Measurements on High Pressure Diffusion
               Flames

                  Arvind V. Menon

          Propulsion Eng...
Soot
   Formed by pyrolysis of hydrocarbons
   between 1300 –1700 K
   Adverse environmental and health
   effects
   Prim...
PM2.5 Emissions from DoD Aircraft




Voluntary compliance of USAF to meet EPA emissions standards
Need to understand soot...
JP-8 Combustion


 JP-8
     Primary aviation fuel used by the US Air Force
     > 100 components
 Surrogate fuels for JP-...
Selecting a Flame Environment

Diffusion flame                        Premixed flame




   Fuel and oxidizer arrive as     ...
Soot formation process


Inception
   Fuel molecules dissociate to form C3 H3 , C2 H2 , etc.
   Formation of first aromatic...
What are we trying to measure?

Soot concentrations
   Soot concentrations measured using Laser-Induced
   Incandescence (...
What are we trying to measure?

 Soot concentrations
     Soot concentrations measured using Laser-Induced
     Incandesce...
Burner and High Pressure Chamber



                                                     Ceramic substrate
               ...
Establishing a Test Diffusion Flame

     1 atm         2 atm        3 atm         4 atm        5 atm


   20 mm


   15 m...
Reducing soot concentrations in C2 H4 flames

     0 mg / s   1mg / s   2 mg / s   3 mg / s   4 mg / s   4 .5 mg / s   5 mg...
Measuring soot and PAH concentrations
          Laser diagnostics: Laser-induced incandescence (LII) and
                 ...
Calibration of LII: Extinction




                                                    Focusing lens 350 mm




          ...
Addition of m-xylene

Ethylene                   Ethylene
    +                          +
Nitrogen                   Nitr...
Flame conditions for current study
Flame 1                                                           Flame 2              ...
Diluted flames at high pressure

Flame 3: 5% Carbon from m-xylene


                                     1 atm             ...
Soot volume fraction images

Flame 3: 5% Carbon from m-xylene
                                        1 atm         2 atm ...
Effect of pressure on soot concentrations


                                       1 atm         2 atm          3 atm     ...
Effect of m-xyleneon soot concentrations
                                        Flame 1             Flame 2             F...
Fluorescence images


                                                        Flame 1
                                    ...
Fluorescence images


                                                        Flame 1                                     ...
Conclusions




Established a flame environment for studying soot formation from
aromatic compounds
Obtained a set of bench...
Thank you



Questions?
Upcoming SlideShare
Loading in …5
×

High Pressure Diffusion Flames

1,098 views

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
1,098
On SlideShare
0
From Embeds
0
Number of Embeds
67
Actions
Shares
0
Downloads
0
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

