Analysis and evaluation of the thermal shock phenomena in the in-cylinder surfaces of a DI diesel engine during its transient operation

Mavropoulos, GC; Rakopoulos, CD; Hountalas, DT

dc.contributor.author	Mavropoulos, GC	en
dc.contributor.author	Rakopoulos, CD	en
dc.contributor.author	Hountalas, DT	en
dc.date.accessioned	2014-03-01T02:04:24Z
dc.date.available	2014-03-01T02:04:24Z
dc.date.issued	2011	en
dc.identifier.issn	0954-4070	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29429
dc.subject	heat transfer	en
dc.subject	unsteady	en
dc.subject	diesel engine	en
dc.subject	transient operation	en
dc.subject	thermal shock	en
dc.subject.classification	Engineering, Mechanical	en
dc.subject.classification	Transportation Science & Technology	en
dc.subject.other	SPARK-IGNITION ENGINE	en
dc.subject.other	INSTANTANEOUS HEAT-TRANSFER	en
dc.subject.other	COMBUSTION-CHAMBER WALLS	en
dc.subject.other	SENSITIVITY-ANALYSIS	en
dc.subject.other	EMISSIONS FORMATION	en
dc.subject.other	FLUX MEASUREMENTS	en
dc.subject.other	FUEL BLENDS	en
dc.subject.other	MODEL	en
dc.subject.other	VALIDATION	en
dc.subject.other	PROPAGATION	en
dc.title	Analysis and evaluation of the thermal shock phenomena in the in-cylinder surfaces of a DI diesel engine during its transient operation	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	This paper presents the results from the analysis of an experimental investigation with the aim of providing an insight into the cyclic thermal shock phenomena occurring in the internal cylinder wall surfaces of a direct injection (DI), air-cooled diesel engine during the initial stage of a transient operation. The mechanism of cyclic heat transfer is investigated during engine transient events, viz. after a sudden change in engine speed and/or load. The experimental installation allowed both long-and short-term signal types to be recorded on a common time reference base during the transient event. Processing of experimental data was accomplished using a modified version of one-dimensional heat conduction theory with Fourier analysis, capable of catering for the special characteristics of transient engine operation. Based on this model, the evolution of local surface heat flux during a transient event was calculated. Two engine transient events are examined, which present a key difference in the way the load and speed changes are imposed on each one. During the analysis of experimental results the most important parameters characterizing thermal shock, such as the heat wave velocity and length of penetration, are quantified for each event, providing a comprehensive insight into the causes and consequences of this dangerous phenomenon. The results, in addition, confirm the theoretical predictions for the development of the thermal field during an engine transient event, as presented by the authors in previous work. Each thermal transient event is characterized by two distinct phases, that is the 'thermodynamic' and the 'structural' one, which are appropriately configured and analysed. From the results it is revealed that in the case of a severe variation, in the first 20 cycles after the beginning of the transient event, the wall surface temperature and heat flux amplitude on the cylinder head was almost three times higher than that observed in the 'normal' temperature oscillations occurring during steady-state operation.	en
heal.publisher	PROFESSIONAL ENGINEERING PUBLISHING LTD	en
heal.journalName	PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING	en
dc.identifier.isi	ISI:000294265300012	en
dc.identifier.volume	225	en
dc.identifier.issue	D9	en
dc.identifier.spage	1265	en
dc.identifier.epage	1289	en