1 / 23

Large-Scale Hydrogen Deflagration and Detonations

Large-Scale Hydrogen Deflagration and Detonations. M. Groethe E. Merilo J. Colton S. Chiba Y. Sato H. Iwabuchi. International Conference on Hydrogen Safety 8-10 September 2005 Pisa, Italy. Objectives 300 m 3 Open-Space Tests 1/5 Scale Tunnel Tests Partial Confinement Test

thomasdonaldson
Download Presentation

Large-Scale Hydrogen Deflagration and Detonations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Large-Scale Hydrogen Deflagration and Detonations M. Groethe E. Merilo J. Colton S. Chiba Y. Sato H. Iwabuchi International Conference on Hydrogen Safety 8-10 September 2005 Pisa, Italy

  2. Objectives 300 m3 Open-Space Tests 1/5 Scale Tunnel Tests Partial Confinement Test Protective Blast Wall Test Large-Scale release (300 Nm3 H2) Summary Outline

  3. Objective • Acquire basic data on hydrogen deflagrations and detonations. • Acquire hydrogen deflagration/detonation data for validation of computer simulations. Studies were performed for IAE and administered through NEDO as part of the “Development for Safe Production and Utilization and Infrastructure of Hydrogen” program.

  4. 300 m3 Open-Space Tests Obstacle-induced enhancement, scaling, free-field blast data. • Deflagration tests with obstacles. • Deflagration tests without obstacles. • Detonation tests without obstacles. Obstacle Test 0.46 m-diam X 3 m-tall 300 m3 5.7 m Volume Blockage ratio: ~11%

  5. Obstacle Test • Standard and infrared video frames ~67 ms ~67 ms ~100 ms

  6. Obstacle Test

  7. Deflagration Data Overpressure Heat Flux Scaled Overpressure Scaled Impulse

  8. Stoichiometric Detonation • High-Speed Video Frames

  9. Detonation Data • Detonation data consistent with previous smaller scale tests Overpressure Heat flux Scaled Impulse Scaled Overpressure

  10. Tunnel Experiments Deflagration, H2 release, Obstacle-induced enhancement. • Homogeneous deflagration tests. • Tests with and without scaled vehicles as obstacles. • Scaled release and ventilation rates. ~ 1/5 scale

  11. Tunnel with Vehicle Models Obstacles representing scaled vehicles. Blockage ratio: 0.03

  12. Pressure and Impulse Overpressure • Overpressure and impulse unchanged by presence of vehicle models. Impulse Overpressure

  13. H2 Release Tests • Ventilation significantly reduces H2 concentration • Test 14 and Test 15: 0.1 kg H2 in 20 sec, no ventilation. • Test 16: 0.1 kg H2 in 20 sec, 1.6 m3/sec ventilation rate. • Test 17: 2.2 kg H2 in in 420 sec, 1.6 m3/sec ventilation rate. H2 concentration H2 concentration

  14. Partial Confinement Test Deflagration enhancement from partial confinement. • Narrow gap between two plates provides partial confinement • Flame position measured by ionization pins. • Overpressure measured inside and outside the source.

  15. Standard Video Frame IR Video Frame ~33 ms ~33 ms Scaled Overpressure Scaled Impulse Partial Confinement Test • Confinement between plates does not enhance deflagration

  16. Protective Wall Tests Assess overpressure reduction by using a protective blast wall. • 4 m-tall by 10 m-wide wall, 4 m from edge of the 5.3 m3 source • Stoichiometric deflagration (bottom, center spark ignition) • Pressure measured inside the source and in the free-field. Test Layout

  17. Protective Wall Test Setup Blast sensors 10 m 4 m Wall 5.3 m3 Source

  18. Scaled Overpressure and Impulse • Deflagration data suggests a reduction in overpressure and impulse. • Previous tests with a 2 m-tall wall show reductions up to 30%. Scaled Overpressure Scaled Impulse

  19. Large-Release Test Rapid release of a large quantity of hydrogen that is ignited. • 300 Nm3 H2 (27 kg) released in about 30 seconds. • Spontaneous ignition occurred at ~360 milliseconds. Sample station 18-m tower Estimated Flame Jet Tower Sample station Sample station Table with drywall insert Nozzle Igniters (15mJ) Nozzle Release valve Pressure and heat flux

  20. Large-Release Test • High-Speed Video Frames

  21. Overpressure Heat Flux Flame Speed Large-Release Test

  22. Large-Release Test

  23. Summary • Large-scale 300 m3 open space deflagrations and detonations. • - Large obstacles do not enhance the deflagration. • - Detonation data consistent with smaller scale tests and analytic expressions. • Partial confinement of mixture between two plates. • - Deflagration was not enhanced for this geometry. • 1/5 scale tunnel tests. • - Homogeneous deflagrations show near constant overpressure and impulse • - 30% H2 blast is much higher than the free-field case. • - Vehicle models do not enhance deflagration (BR = 0.03, which is small) • - Ventilation of the tunnel significantly reduces the H2 concentration. • 4 m-tall protective blast wall. • - Blast reduction is suggested to over twice the wall height. • - Previous tests and calculations show a reduction that diminishes with range1. • Large-scale release of hydrogen. • - Release spontaneously ignite producing a blast followed by a flame jet. • - Ignited release produced a higher blast pressure and lower impulse than a • static homogeneous deflagration. 1 M. Groethe, J. Colton, S. Chiba, and Y. Sato, “ Hydrogen Deflagrations at Large Scale,” 15th World Hydrogen Energy Conference, Yokohama, Japan, 27 June - 2 July, 2004.

More Related