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dc.contributor.authorIzadi Najafabadi, Mohammad
dc.contributor.authorSomers, Bart
dc.contributor.authorJohansson, Bengt
dc.contributor.authorDam, Nico
dc.identifier.citationIzadi Najafabadi M, Somers B, Johansson B, Dam N (2017) Combustion stratification study of partially premixed combustion using Fourier transform analysis of OH* chemiluminescence images. International Journal of Engine Research: 146808741774027. Available:
dc.description.abstractA relatively high level of stratification (qualitatively: lack of homogeneity) is one of the main advantages of partially premixed combustion over the homogeneous charge compression ignition concept. Stratification can smooth the heat release rate and improve the controllability of combustion. In order to compare stratification levels of different partially premixed combustion strategies or other combustion concepts, an objective and meaningful definition of “stratification level” is required. Such a definition is currently lacking; qualitative/quantitative definitions in the literature cannot properly distinguish various levels of stratification. The main purpose of this study is to objectively define combustion stratification (not to be confused with fuel stratification) based on high-speed OH* chemiluminescence imaging, which is assumed to provide spatial information regarding heat release. Stratification essentially being equivalent to spatial structure, we base our definition on two-dimensional Fourier transforms of photographs of OH* chemiluminescence. A light-duty optical diesel engine has been used to perform the OH* bandpass imaging on. Four experimental points are evaluated, with injection timings in the homogeneous regime as well as in the stratified partially premixed combustion regime. Two-dimensional Fourier transforms translate these chemiluminescence images into a range of spatial frequencies. The frequency information is used to define combustion stratification, using a novel normalization procedure. The results indicate that this new definition, based on Fourier analysis of OH* bandpass images, overcomes the drawbacks of previous definitions used in the literature and is a promising method to compare the level of combustion stratification between different experiments.
dc.description.sponsorshipThe author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/2007-2013/ under REA grant agreement No. 607214.
dc.publisherSAGE Publications
dc.rightsThis is under the creative common license.
dc.subjectCombustion stratification
dc.subjectpartially premixed combustion
dc.subjectOH* chemiluminescence
dc.subjectinternal combustion engine
dc.subjectFourier transform
dc.titleCombustion stratification study of partially premixed combustion using Fourier transform analysis of OH* chemiluminescence images
dc.contributor.departmentClean Combustion Research Center
dc.contributor.departmentMechanical Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalInternational Journal of Engine Research
dc.eprint.versionPublisher's Version/PDF
dc.contributor.institutionMultiphase and Reactive Flows, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
kaust.personJohansson, Bengt

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