Development Of A Thermal Constant Analytical Instrument Based On The Transient Plane Source Method

Thermal constant(such as thermal conductivity, thermal diffusivity, etc), in particular to assess the thermal conductivity and thermal insulation materials important thermal parameters, related to the material used within many fields. Its measurement theory and testing technology has become a hot research topic in world. Plane Source(Transient Plane Source) method is a measurement method can simultaneously measure the thermal conductivity and thermal diffusivity, with test speed, wide measuring range, suitable for many kinds of material advantages. Currently, there are no developed to measure the thermal conductivity and thermal diffusivity by Transient Plane Source products. Therefore, the development of Transient Plane Source thermal constant analytical instrument has great significance.This thesis aims to develop a high-precision simultaneous measurement of transient plane source thermal constant analytical instrument can measure thermal conductivity and thermal diffusivity. According to the "the Hot disk temperature probe theoretical model", we propose a new model based on the power function; fitting algorithm design, and detailed analysis of the systematic errors of the new model. Experiments proved that the instrument's measurement accuracy and repeatability are to meet the design requirements.The main work of this thesis is following:1. Introducing the basics of heat transfer and thermal physical properties, the main thermal conductivity measurement method, describing the development of a transient plane source thermal constant analytical instrument; the theoretical analysis of transient plane source has been described, Hot disk temperature probe derivation and correction model.2. Describing the overall hardware design, including the Hot disk probe designing and processing, the DC power source voltage control circuits.3. Based on power function for fitting a function of time, proposing a new model based on power function, systematic errors of the new model are analyzed indetail.4. Designing the software program, Writing the instrument of main program and subroutines, programs were debugged.5. Calibration of the instrument system, including the probe calibration temperature coefficient of resistance and the standard resistance calibrating.6. Experiments were designed to measure thermal conductivity and thermal diffusivity multiple sets of samples, data were analyzed and the results were summarized.