srm suite applications

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srm suite applications

  1. 1. cmcl innovations the application of our software tools
  2. 2. application areas fuels conventional combustion products srm suite biofuels SI mode automated model development natural gas CI mode turbulent combustion – CFD advanced gasoline / diesel how srm suite works emissions advanced combustion CI mode CO, uHC, CO2, NOx multiple direct injection SI mode soot mass low temperature combustion soot size / mass distributions HCCI software coupling SI “downspeeding” / knock 3D CFD 1D cycle modelling
  3. 3. diesel combustion modelling challenges heat transfer compression/expansion mixture preparation/injection combustion premixed premixed/mixing controlled mixing controlled emissions
  4. 4. compression/expansion
  5. 5. diesel combustion: compression key processes compression heat transfer mass loss/blow-by
  6. 6. mixture preparation
  7. 7. diesel combustion: mixture preparation -30 CAD aTDC -10 CAD aTDC 0 CAD aTDC 10 CAD aTDC key processes (no combustion) port injection multiple direct injection 30 CAD aTDC charge cooling temperature stratification mixture stratification 20 CAD aTDC
  8. 8. combustion
  9. 9. diesel combustion: pilot ignition key processes mixture preparation chemical kinetics TDC
  10. 10. diesel combustion: premixed/mixing controlled 10 deg aTDC key processes turbulent mixing chemical kinetics / emissions formation 20 deg aTDC 30 deg aTDC
  11. 11. diesel combustion: mixing controlled key processes turbulent mixing emissions formation 30 deg aTDC 50 deg aTDC
  12. 12. emissions
  13. 13. diesel combustion: emissions where do the emissions come from? soot on-going chemical kinetics exhaust emissions •regulated •non-regulated NOx CO/uHCs •particulates 10 deg aTDC
  14. 14. spark ignition combustion mode
  15. 15. spark ignited combustion modelling challenges heat transfer compression/expansion mixture preparation/injection combustion flame propagation knock (pre-ignition) emissions
  16. 16. mixture preparation
  17. 17. mixture preparation -30 CAD aTDC -10 CAD aTDC 0 CAD aTDC 10 CAD aTDC key processes port injection multiple direct injection charge cooling 30 CAD aTDC temperature stratification mixture stratification (no combustion) 20 CAD aTDC
  18. 18. combustion
  19. 19. SI modelling approach BURNED ENTRAINED UNBURNED
  20. 20. SI combustion: flame propagation key processes mixture preparation ignition chemical kinetics -20 CAD aTDC 0 CAD aTDC 10 CAD aTDC
  21. 21. SI combustion: knock key processes chemical kinetics 20 CAD aTDC 25 CAD aTDC
  22. 22. emissions
  23. 23. SI combustion: emissions where do the emissions come from? soot chemical kinetics – on-going computations gas phase emissions •regulated •non-regulated NOx CO/uHCs particulates 10 deg aTDC (diesel)
  24. 24. advanced combustion mode multiple direct injection
  25. 25. gasoline – fuel for advanced diesel engine ? A 0.537 litre single cylinder diesel engine with a compression ratio of 15.8:1 operated using an 84 RON gasoline fuel. Bosch injectors were adopted with seven holes of 0.13mm diameter. Single injection SOI =-11.2 CAD aTDC, Triple injections a) 25% SOI @ -180 CAD aTDC, b) 15% @ - 76 CAD aTDC and main @ -7 CAD aTDC.
