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Gas behavior during fast filling of a compressed gaseous hydrogen storage tank (Type 3, 35MPa) was simulated numerically to investigate in detail the resulting unsteady temperature distribution and its correlation with the storage tank conditions. The governing equations for the gas phase are the mass, momentum, and energy equations; these equations were discretized using the finite volume method (FVM) in three-dimensional space. The numerical results were carefully compared with the experiment results and have been validated. Consequently, the temperature distributions in space, the time histories of temperature at the measured points, and the filling time to the target pressure were all in good agreement. Furthermore, the unsteady gas and its thermal behavior were clearly visualized in three-dimensional space.

If a compressed hydrogen tank for vehicles is filled with hydrogen gas more quickly, the gas temperature in the tank will increase. In this study, we conducted hydrogen gas filling tests using the TYPE 3 and TYPE 4 tanks. During the tests, we measured the temperature of the internal liner surface and investigated its relationship with the gas temperature in the tank. We found that the gas temperature in the upper portion of the TYPE 4 tank rose locally during filling and that the temperature of the internal liner surface near that area also rose, resulting in a temperature higher than the gas temperature at the center of the tank. To keep the maximum temperature in the tank below the designed temperature (85°C) during filling and examine the representative tank internal temperatures, it is important to examine filling methods that can suppress local rises of tank internal temperature.