Many recent studies have highlighted the substantial health-related impacts of particle number (PMno) rather than particle mass. The aim of this study is to determine the correlation of trace gases with PMno, to identify the chemical composition of particle different sizes and to predict the NOx and PMno over Yanbu Industrial City (YIC). Trace gases (NOx, SO2, H2S, O3, CO), PMno with diameter (7nm-10μm), traffic and meteorological parameters were measured at three sampling sites in YIC. The maximum PMno (333,971 cm-3) at downwind site#1 was about 2.5 times higher than that (123,842 cm-3) at upwind site#2 and about 1.2 times higher than that (263,572 cm-3) at downwind site#3. The average PMno distribution at downwind sites consisted of one distinguishable mode (nucleation mode<20nm) whereas the upwind site had two modes (the nucleation and the accumulation modes). The correlation of PMno with NO/NOx (r>0.7) are generally stronger than with NO2 at sites#1 and 2, whereas for site #3 the correlation between PMno with NO2/NOx are better than with NO. PMno has generally either weak or poor correlation with SO2 and CO, respectively. Particle samples of different sizes (7nm-10?m) were chemically analysed using an ion chromatograph (IC) for inorganic ions and inductively coupled plasma mass spectrometry (ICP-MS) for trace metals at site#3. The ionic analysis revealed that sulfate and ammonium was mainly present in particle of size < 0.38μm while nitrate and chloride was mainly present in particles of size > 0.38μm. Non-sea salt sulfate was dominant in all particle sizes compared to the marine sulfate which is minor. The total sulfate and nitrate contributed 50.3% and 24.4% of the total ionic mass respectively followed by chloride (13.3%) and ammonium (10.6%). The trace-metals analysis results indicated that Na represented more than 94% of the total mass and the contributions of the remaining metals (Al, Sr, Zn, V, Cr, Fe, etc) were about 6%. A further part of this study consisted of the coupling of the WRF/CALMET system with the CALPUFF model, which was applied to predict NOx and PMno concentrations. The WRF model was employed to generate the meteorological input data for CALMET. WRF predictions were evaluated with surface data and upper air profiles using RASS/SODAR and radiosondes. WRF tends to underestimate the surface temperature on average with biases of up to -3.4°C and also underestimates temperature profiles with average biases ranging between -2.7 and -5.2oC when compared to the RASS profiler, but with a lower bias (< -2.4°C) when compared to radiosonde profiles. The mean wind speed bias for the majority of the cases was close to the benchmark of ±0.5m/s, but the mean wind direction bias for half of the cases exceeded the benchmark of 10o. It was concluded that WRF predictions can be used for air dispersion modeling to produce reasonable outputs. NOx predictions by CALPUFF showed that the contribution of the traffic to the highest concentrations during the nighttime was up to 80%, but after sunrise the contribution from industries became higher (up to 70%). The highest predicted NOx concentration (~313μg/m3) was much lower than the national ambient standard (660μg/m3) and the community area is affected much by industries during mid-morning hours when the wind shifting from land breeze to sea breeze. The fractional bias (FB) ranged between -0.1 and 1.06 indicating that the model tends to under-predict the NOx observations. PMno predictions of two sizes (7-40nm and 7nm-10μm) were derived based on the NOx predictions. All FB values were ranged between -0.1 and 0.5. It was concluded that PMno predictions were generally better than those of the NOx due mainly to adding the background term (intercept) for the PMno predictions.

