Fundamental Mechanisms, Predictive Modeling, and Novel Aerospace Applications of Plasma Assisted Combustion

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1 Fundamental Mechanisms, Predictive Modeling, and Novel Aerospace Applications of Plasma Assisted Combustion AFOSR MURI Kick off meeting The Ohio State University Nov 4, 2009

2 Report Documentation Page Form Approved OMB No Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 04 NOV REPORT TYPE 3. DATES COVERED to TITLE AND SUBTITLE Fundamental Mechanisms, Predictive Modeling, and Novel Aerospace Applications of Plasma Assisted Combustion 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Drexel University,A. J. Drexel Plasma Institute,34th St. and Lancaster Ave,Philadelphia,PA, PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR S ACRONYM(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT 11. SPONSOR/MONITOR S REPORT NUMBER(S) 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Same as Report (SAR) 18. NUMBER OF PAGES 49 19a. NAME OF RESPONSIBLE PERSON Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

3 Drexel Group: Main Tasks Thrust 1. Experimental studies of nonequilibrium air-fuel plasma kinetics using advanced non-intrusive diagnostics Task 1: Low-to-Moderate (T= K) temperature, spatial and time-dependent radical species concentration and temperature measurements in nanosecond pulse plasmas in a variety of fuel-air mixtures pressures (P=0.5-5 atm), and equivalence ratios Task 4: Moderate-to-high (T= K) temperature PAC oxidation kinetics in Discharge Shock Tube Facility at pressures up to 10 bar Task 5: PAC oxidation and combustion initiation at high pressure, high temperature conditions Thrust 2. Kinetic model development and validation Task 8: Development and validation of a predictive kinetic model of non-equilibrium plasma fuel oxidation and ignition Task 9: Mechanism Reduction and Dynamic Multi-time Scale Modeling of Detailed Plasma- Flame Chemistry Thrust 3. Experimental and modeling studies of fundamental nonequilibrium discharge processes Task 10: Characterization and Modeling of Nsec Pulsed Plasma Discharges Thrust 4. Studies of diffusion and transport of active species in representative twodimensional reacting flow geometries Task 13: Ignition and flameholding in high-speed non-premixed flows Task 14: High Fidelity Modeling of Plasma Assisted Combustion in Complex Flow Environments

4 Drexel Group: International Collaboration International Collaborators Svetlana Starikovskaya (Ecole Pol) Thrust 1 Alexander Rakitin (NEQLab) Thrust 1 Boris Potapkin (KIAE) Thrust 2 Alexander Konnov (VUB) Thrust 2 Nickolay Aleksandrov (MIPT) Thrust 3 Sergey Pancheshnyi (Univ Toulouse) Thrust 3 Sergey Leonov (IVTAN) Thrust 4

5 Range of Parameters Combustion Kinetics 2500 K T, K φ 3.0 S/I P, atm K

6 Problems of Plasma-Chemical Models Availability and accuracy of data on electron collision cross sections + H 2 CH 4 C 2 H 6 C 3 H 8? C 4 H 10 C 5 H 12 Availability and accuracy of chemical models below self-ignition point + H 2? CH 4 C 2 H 6 C 3 H 8 C 4 H 10 C 5 H 12 Availability and accuracy of physical and chemical models for non-equilibrium conditions + Radical s mechanism? Ionic chain mechanism? Energy chain mechanism

7 Models for Low-Temperature Plasma Assisted Combustion Starikovskii et al., Plasma Physics Reports, 2000 (26) 701 O 2 + e - + M O 2- + M H 2 + O - 2 OH - + OH OH + H 2 H 2 O + H OH - + H H 2 O + e - H + O 2 + M HO 2 + M OH - + HO 2 H 2 O + O 2 + e - Starikovskii, Chemical Physics Reports, 2003 (11) 1 N 2 O* + H N 2 * + OH CO + OH CO 2 * + H CO 2 * + N 2 O N 2 O* + CO 2 N 2 * + N 2 O N 2 O* + N 2

8 1 PAC: Where we are 2500 K T, K φ 3.0 S/I P, atm B/S K 300 E/n, Td 1000

9 Mechanisms of Plasma Influence 1. Heating 2. Turbulization 3. Momentum Transfer 4. Electrons/Ions Diffusion/Drift 5. Dissociation, Ionization

10 Shock Wave - Nonequilibrium Plasma Interaction

11 Relaxation of Nonequilibrium Plasma. Air. P 1 ~ 20 Torr τ E V/V Pre-trigger Time, μs V, Base 3-4 Ms=3.0 Ms=2.3 Ms=2.2 Ms=2.2 Ms=1.8 Ms=1.56

