Evaluation of heat transfer coefficient of tungsten filaments at low pressures and high temperatures

Chondrakis, NG; Topalis, FV

dc.contributor.author	Chondrakis, NG	en
dc.contributor.author	Topalis, FV	en
dc.date.accessioned	2014-03-01T01:35:39Z
dc.date.available	2014-03-01T01:35:39Z
dc.date.issued	2011	en
dc.identifier.issn	1359-4311	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21145
dc.subject	Electronic ballast	en
dc.subject	Fluorescent lamps	en
dc.subject	Heat transfer coefficient	en
dc.subject	Low gas pressure	en
dc.subject	Nitrogen	en
dc.subject	Preheat ratio	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	Electronic ballasts	en
dc.subject.other	Experimental conditions	en
dc.subject.other	Experimental methods	en
dc.subject.other	Heating process	en
dc.subject.other	High temperature	en
dc.subject.other	Low gas pressure	en
dc.subject.other	Low pressures	en
dc.subject.other	Normal operations	en
dc.subject.other	Operating frequency	en
dc.subject.other	Preheat ratio	en
dc.subject.other	Preheating process	en
dc.subject.other	Sealed vessels	en
dc.subject.other	Starting conditions	en
dc.subject.other	Tungsten filaments	en
dc.subject.other	Ballasts (lamp)	en
dc.subject.other	Electron emission	en
dc.subject.other	Fluorescence	en
dc.subject.other	Fluorescent lamps	en
dc.subject.other	Heat transfer coefficients	en
dc.subject.other	Heating	en
dc.subject.other	Lighting	en
dc.subject.other	Mathematical models	en
dc.subject.other	Nitrogen	en
dc.subject.other	Tungsten	en
dc.subject.other	Filaments (lamp)	en
dc.title	Evaluation of heat transfer coefficient of tungsten filaments at low pressures and high temperatures	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.applthermaleng.2010.09.005	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.applthermaleng.2010.09.005	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	The paper presents an experimental method for the evaluation of the heat transfer coefficient of tungsten filaments at low pressures and high temperatures. For this purpose an electrode of a T5 fluorescent lamp was tested under low pressures with simultaneous heating in order to simulate the starting conditions in the lamp. It was placed in a sealed vessel in which the pressure was varied from 1 kM (kilo micron) to 760 kM. The voltage applied to the electrode was in the order of the filament's voltage of the lamp at the normal operation with the ballast during the preheating process. The operating frequency ranged from DC to 50 kHz. The experiment targeted on estimating the temperature of the electrode at the end of the first and the ninth second after initiating the heating process. Next, the heat transfer coefficient was calculated at the specific experimental conditions. A mathematical model based on the results was developed that estimates the heat transfer coefficient. The experiments under different pressures confirm that the filament's temperature strongly depends on the pressure. (C) 2010 Elsevier Ltd. All rights reserved.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	Applied Thermal Engineering	en
dc.identifier.doi	10.1016/j.applthermaleng.2010.09.005	en
dc.identifier.isi	ISI:000284668200014	en
dc.identifier.volume	31	en
dc.identifier.issue	2-3	en
dc.identifier.spage	258	en
dc.identifier.epage	267	en