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By Marriott Waikoloa on October 22, 2007

ISIS-3D General Comments

  • Based on Computational Fluid Dynamics with radiative heat transfer and combustion chemistry
  • Linked model is capable of simulating complex, three-dimensional objects engulfed in fires
  • Provide reasonably accurate estimates of the total heat transfer to objects from large fires
  • Predict general characteristics of temperature distribution in object
  • Accurately assess impact of variety of risk scenarios (wind, % flame coverage, thermal fatigue for given geometry, etc.)
  • Reasonable CPU time requirements on “standard” desktop LINUX workstation


candle flare

Approach to Modeling Full Flare Fields

  • Model Single Burner Test
    • Perform Calibration Tests
    • Calibrate Soot Yield and Reaction Parameters for Test Fuel
    • Predict flame shape and size
  • Model Multi-Burner Test
    • Perform Radiation Calibration Tests
    • Check Tip/Row Spacing
    • Predict flame shape and size
  • Model Full Flare Field
    • Use Calibrated Soot Yield and Radiation Models
    • Predict Flare Performance (Smoke Production/Air Demand)
    • Predict Radiation Load on Wind Fence


  • ISIS-3D Model:
    • Single-burner model used 110,000 cells
    • Three-burner model used 188,000 cells
    • Full-field model used 700,000 cells (Sustained Flow)
    • 1,200,000 cell (Peak Flow)
    • Combustion chemistry for propane, ethylene, mixed gas
  • Modeled flame shape/size for 3 fuels for single and three burner tests
  • Predictions compared to data from 12 tests (2 tip sizes, 3 operating pressures, 2 radiation sample locations)
  • Predicted “reasonable” estimates of radiation heat transfer and air demand for low profile flare
    • Air/fuel ratios range from 28 to 47 for 3-burner test and from 37 (Peak Flow Case) to 51 (Sustained Flow Case)
  • Calibrated flare model applied to full-flare field to estimate:
    • Air demand for specified tip/row spacing
    • Radiation load on wind fence for nominal and peak flow cases
    • Expected flame height and smoke production for nominal and peak flow cases
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