"Non-equilibrium chemically active plasma: modeling with Chemical Workbench
Deminsky MaximKintechLab23 July 2015
Outline
Chemical Work Bench (CWB) – toll for conceptual design of chemically oriented phenomena
Problems arising during elaboration of plasma model
Collection of plasma model in CWB environment
Coupling of plasma models with other models
Data needed for simulation: construction of plasma-chemical mechanism in CWB
Recovering of unknown characteristics of elementary plasma-chemical processes in CWB
Example of modeling of mercury-free light sources
Example of modeling plasma-assisted combustion
CWB computational environment
Substance and process properties, kinetic mechanisms
Kinetic mechanisms
Substance and elementary process
properties
Substance properties
KhimeraKhimera
Chemical workbenchChemical workbench
Automated data importQuantum chemistryQuantum chemistry
KintechDB
CWB software tools
Kintech Lab develops methods and special software tools for development of the predictive kinetic mechanisms and conceptual design of complex combustion and plasma systems:
Kintech Lab develops methods and special software tools for development of the predictive kinetic mechanisms and conceptual design of complex combustion and plasma systems:
Chemical Workbench – an integrated environment for the development and reduction of chemical mechanisms, and conceptual design of the chemistry intensive technological processes
Khimera – a unique tool for calculating microscopic parameters from first-principles calculations
KintechDB – a database of evaluated data for properties of substances, elementary processes and chemical mechanisms
Chemical Workbench©
Combustion Plasma Chemistry Pollution Control Waste Treatment and Recovering Metallurgy General Chemical Kinetics and Thermodynamics High Temperature In-Organic Chemistry Thermal and Plasma Hydrocarbon Pyrolysis Processes Education
Integrated modeling environment for kinetic modeling, kinetic mechanism development and conceptual reactors design in the fields of
Problems arising during elaboration of plasma model
Design of modelDesign of model
Chose ofappropriate model
Chose ofappropriate model
Collection of data set (“mechanism”)
Collection of data set (“mechanism”)
Thermodynamic dataThermodynamic data
Kinetic data (rate coefficient, cross sections)
Kinetic data (rate coefficient, cross sections)
Transport dataTransport data
Adequacy of model to discharge type Adequacy of model to discharge type
Coupling with electric network
Coupling with electric network
Coupling with chemistryCoupling with chemistry
Well Stirred Reactor (WSR), 2 modelsPlug Flow Reactor (PFR), 3 modelsCalorimetrics Bomb Reactor (CBR), 4 models Calorimetric Reactor with Deviation (CRD)/Sensitivity (CRS), 4 modelsPremixed Flame, 1 model
Kinetic models and Surface kinetic modelsKinetic models and Surface kinetic models
Full Thermodynamic Equilibrium Reactor (TER), 8 modelsStoichometric Equilibrium Reactor (STR), 4 models
Thermodynamic modelsThermodynamic models
Plasma models and Plasma models with Surface kineticsPlasma models and Plasma models with Surface kinetics
CWB model’s collection
Detonation and aerodynamic modelsDetonation and aerodynamic models
Chapman-Jouguet Reactor (CJ), 1 modelsZel’dovich-von Neumann-Doering Reactor (ZND), 1 modelExhaust Reactor (EXH), 1 model
CWB Plasma models CWB Plasma models
CWB plasma model’s collection
Is…
0D or 0D(+) dimension
uniform media (T,P,E/N, [Ci])
hydrodynamics time >> plasma & chemical times
coupling of EEDF solution with chemical reactions
Is not…
2D or 3D dimensions
for non-uniform distributed characteristics (T,P,E/N)
Navier-Stokes for CFD
Thus, CWB models is for investigation of plasma-chemical kinetic mechanisms and conceptual design of complex chemically active plasma systems
Thus, CWB models is for investigation of plasma-chemical kinetic mechanisms and conceptual design of complex chemically active plasma systems
EEDF solution with chemistry
The Boltzmann kinetic equation is solved with the use of two-spherical harmonics expansion of electron velocity distributed function, which gives following equation for EEDF:
Qel, Qrot, Qin, Qsup, Qatt, Qee elastic, rotational, inelastic, superelastic, attachment and electron-electron collision integrals
- calculation of rate constant of non-elastic processes
,
,
[ ][ ] j lai
i j lj l
d Ck C
dt - solution of balance equations for chemical species
iter
ativ
e
CWB plasma model’s collection (Types)Types:
Plasma Model – EEDF solution with Chemical reactions
Calorimetric Bomb Reactor (CBR) –0D, uniform, time dependent model
P type – pressure is constantQ type – given heat exchangeV type – volume is constantT type – temperature is constant
Plasma & Surface – EEDF solution withChemical reactions in gas and surface
Calorimetric Bomb Reactor with surface(CBRS) –0D(+), uniform, time dependent model
CWB plasma model’s collection (Subtypes)
Subtypes:
The reactor model is based on numerical solution of the Boltzmann kinetic equation for electron energy distribution function (EEDF) and determination of rate coefficients of electron induced chemical reactions, energy distribution and electron’s swarm parameters in gas discharge. Gas composition in the reactor is changed as a result of chemical and vibrational kinetics plasma.
