Browsing by Author "CHU, HS"

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ANALYSIS OF THERMAL-STRESSES DUE TO MOVING FRICTIONAL LOAD IN AN INFINITE ELASTIC LAYERED MEDIUM
(1989)
CHEN, LS
;
CHU, HS
;
WU, JH
;
機械工程學系
;
Department of Mechanical Engineering
BOLOMETRIC RESPONSE OF HIGH-T-C SUPERCONDUCTING DETECTORS TO OPTICAL PULSES AND CONTINUOUS WAVES
(1995-05-01)
CHEN, RC
;
WU, JP
;
CHU, HS
;
交大名義發表
;
機械工程學系
This work presents a thermal analysis on predicting the temperature increase and the voltage response of high-T-c superconducting bolometers. Two heat transfer models, that is, the surface heating model and the heat generation model considering the skin depth, are introduced and compared. The surface heating model is found to be valid only for situations where the skin depth is much smaller than the film thickness. To consider the thermal boundary resistance between film and substrate, a radiation-boundary-condition model based on acoustic mismatch model (AMM) and an interfacial-layer model (ILM) are employed. The thermal boundary resistance significantly influences the voltage response. Additionally, several common substrates are examined. SrTiO3 (100) or LaAlO3 (100) is a better substrate for high-T-c superconducting bolometers. One interesting finding was that when compared with experimental data, all the theoretical values from the present study as well as the other previously theoretical treatment overestimate the voltage response near the transition temperature.
COMBINED CONDUCTION AND RADIATION IN ABSORBING, EMITTING AND ANISOTROPICALLY-SCATTERING, CONCENTRIC, SPHERICAL MEDIA
(1991-10-01)
CHU, HS
;
WENG, LC
;
TSENG, CJ
;
交大名義發表
;
機械工程學系
The steady energy transfer by simultaneous conduction and radiation in an absorbing, emitting and anisotropically-scattering medium has been studied theoretically. The medium is confined between two concentric, gray, diffuse and/or specular spherical surfaces which are isothermal but at different temperatures. The radiative transfer equation is solved by using the P3-approximation method which results in four coupled ordinary differential equations (ODEs). The set of the four ODEs and energy equation is solved as a two-point boundary-value problem. The effects of the ratio of the conduction-to-radiation parameter, single-scattering albedo, the scattering phase function, and boundary reflectivities on the temperatures and heat-flux distributions in the medium are examined in detail.
COMBINED CONDUCTION AND RADIATION IN ABSORBING, EMITTING AND ANISOTROPICALLY-SCATTERING, CONCENTRIC, SPHERICAL MEDIA
(1991-10-01)
CHU, HS
;
WENG, LC
;
TSENG, CJ
;
機械工程學系
;
Department of Mechanical Engineering
The steady energy transfer by simultaneous conduction and radiation in an absorbing, emitting and anisotropically-scattering medium has been studied theoretically. The medium is confined between two concentric, gray, diffuse and/or specular spherical surfaces which are isothermal but at different temperatures. The radiative transfer equation is solved by using the P3-approximation method which results in four coupled ordinary differential equations (ODEs). The set of the four ODEs and energy equation is solved as a two-point boundary-value problem. The effects of the ratio of the conduction-to-radiation parameter, single-scattering albedo, the scattering phase function, and boundary reflectivities on the temperatures and heat-flux distributions in the medium are examined in detail.
CONDUCTION RADIATION INTERACTION IN ABSORBING, EMITTING, AND ANISOTROPICALLY SCATTERING MEDIA WITH VARIABLE THERMAL-CONDUCTIVITY
(1992-07-01)
CHU, HS
;
TSENG, CJ
;
交大名義發表
;
National Chiao Tung University
HYBRID LAPLACE TRANSFORM FINITE-ELEMENT METHOD FOR TRANSIENT THERMOELASTIC PROBLEM OF COMPOSITE HOLLOW CYLINDER
(1990)
CHEN, LS
;
CHU, HS
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
RADIATIVE HEAT-TRANSFER IN ULTRA-FINE POWDER INSULATIONS
(1988-08-01)
CHU, HS
;
STRETTON, AJ
;
TIEN, CL
;
機械工程學系
;
Department of Mechanical Engineering
STUDY ON THE INTRINSIC THERMAL-STABILITY OF ANISOTROPIC THIN-FILM SUPERCONDUCTORS WITH A LINE HEAT-SOURCE
(1991-08-01)
CHEN, RC
;
CHU, HS
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
This paper presents an analytical method to investigate the intrinsic thermal stability of anisotropic thin film superconductors. A three-dimensional analysis is introduced to consider an instantaneous release of energy in the form of a finite length line source. Through the transformation of coordiantes, an isotropic form of heat conduction equation is obtained. To solve this initial and boundary value problem, the method of separation of variables is employed, which gives an exact solution. The results of limiting cases of this study are compared with those of two previous investigations. Results from this study also show that the anisotropy of highly orientated films of superconductors has a great impact on the thermal stability. The stability parameter also depends on the location of the line source, the length of the line source, the magnitude of disturbance energy, the Biot number and the aspect ratio in the plane of thin film and normal to it.
