A study on phonon heat transfer by solving integral equation and modified hyperbolic models

• Main Authors: Chih-Lung Weng, 翁誌隆
• Other Authors: Chih-Yang Wu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/25102111702690969841

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 96 === The purpose of this work is to investigate heat trasnsfer in a diamond thin film. Two methods based on the equation of phonon radiative transport (EPRT) are considered. First, we transform the EPRT into an integral equation, and then solve the equation by the quadrature method (QM). The results obtained by the QM and by the discrete ordinate method are compared. The results obtained by the QM with less position and direction grids agree well with those obtained by the discrete ordinate method. The former is more accurate than the latter in acoustically thin media, but the former takes more computational time in acoustically thick media. Then, the temporal profile of heat flux profiles of diamond thin films exposed to thermal pulses are discussed. Next, the Schuster-Schwarzschild approximation is used to develop modified boundary conditions of a hyperbolic model in which the hyperbolic heat conduction equation is modified by using the approximation to make heat wave speed to be the same as the EPRT. The results obtained by the modified hyperbolic equation with modified boundary conditions show batter agreement with those obtained by the QM around the boundaries and the wave front.