Experimental evaluation of local instantaneous heat transfer characteristics in the combustion chamber of air-cooled direct injection diesel engine

Rakopoulos, CD; Mavropoulos, GC

dc.contributor.author	Rakopoulos, CD	en
dc.contributor.author	Mavropoulos, GC	en
dc.date.accessioned	2014-03-01T01:28:22Z
dc.date.available	2014-03-01T01:28:22Z
dc.date.issued	2008	en
dc.identifier.issn	0360-5442	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18822
dc.subject	heat transfer coefficient	en
dc.subject	instantaneous	en
dc.subject	diesel engine	en
dc.subject	air-cooled	en
dc.subject	transient	en
dc.subject.classification	Thermodynamics	en
dc.subject.classification	Energy & Fuels	en
dc.subject.other	MODEL	en
dc.subject.other	COMPONENTS	en
dc.subject.other	FLUXES	en
dc.subject.other	BLENDS	en
dc.subject.other	WALLS	en
dc.title	Experimental evaluation of local instantaneous heat transfer characteristics in the combustion chamber of air-cooled direct injection diesel engine	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.energy.2008.02.003	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.energy.2008.02.003	en
heal.language	English	en
heal.publicationDate	2008	en
heal.abstract	An experimental analysis is conducted investigating the differences between the variations of overall and local instantaneous heat transfer coefficients, during the engine cycle, in the combustion chamber walls of a direct injection (DI), air-cooled diesel engine located at the authors' laboratory. For this purpose, a novel experimental installation is developed, which separates the engine transient temperature signals into two parts, namely the long- and the short-term response ones, processed in two independent data acquisition systems. Moreover, a new pre-amplification unit for fast response thermocouples, appropriate heat flux sensors and an object-oriented control code for fast data acquisition have been designed and applied. Experimentally obtained cylinder pressure diagrams are used as a basis for the calculation of the overall heat transfer coefficients, whereas one-dimensional heat conduction theory with Fourier analysis techniques, combined with an iterative procedure between calculated and measured temperature data, are implemented in order to calculate the instantaneous local heat transfer coefficients in the engine cylinder. Analysis of the experimental results reveals interesting aspects of transient engine heat transfer. Significant differences are disclosed between the overall and local heat transfer coefficient variations, with the importance of the latter one on engine design being emphasized. The local heat transfer coefficient on the cylinder head is quantified based on the experimental data. The effect of engine speed and load as well as of the air swirling motion on the heat transfer variations are presented. From the analysis results it is concluded that the instantaneous heat transfer variation is non-uniform, unlike its values calculated from standard correlations that assume spatial uniformity, noting that such information, especially for air-cooled diesel engines, seems to be very scarce in the open literature. (C) 2008 Elsevier Ltd. All rights reserved.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	ENERGY	en
dc.identifier.doi	10.1016/j.energy.2008.02.003	en
dc.identifier.isi	ISI:000257010100008	en
dc.identifier.volume	33	en
dc.identifier.issue	7	en
dc.identifier.spage	1084	en
dc.identifier.epage	1099	en