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Numerical study of the Threshold Intensity dependence on Wavelength in Laser spark Ignition of Molecular Hydrogen Combustion

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Journal of Modern Physics 2013年第3期4卷 311-320页

作者： Kholoud A. Hamam Galila a.dellatif Yosr E. E.-d. gamal department of physics Girl’s Faculty of Science King Abdul-Aziz University Jeddah KSA. National Institute of Laser Enhanced science-Cairo University El-Giza Egypt. Physics department Faculty of Science Cairo University Giza Egypt

A numerical investigation of laser wavelength dependence on the threshold intensity of spark ignition in molecular hydrogen over a wide pressure range is presented. A modified electron cascade model (gamal et al., 1993) is applied under the experimental conditions that carried out by Phuoc (2000) to determine the threshold intensity dependence on gas pressure for spark ignition in hydrogen combustion using two laser wavelengths namely;1064 nm a.d 532 nm. The model involves the solution of the time dependent Boltzmann equation for the electron energy distribution function (EEdF) a.d a set of rate equations that describe the change of the formed excited molecules population. The model takes into account most of the physical processes that expected to occur in the interaction region. The results showed good agreement between the calculated thresholds for spark ignition a.d those measured ones for both wavelengths, where the threshold intensities corresponding to the short wavelength (532 nm) are found to be higher than those calculated for the longer one (1064 nm). This result indicates the depletion of the high density of low energy electrons generated through multi-photon ionization at the short wavelength via electron diffusion a.d vibrational excitation. The study of the EEdF a.d its parameters (viz, the temporal evolution of: the electron density, ionization rate electron mean energy, …) revealed the important role played by each physical process to the spark ignition as a function of both laser wavelength a.d gas pressure. More over the study of the time variation of the EEdF explains the characteristics of the ignited spark at the two wavelengths for the tested pressure values.

关键词： Laser Wavelength Hydrogen Gas Threshold Intensity electron Energy distribution Function Combustion spark Ignition

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Numerical Investigation of the Tri-Atomic Ions Formation during Laser Ionization Based on Resonance saturation

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Journal of Applied Mathematics a.d Physics 2014年第12期2卷 1123-1129页

作者： M. A. a.delati M. A. Mahmoud Y. E. E. gamal National Institute of Laser Enhanced sciences Cairo University El Giza Egypt Physics department Faculty of Science Sohag University Sohag Egypt

We present a theoretical investigation of plasma generation in sodium vapor induced by laser radiation tuned to the first resonance line (3s-3P) at λ = 589 ns. A set of rate equations that describe the rate of change of the ground a.d excited states population as well as the temporal variation of the electron energy distribution function (EEdF), beside the formed atomic ion Na+, molecular ion ?a.d tri-atomic ions are solved numerically. The calculations are carried out at different laser energy a.d different sodium atomic vapor densities under the experimental conditions of Tapalian a.d smith (1993) to test the existence of the formed tri-atomic ions. The numerical calculations of the electron energy distribution function (EEdF) show that a.deviation from the Maxwellian distribution due to the super elastic collisions effect. In a.dition to the competition between associative ionization (3P-3P), associative ionization (3P-3d) a.d Molnar-Horn- beck ionization processes for producing , the calculations have also shown that the atomic ions Na+ are formed through the Penning ionization a.d photoionization processes. These results are found to be consistent with the experimental observations.

关键词： Plasma Laser Collisional Ionization Association Ionization Tri-Atomic Ions Photoionization electron Energy distribution Function

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study of Habitat’s Thermal Performance Equipped with an Adsorption Cooling Unit by Geothermal Heat Pump

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Journal of Power a.d Energy Engineering 2021年第8期9卷 26-52页

作者： djanfar el-Maktoume Xavier Chesneau a.doulaye diallo Zely Arivelo Ra.driamanantany Laboratoire de Modélisation Pluridisciplinaire et simulations (LAMPs) Université de Perpignan Via DOMITIA Perpignan France Laboratoire de Thermodynamique Thermique et Combustion (LTTC) de l'Equipe d'Accueil Doctorale Physique du Globe de l’&#201nergie et de l’Environnement (PGEE) Université d’Antananarivo Antananarivo Madagascar Laboratoire d’Enseignement et de Recherche en Energétique Appliquée (LEREA) Université Gamal Abdel Nasser de Conakry Conakry Guinée

This work concerns a modeling of habitat equipped with an adsorption cooling unit powered by a geothermal heat pump in the context of the climate of the Comoros Isla.ds. Cooling unit is a simple system consisting of a... 详细信息

This work concerns a modeling of habitat equipped with an adsorption cooling unit powered by a geothermal heat pump in the context of the climate of the Comoros Islands. Cooling unit is a simple system consisting of an adspan>span>sorber, condenser and evaporator. The modeling of the habitat-air conditioning system was based on a description of heat and mass transfers. The firstsup> sup>law of thermodynamics on the energy conservation using the analogies between heat and electrical transfers is used to establish the equations of the model. Zeolite-methanol pair and Dubinin-Astakhov adsorption model are used to describe the amount of adsorbed mass. The finite difference method applied to a point of the considered exchange surface is used to discretize equations and resolve them. The coupling of the system takes place through a convective transfer between the air inside habitat and the evaporator’s surface. This article presents results for typical November days in Comoros. Different temperatures of habitat with and without a cooling unit show that using the adsorption cooling unit can help lower internal temperatures. We observe a temperature difference of 2.14 K in particular at 2 p.m., if the air conditioning starts at 8 a.m. The influence of the input parameters on the air inside the habitat makes it possible to ass

关键词： Cooling Habitat Adsorption Geothermal Optimization

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