Ifsttar PhD subject

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Title : CFD-based numerical strategy and full-scale experiment applied to traffic air pollution in urban area: from outdoor/indoor air pollutant cartographies to mitigation through the smart placement of depolluting panel

Main host Laboratory - Referent Advisor COSYS - LISIS  -  WAEYTENS Julien      tél. : +33 181668453

Director of the main host Laboratory KHADOUR Aghiad  -

Laboratory 2 - Referent Advisor COSYS - LICIT  -  LEJRI Delphine  -    -  tél. : +33 472142300

PhD Speciality Sciences pour l'Ingénieur, Qualité de l'Air, Mécanique

Axis of the performance contract 3 - COP2017 - Planning and protecting regions

Main location Marne-la-Vallée

Doctoral affiliation UNIVERSITE PARIS-EST

PhD school SCIENCES, INGENIERIE ET ENVIRONNEMENT (SIE)

Planned PhD supervisor WAEYTENS Julien  -  Université Gustave Eiffel  -  COSYS - IMSE

Planned financing Contrat doctoral  - Ifsttar

Abstract

Air pollution is a major issue regarding health and environmental concerns. In fact, outdoor air pollution in urban areas is responsible for millions of deaths worldwide. One of the main outdoor pollutant sources is vehicle emissions. Moreover, there is a transfer of outdoor air pollution to indoor environments, which results in the deterioration of indoor air quality by traffic pollution. To tackle air pollution issues, today, there is growing interest in the use of panels incorporating photocatalytic technology (depolluting panels). In my Ph.D. research, I have developed a novel approach aimed at efficiently placing depolluting panels in urban districts, with the goal of minimizing human exposure to outdoor and indoor air pollutants. My works aim to propose a practical methodology and its numerical implementation. The proposed method encompasses a comprehensive series of steps; from the automatic creation of 3D urban geometry, the computation of detailed outdoor and indoor pollutant cartography using CFD to the generation of sensitivity indicator maps that pinpoint relevant placement for depolluting panel installation through adjoint-based sensitivity analysis. The proposed method was applied to a full-scale experimental district, "Sense-City" in controlled condition scenarios and a real urban area in Paris. Concerning pollution maps, the interaction between outdoor and indoor air quality was investigated using CFD and validated by measurement campaigns. According to the numerical and experimental results, indoor pollutant concentrations reach the same level as outdoors within 15 minutes after opening windows (natural ventilation). At the district scale, thanks to the proposed sensitivity indicator, I show that depolluting panels should be placed on part of the sidewalks, roads and lower floors of building facades in order to mitigate human exposure to outdoor air pollution and to prevent outdoor air pollutants from entering indoors.Despite various simplifications, the numerical strategy was able to distinguish between non-effective and relevant depolluting panel placement areas as regards of urban airflow. This methodology can potentially serve as a valuable decision-making tool for reducing pollutant exposure during urban planning processes for both new and existing urban areas and buildings.

Keywords : Air quality, Physical Testing, Numerical simulation, Fluid mechanics, Sensor, Inverse problems, Sense-City

Main host Laboratory - Referent Advisor	COSYS - LISIS - WAEYTENS Julien tél. : +33 181668453
Director of the main host Laboratory	KHADOUR Aghiad -
Laboratory 2 - Referent Advisor	COSYS - LICIT - LEJRI Delphine - - tél. : +33 472142300
PhD Speciality	Sciences pour l'Ingénieur, Qualité de l'Air, Mécanique
Axis of the performance contract	3 - COP2017 - Planning and protecting regions
Main location	Marne-la-Vallée
Doctoral affiliation	UNIVERSITE PARIS-EST
PhD school	SCIENCES, INGENIERIE ET ENVIRONNEMENT (SIE)
Planned PhD supervisor	WAEYTENS Julien - Université Gustave Eiffel - COSYS - IMSE
Planned financing	Contrat doctoral - Ifsttar
Abstract Air pollution is a major issue regarding health and environmental concerns. In fact, outdoor air pollution in urban areas is responsible for millions of deaths worldwide. One of the main outdoor pollutant sources is vehicle emissions. Moreover, there is a transfer of outdoor air pollution to indoor environments, which results in the deterioration of indoor air quality by traffic pollution. To tackle air pollution issues, today, there is growing interest in the use of panels incorporating photocatalytic technology (depolluting panels). In my Ph.D. research, I have developed a novel approach aimed at efficiently placing depolluting panels in urban districts, with the goal of minimizing human exposure to outdoor and indoor air pollutants. My works aim to propose a practical methodology and its numerical implementation. The proposed method encompasses a comprehensive series of steps; from the automatic creation of 3D urban geometry, the computation of detailed outdoor and indoor pollutant cartography using CFD to the generation of sensitivity indicator maps that pinpoint relevant placement for depolluting panel installation through adjoint-based sensitivity analysis. The proposed method was applied to a full-scale experimental district, "Sense-City" in controlled condition scenarios and a real urban area in Paris. Concerning pollution maps, the interaction between outdoor and indoor air quality was investigated using CFD and validated by measurement campaigns. According to the numerical and experimental results, indoor pollutant concentrations reach the same level as outdoors within 15 minutes after opening windows (natural ventilation). At the district scale, thanks to the proposed sensitivity indicator, I show that depolluting panels should be placed on part of the sidewalks, roads and lower floors of building facades in order to mitigate human exposure to outdoor air pollution and to prevent outdoor air pollutants from entering indoors.Despite various simplifications, the numerical strategy was able to distinguish between non-effective and relevant depolluting panel placement areas as regards of urban airflow. This methodology can potentially serve as a valuable decision-making tool for reducing pollutant exposure during urban planning processes for both new and existing urban areas and buildings.
Keywords :	Air quality, Physical Testing, Numerical simulation, Fluid mechanics, Sensor, Inverse problems, Sense-City

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