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Cette thèse est consacrée à l’amélioration des capacités de prédiction des émissions d’oxydes d’azote (NO et NO2) des foyers de combustion aéronautiques. Les travaux, exclusivement numériques, consistent d’abord dans une étude de la cinétique chimique responsable des émissions polluantes. Cetteétude conduit à l’écriture d’un modèle, nommé NOMANI (pour Nitrogen Oxide emission model with one-dimensional MANIfold), basé sur l’approche PCM-FPI (pour Presumed Conditional Moments - Flame Prolongation of ILDM) avec une variable de progrès additionnelle afin calculer l’avancement de la chimie azotée une fois la chimie carbonée à l’équilibre. Différentes validations sur des configurations laminaires simples puis des flammes de laboratoire de Sandia sont présentées. Les résultats en terme de structure de flamme et d'émission de monoxyde d’azote sont confrontés aux mesures expérimentales. Le dernier volet de ces travaux, disponible uniquement dans la version confidentielle du manuscrit, consiste dans le développement d’un modèle de prédiction de polluants associé au modèle TF-LES (pour Thickening Flame for Large Eddy Simulation). Le modèle développé est ensuite appliqué à des calculs d’une chambre de combustion aéronautique. / This thesis is focused on the prediction capabilities of nitrogen oxides (NO and NO2) for numerical tools applied to aeronautical combustion chambers. The modeling work is based on a study of the chemical kinetic that produced the pollutant emissions. This study leads to a model, called NOMANI (Nitrogen Oxide emission model with one-dimensional MANIfold), based on PCM-FPI (Presumed Conditional Moments - Flame Prolongation of ILDM) with an additional progress variable to compute the NO evolution once the carbon chemistry is at the equilibrium. Several benchmarks and test-cases (laminar and turbulent flames) are gathered in this study : Sandia flame have been computed and satisfactory comparisons with measurements are obtained. The last part of this work, only available in the confidential version of the manuscript, is the development of a model to predict pollutant associated with the model TF-LES (for Thickening Flame for Large Eddy Simulation). This model is then applied to computations of a aeronautical combustion chambers.

Cette thèse est consacrée à l’amélioration des capacités de prédiction des émissions polluantes (CO, NOx . . . ) des foyers de combustion de turboréacteurs. L’étude, exclusivement numérique, repose sur des simulations aux grandes échelles (ou LES pour Large-Eddy Simulation) basées sur des méthodes de tabulation de la chimie détaillée. L’approche PCM-FPI (pour Presumed Conditional Moments - Flame Prolongation of ILDM) a été étendue à la chimie des oxydes d’azote via la modification de la variable d’avancement. Différentes validations sur des configurations laminaires simples puis des flammes de laboratoire (Cabra, Sandia) sont présentées. Les résultats en terme de structure de flamme et de champs d’espèces chimiques sont confrontés aux mesures expérimentales. Le rôle du formaldéhyde comme marqueur de la zone réactionnelle est illustré à l’aide de calculs de flammes laminaires puis confirmé par un calcul 3D LES. Une analyse des spécificités de l’implantation de ce type de modèle sur des machines à architecture massivement parallèle est ensuite menée. Diverses modifications de la structure de la table et des méthodes d’interpolation sont réalisées, servant de base à une étude de sensibilité de maillage appliquée à la flamme Sandia D. Les difficultés relatives à la prédiction du NO dans les flammes turbulentes sont exposées : divers modèles de sous-maille sont alors employés et comparés. / This thesis is focused on the prediction capabilities of pollution (CO, NOx especially) for numerical tools applied to aeronautical combustion chambers. The modeling work is based on Large-Eddy Simulation methods coupled with a tabulated detailed chemistry approach. The PCM-FPI model, which stands for Presumed Conditional Moments - Flame Prolongation of ILDM, has been revised to take into account nitrogen chemistry through a modification of the progress variable. Several benchmarks and test-cases (laminar and turbulent flames) are gathered in this study : Cabra and Sandia flames have been computed and satisfactory comparisons with measurements are obtained. The role of CH2O as a marker of heat release is investigated, first in the frame of laminar premixed flames and then validated through LES runs. The challenges of the implementation of tabulated chemistry methods on massively parallel machines are discussed. Modifications are proposed regarding both the table structure and the interpolation methods leading to a mesh sensitivity review applied to the Sandia D flame. Difficulties arising when dealing with NOx chemistry in turbulent flows are presented : new Sub-Grid Scale models are introduced and investigated.