The hydrogen valve used in this study is intended to be applied to a automobile, and since there is a limit to the length of the stem, it is necessary to review the optimized stem, and for this, it is required to investigate the heat transfer characteristics of the hydrogen shut-off valve. For this, the temperature of the entire shut-off valve and especially the plunger and O-ring, which are key components in the solenoid valve driving the hydrogen shut-off valve, was calculated using the ANSYS-CFX flow analysis program. From the analysis results, the length of the stem capable of maintaining the design temperature of -40℃ or higher should be at least 139 mm, and it is judged that it should be 140 mm or more considering safety. When determining the stem length of the hydrogen blocking valve for automobiles, constraints on installation in automobiles should be considered.

In this study, a numerical analysis study was conducted on the flow characteristics according to the internal flow path change and differential pressure of the hydrogen shut-off valve, and through this, the pressure loss characteristics and flow coefficient of the hydrogen shut-off valve were predicted. ANSYS CFX program was used to predict the flow characteristics of the hydrogen shut-off valve. When the flow path gap was 1.3 mm, the design conditions of the hydrogen shut-off valve were satisfied, and the value of the flow coefficient of the valve was about 1.53. As the inlet pressure of the hydrogen shut-off valve increases, the outlet flow rate increases, but regardless of the inlet pressure, the flow coefficient of the valve is almost constant, ranging from 1.53 to 1.56, indicating that it is the inherent flow coefficient of the designed hydrogen shut-off valve.