Optical methods for combustion research

Transcription

1 KCFP Södertälje May 8, 2008 Optical methods for combustion research Mattias Richter Associate Professor Division of Combustion, Sweden Tolvan Tolvansson, 2007 Johannes Lindén, Division of Combustion

2 Chemiluminescence Photographs What is optical diagnostics Utilization of electromagnetic radiation (light) for the purpose of measuring or visualizing certain properties High-speed video recordings Spectroscopic studies Measurements, e.g. EGR, Temperature Black-body radiation IR- pyrometry Laser induced radiation LIF, LIP, LII Raman scattering Rayleigh scattering Bunch of other techniques

3 What can optical diagnostics do in engines? Species distributions / concentrations LIF Absorption Raman / Rayleigh Chemiluminescence Flow PIV LDA / LDV /PDA Tagging techniques Temperature LIF CARS (Raman) Rayleigh Absorption spectroscopy Mixture preparation Spray penetration Spray angles Evaporation Fuel/Air mixing Combustion characteristics Ignition events Flame propagation Flame quenching Knock centers Low / High temperature regions Causes of misfires Pollutant formation NOx Soot Unburnt HC

4 Is it a playground? What was this man doing in 1876? Nicolaus Otto presented the four-stroke engine Otto s try-out engine engine displacement bore * stroke cooling power rated speed weight one-cylinder 6107 cm³ year * 300 mm water (usage) 2 kw (3 HP) 180 1/min around 1500 kg

5 Is it a playground? What was this man doing in 1872? Nicolaus Otto developed his prototype using optical engines

6 The industry is (was) definitely using it Rassweiler & Withrow, GM 1930 s by using a large quartz window extending across the entire combustion chamber and using high-speed motion picture film, we could photograph the entire burning process from the moment of ignition to its completion. "This insight into the mysteries of combustion helped clarify the knock problem. From the book: The future is our assignment, GM, Tolvan Tolvansson, 2007 Johannes Lindén, Division of Combustion

7 KCFP Södertälje May 8, 2008 The industry is definitely using it Tolvan Tolvansson, 2007 Johannes Lindén, Division of Combustion

8 Large bore gas engine Study of the Early Flame Development in a Spark-Ignited Lean Burn Four-Stroke Large Bore Gas Engine

9 Ignition process in large bore lean burn gas engines Spark ignites richer mixture in pre-chamber Energetic jets emerges from pre-chamber and ignites main-chamber gas 34 cm bore Tolvan Tolvansson, 2007 Johannes Lindén, Division of Combustion Rikard Wellander, Lund University, Paper

10 Ignition process in large bore lean burn gas engines Engine type: 4-stroke Cylinder bore: 340 mm Cylinder stroke: 430 mm Displacement: 39.0 dm3 / cylinder Comp. ratio: 11.6:1 Nbr of valves: 4 Engine speed: 750 rpm Nominal output: 500 kw/cylinder Nominal BMEP: 22.0 bar

11 Planar Laser Induced Fluorescence Imaging

12 Fuel tracer PLIF imaging Signal Toluen Aceton Excitation in the UV at 266 nm Resulting fluorescence according to spectra Cyclohexanone Wavelength

13 Flame jet appearance (Imaged at -9 CAD BTDC) Pree-chamber seeded Main-chamber seeded (TOI: -14 CAD BTDC) Tolvan Tolvansson, 2007 Johannes Lindén, Division of Combustion Rikard Wellander, Lund University, Paper

14 High-speed imaging in the Scania D12 engine Cyl. Volume 1951 cm 3 Bore 127 mm Stroke 154 mm Comp. Ratio 16:1 Chamber design Pancake Fuel Ethanol Tracer Acetone Lambda 3.85 Excitation 266 nm

15 High-speed fuel tracer PLIF in HCCI engines Tracer: Acetone (1 CAD = 139 µs) 50 mm 2 ATDC 2.5 ATDC 3 ATDC 3.5 ATDC 4 ATDC 4.5 ATDC 5 ATDC 5.5 ATDC Gradual consumption of fuel Multiple ignition kernels Sharp gradients at the end of combustion

16 High-speed fuel tracer PLIF in SI engine 7 ATDC 7.75 ATDC 8.5 ATDC 9.25 ATDC 10 ATDC ATDC 11.5 ATDC 12,25 ATDC 7 ATDC 7.75 ATDC 8.5 ATDC 9.25 ATDC 10 ATDC ATDC 11.5 ATDC 12,25 ATDC 13juni_v2_5

17 Probing of formaldehyde distributions Formaldehyde Excitation at 355nm Detection: >400nm 1 0,8 Intensity (a.u.) 0,6 0,4 0,2 Tolvan Tolvansson, lambda (nm)

18 Formaldehyde distributions recorded at 7 CAD BTDC for different SOI

19 Simultaneous detection of formaldehyde and OH Formaldehyde Excitation at 355nm Detection: >400nm OH Excitation at 283nm Detection at 308 nm Delay between the two lasers: 500ns ( rpm)

20 Formaldehyde and OH distributions for SOI 80 CAD BTDC

21 Comparison - Different fuels iso-oktan + n-heptan n-dekan SOI=80CAD BTDC, 40% EGR Tolvan Tolvansson, 2007 Johannes Lindén, Division of Combustion

22 CH visualization in a turbulent flame Tolvan Tolvansson, 2007 Kiefer et al, 31 st Comb. Symp Johannes Lindén, Division of Combustion

23 Multi species visualization CH, OH

24 Simultaneous dual-species visualization CH, CH 2 O Li Tolvan et al. Comb. Tolvansson, and Flame, Johannes Lindén, Division of Combustion Courtesy: Z-S. Li et al.

25 KCFP Södertälje May 8, 2008 Multi-Species Measurements Tolvan Tolvansson, 2007 Johannes Lindén, Division of Combustion

26 Multi-Species Laminar flame OH CH CH 2 O Toluene

27 Multi-Species Turbulent Flames 30 m/s 60 m/s 120 m/s OH CH CH CH 2 O CH 2 O Tolu. OH CH CH CH 2 O CH 2 O Tolu. OH CH CH CH 2 O CH 2 O Tolu.

28 Thank you for your attention!