C.A.R.S. temperature measurements and chemical kinetic modelling of autoignition in a methanol-fuelled internal combustion engine

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dc.contributor.advisorRobertson, G Nen_ZA
dc.contributor.authorLockett, R Den_ZA
dc.date.accessioned2016-02-29T12:08:23Z
dc.date.available2016-02-29T12:08:23Z
dc.date.issued1993en_ZA
dc.descriptionBibliography: p. 258-268.en_ZA
dc.description.abstractThe temperature inside the cylinder of a methanol-fuelled single-cylinder Ricardo E6 research engine running under knocking conditions, is measured by means of Coherent Anti-Stokes Raman Spectroscopy (CARS), and the pressure is measured with a pressure transducer. In order to obviate any errors arising from deficiencies in the spectral scaling laws which are commonly used to represent nitrogen Q-branch spectra at high pressure, a purely experimental technique is employed to derive temperatures from CARS spectra by cross-correlation with a reference library of spectra recorded in an accurately calibrated high-pressure high-temperature optical cell. The temperature and pressure profiles obtained from the engine running under knocking conditions, are then used as input data for chemical kinetic modelling of end-gas autoignition. Five published mechanisms (Grotheer et al 1992, Grotheer and Kelm 1989, Norton and Dryer 1989, Dove and Warnatz 1983, .and Esser and Warnatz 1987) are used in the autoignition study, and the results for the different mechanisms are compared. A good qualitative understanding of the mechanism underlying end-gas autoignition in the engine is obtained, although the calculated autoignition points occur slightly earlier than the observed point. A sensitivity analysis of the methanol autoignition system is undertaken, and the importance of the decomposition of hydrogen peroxide and the hydroperoxyl chemistry is demonstrated. The discrepancies between the predicted results of the different mechanisms is shown to be caused by a small number of sensitive reactions for which there are conflicting data. Finally, a linear mode analysis from the geometric qualitative theory of differential equations is performed on the non-linear chemical rate equations. The equilibrium points in the generalised phase space of the non-linear chemical system are shown to be defined in terms of three regions. The equilibrium points are unstable improper nodes in the first region (T < ll00K), unstable focii in the second region ( 1100K<T<1170K), and stable focii in the third region (T> 1170K).en_ZA
dc.identifier.apacitationLockett, R. D. (1993). <i>C.A.R.S. temperature measurements and chemical kinetic modelling of autoignition in a methanol-fuelled internal combustion engine</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Physics. Retrieved from http://hdl.handle.net/11427/17388en_ZA
dc.identifier.chicagocitationLockett, R D. <i>"C.A.R.S. temperature measurements and chemical kinetic modelling of autoignition in a methanol-fuelled internal combustion engine."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Physics, 1993. http://hdl.handle.net/11427/17388en_ZA
dc.identifier.citationLockett, R. 1993. C.A.R.S. temperature measurements and chemical kinetic modelling of autoignition in a methanol-fuelled internal combustion engine. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Lockett, R D AB - The temperature inside the cylinder of a methanol-fuelled single-cylinder Ricardo E6 research engine running under knocking conditions, is measured by means of Coherent Anti-Stokes Raman Spectroscopy (CARS), and the pressure is measured with a pressure transducer. In order to obviate any errors arising from deficiencies in the spectral scaling laws which are commonly used to represent nitrogen Q-branch spectra at high pressure, a purely experimental technique is employed to derive temperatures from CARS spectra by cross-correlation with a reference library of spectra recorded in an accurately calibrated high-pressure high-temperature optical cell. The temperature and pressure profiles obtained from the engine running under knocking conditions, are then used as input data for chemical kinetic modelling of end-gas autoignition. Five published mechanisms (Grotheer et al 1992, Grotheer and Kelm 1989, Norton and Dryer 1989, Dove and Warnatz 1983, .and Esser and Warnatz 1987) are used in the autoignition study, and the results for the different mechanisms are compared. A good qualitative understanding of the mechanism underlying end-gas autoignition in the engine is obtained, although the calculated autoignition points occur slightly earlier than the observed point. A sensitivity analysis of the methanol autoignition system is undertaken, and the importance of the decomposition of hydrogen peroxide and the hydroperoxyl chemistry is demonstrated. The discrepancies between the predicted results of the different mechanisms is shown to be caused by a small number of sensitive reactions for which there are conflicting data. Finally, a linear mode analysis from the geometric qualitative theory of differential equations is performed on the non-linear chemical rate equations. The equilibrium points in the generalised phase space of the non-linear chemical system are shown to be defined in terms of three regions. The equilibrium points are unstable improper nodes in the first region (T < ll00K), unstable focii in the second region ( 1100K<T<1170K), and stable focii in the third region (T> 1170K). DA - 1993 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1993 T1 - C.A.R.S. temperature measurements and chemical kinetic modelling of autoignition in a methanol-fuelled internal combustion engine TI - C.A.R.S. temperature measurements and chemical kinetic modelling of autoignition in a methanol-fuelled internal combustion engine UR - http://hdl.handle.net/11427/17388 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17388
dc.identifier.vancouvercitationLockett RD. C.A.R.S. temperature measurements and chemical kinetic modelling of autoignition in a methanol-fuelled internal combustion engine. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Physics, 1993 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17388en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Physicsen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMethanolen_ZA
dc.titleC.A.R.S. temperature measurements and chemical kinetic modelling of autoignition in a methanol-fuelled internal combustion engineen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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