The Model Building And Emulation Of G-M Refrigerator Based On MATLAB

After the history of development and the present state of researches on Gifford-Mcmahon refrigerator all of the world are reviewed at the very start, the work mechanism of a G-M refrigerator is introduced as the central content in this dissertation and some researches about it are as follows:(1)Based on thermodynamics, the analytic method of system quasistatic is used to analyse G-M cyclic processes and the differences between the ideal and the actual refrigerating output and the efficiency of refrigerator;(2)As the key working element of a G-M refrigerator, the regenerator should be paid more attention. The theories about regenerator are expatiated in this dissertation, for example, the work condition and the efficiency on regenerator, and especially, the analyzing for most of the heat losses about regenerator becomes more and more complicated. The author puts stress on the curve fitting about the results of two solutions about the efficiency of regenerator by CurveFitTooI which is one of the softwares in MATLAB, then functions of estimating the efficiency of the regenerator are gained, and initial values are supplied for the optimum design of the generator;(3) After some working parameters of G-M refrigerator are selected and a G-M cycle is subdivided into eight working steps, the mathematical models of eight working steps are transformed into the Simulink model respectively and then the corresponding emulation programming (M file) also be done;(4) When every Simulink models and M files are run, many change charts of temperature, pressure, volume and quantity can be obtained in all of the eight working steps respectively. If these parameters are exported as a whole G-M cycle, then the T-t, P-t, V-t, m-t and P-V charts can also be obtained. In the end, the emulation results are analysed as the conclusion.(5) The effect of emulation is good and the task of the subject is finished.