Effects of fouling on the efficiency of heat exchangers in lignite utility boilers

Bergeles, G; Bouris, D; Yianneskis, M; Balabani, S; Kravaritis, A; Itskos, S

dc.contributor.author	Bergeles, G	en
dc.contributor.author	Bouris, D	en
dc.contributor.author	Yianneskis, M	en
dc.contributor.author	Balabani, S	en
dc.contributor.author	Kravaritis, A	en
dc.contributor.author	Itskos, S	en
dc.date.accessioned	2014-03-01T01:12:48Z
dc.date.available	2014-03-01T01:12:48Z
dc.date.issued	1997	en
dc.identifier.issn	1359-4311	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/12253
dc.subject	Ash deposition model	en
dc.subject	Fouling	en
dc.subject	Heat exchangers	en
dc.subject	Laser Doppler Anemometry	en
dc.subject.classification	Thermodynamics	en
dc.subject.classification	Energy & Fuels	en
dc.subject.classification	Engineering, Mechanical	en
dc.subject.classification	Mechanics	en
dc.subject.other	Coal fired boilers	en
dc.subject.other	Energy efficiency	en
dc.subject.other	Flow visualization	en
dc.subject.other	Fouling	en
dc.subject.other	Heat transfer	en
dc.subject.other	Laser Doppler velocimeters	en
dc.subject.other	Lignite	en
dc.subject.other	Mathematical models	en
dc.subject.other	Particles (particulate matter)	en
dc.subject.other	Tubes (components)	en
dc.subject.other	Two phase flow	en
dc.subject.other	Laser Doppler anemometry	en
dc.subject.other	Heat exchangers	en
dc.title	Effects of fouling on the efficiency of heat exchangers in lignite utility boilers	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S1359-4311(97)00006-9	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S1359-4311(97)00006-9	en
heal.language	English	en
heal.publicationDate	1997	en
heal.abstract	The work presented in this article is directed towards the understanding of the mechanism of ash deposition on the surfaces of tubes of heat exchangers in lignite utility boilers and the evaluation of the influence of fouling on heat exchanger efficiency. For this purpose a numerical model was developed to predict the deposition of particles onto the heat transfer surfaces. The deposition model is combined with a numerical procedure that solves the two phase flow and temperature field around the tubes of the heat exchanger. Predictions of the flow field in both in-line and staggered tube bundles are validated through comparisons with experimental measurements that are conducted in laboratory model geometries. Experimental techniques include laser-sheet flow visualisation and laser Doppler Anemometry (LDA). Observations in full scale geometries of lignite utility boiler heat exchangers that are in current operation are provided by the industrial partner. The results of the work performed indicate that the maximum deposit height on the surface of the first tube is reached in about two weeks for a staggered tube bundle arrangement. It is the actual spacing of the tube arrangement that plays an important role in reducing the fouling rate while closely spaced tubes in in-line arrangements show signs of bridge formation between subsequent tube rows. (C) European Communities 1997. Published by Elsevier Science Ltd.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	Applied Thermal Engineering	en
dc.identifier.doi	10.1016/S1359-4311(97)00006-9	en
dc.identifier.isi	ISI:A1997YC80500006	en
dc.identifier.volume	17	en
dc.identifier.issue	8-10	en
dc.identifier.spage	739	en
dc.identifier.epage	749	en