12 Relaxation of Nonequilibrium Plasma. Air. P 1 ~ 20 Torr

13 Mechanism of fast heating in discharge plasmas (low E/N) Air Fractional energy deposition, % O 2 (rot) O 2 (vib) N 2 (rot) N 2 (vib) O 2 (el) N 2 (el) N 2 (ion) O 2 (ion) E/n, Td Low (< 20 Td) E/N: e+n 2,O 2 - elastic scattering - rotational excitation

14 Mechanism of fast heating in discharges (moderate E/N) Moderate ( Td) E/N: Popov (2001) heating 28 % of power spent on N * 2 +O * 2 e+o 2 e+2o+δe e+n 2 e+n 2* (A, B, C, a,...) N 2* (A, B, C, a,...) + O 2 N 2 +2O+ΔE O( 1 D) + N 2 O+N 2 + ΔE k~10-10 cm 3 /s

15 Mechanism of fast heating in discharge plasmas (high E/N) Aleksandrov et al. (2009) Heating percentage, % n e0 =10 14 cm -3 ; dry air n e0 =10 15 cm -3 ; dry air n e0 =10 14 cm -3 ; 1 % H 2 O n e0 =10 15 cm -3 ; 1 % H 2 O 28% of energy spent on N 2 (el) + O 2 (el) (Popov (2001)) E/N, Td High (> 200 Td) E/N: electron-ion and ionion recombination kinetics e + O 2+ O + O * + ΔE O 2- + O 2+ + M 2O 2 + M + ΔE

16 Heat Release and Shock Waves Formation by Nonequilibrium Plasma 50 ns, ΔT = 420 K 7 ns, ΔT = 240 K

17 Energy Distribution in Gas Discharge 100 Fractional energy deposition, % 50 O 2 (rot) O 2 (vib) Air N 2 (rot) N 2 (vib) O 2 (el) N 2 (el) N 2 (ion) O 2 (ion) E/n, Td

18 Molecular Oxygen Excitation To directly observe the influence of SDO on the combustion of H 2 -O 2 mixture Delivering sufficient amount of SDO Minimizing the effect of O atom Lower the inlet temperature V V Smirnov, O M Stelmakh, V I Fabelinsky, D N Kozlov, A M Starik and N S Titova, J. Phys. D: Appl. Phys. 41 (2008)

19 SDO kinetic analysis lg(t,s) -1,5 Experiment Calculations Calculations with laminar boundary layer -2,0 0% 1.2% 4% 6% SDO mole fraction The ignition time as a function of SDO mole fraction in oxygen. T=775 K and P=10 Torr in the H2:O2=5:2 mixture

20 SDO kinetic analysis E-3 1E-4 1E-5 1E-6 1E-7 H2 O2 SDO H O OH HO2 H2O H2O2 O(1D) O2(1S) O3 Temp 1E-8 1E-6 1E-5 1E-4 1E Time s Auto-ignition Temperature, K E-3 1E-4 1E-5 1E-6 1E-7 H2 O2 SDO O H OH HO2 H2O H2O2 O(1D) O2(1S) O3 Temp 6% SDO 1E-8 1E-6 1E-5 1E-4 1E Temeprature, K The evolution in time of the mole fractions of the main component for autoignition (a) and ignition with 6% singlet delta oxygen. The gas temperature evolution is represented by the thick red line.

21 Possible reasons SDO kinetic analysis Auto O 2 +M=O+O+M (slow) H 2 +O=OH+H O 2 +H=OH+O OH+OH=H 2 O+O SDO O 2 (a 1 Δ g )+H 2 =OH+OH (fast) OH+H 2 =H 2 O+H O 2 (a 1 Δ g )+H=OH+O O 2 +H=OH+O OH+OH=H 2 O+O Radical generation efficiency O 2 (a 1 Δ g )+H 2 =OH+OH O 2 (a 1 Δ g )+H=OH+O ~80 μs 200% 100%

22 Energy Distribution in O 2 -Ar (15%:85%) Mixture Energy deposition, % H + O 2 ( 1 Δ) = OH + O Reduced Electric Field, Td Ar(elastic) Ar(11.6eV) Ar(11.3eV) Ar(Ionization) O2(v=1) O2(v=2) O2(v=3) O2( 1 Δ) O2( 1 Σ) O2(4.5eV) O2(6.0eV) O2(8.4eV) O2(Ionization) 74% energy in excitation of singlet oxygen at E/n= 5 Td Approximately 53% in singlet delta state About 21% in singlet sigma state

