Name: RODRIGO XAVIER DE ALMEIDA LEÃO
Publication date: 29/06/2022
Advisor:
Name |
Role |
|---|---|
| HUMBERTO BELICH JUNIOR | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| CARLOS AUGUSTO CARDOSO PASSOS | Internal Examiner * |
| HUMBERTO BELICH JUNIOR | Advisor * |
| LEANDRO SILVA AMORIM | Internal Examiner * |
| MARCIO FERREIRA MARTINS | Co advisor * |
Summary: This is a study on the formation of dust that occurs in bulk material chutes in open environments. Dust formation is characterized by the suspension of nano and microparticles that are easily dragged into the atmosphere and transported over great distances causing socio-environmental damage. The following guiding question was taken as a starting point: Why in some situations is the installation of windbreak screens (wind-fences) not enough to avoid the formation of dust?. The windbreak screens are intended to prevent the passage of air currents over the process and thus avoid the suspension of particles, but their installation alone may not result in a significant reduction of dust. The methodology starts from an analytical relationship for the pressure field near the chute whose solution of the velocity field is obtained through Computational Fluid Dynamics (CFD) and makes it possible to identify flow regions generated by the process as well as to delimit the diameter of the particles subject to transported. It was found that if the chute occurs above a limit fall height, called critical fall height, hydrodynamic phenomena lead to the formation of a toroidal vortex near the impact zone that alters the velocity field, giving rise to ascending air currents and preferential escape paths for nano and microparticles, demonstrating that dust formation can occur even in a quiescent environment. The probability of the chute generating dust strongly depends on design characteristics such as main dimension and fall height, as well as the grain size and type of the material being transported.
