Hydrogen Pipeline Consequence Modelling
Budget: €250 – €750 EUR
Hydrogen Pipeline Leakage Dispersion Study
1. Objective
Perform consequence modelling in PHAST to determine the downwind distance to the lower flammability limit (LFL = 4% v/v) for high-pressure hydrogen pipeline leak scenarios. Results will be used as reference data for simplified model development and comparison.
2. Modelling Approach
• Software: PHAST (latest available version)
• Release type: Continuous gaseous release
• Release model: Orifice leak from pressurized pipeline
• Flow regime: Determined by PHAST (choked flow expected)
• Terrain: Flat, open terrain, no obstacles
• Release height: Ground level (H = 0 m)
• Release direction: Vertical
• Surface roughness: 0.03 m
• Gas: Hydrogen (100%)
• Gas temperature: 298 K
• Relative humidity: 50%
3. Scenario Matrix
Pipeline diameter:
• 500 mm
• 900 mm
• 1200 mm
Operating pressure:
• 5 MPa
• 8 MPa
• 10 MPa
Leak diameter (circular hole):
• 1 mm
• 3 mm
• 6 mm
• 12 mm
Meteorological conditions:
• Case M1: 1.5 m/s, stability class F
• Case M2: 3.0 m/s, stability class D
• Case M3: 5.0 m/s, stability class D
Total scenarios: 108
4. Release Assumptions
• Continuous steady-state release (no blowdown modelling)
• Infinite supply assumption (no inventory depletion)
• Pipeline treated as pressurized source, not full rupture
• Discharge coefficient: PHAST default
• No obstacle or terrain effects
5. Output Requirements
Primary result (for each scenario):
• Maximum downwind distance to LFL (4% v/v), m
o Based on centreline concentration at 1.5 m height
Additional outputs:
• Mass flow rate at release (kg/s)
• Exit velocity (m/s)
• Cloud height at LFL distance (if available)
6. Visual Outputs
Provide for each scenario or agreed representative subset:
• Concentration contour plot with LFL boundary (4%)
• Side view (plume profile)
• Top view (dispersion footprint)
Requirements:
• Clear distance scale
• LFL contour indicated
• Scenario ID shown
7. Data and Model Files
Provide full reproducibility package:
• PHAST project files (.psu or equivalent)
• All input files
• Exported calculation outputs
8. Data Format
Excel table including:
• Scenario ID
• Pipeline diameter
• Pressure
• Leak size
• Meteorology case
• Mass flow rate
• LFL distance
9. Deliverables
• Excel dataset
• PHAST model files
• Plot package (images)
• Short technical note (1–2 pages) describing setup
1. Objective
Perform consequence modelling in PHAST to determine the downwind distance to the lower flammability limit (LFL = 4% v/v) for high-pressure hydrogen pipeline leak scenarios. Results will be used as reference data for simplified model development and comparison.
2. Modelling Approach
• Software: PHAST (latest available version)
• Release type: Continuous gaseous release
• Release model: Orifice leak from pressurized pipeline
• Flow regime: Determined by PHAST (choked flow expected)
• Terrain: Flat, open terrain, no obstacles
• Release height: Ground level (H = 0 m)
• Release direction: Vertical
• Surface roughness: 0.03 m
• Gas: Hydrogen (100%)
• Gas temperature: 298 K
• Relative humidity: 50%
3. Scenario Matrix
Pipeline diameter:
• 500 mm
• 900 mm
• 1200 mm
Operating pressure:
• 5 MPa
• 8 MPa
• 10 MPa
Leak diameter (circular hole):
• 1 mm
• 3 mm
• 6 mm
• 12 mm
Meteorological conditions:
• Case M1: 1.5 m/s, stability class F
• Case M2: 3.0 m/s, stability class D
• Case M3: 5.0 m/s, stability class D
Total scenarios: 108
4. Release Assumptions
• Continuous steady-state release (no blowdown modelling)
• Infinite supply assumption (no inventory depletion)
• Pipeline treated as pressurized source, not full rupture
• Discharge coefficient: PHAST default
• No obstacle or terrain effects
5. Output Requirements
Primary result (for each scenario):
• Maximum downwind distance to LFL (4% v/v), m
o Based on centreline concentration at 1.5 m height
Additional outputs:
• Mass flow rate at release (kg/s)
• Exit velocity (m/s)
• Cloud height at LFL distance (if available)
6. Visual Outputs
Provide for each scenario or agreed representative subset:
• Concentration contour plot with LFL boundary (4%)
• Side view (plume profile)
• Top view (dispersion footprint)
Requirements:
• Clear distance scale
• LFL contour indicated
• Scenario ID shown
7. Data and Model Files
Provide full reproducibility package:
• PHAST project files (.psu or equivalent)
• All input files
• Exported calculation outputs
8. Data Format
Excel table including:
• Scenario ID
• Pipeline diameter
• Pressure
• Leak size
• Meteorology case
• Mass flow rate
• LFL distance
9. Deliverables
• Excel dataset
• PHAST model files
• Plot package (images)
• Short technical note (1–2 pages) describing setup