Nonequilibrium plasma reactor models available for different electric circuit configuration:• Current is given (J)– reactor with specified fixed value of the discharge current. Corresponds to electric circuit with plasma-gap connected in series with current generator (high voltage generator with high internal resistance).• L-C-R Circuit – the dependence of reactor electric field intensity and current density is determined by external LCR circuit. The plasma-gap is connected in series with a resistor, capacitor and inductance. Initial voltage on the capacitor is used as initial voltage on gap. It is assumed that the initial current at zero.• E/N is given (U) – time dependence of the reduced electric field is specified.• U-L-C-R Circuit – the plasma-gap is connected in series with resistor, capacitor, inductance and voltage source. It is assumed that the initial current and initial voltage on the capacitor is zero. Time dependence of the voltage at the voltage source is specified.• V-R – the plasma-gap is connected in series with a resistor and voltage source.
Extension of plasma models capabilities by flow sheet simulations
Non-uniformity: treatment by many streamersNon-uniformity: treatment by many streamers
1) treatment by plasma
2) extension,mixing with gas
3) relaxation &chemistry
1st pulse 2nd pulse
Time1) Plasmamodel with E/N(t)
2) Well Stirred Reactormodel with
3) Plug flow reactormodel
Loop for number of pulses
Admixing of surrounding gas
FlowRate2
FlowRate1
Need to know:a) FlowRate1/ FlowRate2 ~ Streamers Volume / Total Volumeb) Mixing time tmix
tmix
Data needed for simulation: construction of plasma-chemical mechanism in CWB
Tree ofplasma-chemical
processes
Quantum chemistry--------------------------------------------
(Gaussian®, GAMESS®, Jaguar®)
Microkinetics---------------------------------------
(Khimera®)
Kin
tec
hD
BChemical kinetics
---------------------------------------(CWB®, Chemkin®)
Applications-----------------------------------------------
-(CWB®, TRASS®, Chemkin®,
Fluent®, ANSYS CFX®, Star-CD®)
KintechDB - databank of physical-chemical data and information system for multidisplinary R&D projects
Database content
Particle properties
Thermodynamic properties of individual substances
Particle properties
Thermodynamic properties of individual substances
Elementary processes characteristics
Elementary processes characteristics
Kinetic mechanismKinetic mechanism
Data analysis and visualization tools
Data analysis and visualization tools
KintechDB data analysis and visualization tools
Thermodynamic and kinetic data. Analysis and visualization
• Substance thermodynamic functions visualization and comparison
• JANAF, TPIS table generation
• Thermochemical reaction analysis
• Forward/reverse rate constants calculation
• Rate constants temperature/pressure dependence visualization
•Rate constants for different reactions/sources comparison
Operation with data: How construct mechanism?
1. Putting data by hands in the calculation from external sources2. Data export from database of processes and substances
3. Mechanism export from database of mechanism
3 general ways:3 general ways:
• Khimera: model library– Chemistry of heavy particles
• Direct Bimolecular Reactions
• Bimolecular reactions via long lived Intermediate complex
• Multi-channel unimolecular reactions
• Dissociation of diatomic molecules
• Ion - molecular reactions
• Gas - Surface reactions
– Electron molecular reaction • Excitation
• Ionization
• attachment
– Vibrational Energy Transfer • VV and VT exchange
– Photochemical Reactions • photo dissociation
• quenching
• isomerization
– Classical trajectories methods– Surface diffusion – Multicomponent thermodynamic properties model– Multicomponent gas transport properties model
Khimera© or “What to do if there is now data?”
