Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
INVESTIGATING INTERNAL FLOW AND THE INFLUENCE OF INTERNAL MIXERS ON THE USEPA DYNAMIC FLUX CHAMBER FOR ODORANT COMPOUND EMISSIONS
Submission Author:
Kamila Furtado Cupertino , ES , Brazil
Co-Authors:
Kamila Furtado Cupertino, Laize Nalli de Freitas, jane meri Santos, Bruno Furieri, Philipe Uhlig Siqueira
Presenter: Laize Nalli de Freitas
doi://10.26678/ABCM.COBEM2023.COB2023-2399
Abstract
The USEPA dynamic flux chamber (USEPA DFC) is widely utilized for measuring air pollutants emitted from various area sources, including Wastewater Treatment Plants, due to its versatility and accuracy. The volatilization mechanisms of compounds in the chamber are governed by mass transfer equations, such as the Two Film Theory. According to this theory, the emission flux is directly related to the concentration difference between the liquid and gaseous phases, regulated by a constant known as the global mass transfer coefficient. Despite its widespread use, there is limited literature available on the internal flow characteristics of the DFC. Some studies suggest that the use of internal mixers can enhance sampling efficiency. Therefore, the objective of this study was to investigate the internal flow of the DFC and assess the influence of internal mixers on flow distribution and velocity. To achieve this, computational fluid dynamics (CFD) simulations were conducted using Ansys Fluent software. The geometry of the USEPA DFC model, with variations in inlet flows and the addition of two internal fans, was used for the simulations. Acetic acid was chosen as the pollutant for analysis. The fluid flow within the chamber was assumed to be isothermal, incompressible, and turbulent, with the k-w SST turbulence model employed. The analyzed inlet flows were 2, 5, and 10 L/min, and two fans of different sizes (large and small) were introduced, with ascending and descending flow configurations considered. The simulation results revealed that both the variation in flow rate and the addition of fans had a direct impact on friction velocity and shear stress, particularly along the chamber wall. The inclusion of fans improved mixing inside the chamber; however, it also had a minor effect on the mass transfer coefficients of the analyzed compound, albeit not significantly. In summary, this study provided insights into the internal flow characteristics of the USEPA DFC and examined how the introduction of internal mixers, represented by fans, affected flow distribution and velocity. The findings underscore the importance of considering these factors when using the DFC for measuring emissions, contributing to improved sampling accuracy and reliability.
Keywords
odorous compounds, dynamic flux chamber, Acetic Acid, Wastewater Treatment Plants
