The Study of a Simplified Hot Plate Method for a Steady-State Thermal Conductivity Measurement

• Main Authors: Chang, Chin-Hsiang, 張錦祥
• Other Authors: Sun, Ming-Tsung
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/86121300396261593721

博士 === 長庚大學 === 機械工程研究所 === 95 === In order to better understand the accuracy of a newly developed simplified hot plate method in measuring steady-state thermal conductivity, a numerical model for simulating the measurement is devised and verified by experimental results to perform the accuracy analysis. The ratios of the thermal conductivity derived from the temperature distribution solutions to that given in the numerical model are obtained and shown. They can be used to correct the systematic error of measurement introduced by the one-dimensional approximation in real applications. Furthermore, the measurement uncertainty due to power control, misalignment of the temperature sensors, and the limitation of sensing devices is also investigated using the numerical model. The results are suitable for the estimation of confidence range in practical measurements. Although the systematic error derived from this study can be use to calibrate the measured thermal conductivity, it is a function of the variable to be measured. Therefore to solve the problem, artificial neural networks (ANNs), which are trained using a variey of simulated measurement given by the numerical model, are used. A trained ANN can be used to predict directly the correct thermal conductivity without calibration using the measurement data. Finally, applying the results of accuracy analysis together with the correction of a prototype using the simplified hot plate method, a new device is designed and built with an accurate temperature control system and a well constructed ANN to promote the practical value of the measuring method.