STUDY ON THE INTRINSIC THERMAL-STABILITY OF THIN-FILM SUPERCONDUCTORS DUE TO A POINT HEAT-SOURCE
(1992-09-01)
CHU, HS
;
CHEN, RC
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
Intrinsic thermal stability denotes a situation where a superconductor can carry the operating current without Joule heating at all times after the occurrence of a localized release of thermal disturbance. The present work deals with the intrinsic thermal stability of an anisotropic thin-film superconductor under a localized release of thermal energy. A three-dimensional analysis is introduced to consider an instantaneous release of energy in the form of a point source at different locations. Through the transformation of coordinate, an exact solution is obtained by the method of separation of variables. Results from this study indicate that the thermal stability parameter of highly oriented films of superconductors is strongly under the influence of anisotropy. The stability parameter also depends on the location of point source, the amount of disturbance energy, the Biot number, and the aspect ratio in the plane of thin film and normal to it.
THERMAL-ANALYSIS OF HIGH-T(C) SUPERCONDUCTING BOLOMETERS
(1993-12-01)
WU, JP
;
CHEN, RC
;
CHU, HS
;
交大名義發表
;
機械工程學系
In this work we have presented a 2D analysis on predicting the temperature increase and the voltage response of high-T(c) superconducting bolometers. A heat generation model is used to consider absorption of irradiation of energy by film. The type of laser beam is continuous waves (CW). To consider the thermal boundary resistance, a radiation-boundary-condition model based on acoustic mismatch model (AMM) is employed. The effects of the incident energy and radius of laser beam, as well as the thermal conductivity ratio in x and y directions for thin-film superconductors on the voltage response are investigated. The results of our work are also compared with previously experimental and 1D theoretical analyses for various initial temperatures.
TRANSIENT COMBINED CONDUCTION AND RADIATION IN AN ABSORBING, EMITTING AND ANISOTROPICALLY-SCATTERING MEDIUM WITH VARIABLE THERMAL-CONDUCTIVITY
(1992-07-01)
TSENG, CJ
;
CHU, HS
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
TRANSIENT COMBINED CONDUCTION AND RADIATION IN ANISOTROPICALLY SCATTERING SPHERICAL MEDIA
(1992-07-01)
CHU, HS
;
WENG, LC
;
機械工程學系
;
Department of Mechanical Engineering
TRANSIENT NATURAL-CONVECTION HEAT-TRANSFER BETWEEN CONCENTRIC SPHERES
(1993-09-01)
CHU, HS
;
LEE, TS
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交大名義發表
;
機械工程學系
;
National Chiao Tung University
The transient laminar natural convection heat transfer of fluids between two concentric isothermal spheres is investigated theoretically. The fluid is initially at rest and then the inner wall is subjected to a step change of temperature. The stream function/vorticity formulation is employed for the analysis because of the symmetry of the problem. The transient behavior of the flow field and its subsequent effect on the temperature distribution for different Rayleigh numbers and radius ratios are analyzed by finite difference methods. Forward differences are used for the time derivatives and second-order central differences for the space derivatives. The alternating direction implicit method is used for solution of the discretization equations. The results show that the Rayleigh number and radius ratio have a profound influence on the temperature and flow fields. The results of average Nusselt numbers are also compared with those of previous experimental and numerical investigations. Excellent agreement is obtained.
TRANSIENT THERMAL-STRESSES DUE TO PERIODIC MOVING FRICTIONAL LOAD IN LAYERED MEDIA
(1989)
CHEN, LS
;
CHU, HS
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
TRANSIENT THERMAL-STRESSES DUE TO PERIODICALLY MOVING LINE HEAT-SOURCE OF COMPOSITE HOLLOW CYLINDER
(1990)
CHEN, LS
;
CHU, HS
;
機械工程學系
;
Department of Mechanical Engineering
TRANSIENT THERMAL-STRESSES OF A COMPOSITE HOLLOW CYLINDER HEATED BY A MOVING LINE SOURCE
(1989)
CHEN, LS
;
CHU, HS
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
TRANSIENT THERMOELASTIC PROBLEM OF RING-STIFFENED HOLLOW CYLINDER HEATED BY A MOVING LINE SOURCE
(1991)
CHEN, LS
;
CHU, HS
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
The transient temperature and thermal stress distributions of a ring-stiffened hollow cylinder are analyzed. The cylinder is heated by a moving line source on its inner boundary and cooled convectively on the exterior surface. To solve this problem, the Laplace transform and finite-element method are adopted. In addition, the inverse Laplace transform is accomplished by utilizing the Fourier series technique. The effects of width and thickness of the stiffening ring on the temperature and thermal stress distributions are the main factors investigated in this article. The results show that the stiffening ring can function as a fin and the axial thermal stress dominates the thermal stress field.