Sensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flames

Handle URI:
http://hdl.handle.net/10754/621822
Title:
Sensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flames
Authors:
Alquaity, Awad ( 0000-0002-9306-0154 )
Abstract:
With global emission regulations becoming stringent, development of new combustion technologies that meet future emission regulations is essential. In this vein, this dissertation presents the application of sensitive diagnostic tools to validate and improve chemical kinetic mechanisms that play a fundamental role in the design of new combustion technologies. First, a novel high sensitivity laser-based sensor with a wide frequency tuning range (900 – 1000 cm-1) was developed utilizing pulsed cavity ringdown spectroscopy (CRDS) technique. The novel laser-based sensor was illustrated by measuring trace amounts of multiple combustion intermediates, namely ethylene, propene, allene, and 1-butene in a static cell at ambient conditions. Subsequently, pulsed CRDS technique was utilized to develop an ultra-fast, high sensitivity diagnostic to monitor trace concentrations of ethylene in shock tube pyrolysis experiments. This diagnostic represented the first ever successful application of CRDS technique to transient species measurements in a shock tube. The high sensitivity and fast time response (10μs) diagnostic may be utilized for measuring other key neutrals and radicals which are crucial in the oxidation chemistry of practical fuels. Secondly, a quadrupole mass spectrometer (QMS) was employed to measure relative cation mole fractions in atmospheric and low-pressure (30 Torr) flames of methane/oxygen diluted in argon. Lean, stoichiometric and rich flames were 4 examined to evaluate the dependence of ion chemistry on flame stoichiometry. Spatial distribution of cations was compared with predictions of an existing ion chemistry model. Based on the extensive measurements carried out in this work, modifications were suggested to improve the ion chemistry model to enhance the fidelity of such mechanisms. In-depth understanding of flame ion chemistry is vital to model the interaction of flames with electric fields and thereby pave the way to enable active combustion control for increased efficiency and reduced emissions. Finally, a compact fast time-response time-of-flight mass spectrometer (TOFMS) was coupled to the shock tube through a pin-hole end-wall to enable timeresolved species concentration measurements. This diagnostic tool was demonstrated by investigating the decomposition of 1,3,5-trioxane over a wide range of shock conditions. Reaction rate coefficients were extracted by the best fit to the experimentally measured species time-histories. TOF-MS coupled to the shock tube is an ideal diagnostic tool for developing kinetic mechanisms for future fuels due to its ability to simultaneously measure several species during fuel pyrolysis/oxidation processes.
Advisors:
Farooq, Aamir ( 0000-0001-5296-2197 )
Committee Member:
Dibble, Robert ( 0000-0002-4002-9356 ) ; Sarathy, S. Mani ( 0000-0002-3975-6206 ) ; Chung, Suk-Ho ( 0000-0001-8782-312X ) ; Rieker, Gregory
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Program:
Mechanical Engineering
Issue Date:
1-Nov-2016
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorFarooq, Aamiren
dc.contributor.authorAlquaity, Awaden
dc.date.accessioned2016-11-13T12:01:14Z-
dc.date.available2016-11-13T12:01:14Z-
dc.date.issued2016-11-01-
dc.identifier.urihttp://hdl.handle.net/10754/621822-
dc.description.abstractWith global emission regulations becoming stringent, development of new combustion technologies that meet future emission regulations is essential. In this vein, this dissertation presents the application of sensitive diagnostic tools to validate and improve chemical kinetic mechanisms that play a fundamental role in the design of new combustion technologies. First, a novel high sensitivity laser-based sensor with a wide frequency tuning range (900 – 1000 cm-1) was developed utilizing pulsed cavity ringdown spectroscopy (CRDS) technique. The novel laser-based sensor was illustrated by measuring trace amounts of multiple combustion intermediates, namely ethylene, propene, allene, and 1-butene in a static cell at ambient conditions. Subsequently, pulsed CRDS technique was utilized to develop an ultra-fast, high sensitivity diagnostic to monitor trace concentrations of ethylene in shock tube pyrolysis experiments. This diagnostic represented the first ever successful application of CRDS technique to transient species measurements in a shock tube. The high sensitivity and fast time response (10μs) diagnostic may be utilized for measuring other key neutrals and radicals which are crucial in the oxidation chemistry of practical fuels. Secondly, a quadrupole mass spectrometer (QMS) was employed to measure relative cation mole fractions in atmospheric and low-pressure (30 Torr) flames of methane/oxygen diluted in argon. Lean, stoichiometric and rich flames were 4 examined to evaluate the dependence of ion chemistry on flame stoichiometry. Spatial distribution of cations was compared with predictions of an existing ion chemistry model. Based on the extensive measurements carried out in this work, modifications were suggested to improve the ion chemistry model to enhance the fidelity of such mechanisms. In-depth understanding of flame ion chemistry is vital to model the interaction of flames with electric fields and thereby pave the way to enable active combustion control for increased efficiency and reduced emissions. Finally, a compact fast time-response time-of-flight mass spectrometer (TOFMS) was coupled to the shock tube through a pin-hole end-wall to enable timeresolved species concentration measurements. This diagnostic tool was demonstrated by investigating the decomposition of 1,3,5-trioxane over a wide range of shock conditions. Reaction rate coefficients were extracted by the best fit to the experimentally measured species time-histories. TOF-MS coupled to the shock tube is an ideal diagnostic tool for developing kinetic mechanisms for future fuels due to its ability to simultaneously measure several species during fuel pyrolysis/oxidation processes.en
dc.language.isoenen
dc.subjectMid-IR Sensitive Laser Sensoren
dc.subjectCombustion Diagnosticsen
dc.subjectShock Tubeen
dc.subjectIon Chemistryen
dc.subjectMass Spectrometeren
dc.subjectLaminar Flamesen
dc.titleSensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flamesen
dc.typeDissertationen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberDibble, Roberten
dc.contributor.committeememberSarathy, S. Manien
dc.contributor.committeememberChung, Suk-Hoen
dc.contributor.committeememberRieker, Gregoryen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id118387en
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