INFLUENCE OF THE DESIGN AND OPERATIONAL CONDITIONS ON THE AIRFLOW AND MASS TRANSFER PHENOMENA INSIDE A PORTABLE WIND TUNNEL USED TO ESTIMATE ODORANT COMPOUNDS MEASURED OVER PASSIVE LIQUID SURFACES
Name: Matheus de Araújo Siqueira
Type: MSc dissertation
Publication date: 29/08/2022
Advisor:
Name |
Role |
|---|---|
| Bruno Furieri | Co-advisor * |
| Jane Meri Santos | Advisor * |
| Neyval Costa Reis Jr. | Co-advisor * |
Examining board:
| Name |
Role |
|---|---|
| Bruno Furieri | Co advisor * |
| Igor Braga de Paula | External Examiner * |
| Jane Meri Santos | Advisor * |
| Neyval Costa Reis Jr. | Co advisor * |
Summary: The emissions to the atmosphere by liquid passive area sources, that is, extensive
liquid surfaces swept by the atmospheric flow in which occurs the emission of a certain
chemical, like the tanks and lagoons in wastewater treatment plants are significative
sources of odorant compounds, such as the H2S and the acetic acid. The health effects
of these gaseous compounds include eye and throat irritation, and nausea. Different
equipments are being used to perform a direct estimation of the emission of the odorant
compound on passive surfaces. However, it is well known in the literature that the use
of different equipments for the same source is conducing to different results. In general,
these equipments are open-bottomed boxes in which is fluxed a clean gas in its inside
that enters in contact with the gas-liquid interface and carries the odorant compound,
to be posterior sampled at the equipment outlet and analyzed. Thereafter, the results
provided by these equipments are straightly connected with the airflow and mass transfer
phenomena on its inside. So, to properly assist the answer of the question of which
equipment is more adequated to estimate the emission rate of an odorant compound
in passive area sources it is first required to understand the airflow and how the mass
transfer phenomena occur on its inside occurs. In this way, the present work objectives
to analyze, using numerical simulations, the airflow and mass transfer phenomena inside
one the of equipments used in the direct estimative of odorant compounds, namely the
portable wind tunnel. The turbulent effects were incorporated using the κ −ω SST model.
The finite volume method was used via the ANSYS Fluent software to numerically solve
the involved equations. The analysis of the streamlines, profiles, vectors, and contours
of the velocity, turbulent kinetic energy, and concentration showed that the flow inside the
device is quite complex and 3D, with several recirculation zones and thus reversed flow.
This feature of the flow have a direct impact on the volatilization process. Nevertheless,
the results showed that the geometry configuration of the equipment has a direct impact
on the airflow and thus on its mass transfer phenomena, in this way, it seems that small
changes in its geometry could lead to an improvement of the flow in its inside.
