Prof' A' Khalatov, Dr' S' Kobzar, Dr' G' Kovalenko,

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Institute for Engineering Thermophysics National
Academy of Sciences of Ukraine
THERMOGASDYNAMICS AND ECOLOGICAL CHARACTERISTICS
OF COMBUSTION CHAMBERS RUNNING THE NATURAL GAS

• Prof. A. Khalatov, Dr. S. Kobzar, Dr. G.
  Kovalenko,
• Dr. V. Demchenko

The 11th PHOENICS Users Conference, London, UK,
2006
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? ? N T E N T S

• Introduction
• Boiler Victor and Combustion Chamber
• Results and Discussions
• 3.1. Basic design
• 3.2. H2S in the natural gas
• 4. Conclusions.

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1. Introduction

• Computer design is based on the flow, heat and
  mass transfer modeling using numerical simulation
  of basic transport equations.
• Commercial packages FLUENT, STAR-CD,
  PHOENICS and others are widely used in various
  applications.
• Advantages
• - saving of time and money
• - wide range of designs and boundary conditions
• - easy changes in air and fuel regimes
• - easy changes in combustion chamber design
• - clear demonstration of results
• - finding of information not registered in
  experiments.

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• Examples of Computer Modeling

• Flow streamlines inside the burner.

• Aerodynamics of the be-burner combustion
  chamber.

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2. Boiler Victor and Combustion Chamber
Exit of gases

• Burner

• Boiler Victor

Boiler Victor, 100 kWt power. Combustion
chamber D 412mm, L 1140 mm, Burner
Giers?hRG20 (gas flow rate 12,6 m3/h air
excess 1,2)
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3. Results and Discussions

• Kintetics of natural gas burning

1. Chemical reaction ??4 1,502
CO 2H20 CO 0,5O2 CO2
2. Average speed of the methane burning (first
reaction model of the vortex breakdown -
EBU) RCH4 - CEBUmin CH4
O2/3,0???k , ?g/(m3?), CEBU2,0
3. Average speed of ?? to ??2 oxidation (minimal
magnitude of a speed according to EBU-model and
Arrenius law) - RCO - min REBU RAr )
- RAr 5,4 109 exp - 15000 / TCOO20,25
H200,5 , ?mol / (m3?)
4. NOx formation Thermal and Prompt ?echanizm.
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3.1. Basic design
Grid (?, Y, Z) 90 ? 19 ? 46 Global
convergence parameter 0,1
Commercial CFD Package PHOENICS v.3.6 was used in
all calculations

• Flow field.

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• Temperature field Tavr. 1060 0C, T???
  1493 0C .

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• NOx concentration .
• Prediction 19,56 ?g/?3, Experiment 24
  ?g/m3.

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• Methane concentration.

• CO concentration.
• - Prediction 2,4 ?g/m3, Experiment 4 ?g/m3

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3.2. H2S in the natural gas
- Direct chemical reaction of H2S burning
H2S 1,5O2 SO2 H20
- Average speed of H2S burning (EBU - model)
RH2S - CEBU min H2S O2 / 1,41
(???k), ?g/(m3?), CEBU4,0

• Temperature field Toutlet 966 0C , T???
  1334 0C

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• Temperature field (basic design)

• Temperature field
• Toutlet 966 0C, T??? 1334 0C

Toutlet 1060 0C, T??? 1493 0C
The primary reason of the temperature in the
combustion chamber reduction decrease in the
fuel lowest caloric value.
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• NOx concentration
• Prediction 20,83 ?g/m3

• ?? concentration
• Prediction 6 ?g/m3

Temperature decrease in the combustion chamber
leads to the increased carbon monoxide (CO)
generation.
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4. C o n c l u s I o n s

• The modern computer technologies are widely
  employed for design and modernization of boilers
  and combustion chambers.
• Computer technologies enables to analyzing the
  number of design variants and flow regimes before
  the fabrication or modernization this allows us
  to take more justified solutions, to save the
  time and funding.
• Computer modeling enables detecting some specific
  features of the combustion chamber flow and
  temperature fields, which are actually unable to
  be detected in experiments.
• The experiment keeps its important meaning
  however it should be employed after basic
  decisions regarding combustion chamber design and
  flow regimes.