Research And Design Of Measuring System Of Thermal Boundary Resistance Using Laser Photothermal Method

In view of relating to the heat analyses calculation, design and making of the aerospace devices, the thermal boundary resistance becomes the key problem of thermal control technique in aerospace. The cryocooler directly cooled system has been widely applied in the high temperature superconducting (high-Tc) techniques. The changes of heat transfer mechanism resulted in that thermal boundary resistance and its optimization design have become a key techniques and science problem in directly cooled technology. In the fields of electronictechnology, the design of the heat dissipation of the high-power IC chip. The performance and reliability of electronic product are greatly decided by their thermal boundary resistance.This dissertation emphasises on beginning with the measuring method of the thermal boundary resistance particularly, and puts forward a new kind of measurement which is named laser photothermal method to measure the thermal boundary resistance, based on it and also has designed a set of experimental provisions which is used to measure the thermal boundary resistance. During the course of study about the thermal boundary resistance, for the most part of it set up on the foundation of the experiment that measured the thermal boundary resistance, and the accuracy, dependability of the experimental data have influenced the research work to the thermal boundary resistance directly. Because in the course of actual measurement the traditional measuring method exists some measuring errors and deficiencies , they have influenced the study of the interface thermal resistance too. So we need to look for a new method to solve this problem. The main research contents of the thesis are as follows:Firstly , it introduces the research purpose and the meaning of the subject ,and outlines the producing mechanism, the definition and some influenced factors of the low-temperature thermal boundary resistance in terms of macroscopic. And then introduces the current studying situation both at home and abroad of the solid thermal boundary resistance briefly.Secondly, the paper informs the traditional method and devices to measure the thermal boundary resistance according to the experimental research example of the solid thermal boundary resistance, then analyses the existing deficiencies to measure the thermal boundary resistance with the above method and devices .And puts forward a new method called the dynamic laser photothermal method to measure the thermal boundary resistance.Then, briefly recommends the measuring principle of the faint signal in the photoelectric detection system and the composition and the principle of the typical lock-in amplifier which is on the basis of the synchronous and relevant measuring principle, and puts forward to design a dual phase lock-in amplifier to measure the main parameter called phase difference. Then mainly discusses the design of the measuring system of the solid thermal boundary resistance, mainly including the measuring circuit of a dual phase lock-in amplifier, the data gathering circuit and software of SCM are fulfilled, and the software design of data processing based on Labview.Then, we carry on experimental research using the measuring device, and has carried on the data analysis to the measuring result . Verificating the rationality and feasibility of the measuring method and device , and it has a certain meaning for research of the thermal boundary resistance.At last, the dissertation makes a summary of the work in the course of system development, points out what the system needs to be improved, and offers the reference for following the development work.