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PhD on Experimental study of the resuspension of microparticles in air induced by transient events, IMT Atlantique, Nantes, France

Du 1 septembre 2020 au 31 août 2023

Starting date : October 2020
IMT Atlantique
Nantes, France

Contact:
Félicie Théron, Associate Professor IMT Atlantique, Nantes Campus
Mail : 
felicie.theron@imt-atlantique.fr 
Tel : +33 2 51 85 82 60

Lionel Fiabane, Research Engineer INRAE Rennes
Mail : lionel.fiabane
@inrae.fr
Tel : +33 2 23 48 21 22

This subject concerns the risks to human health related to airborne microparticles which nature can be diverse (inert, chemical, biological or radioactive). More precisely the objective is to understand the mechanisms responsible for the resuspension of microparticles from free surfaces, when they are submitted to aerodynamic transient events such as airflow acceleration. Therefore this study aims at better understanding and controlling the risks associated with indoor airborne contaminations.


PhD position

Experimental study of the resuspension of microparticles in air induced by transient events

Research area: Aerosol Physics / Multiphase flows

Context of the subject:

This subject concerns the risks to human health related to airborne microparticles which nature can be diverse (inert, chemical, biological or radioactive). More precisely the objective is to understand the mechanisms responsible for the resuspension of microparticles from free surfaces, when they are submitted to aerodynamic transient events such as airflow acceleration. Therefore this study aims at better understanding and controlling the risks associated with indoor airborne contaminations.

Objectives:

This study follows the work initiated in the GEPEA laboratory dedicated to the development of an experimental methodology at local scale to improve the understanding of the microparticle resuspension mechanisms, and in particular under transient accelerated flows. The resuspension phenomenon is based on the competition between forces keeping the particles on the solid surface (adhesion and gravity forces) and forces that tend to detach them (aerodynamic and / or mechanical forces). The resuspension phenomenon thus depends on air thermodynamic properties, as well as on many parameters related to particles (size, morphology, density, surface properties), to the surface on which particles are initially deposited (e.g. roughness, electrostatic charge), and to aerodynamic forces to which particles are submitted. This PhD work will focus on the simultaneous temporal evolution of the fraction of resuspended particles (the resuspension kinetics) and of the parameters influencing the removal forces. Those last parameters, like the instantaneous air velocity, will be characterized at local scale, i.e. at wall distances relevant with particle sizes.

To carry out those investigations, resuspension kinetics will be acquired by optical counting, and the temporal evolution of the air velocity will be recorded thanks to Hot Wire Anemometry. The experiments will be carried out for initial deposits involving surrogate particles representative of indoor air (e.g. buildings or vehicles) in terms of size and density. The trajectory of particles will be tracked through a Lagrangian approach in order to describe their motion before being released in air (rolling, sliding, direct lift-off,...). A PTV (Particle Tracking Velocimetry) algorithm such as those used by ACTA research team will be implemented to treat those last data in order to determine particle velocity and compare it to the airflow velocity.

Location: the thesis will take place at IMT Atlantique, Energy and Environmental Systems department, Nantes, France. Research will be carried out with collaborators from INRAE, located nearby in Rennes. Contacts with the University of San Luis, Argentina will occur throughout the thesis for the modeling of the obtained resuspension kinetics. https://www.imt-atlantique.fr/en/school/departments/energy-and-environmental-systems

Profile required:

Skills in terms of physics of aerosols, fluid mechanics and related experimental methods (Hot Wire Anemometry, Particle Tracking), and data treatment (velocity signals, optical counting) are required to carry out this PhD work.

Starting date: from October 2020
Requested fundings : Direction Générale de l’Armement (Ministry of Military Affairs) – Pays de la Loire region.
Condition to apply : it is required to be citizen of a European Union country or from Switzerland to apply.

Contact:

Félicie Théron, Associate Professor IMT Atlantique, Nantes Campus
Mail : 
felicie.theron@imt-atlantique.fr Tel : +33 2 51 85 82 60

Lionel Fiabane, Research Engineer INRAE Rennes
Mail : lionel.fiabane
@inrae.fr
Tel : +33 2 23 48 21 22