| A novel cryogenic heat-transfer device, Natural cooling circula- tion(NCC) and cryogenic heat pipe(CHP)-coupled system ,is under development currently. Combining the advantages of both methods, The system should be fast-precooling and highly efficient heat-transferring, which give the system a bright perspective on the future ground application. As one of the two basic components of the coupled system, cryogenic thermosyphon takes the most responsibility under steady working conditions, whose efficiency determines the performance of the whole system directly.Through theoretical analysis on the performance of cryogenic heat pipe, mathematic models are founded for both the condensing section and evaporating section. Using discrete approximation and iterative algorithm in the compiled FORTRAN programs, numerical computation result is obtained. Both of interface shear force and sub-cooled temperature are taken into consideration for liquid film part. As a result, the correlation of film thickness, interface shear force and film height is figured out, therefore the film distribution and heat transfer performance can be calculated. For the liquid pool, heat flux is divided by void-fraction-related areas, based on two different heat transfer mechanisms existed in this part which are natural convection and nucleate boiling respectively. The integrative heat transfer coefficient and wall temperature distribution are calculated. Furthermore, the influences of Several major parameters, such as length, heat load and working fluid charge are investigated and analyzed.There are some important results are concluded as below:1 The distribution of working fluid: Most of fluid masses in the bottom pool.There is a liquid downstream-flowing film clinging to the inner wall, whosethickness is less than 1% of pipe diameter and changes from thicker to thinner.2 Heat transfer performance of heat pipe: The entire pipe performs high...
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