
• Subjects: Aerosols; Boundary layers; Dust; Environmental protection; Flow separation; Flow simulation; Flow velocity; Homogeneity; Low speed wind tunnels; Measuring instruments; Outdoor air quality; Particulate matter; Performance evaluation; Reynolds number; Tunnel construction; Velocity; Wind tunnels; United States > US; India; Theoretical designing; CFD evaluation; D_ cutoff of WINS and VSCC; Wind tunnel; Performance check of PM sensor
• ISSN: 1680-8584; 2071-1409
• DOI: 10.4209/aaqr.210006

In this study, we developed a compact low-speed wind tunnel. First, we computationally analysed the flow quality of different wall shapes for the contraction section, the most critical part of a wind tunnel, and selected the design exhibiting minimal boundary layer separation at simulated flow velocities of 2 and 8 km h^(-1). Then, after constructing the wind tunnel, we experimentally evaluated its overall performance based on different parameters per the United States Environmental Protection Agency (U.S. EPA) guidelines (40 CFR 53.62). The air velocity and turbulence profiles were uniform, displaying ≤ 10% variation in the section we tested. Additionally, we measured the mass concentrations and size distributions of polydisperse dust particles, which were generated by a custom-made rotary dust feeder to ensure the homogeneity of the aerosol, inside the wind tunnel at air velocities of 2 and 8 km h^(-1) and found ≤ 10% deviation for the mean values across the test section relative to those for the central sampling point. We also assessed the effectiveness of the Well Impactor Ninety-Six (WINS) and Very Sharp Cut Cyclone (VSCC) in the wind tunnel at an air velocity of 8 km h^(-1) by determining the D_(50) cutoffs, which, being 2.44 ± 0.05 μm and 2.54 ± 0.05 μm, respectively, fulfilled U.S. EPA's criteria. Furthermore, we compared the performance of a low-cost sensor against that of a reference instrument in measuring PM_(2.5) concentrations, and our results agreed with those from previous studies.