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

Prashant Patel ； Shankar G. Aggarwal

《Aerosol and Air Quality Research》 21卷7期 (2021/07) Pp. 1-20

https://doi.org/10.4209/aaqr.210006

摘要

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.

關鍵字

Wind tunnel ； Theoretical designing ； CFD evaluation ； D_(50) cutoff of WINS and VSCC ； Performance check of PM sensor