High Pressure Diffusion Flames

  1. 1. Measurements on High Pressure Diffusion Flames Arvind V. Menon Propulsion Engineering Research Center, Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802 March 15, 2010 Independent Project Analysis Inc. Ashburn, VA
  2. 2. Soot Formed by pyrolysis of hydrocarbons between 1300 –1700 K Adverse environmental and health effects Primary route of radiation output from flames
  3. 3. PM2.5 Emissions from DoD Aircraft Voluntary compliance of USAF to meet EPA emissions standards Need to understand soot formation in gas turbine engines Improve chemical mechanisms of soot formation and oxidation
  4. 4. JP-8 Combustion JP-8 Primary aviation fuel used by the US Air Force > 100 components Surrogate fuels for JP-8 Fewer components than JP-8 Simpler chemical mechanisms with fewer elementary reactions Current work Surrogate fuel for current study 77% n-dodecane (C12 H26 ) 23% m-xylene (C8 H10 ) Preliminary study to investigate soot formation m-xylene from m-xylene in a diffusion flame environment
  5. 5. Selecting a Flame Environment Diffusion flame Premixed flame Fuel and oxidizer arrive as Fuel and oxidizer are separate streams homogeneously mixed Mixing occurs through One-dimensional flame diffusion at stoichiometric ratio
  6. 6. Soot formation process Inception Fuel molecules dissociate to form C3 H3 , C2 H2 , etc. Formation of first aromatic ring Ring growth to form larger rings Formation of first soot particle (soot incipient) Growth Surface reactions – soot particles grow by consuming C2 H2 and aromatics Agglomeration – coalescence of two or more particles forming larger particles Oxidation Burnup of soot particles by oxidizer (depending on environment)
  7. 7. What are we trying to measure? Soot concentrations Soot concentrations measured using Laser-Induced Incandescence (LII) Calibrated using laser extinction
  8. 8. What are we trying to measure? Soot concentrations Soot concentrations measured using Laser-Induced Incandescence (LII) Calibrated using laser extinction PAH (Polycyclic Aromatic Small PAH Hydrocarbons) Qualitative concentrations measured using laser-induced m-xylene naphthalene fluorescence (LIF) Excited in the UV at 266 nm Large PAH Small PAH detected between 320 – 380 nm Large PAH detected between 420 – 480 nm coronene pyrene
  9. 9. Burner and High Pressure Chamber Ceramic substrate (Flow straightener) 3 mm glass beads Copper mesh Brass support plate with holes Fuel Compressed Air Diffusion burner High pressure flame reactor
  10. 10. Establishing a Test Diffusion Flame 1 atm 2 atm 3 atm 4 atm 5 atm 20 mm 15 mm 10 mm 5 mm 0 mm C2 H4 flow rate = 1.0 mg/s, Air flow rate = 700 mg/s Ethylene flames Stable at high pressures Large soot loads at high pressures
  11. 11. Reducing soot concentrations in C2 H4 flames 0 mg / s 1mg / s 2 mg / s 3 mg / s 4 mg / s 4 .5 mg / s 5 mg / s 5.5 mg / s 6 mg / s 2 0 15 10 5 0 Ethylene flame at a flow rate of 1.0 mg/s at different levels of nitrogen dilution Nitrogen dilution Lower soot concentration ⇒ easier laser diagnostics Final flame conditions: C2 H4 (1.0 mg/s) + N2 (5.5 mg/s)
  12. 12. Measuring soot and PAH concentrations Laser diagnostics: Laser-induced incandescence (LII) and fluorescence (LIF) ICCD Camera Cylindrical lens S1-UV Glan-Thompson polarizer lens S1-UV 500 mm 105 mm UV lens Convex focusing 1/2 wave plate Laser Filters S1-UV fused silica windows Beam block Dichroic mirror Schematic of LII and LIF
