극저온 유체의 무배기 충진 기술의 수치적 해석에 대한 연구

Abstract

It is common opinions that thermodynamic equilibrium model is more accurate than non-equilibrium model for current model of no-vent filling (NVF). The NVF, however, is a result of complex behavior between evaporation and condensation. In this paper, it is suggested that a numerical model for NVF with consideration of thermodynamic non-equilibrium by using tetrafluoromethane (CF4) as working fluid. The model is verified the applicability for various experimental apparatuses by using correlations which are based on various theories. As the concept of NVF is the filling technology of cryogen in space, the model also considers microgravity condition. The reliability of the heat transfer calculation is verified by the comparison between numerical results and experimental data. Although the bottom temperature of the receiver tank is calculated with a relatively big error in the initial state of NVF, the mid-height temperature of the receiver tank is simulated within the error of 7%. The receiver tank pressure, the most important factor of NVF, is calculated within the error of 2% in steady state and the maximum pressure is simulated with the error of 15%. Finally, the model simulates the pressure of the experimental data from the previous research within the mean error of 14.7%.