23 SDO Excitation efficiency in air plasma E/n = 6 Td (=10 17 Vcm 2 ) 2,5 SDO Excitation Efficiency, % 2,0 1,5 1,0 0,5 0,0 0, E/n, Td Air Plasma N2 Elastique 1.8 % N2(ROT) 4 % N2 (V=1) 49 % N2 (V=2) 7.3 % N2 (V=3) 1.4 % N2 (V=4) 0.2 % O2 Elastique 0.3 % O2 (ROT) 0.2 % O2 (V=1) 17 % O2 (V=2) 11 % O2 (V=3) 4.1 % O2 (V=4) 1.4 % O2 (a 1 Δ g ) 2.2 % O2 (b 1 Σ) 0.1%

24 Shock Tube with Discharge Section. U 0.3 MV, M 3 Starikovskaya et al Test Section of the Shock Tube

25 Main Processes During Discharge Phase Reaction Rate Ar + e - Ar + + e - + e - 2 O 2 + e - O + O + e - 3 CH 4 + e - CH 3 + H + e - 4 Ar + e - Ar * + e - 5 Ar * + O 2 Ar + O + O Ar * + CH 4 Ar + CH 2 + H + H 7 O 2 + e - O 2 * + e O 2 * + CH 4 O 2 + CH 3 + H Time, ns

26 Radicals Production in Discharge CH 4 -containing mixture

27 Ignition Delay Time: Methane-Containing Mixture II autoignition, experiment autoignition, calculations Ignition delay time, μs autoignition I I II PAI, experiments PAI, experiments PAI, calculations PAI, calculations 10 0 PAI PAI CH /T 5, K

28 RAMEC (for C1) + Westbrook (C2-C7) + High Pressure Adjustment CH (C 5 H 12 :O 2 ) + 90% Ar Induction time, μs b) /T, K -1 Auto Exp Auto Calc FIW Exp FIW Calc

29 Experiment and Calculations in H 2 -Air Mixture

30 Modeling of Radicals Formation vs E/n (W=14 mj/cm 3 ) H2:O2:N2=29.5:14.75:55.75 Density, cm x x x x x x x x x x10-4 H2:O2:Ar=29.5:14.75:55.75 O H Sum Density, cm x x x x x x x x E/N, Td O H Sum E/N, Td

31 Delay time for autoignition and plasma assisted ignition in CH 4 -containing mixture Ignition delay time, μs Aleksandrov et al. (2009) auto 0.5 atm ~2 atm PAI auto ~0.5 atm 10 2 PAI with E(t)/N CH 4 :O 2 :N 2 :Ar = 1:4:15: /T, K -1

32 Plasma Recombination at High Pressures and Temperatures N 2 :H 2 :O 2 :CO 2 =67:15:11: N 2 :O 2 :CO 2 =76:19:5 n e, cm n e, cm p=1.1атм.,t=2990k p=1.5атм.,t=2680k p=1.8атм.,t=2558k p=1.9атм.,t=2270k p=2атм.,t=2100k p=2атм.,t=2150k p=2.1атм.,t=1989k p=1.1атм.,t=2845к p=1.3атм.,t=2517к p=1.7атм.,t=2442к p=2атм.,t=2411к p=2.3атм.,t=2316к Время, мкс N2:H2:O2:CO2=67:15:11:7 n e, cm Время, мкс N 2 p=2.56atm,t=2036k p=2.2atm,t=2036k p=1.96atm,t=2065k p=1.9atm,t=2276k p=1.68atm,t=2384k p=1.5atm,t=2598k p=1.07atm,t=2770k After 10 μs, at 1atm., 2800К N 2 :H 2 O:O 2 :OH:CO:CO 2 :H:O:H 2 =67:10:5:4:3.5:3:3:3: Время, мкс

33 Evolution in Time of Electron Density During Plasma Decay Effective recombination coefficient, cm 3 s -1 Effective recombination coefficient, cm 3 s -1 ) 10-6 p=0.4 atm T, K 10-6 p=0.4 atm air Effective recombination coefficient, cm 3 s -1 ) O 2 :N 2 :CO 2 =1:4:5 O 2 :N 2 :CO 2 =5:86: T, K 10-6 p=0.4 atm T, K Dissociative electron-ion recombination e + O 2+ O + O Electron attachment and detachment e + O 2 + M O 2- + M O 2- + O e + O 3

34 Types of Gas Discharges and Their Applications Types of Gas Discharges and Their Applications Arc Discharge: equilibrium plasma Applications: melting & welding 1E16 T = 4000 K T = 8000 K T = 350 K Streamer Discharge: overvoltage up to 200% Applications: surface treatment, flue gases treatment, electrical breakdown, power switches Electron Dencity, cm-3 1E15 1E14 1E13 MW Discharge: partial equilibrium Applications: plasma chemical conversion, chemical vapor 1E12 deposition (CVD) 1E11 Glow Discharge: E/n close to the breakdown threshold Applications: light sources, surface treatment, CVD T = 400 K Reduced El ectr ic Fi eld, Td T = 300 K Discharge Development at Different Overvoltage and Plasma Generation Nanosecond Pulsed Discharge: overvoltage up to 10 times Applications: Plasma supported combustion Plasma supported aerodynamics Chemical conversion CVD

