gtr#13: towards inherently safer hydrogen-powered vehicles
TRANSCRIPT
ulster.ac.uk
GTR#13: towards inherently
safer hydrogen-powered vehicles
Prof Vladimir Molkov
Recent advances by Hydrogen Safety Engineering and Research Centre
(HySAFER)
Outline of presentation
▪ Fire test (improved reproducibility)
▪ Pressure peaking phenomenon (new phenomenon)
▪ System storage container-TPRD (“coupled” approach)
▪ Concluding remarks
▪ List of relevant urgent PNR topics
2
ulster.ac.uk
Fire test reproducibility
Definitions
Bare container - ordinary (unprotected)
container
Protected container - container with thermal
protection, e.g. intumescent
paint, Ulster IP, etc.
Heat release rate (HRR) - heat release rate in a fire [kW]
Fire resistance rating (FRR) - time from burner ignition until
container rupture in a fire
(without TPRD)
4
Issues of GTR#13 fire test
▪ Poor reproducibility of the fire test in different
laboratories.
▪ No test without TPRD (a serious first
responders’ concern, EU HyResponse). EU
FireCOMP: there is a non-zero probability of
TPRD failure.
▪ No test procedure for novel thermally protected
storage containers, e.g. explosion-free in a fire
containers.
5
CFD: revealed dependence of FRR on HRR
Poor reproducibility
6
[1] D. Makarov, Y. Kim, S. Kashkarov, V. Molkov, Thermal protection and fire resistance
of high-pressure hydrogen storage, in Proceedings 8th ISFEH, Hefei, China, 2016.
[2] N. Weyandt, Analysis of Induced Catastrophic Failure Of A 5000 psig Type IV Hydrogen
Cylinder, Southwest Research Institute report for the MVFRI, 01.06939.01.001, 2005.
[3] R. Zalosh, Blast waves and fireballs generated by hydrogen fuel tank rupture during fire
exposure’, in Proceedings 5th ISFEH, Edinburgh, UK, 2007.
[4] L. Bustamante Valencia, P. Blanc-Vannet, L. Heudier, D. Jamois, ‘Thermal history
resulting in the failure of lightweight fully-wrapped composite pressure vessel for hydrogen
in a fire experimental facility’, Fire Technology, no. 52, pp. 421–442, 2016.
Heat release
rate
Fire source Fire resistance
rating
79 kW [1] Premixed CH4-air burner 16 min
170 kW [1] Premixed CH4-air burner 9 min
370 kW [2, 3] Diffusion C3H8 burner 6.5 min
4100 kW [4] n-C7H16, pool fire 6 min
Experimental validation of numerical study
Poor reproducibility
7
Poor reproducibility: way outSaturation of FRR at HRR>350 kW
8
▪ Constant HRR above 350 kW
▪ Heat flux (input) of minimum 100 kW/m2
9
Two ways to ensure reproducibility:
Type 4 (CFRP)
Steel?
HRR: saturation above 350 kW Heat flux: continuous decrease
10
Two ways to ensure reproducibility:
Parameter HRR (burner + LPG flow rate)
Heat flux (input)
Technical realisation Easy (as now) Complicated and questionable (suggested minimum is too high)
Additional cost per test No $600 per sensor in a destructive test
Location and number of sensors
Easy (as now) Where and how? How many?
Provision of required control parameter level
Easy (as now) Is it possible to provide minimum of 100 kW/m2 for type 4
Steadiness of parameter in steady-state fire
Yes No (decreases during the test)
▪ Constant HRR above 350 kW
▪ Heat flux (input) of minimum 100 kW/m2
ISO TC58: fire test without TPRDRight move: “Fire test until rupture”
11
Right approach of ISO TC58 (‘Gas Cylinders — Guidance for
design of composite cylinders — Part 2: Bonfire test issues’,
ISO/TC 58/SC 3 N 1714, 2017):
▪ ”For cylinders tested under option B – fire test until
rupture”
Engulfing fire test update
Current Engulfing fire test
Method 1E: Bare tank
Method 2E: Thermally protected tank
12
Need in thermally protected tank test
Method 1E: Bare tank (minor changes)
Fire source
Bare tank
10
0
75
Thermocouple
1650
New requirements: HRR ≥ 350 kW, TC location
25
13
Method 2E: Thermally protected tank
Thermally protected container (no TPRD)
L2=1
00
Intumescent paint initial (unreacted)
L3=7
5
Fire source
L1
Intumescent paint (expanded)
Provide functioning of thermocouples
165014
590
0 5
Time, min
Te
mp
era
ture
, °C
Till end of test
Not less than 590°C
2 hours
Maximum recorded duration of car fire is 2 hours (e.g. K.
Okamoto, et al., ‘Burning behaviour of minivan passenger
cars’, Fire Safety Journal, vol. 62, pp. 272–280, 2013).
