Measured effects of filling time and initial mass on the temperature distribution within a hydrogen cylinder during refuelling

We have measured the effects of the initial mass and the total fill time on the temperature rise and the temperature distribution within a compressed hydrogen cylinder during refuelling. A type 3, 74 L hydrogen cylinder was instrumented internally with 63 thermocouples distributed along the mid vertical plane. The experimental fills were performed from initial pressures of 50, 75, 100, 150, and 200 bar at gas delivery rates corresponding to nominal fill times of 1, 3, and 6 min. The experimental conditions with larger ratios of final to initial mass produced larger temperature changes. However, the lower ratios generated the largest rates of temperature rise. Longer fill times produced lower final average gas temperatures (compared to shorter fills), and a temperature field with significant vertical stratification due to buoyancy forces at lower gas inlet velocities. A sensor located at the end opposite to the gas inlet could be suitable for fuel metering via temperature and pressure measurements only.