Investigating the effect of crevice flow on internal combustion engines using a new simple crevice model implemented in a CFD code

Rakopoulos, CD; Kosmadakis, GM; Dimaratos, AM; Pariotis, EG

dc.contributor.author	Rakopoulos, CD	en
dc.contributor.author	Kosmadakis, GM	en
dc.contributor.author	Dimaratos, AM	en
dc.contributor.author	Pariotis, EG	en
dc.date.accessioned	2014-03-01T01:35:53Z
dc.date.available	2014-03-01T01:35:53Z
dc.date.issued	2011	en
dc.identifier.issn	0306-2619	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21238
dc.subject	Engine	en
dc.subject	CFD code	en
dc.subject	Crevice model	en
dc.subject	Blow-by	en
dc.subject	Motoring	en
dc.subject	Heat transfer	en
dc.subject.classification	Energy & Fuels	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.other	TURBOCHARGED DIESEL-ENGINE	en
dc.subject.other	PISTON-RING DYNAMICS	en
dc.subject.other	K-EPSILON MODELS	en
dc.subject.other	COMPLEX GEOMETRIES	en
dc.subject.other	MULTIZONE MODEL	en
dc.subject.other	TURBULENT FLOWS	en
dc.subject.other	SPARK-IGNITION	en
dc.subject.other	COLD START	en
dc.subject.other	BLOW-BY	en
dc.subject.other	CYLINDER	en
dc.title	Investigating the effect of crevice flow on internal combustion engines using a new simple crevice model implemented in a CFD code	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.apenergy.2010.07.012	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.apenergy.2010.07.012	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	A theoretical investigation is conducted to examine the way the crevice regions affect the mean cylinder pressure, the in-cylinder temperature, and the velocity field of internal combustion engines running at motoring conditions. For the calculation of the wall heat flux, a wall heat transfer formulation developed by the authors is used, while for the simulation of the crevices and the blow-by a newly developed simplified simulation model is presented herein. These sub-models are incorporated into an in-house Computational Fluid Dynamics (CFD) code. The main advantage of the new crevice model is that it can be applied in cases where no detailed information of the ring-pack configuration is available, which is important as this information is rarely known or may have been altered during the engine's life. Thus, an adequate estimation of the blow-by effect on the cylinder pressure can be drawn. To validate the new model, the measured in-cylinder pressure traces of a diesel engine, located at the authors' laboratory, running under motoring conditions at four engine speeds were used as reference, together with measured velocity profiles and turbulence data of a motored spark-ignition engine. Comparing the predicted and measured cylinder pressure traces of the diesel engine for all cases examined, it is observed that by incorporating the new crevice sub-model into the in-house CFD code, significant improvements on the predictive accuracy of the model is obtained. The calculated cylinder pressure traces almost coincide with the measured ones, thus avoiding the use of any calibration constants as would have been the case with the crevice effect omitted. Concerning the radial and swirl velocity profiles and the turbulent kinetic energy measured in the spark-ignition engine, the validation process revealed that the developed crevice model has a minor influence on the aforementioned parameters. The theoretical study has been extended by investigating in the same spark-ignition engine, during the induction and compression strokes, the way crevice flow affects the thermodynamic properties of the air trapped in the cylinder. (C) 2010 Elsevier Ltd. All rights reserved.	en
heal.publisher	ELSEVIER SCI LTD	en
heal.journalName	APPLIED ENERGY	en
dc.identifier.doi	10.1016/j.apenergy.2010.07.012	en
dc.identifier.isi	ISI:000283209300010	en
dc.identifier.volume	88	en
dc.identifier.issue	1	en
dc.identifier.spage	111	en
dc.identifier.epage	126	en