dc.contributor.author	Hibshman, Randolph Joell II	en
dc.contributor.committeechair	Vandsburger, Uri	en
dc.contributor.committeemember	Dancey, Clinton L.	en
dc.contributor.committeemember	Roby, Richard J.	en
dc.contributor.department	Mechanical Engineering	en
dc.date.accessioned	2014-03-14T21:53:00Z	en
dc.date.adate	1998-10-10	en
dc.date.available	2014-03-14T21:53:00Z	en
dc.date.issued	1998-04-09	en
dc.date.rdate	1999-10-10	en
dc.date.sdate	1998-04-09	en
dc.description.abstract	An experimental study of sooting characteristics of laminar underventillated ethylene non-premixed flames in hot vitiated environments was performed using a modified Wolfhard-Parker co-flowing slot burner. The burner could be operated in "single mode" with a cold air/oxygen mixture as the oxidizer for the non-premixed flame or in varying degrees of "dual mode" where the products of lean premixed hydrogen/air/oxygen flames were used as the oxidizer for the non-premixed flame. Premixed flame stoichiometries of 0.3 and 0.5 were considered for the dual mode cases. Dual mode operation of the burner was intended to simulate the conditions of fuel rich pockets of gas burning in the wake of previously burned fuel/air mixture as typically found in real nonpremixed combustion devices. Dual mode operation introduced competing thermal and chemical effects on soot chemistry. Experimental conditions were chosen to match peak nonpremixed flame temperatures among the cases by varying oxidizer inert (N2) concentration to minimize the dual mode thermal effect. In addition the molecular oxygen (post premixed flame for dual mode cases) and ethylene fuel flow rates were held constant to maintain the same overall equivalence ratio from case to case. Thermocouple thermometry utilizing a rapid insertion technique and radiation corrections yielded the gas temperature field. Soot volume fractions were measured simultaneously with temperature using Thermocouple Particle Densitometry (TPD). Soot volume fraction, particle size and particle number density fields were measured using laser light scattering and extinction. Gas velocities were measured using Particle Imaging Velocimetry (PIV) on the non-premixed flame centerline by seeding the ethylene flow and calculated in the oxidizer flow stream. Porous sinters in the oxidizer slots prevented oxidizer particle seeding required for PIV measurements. In general as the degree of dual mode operation was increased (i.e. increasing stoichiometry of the premixed flames) soot volume fractions decreased, particle sizes increased and soot particle number densities decreased. This trend is suspected to be result of water vapor elevating OH concentrations near the flame front in dual mode operation reducing soot particle nucleation early in the flame by oxidizing soot precursors. The larger particle sizes measured at later stages of dual mode flames are suspected to be the result of lower competition for surface growth species for the lower particle number densities in those flames. Integrated soot volume fraction and particle number fluxes at various heights in the flame decreased with increasing degree of dual mode operation.	en
dc.description.degree	Master of Science	en
dc.identifier.other	etd-93198-12137	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-93198-12137/	en
dc.identifier.uri	http://hdl.handle.net/10919/46521	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	WPCONTEN.PDF	en
dc.relation.haspart	WPappBCD.PDF	en
dc.relation.haspart	WPappA.PDF	en
dc.relation.haspart	WPcpt456.PDF	en
dc.relation.haspart	WPcpt123.PDF	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	diffusion flame	en
dc.subject	laminar	en
dc.subject	coflowing	en
dc.subject	Wolfhard-Parker	en
dc.subject	thermocouple	en
dc.subject	premixed flame	en
dc.subject	nonpremixed flame	en
dc.subject	soot	en
dc.title	An Experimental Study of Soot Formation in Dual Mode Laminar Wolfhard-Parker Flames	en
dc.type	Thesis	en
thesis.degree.discipline	Mechanical Engineering	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	masters	en
thesis.degree.name	Master of Science	en

An Experimental Study of Soot Formation in Dual Mode Laminar Wolfhard-Parker Flames

Files

Original bundle

Collections