  26. 26. multiple injection strategies ~12 bar IMEP dp/dt [bar/CAD] burn duration [CAD] uHCs emissions [-] CO emissions [-] NOx emissions [-]
  27. 27. advanced diesel combustion
  28. 28. Optimal second injection JSAE 20077195 JSAE 20077195
  29. 29. emissions: uHCs and NOx Euro V, NOx = 2000 mg/kWh Multiple steady state operating points Euro V = 0.46 g/kWh Scania turbocharged truck engine
  30. 30. emissions: system level soot model system level soot model – a fast solution for soot mass predictions THE CHALLENGE Predict soot emissions from typical diesel engine THE SOLUTION Optimise “Soot system level model” parameters from diesel engine DOE database Use optimised parameters for predicting results
  31. 31. emissions: system level soot model 0.2 Experiment Model example of model performance 0.16 Soot concentration [g/kW-hr] 0.12 0.08 0.04 0 1 2 3 4 5 6 7 8 9 10 Operating Point
  32. 32. emissions: detailed soot model
  33. 33. aggregate size distribution evolution Experiment Simulation
  34. 34. detailed soot size distribution: role of EGR
  35. 35. software coupling: 3D CFD codes NO (ppm) CO (ppm) uHC (ppm) CO/CO2 Experiment 54.9 2673.0 190.0 0.21 CFD-SRM 65.5 2722.0 376.0 0.32 CFD 0.7 5225.0 2772.0 0.26
  36. 36. software coupling: 3D CFD codes KIVA-srm suite coupling KIVA- 1 month, KIVA/srm suite – 8 hours + 1 hour NOx CO uHC [ppm] [ppm] [ppm] Open bowl 66 2720 376 Re-entry bowl 6 2480 580 Vertical side wall 35 2450 482 bowl
  37. 37. software coupling: 3D CFD codes CO HC
  38. 38. SI engine applications
  39. 39. GDI SI Cycle to cycle variation (CCV) in SI engine.
  40. 40. srm suite: multi-cycle simulation • srm suite coupled with GT-Power for multi-cycle simulation. • 40 simulated and 200 experimental cycles. • NOx emissions: - 496 ppm simulation - 528 ppm experiment
  41. 41. SI “knocking” combustion
  42. 42. SI combustion: “downspeeding” Intake pressure 2.2 bar, 1000rpm retarded ignition some cycles pre-ignited oil-ignition was simulated
  43. 43. SI emissions
  44. 44. Soot in DISI operation Optimisation of injection strategy
  45. 45. Soot in DISI operation Late injection produces stratified mixture. λ = 1.0 EOI = -50 CAD ATDC Fuel rich regions close to spark gap. Spark = -30 CAD ATDC
  46. 46. detailed soot size distribution 2.6 CAD ATDC 12.6 CAD ATDC 32.6 CAD ATDC
  47. 47. SI-CAI-SI transients: mode switching experiment simulation
  48. 48. tabulation - RT
  49. 49. real-time (RT) transient simulation • Collaboration with M. Sjöberg, J. Dec • Studies of transient engine operation, control, DOE, and optimization involve simulations over many cycles • Problem: Computational expense (1-2 hrs per cycle) • Solution: Storage/retrieval • Incorporate tabulation as external cylinder model into GT-Power
  50. 50. control application: fuel blending • GT-Power engine map, with sensors and controller:
  51. 51. Load transients - RT • Imposed equivalence ratio profile • PID controller changes fuel composition (octane number) such that… • … ignition timing (CA50) is held at a given set point.
  52. 52. transient RT: emissions • Since SRM accounts for inhomogeneities, turbulent mixing, and detailed chemical kinetics, can look at… • maximum pressure rise rates, • and emissions (e.g.) misfire cycle
  53. 53. SI modelling approach BURNED ENTRAINED UNBURNED
  54. 54. chemical kinetics and fuel modelling
  55. 55. chemical kinetics and fuel modelling “The implementation of detailed chemical kinetics is critical in expanding the predictive capabilities of reactive flow modelling” chemical fuel models practical fuel modelling emissions chemistry and validation fuel models in srm suite: applications
  56. 56. chemical fuel models
  57. 57. complexity of chemical kinetics Law et al.
