Browsing by Author "Wu, SK"

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Inverse determination of surface temperature in thin-film/substrate systems with interface thermal resistance
(2004-07-01)
Wu, SK
;
Chu, HS
;
機械工程學系
;
Department of Mechanical Engineering
This work examines the effect of interface thermal resistance on the estimation of surface temperatures in thin-film/ substrate systems. A radiation-boundary-condition model based on the acoustic mismatch model (AMM) is employed to consider the interface thermal resistance between thin-film and substrate. The inverse beat conduction problem is solved using the space-marching technique. The influences of interface thermal resistance, measurement locations, and measurement errors on this method are studied in detail. Numerical results show that the inverse method accurately estimates surface conditions and temperature distributions in a two-layer system even with an abrupt temperature drop at the interface. Sensor locations and interface thermal resistance only slightly affect the accuracy of the inverse estimation during the transient process when the exact input data (without measurement errors) are applied. However, the inaccuracy might be amplified by the interface thermal resistance and sensor locations if measurement errors exist. (C) 2004 Elsevier Ltd. All rights reserved.
Transient heat conduction in dielectric thin films
(2000)
Chu, HS
;
Wu, SK
;
機械工程學系
;
Department of Mechanical Engineering
This paper discusses transient heat transfer phenomena in solid dielectric thin films from both macroscopic and microscopic points of view. Phonon radiative transfer model as well as Fourier's law and thermal wave theory are utilized to analyze the transient heat conduction phenomena in dielectric thin films. Diamond and GaAs thin films are chosen as the examples to demonstrate the differences between the macroscale and microscale heat transfer models. The phonon radiative transfer model is partially ballistic, partially wavelike, and partially diffusive depends on the film thickness. Phonon radiative transfer model predicts temperature jumps at boundaries due to its ballistic nature when the film thickness is less than the mean free path, A. In contrast, the results predicted by the phonon radiative transfer model approaches to that of Fourier's law when the film thickness is larger than 10 times of the mean free path. The results show that as the ratio of thin film thickness to phonon mean free path, L/Lambda, is greater than 100, Fourier's law is a good approximation to deal with the transient heat transfer problems in dielectric thin films.