Numerical modeling and mathematics of Building Energy Rating

The main objective of this study is to determine the quality of the heat transfer and the quality of the water.The physical problem is governed by the equations of continuity, momentum and energy. These governing equations are written in terms of primitive variables and are recast into a general form considering the hypothesis of Boussinesq.Generally, these equations do not admit analytical solutions, so recourse to numerical methods appears mandatory. We opted for the method of "Runge-Kutta". The results of this work are presented in the following table.Keywords. Optimizing energy efficiency of housing, The method of "Runge-Kutta, Numerical methods, Numerical modeling and mathematics of Building Energy Rating

Numerical modeling of mass loss and temperature profiles in the thermal decomposition of bagasse in a fixed rectangular oven

This work deals with the numerical study of the pyrolysis process in the thermochemical conversion of bagasse in an inert atmosphere and a two-dimensional numerical code (2D) of the reactions involved in the pyrolysis of bagasse of the sugarcane located in Morocco. The finite difference and the Range-Kutta method of second order have been used to simulate the pyrolysis of bagasse in a fixed rectangular oven of the bagasse. Transport modeling is made using homogenized equations at the Darcy scale. The thermal imbalance between the solid and the gas phase under the implementation of a temperature model of two fields has been revealed by previous studies, one for gas and one for solid. During this study, the aim has been to model the degradation of bagasse by pyrolysis. It is a very complex phenomenon that usually precedes the stage of heterogeneous combustion. The results provided by the numerical code developed are almost in agreement with the ones obtained by the experimental study presented in literature. This code is quite flexible; it can take into account different boundary conditions and allows changing easily the order of spatial discretization

Filtration performance of lab-scale pulse-jet bag filter

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Influence de l'humidité sur les performances de collecte de particules submicrométriques d’un filtre à manche

International audienceFiltration performance of pulse-jet bag filters implemented in flue gas treatment of waste incineration plant was studied at laboratory scale in order to evaluate the influence of humidity during clogging/unclogging cycles. Several cycles of clogging/unclogging with on-line cleaning were done with submicronic particles with a nanosized fraction at the operating conditions as similar as possible to those found in flue gas treatment of waste incineration plants (150°C-3% RH) and in dry conditions (150°C-0% RH). The experimental results revealed a significant influence of humidity on the filtration performance mainly due to capillary condensation, namely faster increase of bag filter pressure drop, lower efficiency of particulate cake dislogment and better collection efficiency of particles between 110 and 300 nm.Les performances de filtration des filtres à manche mis en oeuvre dans les lignes de traitement des fumées d’incinération de déchets ont été étudiées à l’échelle du laboratoire afin d’évaluer l’influence de l’humidité. Plusieurs cycles de colmatage et décolmatage ont été réalisés à l’aide d’un aérosol représentatif des émissions d’incinération de nanodéchets, d’une part pour des conditions opératoires représentatives de celles rencontrées dans les lignes de traitement des fumées d’incinération (150°C- 3% HR) et d’autre part en conditions d’air sec (150°C- 0% HR). Les résultats expérimentaux ont montré une influence significative de la présence d’humidité sur les performances de filtration principalement en raison de la condensation capillaire, à savoir une augmentation plus rapide de la perte de charge du filtre, un décolmatage moins efficace du gâteau de particules et une efficacité de collecte des particules entre 110 et 300nm plus importante

Performances de traitement d’un filtre à manche de laboratoire en condition de filière d’incinération

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MATHEMATICAL AND NUMERICAL MODELING OF NANOPARTICLES TRANSPORT

International audienceThis study aims at numerical simulation of nanoparticle transport in flue-gas treatment at a waste incineration plant. The purpose of this work is to assess the effect of temperature, particle size, and fluid velocity on nanoparticle transport around a single spherical collector considered as a filter medium for nanoparticles filtration. Thus, the stochastic Langevin equation was used to describe the dynamic behavior of particles with account for different forces acting simultaneously on these particles, namely, drag force, gravitational force, and Brownian force. The results indicated, on the one hand, that the effect of temperature on the nanoparticle movement increases with temperature and, on the other hand, that the fluctuation of the particle trajectory is a significant factor in decreasing the particle diameter. Concerning the effect of the fluid velocity, the role of the nanoparticles trajectory becomes more significant the higher the value of the fluid velocity. The results of this work which are expressed as the bivariate velocity and displacement distribution function aim at understanding the experimental filtration efficiency studied in laboratory conditions at two different temperatures and fluid velocities

Influence of air humidity on particle filtration performance of a pulse-jet bag filter

International audienceA pulse-jet bag filter, representative of those implemented in waste incineration plants for flue gas treatment, was studied at laboratory scale to evaluate the influence of air humidity on the filtration performance. Several cycles of clogging/unclogging were performed with non-hygro-scopic submicronic particles with a nanosized fraction with on-line cleaning at operating conditions as similar as possible to those found in the flue gas treatment of waste incineration plants (150°C-73 g/m 3 of absolute humidity), and in dry conditions (150°C). The results revealed a significant influence of air humidity on the bag filter performance: faster increase of bag filter pressure drop during clogging in presence of humidity due to water capillary condensation, lower efficiency of particulate cake unclogging and better collection efficiency of particles between 110 and 300 nm in diameter

Influence of humidity and temperature on bag filter performances for incineration fumes treatment

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INFLUENCE OF FILTRATION VELOCITY AND FILTER IMPLEMENTATION ON BAG FILTER PERFORMANCES FOR THE TREATMENT OF INCINERATION RAW FUMES

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INFLUENCE OF OPERATING CONDITIONS ON BAG FILTER PERFORMANCES FOR INCINERATION FUMES TREATMENT

International audienceFiltration performances of a bag filter implemented for the flue gas treatment of waste incineration plant were studied at laboratory scale in order to evaluate the influence of filtration cycles (clogging/unclogging). The filtration performances were evaluated during clogging with a submicronic aerosol with nano-size fraction, at a filtration velocity of 1.9 cm.s-1. Investigations of the influence of filter washing and filtration velocity on the filtration performances were performed with the same filtering media in flat configuration. Experimental results showed an influence of filtration velocity on fractional filtration efficiency in particular for particle diameter close to the Most Penetrating Particle Size of the filter. Moreover, results indicated that new filters were significantly less efficient than washed filters at the beginning of the clogging. Finally the influence of clogging/unclogging cycles on bag filter performances was demonstrated both for pressure drop and filtration efficiency evolutions during clogging