  58. 58. conventional and futuristic fuels we have chemical fuel models for Surrogate chemical kinetic models can be generated based on the Research Octane Number (RON) and Motor Octane Numbers (MON) of the desired fuel biofuels Detailed fuel models of conventional practical fuels such as gasoline and diesel Reference fuels such as iso-octane, n-heptane, toluene, n-decane Hydrogen, CNG, ethanol, methanol, bio-diesel Future fuels and blended fuels such as dieseline, M85 and E85. Conventional mechanism development for hydrocarbons and inorganic chemistry such as titania, iron and silver chemistry.
  59. 59. practical fuel modelling
  60. 60. practical fuel modelling (a) Research Octane Number (RON) (b) Octane "Sensitivity" (RON – MON) Tri-component surrogate fuels increase the robustness of practical fuel modelling as fuel sensitivity can also be simulated Conventional fuels fuel blends practical gasoline ethanol/gasoline blending biofuels & future fuels
  61. 61. practical fuel modelling: validation Case 711 - Experiment (Surr. B) 100 Case 711 - Model (Surr. B) - 100pt Case 710 - Experiment (Surr. A) 80 Case 710 - Model (Surr. A) - 100pt Pressure [bar] 60 40 20 0 -40 -20 0 20 40 Crank Angle [deg. ] validation of tri-component surrogate blends detailed modelling of practical fuels range of engines 98.5RON/88MON gasoline operating points Gasoline/ethanol blends
  62. 62. practical fuel modelling: application Simulation of HCCI peak operating limit using SRM for fuel with/without octane sensitivity
  63. 63. emissions chemistry and validation
  64. 64. soot precursors and validation C10H8 C10H7 Na-Na 9.0E-2 8.0E-5 1.6E-5 6.0E-5 1.2E-5 6.0E-2 4.0E-5 8.0E-6 3.0E-2 2.0E-5 4.0E-6 Mole Fraction 0.0E+0 0.0E+0 0.0E+0 0 0.3 0.6 0.9 1.2 0 0.4 0.8 1.2 1.6 0 0.5 1 1.5 Perylene Benzo(ghi)Perylene Coronene 2.5E-6 6.0E-6 1.0E-5 2.0E-6 8.0E-6 4.0E-6 1.5E-6 6.0E-6 1.0E-6 4.0E-6 2.0E-6 5.0E-7 2.0E-6 0.0E+0 0.0E+0 0.0E+0 0 0.5 1 1.5 0 0.5 1 1.5 0 0.5 1 1.5 Height Above Burner (cm) soot chemistry includes a variety of unsaturated HCs and PAHs interaction of soot chemistry with the gas phase chemistry validation carried out in fuel-rich flame and engine experiments
  65. 65. PAH reaction steps Armchair ring growth 5-member ring desorption 6-member ring desorption Free edge growth 5-member ring conversion at AC 5-member ring addition 6- to 5-member ring conversion 5-member ring free edge desorption Oxidation steps: rates from quantum chemistry
  66. 66. quantum calculations to reaction rates electronic energy geometry optimisation rotational constants vibrational frequencies temperature variation of Cp, H, and S transition state theory kbT QTST k (T ) exp( Eact / kbT ) h QAQB
  67. 67. fuel models in srm suite: applications
  68. 68. Soot composition and size distribution chemical model: 208 species, 1002 reversible reactions recirculated aggregates
  69. 69. fuel reformed hydrogen gas HRG added to gasoline
  70. 70. DEE/EtOH blending Point with optimal HC emissions recommended to test cell engineers
  71. 71. CNG with EGR 6 6 10 Model Exptl. Cooled eEGR [27-51%] 5 10 6 Volvo TD 100-series diesel engine 4 10 6 p [Pa] Fuel: CNG 6 3 10 6 2 10 -30 -20 -10 0 10 20 30 CAD 6 5 10 6 Model 4.5 10 Exptl. 6 4 10 6 3.5 10 p [Pa] 6 3 10 6 2.5 10 6 2 10 6 1.5 10 -30 -20 -10 0 10 20 30 CAD

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