| 초록 |
Hydrogen refueling in a cryogenic and high-pressure environment causes turbulence inside the check valve, and hydrogen with high turbulent kinetic energy shows turbulent dissipation due to an energy cascade process. Moreover, the internal temperature rises due to the Joule-Thomson effect of hydrogen under cryogenic temperature conditions, while irreversible energy loss occurs during the throttling process. In this study, the RANS-based Realizable k - e model is applied to reduce the irreversible energy losses of the check valve, and the nozzle distance(ND) and fillet(R) geometry change conditions in the operating section are considered. Then, the turbulent dissipation rate, generated entropy, temperature, and exergy losses were compared with the basic geometry condition to analyze the system efficiency of the check valve. The results of the analysis show that the R = 0.3 mm condition is the design factor that causes the decrease in efficiency due to the temperature difference of up to 5 K and the increase in entropy generation and exergy loss. Furthermore, the design factor with the maximum system efficiency is determined as the design factor with the decrease in exergy loss by 15.08 % and 13.59 % as the size of ND increases. |
