Investigation On The Computer Simulation Of Boundary Heat Transfer Process Between Solids At Low Temperature

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. As a result of the application of directly cooled techniques, the cooled mode of helium and solid is displaced by another heat transfer mode, which mainly depended on the thermal conductance between one solid (superconducting device) and another solid (cold head of cryocooler). 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 electronic technology, the heat transfer problem of electronic product includes heat transfer between integrated circuit and its submarine in chip as well as the design of heat removal on chip's crust. The performance and reliability of electronic product are greatly decided by their thermal boundary resistance.Since the famous cryogenic physicist Kapitza (Kapitza, Peter,1894-1984,Soviet physicist who in 1978 shared a Nobel prize for his work on magnetism and low-temperature physics) firstly measured thermal boundary resistance between 4He II and solids(Kapitza resistance) in 1941 , the thermal boundary resistance between solids at low temperature has been several decades research history. The problem of boundary heat transfer has been expanded from initial problem of liquid and solid to the other boundary heat transfer between matter state such as between solids, become an research hot in heat transfer as well in view of its wildly application background and great scientific significance. Based on the fruits of other research, it is described in this dissertation that the process of boundary heat transfer between solids at low temperature were investigated by use of the computer simulation method and techniques. The fruits of this dissertation are followed:(1) the mathematical method and tools of heat transfer logic analyses;(2) parameter measurement and control of cryogenic experiment on the boundary heat transfer between solids;(3) simulation model method and technology of boundary heat transfer between solids at low temperature; (4) digital simulation and visual simulation on the process of boundary heat transfer between solids at low temperature.Firstly, it is suggested in this dissertation that the logic algebra theory and method used as a mathematic tool to analyses the process of boundary heat transfer. The pan-Boolean algebra was applied to investigating the problem of boundary heat transfer between solids at low temperature. The ideal model of thermal switch, which make the sequence heat flow become discrete, was built up for suggesting a new idea of digital thermal routine and the initial idea of phone or electron calculator and computer driven directly by heat current. When the ideal model of heat current routines that is consisted of thermal switch, heat source and load was built up at first, author found that the basic motion law of heat current in this model was close in agreement with basic operation law of pan-Boolean algebra. Hence, thermal switch algebra, which was used as the logic analyses tool for the heat transfer process, was put forward and built up. Usually, object or process experiment is regarded as an important parts of its simulation research, and the automatic measurement and control of the experiment' parameter is a basic work in experiment. In order to solve the problem of automatic measurement of the vacuum in cryogenic experiment of thermal boundary resistance, the hardware and software embedded cryogenic vacuum measurement and control has been designed and made. On the other hand, in this dissertation, there are many detailed analyses and discussion about low temperature measurement and control, such as low temperature sensor's selection, fitting of sensor, heat leak error...