Example: Te ionization cross sectionThe cross section of the reaction is evaluated in the framework of Born-Compton similarity function method. Three subshells give the main contribution into the total atomic ionization cross section, namely, 5p4 (IP=9 eV, N=4), 5s2 (IP=17.84 eV, N=2) and 4d10 (IP=47 eV, N=10). The account of the contributions of these subshells to total atomic cross section is sufficient for the incident electron energy up to 200–300 eV.
0 50 100 150 2000
2
4
6
8
10 Te+e=Te++e+e
, A
2
E, eV
experiment, R.S.Freund et al. 1990 Born-Compton resultsCross section of the process . Results of
calculations described are shown by red line, experimental data is shown by black squares (R.S.Freund et al. Phys.Rev.A, 41, 3575 (1990)).
Transport properties calculation
Data Base of interaction potentials and collisional integrals
Transport properties calculation
0 5000 10000 15000 20000 25000 300000
1
2
3
4
5
6
7
T, K
Thermalconductivity
totalW/m/K
Khimera
Cressault
Narayanan
Capitelli
0 5000 10000 15000 20000 25000 300000
2000
4000
6000
8000
10000
12000
14000
16000
T, K
Electricalconductivity
S/m
Khimera
Narayanan
Capitelli
0 5000 10000 15000 20000 25000 300000
0.0001
0.0002
0.0003
Khimera
T, K
ViscosityPa*s
Cressault
Narayanan
Capitelli
Transport coefficients are calculated by the accurate formulas of the Chapman-Enskog method with account for higher approximations 14, here is the number of approximations, i.e. the number of retained terms in Sonine polynomials expansions.
Example: calculation of transport properties of Air at P=1 atmExample: calculation of transport properties of Air at P=1 atm
Example of modeling of mercury-free light sources
Boltzmann equation for
the EEDF
Cross sectionsdata base
Rate coefficientsdata base
System of kineticequations for charged
and neutral species
Electric circuitequation
Рисунок лампы с травлением
GaI3(pellet)
GaI3 + e =>GaI3(-)=>….=>…GaI+e.=>Ga + I,I2(-)
Ga, GaI2, GaI3 (wall)
evaporationetching
condensation
I2(-) +M*=>I2 + e +M
Ga +e=>Ga*=> Ga + hjj
Рисунок лампы с травлением
GaI3(pellet)
GaI3 + e =>GaI3(-)=>….=>…GaI+e.=>Ga + I,I2(-)
Ga, GaI2, GaI3 (wall)
evaporationetching
condensation
I2(-) +M*=>I2 + e +M
Ga +e=>Ga*=> Ga + hjj
2.00 Torr Ar-ZnT ~ 400oC,
Zn pressure ~ 10 mTorr
R~1.3 cm, J~300 mA
Candidates:Halides of Ga, Zn, In,Cu, Al, Cd, Sb, Bi, Tl
Hierarchy of the processes leading to Ga formation
GaI3
GaI2
GaI
Ga +3I
GaI4-
GaI3-
Ga+3I-
+e
+e
+e
+e
+2e
+GaI2
GaIy ,Ga, I +Wall GaIn(wall)
Kinetic Modeling and Approach Validation
GaI+e=>Ga(4p3/2)+I+eGaI3+e=>GaI+I2+eGaI2+e=>GaI+I+e
GaI+e=>Ga(4p1/2)+I+eGa(4p3/2)+e=>Ga(4d)+eGa(4p1/2)+e=>Ga(4d)+eGa(4p3/2)+e=>Ga(5s)+eGa(4p1/2)+e=>Ga(5s)+e
Ga(4p3/2)=>Ga(Wall)I=>I(Wall)
GaI2=>GaI2(Wall)GaI=>GaI(Wall)
Ga(4p1/2)=>Ga(Wall)Ga(4p1/2)+GaI3=>GaI+GaI2
-0.6 -0.4 -0.2 0.0 0.2 0.4
Sensitivity
X A
xis
Titl
e
48
1216
20
0
10
20
30
40
6070
8090 100
Em
issi
on E
ffici
ency
, %
Sensitivity analysis Optimization of Emission
Calculation of emissivity properties of Ar-GaI plasmaCalculation of emissivity properties of Ar-GaI plasma
Comparison with experiment: emission spectra of GaI plasma
260 280 300 320 340 360 380 400 4200
1
2
3
4
5
6
6s => 4p3/2, 1/2
4d => 4p1/2
4d => 4p3/2
5s => 4p1/2
Em
issi
on In
tesi
ty, a
.u.
