Study of an integrated thermal sensor in different operational modes, under laminar, transitional and turbulent flow regimes

Stamatopoulos, Ch; Petropoulos, A; Mathioulakis, DS; Kaltsas, G

dc.contributor.author	Stamatopoulos, Ch	en
dc.contributor.author	Petropoulos, A	en
dc.contributor.author	Mathioulakis, DS	en
dc.contributor.author	Kaltsas, G	en
dc.date.accessioned	2014-03-01T01:29:14Z
dc.date.available	2014-03-01T01:29:14Z
dc.date.issued	2008	en
dc.identifier.issn	0894-1777	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/19180
dc.subject	Difference Operator	en
dc.subject	Electrical Resistance	en
dc.subject	Gas Flow	en
dc.subject	Modes of Operation	en
dc.subject	Probability Density Function	en
dc.subject	Reynolds Number	en
dc.subject	Temperature Gradient	en
dc.subject	Turbulent Flow	en
dc.subject.classification	Thermodynamics	en
dc.subject.classification	Engineering, Mechanical	en
dc.subject.classification	Physics, Fluids & Plasmas	en
dc.subject.other	Aerodynamics	en
dc.subject.other	Reynolds number	en
dc.subject.other	Turbulence	en
dc.subject.other	Flow regimes	en
dc.subject.other	Flow sensors	en
dc.subject.other	Gas flowing	en
dc.subject.other	Operational modes	en
dc.subject.other	Reynolds	en
dc.subject.other	Sensors	en
dc.title	Study of an integrated thermal sensor in different operational modes, under laminar, transitional and turbulent flow regimes	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.expthermflusci.2008.06.003	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.expthermflusci.2008.06.003	en
heal.language	English	en
heal.publicationDate	2008	en
heal.abstract	The behaviour of a thermal flow sensor attached to the wall of a square tube is examined, exposed to gas flow for Reynolds numbers in the range 0-4.1 × 104. Consisting of a polysilicon heater and a pair of thermopiles, the sensor's three output signals (heater power, its electric resistance and the thermopile signal) are analyzed as a function of Re. Employing three different modes of operation (constant power (CP), constant voltage (CV) and constant temperature (CT)), it was found that the sensor sensitivity maximizes in CT mode. Heater power and its resistance vary with Rea where a changes significantly for Re > 2000. The thermopile signal, which corresponds to the streamwise temperature gradient across the heater, in contrast to the other two signals, is more sensitive in detecting flow disturbances. Its fluctuations increase with a high rate close to Re = 1800, a value which is smaller than the corresponding increase of the other two signals. The probability density function (pdf) of its fluctuations is negatively skewed consistently for the range 1500 < Re < 11,000 while for Re > 11,000 it turns to a symmetric one. The pdf of the other two signals do not show any systematic trends with Re. The most striking difference of the thermopile signal behaviour compared to the other two is its multivalued relationship with Re in the range 2000 < Re < 11,000. © 2008 Elsevier Inc. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE INC	en
heal.journalName	Experimental Thermal and Fluid Science	en
dc.identifier.doi	10.1016/j.expthermflusci.2008.06.003	en
dc.identifier.isi	ISI:000259747900028	en
dc.identifier.volume	32	en
dc.identifier.issue	8	en
dc.identifier.spage	1687	en
dc.identifier.epage	1693	en