Download presentation
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
Outline 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
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 Volume Blockage ratio: ~11%
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 Overpressure Scaled Impulse
10
Deflagration, H2 release, Obstacle-induced enhancement.
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. Overpressure Impulse
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
Partial Confinement Test
Confinement between plates does not enhance deflagration Scaled Overpressure Scaled Impulse ~33 ms Standard Video Frame IR Video Frame
16
Assess overpressure reduction by using a protective blast wall.
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
Rapid release of a large quantity of hydrogen that is ignited.
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 Igniters (15mJ) Nozzle Nozzle Release valve Pressure and heat flux
20
Large-Release Test High-Speed Video Frames
21
Large-Release Test Heat Flux Overpressure Flame Speed
22
Large-Release Test Release to Free Field Static Hydrogen Amount about 5 m3NTP 11 m3 NTP Hydrogen Concentration heterogeneous homogeneous (30 vol%, 37 m3) Status at Ignition Turbulent Flame Propagation Velocity about 100 m/sec 44 m/sec Pressure Measurement Range from Ignition Peak Overpressure (kPa) Impulse (Pa-s) (5.3m) 5.6 (5.3m) 40 (5.9m) 4.4 (5.9m) 122 11 m 3.8 25 2.9 82 21 m 2.3 13 1.7 44
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.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.