Numerical Study of Electric Field Enhanced Combustion

Handle URI:
http://hdl.handle.net/10754/622070
Title:
Numerical Study of Electric Field Enhanced Combustion
Authors:
Han, Jie ( 0000-0002-6176-8684 )
Abstract:
Electric fields can be used to change and control flame properties, for example changing flame speed, enhancing flame stability, or reducing pollutant emission. The ions generated in flames are believed to play the primary role. Although experiments have been carried out to study electric field enhanced combustion, they are not sufficient to explain how the ions in a flame are affected by an electric field. It is therefore necessary to investigate the problem through numerical simulations. In the present work, the electric structure of stabilized CH4/air premixed flames at atmospheric pressure within a direct current field is studied using numerical simulations. This study consists of three parts. First, the transport equations are derived from the Boltzmann kinetic equation for each individual species. Second, a general method for computing the diffusivity and mobility of ions in a gas mixture is introduced. Third, the mechanisms for neutral and charged species are improved to give better predictions of the concentrations of charged species, based on experimental data. Following from this, comprehensive numerical results are presented, including the concentrations and fluxes of charged species, the distributions of the electric field and electric potential, and the electric current-voltage relation. Two new concepts introduced with the numerical results are the plasma sheath and dead zone in the premixed flame. A reactive plasma sheath and a Boltzmann relation sheath are discovered in the region near the electrodes. The plasma sheath penetrates into the flame gas when a voltage is applied, and penetrating further if the voltage is higher. The zone outside the region of sheath penetration is defined as the dead zone. With the two concepts, analytical solutions for the electric field, electric potential and current-voltage curve are derived. The solutions directly describe the electric structure of a premixed flame subject to a DC field. These analytical solutions, together with the discovery of the plasma sheath and dead zone in flames, are the novel contributions of this work.
Advisors:
Bisetti, Fabrizio ( 0000-0001-5162-7805 )
Committee Member:
Im, Hong G. ( 0000-0001-7080-1266 ) ; Farooq, Aamir ( 0000-0001-5296-2197 ) ; Sarathy, S. Mani ( 0000-0002-3975-6206 ) ; v.Oijen, A. Jeroen
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Program:
Mechanical Engineering
Issue Date:
26-Dec-2016
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorBisetti, Fabrizioen
dc.contributor.authorHan, Jieen
dc.date.accessioned2016-12-26T12:13:01Z-
dc.date.available2016-12-26T12:13:01Z-
dc.date.issued2016-12-26-
dc.identifier.urihttp://hdl.handle.net/10754/622070-
dc.description.abstractElectric fields can be used to change and control flame properties, for example changing flame speed, enhancing flame stability, or reducing pollutant emission. The ions generated in flames are believed to play the primary role. Although experiments have been carried out to study electric field enhanced combustion, they are not sufficient to explain how the ions in a flame are affected by an electric field. It is therefore necessary to investigate the problem through numerical simulations. In the present work, the electric structure of stabilized CH4/air premixed flames at atmospheric pressure within a direct current field is studied using numerical simulations. This study consists of three parts. First, the transport equations are derived from the Boltzmann kinetic equation for each individual species. Second, a general method for computing the diffusivity and mobility of ions in a gas mixture is introduced. Third, the mechanisms for neutral and charged species are improved to give better predictions of the concentrations of charged species, based on experimental data. Following from this, comprehensive numerical results are presented, including the concentrations and fluxes of charged species, the distributions of the electric field and electric potential, and the electric current-voltage relation. Two new concepts introduced with the numerical results are the plasma sheath and dead zone in the premixed flame. A reactive plasma sheath and a Boltzmann relation sheath are discovered in the region near the electrodes. The plasma sheath penetrates into the flame gas when a voltage is applied, and penetrating further if the voltage is higher. The zone outside the region of sheath penetration is defined as the dead zone. With the two concepts, analytical solutions for the electric field, electric potential and current-voltage curve are derived. The solutions directly describe the electric structure of a premixed flame subject to a DC field. These analytical solutions, together with the discovery of the plasma sheath and dead zone in flames, are the novel contributions of this work.en
dc.language.isoenen
dc.subjectElectric Fielden
dc.subjectCombustionen
dc.subjectPlasma Shealthen
dc.subjectPremixed flameen
dc.subjectDead Zoneen
dc.titleNumerical Study of Electric Field Enhanced Combustionen
dc.typeDissertationen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberIm, Hong G.en
dc.contributor.committeememberFarooq, Aamiren
dc.contributor.committeememberSarathy, S. Manien
dc.contributor.committeememberv.Oijen, A. Jeroenen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id115864en
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