  13. 13. Calibration of LII: Extinction Focusing lens 350 mm Argon Ion Laser Optical chopper Beam splitter S1-UV fused fused silica windows Iris Integrating sphere Mirror Focusing lens 100 mm Iris Photo-diode Photo-diode Calibration flame C2 H4 (1.0 mg/s) + Air (700 mg/s) at 3 atm
  14. 14. Addition of m-xylene Ethylene Ethylene + + Nitrogen Nitrogen + m-Xylene Inlet Outlet m-Xylene 40% Ethylene Glycol + 60% Distilled Water
  15. 15. Flame conditions for current study Flame 1 Flame 2 Flame 3 20 20 20 18 18 18 Distance from fuel tube (mm) Distance from fuel tube (mm) Distance from fuel tube (mm) 16 16 16 14 14 14 12 12 12 10 10 10 8 8 8 6 6 6 4 4 4 2 2 2 0 0 0 −4 −2 0 2 4 −4 −2 0 2 4 −4 −2 0 2 4 Distance from center (mm) Distance from center (mm) Distance from center (mm) C2 H4 1.0 mg/s C2 H4 0.975 mg/s C2 H4 0.95 mg/s N2 5.5 mg/s N2 5.5 mg/s N2 5.5 mg/s C8 H10 0 mg/s C8 H10 0.0236 mg/s C8 H10 0.0473 mg/s All C from C2 H4 2.5% of C from C8 H10 5% of C from C8 H10 Total Carbon flow rate is maintained.
  16. 16. Diluted flames at high pressure Flame 3: 5% Carbon from m-xylene 1 atm 2 atm 3 atm 4 atm 5 atm 20 Distance from center (mm) 18 16 14 12 10 8 6 4 2 0 −4 −2 0 2 4 −4 −2 0 2 4 −4 −2 0 2 4 −4 −2 0 2 4 −4 −2 0 2 4 Distance from center (mm)
  17. 17. Soot volume fraction images Flame 3: 5% Carbon from m-xylene 1 atm 2 atm 3 atm 4 atm 5 atm 20 Distance from fuel tube (mm) 4.5 18 4 16 3.5 14 3 12 2.5 10 2 8 1.5 6 4 1 2 0.5 0 0 −2 −1 0 1 2 −2 −1 0 1 2 −2 −1 0 1 2 −2 −1 0 1 2 −2 −1 0 1 2 Distance from center (mm) Soot volume fraction, fv ≡ Fractional volume of soot in a unit volume of flame gases Images obtained using LII
  18. 18. Effect of pressure on soot concentrations 1 atm 2 atm 3 atm 4 atm 5 atm 20 Distance from fuel tube (mm) 18 4 16 3.5 14 3 12 2.5 10 2 8 1.5 6 4 1 2 0.5 0 0 −2 −1 0 1 2 −2 −1 0 1 2 −2 −1 0 1 2 −2 −1 0 1 2 −2 −1 0 1 2 Distance from center (mm) Contour ∆fv = 0.28 ppm, Minimum contour ≡ 0.10 ppm Flame 3: 5% Carbon from m-xylene
  19. 19. Effect of m-xyleneon soot concentrations Flame 1 Flame 2 Flame 3 20 18 4 Distance from fuel tube (mm) 16 3.5 14 3 12 2.5 10 2 8 1.5 6 1 4 2 0.5 0 0 −2 −1 0 1 2 −2 −1 0 1 2 −2 −1 0 1 2 Distance from center (mm) Pressure = 5 atm Contour ∆fv = 0.28 ppm, Minimum contour ≡ 0.10 ppm
  20. 20. Fluorescence images Flame 1 Soot Small PAH Large PAH x 10 4 20 2 7 18 Distance from fuel tube (mm) 6 16 1.5 14 5 12 4 10 1 8 3 6 2 0.5 4 1 2 0 0 0 −2 0 1 2 −1 −2 0 1 2 −1 −2 0 1 2 −1 Distance from center (mm) C2 H4 1.0 mg/s N2 5.5 mg/s C8 H10 0.0 mg/s Pressure = 5 atm
  21. 21. Fluorescence images Flame 1 Flame 3 Soot Small PAH Large PAH x 10 4 Soot Small PAH Large PAH x 10 5 20 2 7 20 7 18 18 Distance from fuel tube (mm) Distance from fuel tube (mm) 6 4 16 16 6 1.5 14 5 14 5 3 12 12 4 4 10 1 10 3 2 3 8 8 6 2 6 2 0.5 4 4 1 1 1 2 2 0 0 0 0 0 0 −2 0 1 2 −1 −2 0 1 2 −1 −2 0 1 2 −1 −2 0 1 2 −1 −2 0 1 2 −1 −2 0 1 2 −1 Distance from center (mm) Distance from center (mm) C2 H4 1.0 mg/s C2 H4 0.95 mg/s N2 5.5 mg/s N2 5.5 mg/s C8 H10 0.0 mg/s C8 H10 0.0473 mg/s Pressure = 5 atm Pressure = 5 atm
  22. 22. Conclusions Established a flame environment for studying soot formation from aromatic compounds Obtained a set of benchmark data for comparison with numerical models Can be used to study a variety of aromatic compounds One of the first measurements of its kind in high pressure flames
  23. 23. Thank you Questions?

×