HRR at least 350 kW
Method 2E: Thermally protected tank
15
ulster.ac.uk
Pressure peaking phenomenon
Pressure peaking phenomenonPhysics
Example
Garage 4.5x2.6x2.6 m,
“brick” vent.
Car (350 bar, D=5.08 mm):
mass flow rate from TPRD
390 g/s.
Overpressure limit for structures (10-15 kPa)
Solution: decrease TPRD
diameter + increase fire
resistance rating of
onboard storage tank!17
2
1
12
1
2
encl
S
encl
S
encl
Svent
P
P
P
PPCAV
Pressure peaking phenomenonValidation: air (no pressure peaking)
Air release 2.8 g/s (enclosure 1 m3, vent D=11 mm). Only
gases lighter than air can generate pressure peaking.
18
0 10 20 30 40 50 60 70 80 90 100
Time, s
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Ov
erpre
ssure
, kP
a
HIWP4-044
Model prediction, CD=0.72
Steady-state pressure without peak
Pressure peaking phenomenonValidation: helium
Helium release 0.99 g/s (enclosure 1 m3, vent D=11 mm)
19
0 25 50 75 100 125 150 175 200 225 250 275
Time, s
0
0.5
1
1.5
2
2.5
3
Ov
erpre
ssure
, kP
a
HIWP4-046
MOdel prediction, CD=0.85
Pressure peak
Pressure peaking phenomenonValidation: hydrogen
Hydrogen release 0.55 g/s (enclosure 1 m3, vent D=11 mm)
200 10 20 30 40 50 60 70 80 90 100
Time, s
0
0.5
1
1.5
2
2.5
3
3.5
Ov
erpre
ssure
, kP
a
HIWP4-049
Model prediction, CD=0.85
Pressure peak
0 10 20 30 40 50 60
Time, s
0
2
4
6
8
10
12
14
Ov
erp
ress
ure
, kP
a
1 brick vent
2 bricks vent
3 bricks vent
4 bricks vent
Pressure peaking phenomenonCase 1
Ignited release in the garage:
TPRD D=2.0 mm, P=70 MPa
(107 g/s).
0 10 20 30 40 50 60
Time, s
0
20
40
60
80
100
120
140
160
180
200
220
Ov
erp
ress
ure
, kP
a
1 brick vent
2 bricks vent
3 bricks vent
4 bricks vent
Unignited release in the
garage: TPRD D=2.0 mm,
P=70 MPa (107 g/s).
Pressure peaking phenomenonCase 2
▪ Ignited release from TPRD with D=0.3 mm in a garage
2.6x2.6x4.5 m with vent 1 brick (left) or 0.5 brick (right).
▪ Onboard tank storage pressure 700 bar.
▪ Garage can withstand overpressure 10 kPa.
22
ulster.ac.uk
System tank-TPRD
24
ISO/TC 58: decoupled tank-TPRD testCould we model coupled functioning (reality)?
24
ISO, ‘Gas Cylinders — Guidance for design of composite
cylinders — Part 2: Bonfire test issues’, ISO/TC 58/SC 3 N
1714, 2017
Simulation of tank-TPRD systemInitial model development
25
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
0
5
10
15
20
25
0 100 200 300 400 500 600 700 800 900 1000
Decomposed front of the wall
Load bearing front of the wall
Pressure
Time (s)
Wal
l th
ickn
ess
(mm
)
Pre
ssu
re (
bar
)
No TPRD
0.3 mm TPRD
0.5 mm TPRD
Init
iati
ng
tim
e
180 bar
15 bar
750 bar
Concluding remarks
▪ Improvement of GTR#13 fire test reproducibility is
suggested through requirements of a burner to have
heat release rate above 350 kW. Development of a
burner requires additional PNR.
▪ Pressure peaking phenomenon could be practically
eliminated using TPRD diameter of 0.3-0.5 mm. This
would require increase of fire resistance rating (time
to rupture in test without TPRD).
▪ The use of TPRD diameter 0.3-0.5 mm increases fire
resistance (to let first responders more time to
control and eliminate “hazards”) yet doesn’t exclude
the tank rupture (preliminary result).
▪ Explosion-free in a fire tanks could be a solution. 26
List of relevant urgent PNR topics
▪ Burner design to provide GTR#13 fire test
reproducibility, including effects of wind
▪ Testing pressure peaking phenomenon at realistic
garage-like enclosures.
▪ Inherently safer tank-TPRD system with minimised
TPRD diameter (to exclude pressure peaking
phenomenon and yet to avoid tank rupture)
▪ TPRD reliability data for risk assessment
▪ Development of explosion-free in a fire tanks
▪ Vehicles in tunnels, underground parking
▪ In-situ dumping of compressed gas potential energy
▪ … 27
Thank you