35 Setup for OH Dynamic Measurements in Streamer Channel Afterglow Pancheshnyi et al

36 LIF Diagnostics Setup: Doubling system LIF OH Dye laser burner OH Profile Control NdYAG laser Spectrometer LIF OH OH (X-A): Excitation: Q 1 (6) nm; Emission: 315nm, δλ=1.8 нм; Registration PicoStar LaVision ICCD камера ICCD - camera

37 250 LIF Emission of OH at 300 K OH LIF, 300 K, 1 atm Methane lean Ethane lean Propane lean Butane lean Methane St Ethane St Propane St Methane Rich Time, μs 100 OH LIF, 300 K, 1 atm 10 1 Methane lean Ethane lean Propane lean Butane lean Methane St Ethane St Propane St Methane Rich Time, μs

38 LIF Emission of OH at 500 K

39 300 K Versus 500 K LIF of OH Methane Ethane

40 High-pressure Conditions: Always Non-Uniform 9 ns 11 ns Pancheshnyi et al

41 Rapid Compression Machine: High-Pressure, Low-Temperature

42 PAC at High Pressure: ER = 1 (Rakitin et al) T2 = 713 K P2 = 26.5 bar Propane, Surface DBD, < 50mJ

43 PAC at High Pressure: ER = 0.4 (Rakitin et al) T2 = 794 K P2 = 32 bar Propane, Surface DBD, < 50mJ

44 Propane-Butane-Air Lean Mixtures. φ =0.5(C 3 :C 4 =85:15) 100 Ignition Delay, µs 10 P=500 atm P=210 atm P=66 atm P=20 atm P=4.7 atm Cadman et. al P=10 atm 0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00 1,05 1,10 1, /T, K -1

45 Propane-Butane-Air Mixture Ignition. φ =0.5(C 3 :C 4 =85:15). Calculations

46 Propane-Butane-Air Mixture Ignition. Experiment vs Calculations Ignition Delay, µs , P=500 atm, P=210 atm, P=66 atm, P=20 atm, P=4.7 atm 10 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1000/T, K -1

47 Channels of Kinetic Scheme Optimization Reaction T k C 3 H 8 + HO 2 = C`H 2 C 2 H 5 + H 2 O C 3 H 8 + HO 2 = CH 3 C`HCH 3 + H 2 O O 2 C 3 H 7 = HOOCH 2 C`HCH CH 3 CHO 2 CH 3 = CH 3 CH(OOH)C`H OCHCH(OOH)CH 3 = CH 3 CHO + HCO + OH OCHCH 2 CH(OOH) 2 = CH 2 O + CH 2 CHO + OH CH 3 COCH 2 (OOH) = CH 2 O + CH 3 CO + OH H 2 O 2 +M -> OH+OH+M Konnov, Potapkin Ignition Delay (µs) CH 3 +CH 3 O 2 = CH 3 O+CH 3 O Fuel decomposition H 2 O 2 and HO 2 Formation and Decomposition Alkyl Hydroperoxides formation and decomposition n-hexane P = 220 atm n-pentane P = 250 atm C 3 H 8 +C 4 H 10 P=210 atm Methane P = 150 atm 0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00 1,05 1,10 1,15 1,20 1, /T (K -1 )

48 Mixture C 3 H 8 :C 4 H 10 :Air = 1.8:0.3:97.9 C 3 H 8 :C 4 H 10 :Air=1.8:0.3:97.9 Ignition Delay, µs , P = 4.7 atm, P = 20 atm, P = 66 atm, P = 210 atm, P = 500 atm 0,7 0,8 0,9 1,0 1,1 1,2 1000/T, K -1

49 Discharge Formation and Flame Stabilization in High Speed Flow IVTAN (Sergey Leonov): M = 2 Maximal stagnation pressure 1.8 Bar Stagnation temperature 670 K Discharge Power ~ 1 kw DPI Shock Tunnel: M = 2-5 Static pressure Bar Static temperature K Discharge Power ~ 1 kw

50 Summary Range of Parameters P = atm T = K M = 0-5 φ = E/n = Td (Air) Fuels: H 2, C 1 C 4 Acetones, Alcohols, CO Experiment: Shock Tube Shock Tunnel Rapid Compression Machine Premixed Flow Nozzle Theory: Discharge Models Plasma Models Chemical Kinetic Models