FURNACE TROUBLESHOOTING WITH PHOENICS

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FURNACE TROUBLESHOOTING WITH PHOENICS

• IX International PHOENICS Users Conference
• Moscow, 25th September 2002

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AUTHORS
Chemtech - A Siemens Company, Rio de Janeiro / RJ
Brazil Petrobras / CENPES, Rio de Janeiro /
RJ Brazil
Flávio Martins de Queiroz Guimarães Bruno de
Almeida Barbabela Luiz Eduardo Ganem Rubião
Ricardo Serfaty
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INTRODUCTION THE SYSTEM
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INTRODUCTION THE PROBLEM

• The increase in the pre-heated air mass-flow lead
  to several problems during the furnace operation
• Problem 1 Hot air has a high swirl flow inside
  the underground duct
• Problem 2 The mass flux distribution between the
  two plenum is not uniform
• Problem 3 The mass flux distribution between the
  burners within the plenum is not uniform
• Problem 4 The flames in the two combustion
  chambers are leading.

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PROBLEM 1 UNDERGROUND DUCTDescription
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PROBLEM 1 UNDERGROUND DUCTSGeometry
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PROBLEM 1 UNDERGROUND DUCTGeneral Settings

• All simulations were run on PHOENICS v3.3. The
  follow configuration was setting

• Grid cartesian
• PARSOL no
• Energy Equation no
• noCombustion
• Turbulence Model standard k-?, Chen-Kim k-? and
  RNG k-?
• Transient no

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PROBLEM 1 UNDERGROUND DUCTOriginal Case
Simulation
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PROBLEM 1 UNDERGROUND DUCTProblem
Identification
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PROBLEM 1 UNDERGROUND DUCTProblem Solution
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PROBLEM 1 UNDERGROUND DUCTProblem Solution
Results
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PROBLEM 2 UNDERGROUND DUCTDescription
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PROBLEM 2 UNDERGROUND DUCTSGeometry
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PROBLEM 2 UNDERGROUND DUCTGeneral Settings

• All simulations were run on PHOENICS v3.3. The
  follow configuration was setting

• Grid cartesian
• PARSOL no
• Energy Equation no
• Combustion no
• Turbulence Model standard k-?, Chen-Kim k-? and
  RNG k-?
• Transient no

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PROBLEM 2 UNDERGROUND DUCTOriginal Case
Simulation
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PROBLEM 2 UNDERGROUND DUCTProblem
Identification
Mass Flow 35 Greater
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PROBLEM 2 UNDERGROUND DUCTProblem Solution
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PROBLEM 2 UNDERGROUND DUCTProblem Solution
Results
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PROBLEM 2 UNDERGROUND DUCTProblem Solution
Results
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PROBLEMS 3 4 PLENUMDescription
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PROBLEM 3 4 PLENUMGeometry
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PROBLEM 3 4 PLENUMGeneral Settings

• All simulations were run on PHOENICS v3.3 and
  v.3.4. The follow configuration was setting

• Grid cartesian
• PARSOL active (on some cases)
• Energy Equation no
• Combustion no
• Turbulence Model standard k-?, Chen-Kim k-? and
  RNG k-?
• Transient no

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PROBLEM 3 4 PLENUM Problem Identification
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PROBLEM 3 4 PLENUM Problem Identification
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PROBLEM 3 4 PLENUM Problem Solution
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PROBLEM 3 4 PLENUM Problem Identification
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PROBLEM 3 4 PLENUM Problem Solution Results
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PROBLEM 3 4 PLENUM Problem Solution Results
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PROBLEM 4 COMBUSTION CHAMBERDescription
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PROBLEM 4 COMBUSTION CHAMBER Geometry
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PROBLEM 4 COMBUSTION CHAMBER General Settings

• All simulations were run on PHOENICS v3.4. The
  follow configuration was setting

• Grid cartesian
• PARSOL active
• Energy Equation active
• Combustion active (SCRS)
• Turbulence Model Chen-Kim k-?
• Transient no

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PROBLEM 4 COMBUSTION CHAMBER Original Case
Simulation
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PROBLEM 4 COMBUSTION CHAMBER Problem Solution
Results
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CONCLUSIONS

• The results showed good qualitative agreement
  with observed behavior during furnace operation.
• Although the Chen-Kim and RNG k-? models
  converged to the same solution behavior, the
  standard k-? one seems to under-predict the
  recirculation zones and the flames inclination.
• That result indicates that the leaning flames are
  not only caused by bad distribution of air but
  may also be caused by the number of firing ports
  in each burner. Decreasing the number of ports
  might lead to a higher momentum jet from the
  residing ports, which might in turn mix the fuel
  better with the preheated air stream and create
  shorter flames. This would result in a smaller,
  more compact flame envelope, which would have
  less tendency of leaning to either side of the
  furnace