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Experiment ID HSL Un-ignited High-Pressure Hydrogen Releases in the Atmosphere Experiment no. 7
Short Description A set of experiments involving horizontal high-pressure hydrogen jet releases was conducted at HSL. Different release pressures and nozzle diameters were used.

Figure 1 Experimental setup, viewed from upstream of the nozzle        Figure 2 Experimental setup, looking towards the nozzle

What phenomena were studied The hydrogen concentration was measured at a number of locations along the (perceived) centreline of the jet. Figures 1 and 2 show the experimental set-up from two different angles. Figure 3 shows the locations of the oxygen concentration sensors.
What phenomena / effects can be studied Hydrogen concentrations in the horizontal direction. These concentrations are derived from the oxygen sensor readings
Instrumentation 13 CiTicel AO2 oxygen concentration sensors were located between 3 m and 11 m from the release point, see Figure 3 below.

Figure 3 Location of the oxygen concentration sensors

Test variables Different release pressures, ranging from 1.1 MPa to 13.7 MPa, and different nozzle diameters, e.g. 3 mm, 4mm, 6 mm and 12 mm. Ambient wind conditions were also recorded. The experiment, no. 7, chosen here was conducted at near-still conditions.
Data description / Data completeness All concentration data are available in digital format.
Data availability Restricted to Shell Hydrogen Projects BV, Shell Global Solutions and HSL currently, but the data will be made available to the HySafe partners.
Source of data / Reference Shirvill, L. C., Roberts, P. T., Roberts, T. A., Butler, C. J. and Royle, M., Dispersion of hydrogen from high-pressure sources, presented at Hazards XIX Conference in Manchester, UK, 27-30 March 2006.
Why were chosen No similar experiments have been carried out, to our knowledge. We also have ready access to the raw data.
Relevance to the project purposes Provides information relating to high-pressure jet releases in the atmosphere. The experiments will provide an opportunity to investigate the best way to represent high-pressure jets. Most, if not all, accidental releases are likely to involve high reservoir pressure so that the flow would be sonic.
Experimental data
Results of simulations


HSL carried out a series of horizontal high-pressure releases at various reservoir pressures and through different size nozzles. These experiments are conducted outdoors so are subject to the vagaries of the Buxton weather. Experiment no. 7 was selected as it was conducted during a relatively still day and what little wind there was was essentially a co-flow.

Brief Description of the Experiments

The particulars of exp. no. 7 are:

  • Pressure: 100 bar
  • Diameter: 3 mm

The hydrogen concentration was measured at nine locations downstream of the nozzle, at x = 1, 2, 3, 4, 5, 6, 7, 8, and 9 m. The probes were located at a height of 1.5 m above the ground.

Experimental Data

Further details and link to the experimental data will be supplied in the near future.


Roberts, P. T., Shirvill, L. C., Roberts, T. A., Butler, C. J., and Royle, M., Dispersion of hydrogen from high-pressure sources, confidential paper provided to HySafe partners only

Shirvill, L. C., Roberts, P., Butler, C. J., Roberts, T. A., and Royle, M., Characterisation of the hazards from jet releases of hydrogen, Proceedings of 1st International Conference on Hydrogen Safety, 8-10 September, 2005, Pisa, Italy, 2005.

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Page last modified on March 11, 2009, at 01:24 PM