Wave length, nm
Simulation Experiment
5s => 4p3/2
380 384 388 392 396 4000.0
0.2
0.4
0.6
0.8
1.0 Simulation Experiment
Rel
ativ
e in
ten
sity
Wave length, nm
Atomic emission Molecular emission
[1] J. Phys. D: Appl. Phys. 40 (2007) 3857–3881 Multiscale multiphysics nonempirical approach to calculation of light emission properties of chemically active nonequilibrium plasma: application to Ar–GaI3 system, S Adamson, M Deminsky, et al.
[2] Journal of Physics D Applied Physics 05/2015; 48(20). Comparative nonempirical analysis of emission properties of the Ar–MeIn glow discharge (Me = Ga, Zn, Sn, In, Bi, Tl) M Deminsky at al
Modeling plasma-assisted combustion for turbine appl.
air
swirl fuel
plasmans
afterglow1 ms
flame0.5 ms
downstream30 ms
plug flowperfectlystirred
plug flowBoltzmann
electron-impact cross-sections on
air + methane
Mechanism* for natural gas combustion, including NOx chemistry+ low-temperature extension for methane+ plasma species reactions (ions, excited)
plasma afterglow waiting forignition
Vibrkin CBR WSR
t1 – dischargeduration
t2=L/v – afterglow time
tresid = 0.5 msec, Tburn = 1900 K
E/N=200 Tdt1~0.55 nsecEinp≈320 J/g
t2=3 msec
P=18.6 atmTgas inp=700 K
Process
Parameter
Conditions
CBR
t3=30 msec
burnout
Discharge model. Calculated E/N and current
0 50 100 150-80
-40
0
40
80
120
160
200
240
1st pulse
151st pulse Experiment
Air, 1 atm, T = 20 s, C = 33 pF
Dis
char
ge c
urr
ent,
A
Time, ns
С
Pulse generator
Electric chain
The waveform of the calculated form changes within about 20 pulses. In the established form first and second half cycles are nearly equal. Experiment and theory reasonably agree.
0.0 0.5 1.0 1.5 2.0 2.5 3.0
-50
0
50
100
150
200
250
Air, 1 atm, T = 20 s, C = 33 pF
Dis
char
ge c
urr
ent,
A
Time, ms
151st pulse1st pulse
Extension of combustion limits
equ
iva
len
ce r
atio
lean
rich
10–5 10–4 10–30.1
1
0.4
320 J/g, 200 Td pulsed plasma
residence time in recirculating flame zone (s)
0.31
noplasma
2 [CH4]
[O2]
equivalenceratio
=
[1]. Russian Journal of Physical Chemistry B, 2013, Vol. 7, No. 4, pp. 410–423. LowTemperature Ignition of Methane–Air Mixtures under the Action of Nonequilibrium Plasma, M. A. Deminskii at al ,
Effect of additional NOx production by plasma
25 ppm9 ppm3 ppm
25 ppm9 ppm3 ppm
flame temperature (K)
NO
x (p
pm)
2400200016001
10
100
1000 0.35 0.5
0.7 0.9
0.45
0.6
0.8
equivalenceratios
plasma off
320 J/g, 200 Td pulse plasma
Optimization: flame stabilization vs NOx generation
ΔNOx (ppm)
ΔT
turn
dow
n (K
)
10 100 100010
100
1000
100 J/l0
50 J/l0
100 J/l0
240 J/l0
Thank you !
[email protected] for general service and product [email protected] for all questions concerning Kintech Lab software
http://www.kintechlab.com +7 (499) 704 2581
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