Electrical discharges in the Electrical discharges in the Reverse Vortex Flow Reverse Vortex Flow ––

Tornado DischargesTornado Discharges

ChiranjeevChiranjeev S. S. KalraKalra, Mikhail , Mikhail KossitsynKossitsyn, , KamillaKamillaIskenderovaIskenderova, , AlexandreAlexandre ChirokovChirokov, ,

Young I. Young I. ChoCho, , Alexander Alexander GutsolGutsol, Alexander , Alexander FridmanFridman

ISPCISPC--16 16 TaorminaTaormina 20032003

ScopeScope-- Forward and Reverse Vortex FlowsForward and Reverse Vortex Flows-- MW Discharge in Vortex FlowsMW Discharge in Vortex Flows-- Flame Stabilization in Vortex Flows Flame Stabilization in Vortex Flows -- ICP Discharge in Vortex FlowsICP Discharge in Vortex Flows-- Arc and Gliding Arc in Reverse Vortex FlowArc and Gliding Arc in Reverse Vortex Flow-- Main Peculiarities of Reverse Vortex FlowsMain Peculiarities of Reverse Vortex Flows

Forward Vortex FlowsForward Vortex Flows

Straight flow Direct vortex flow with low rotation

S < 1.4

S = ( ∫ r2 w u dr ) / ( R ∫ r u2 dr )

Ru

S > 1.4

Forward vortex flow with strong rotation

Conventional (Forward Vortex) Method for Conventional (Forward Vortex) Method for Gas Flame StabilizationGas Flame Stabilization

3

1

6

4

52

à

1 – Quartz tube;

2 – Tangential Air Inlet;

4 – Axial Fuel Gas Inlet

6 – Flame Zone

Conventional (Forward Vortex) Conventional (Forward Vortex) Method for ICP StabilizationMethod for ICP Stabilization

1

2

3

4

7

1 - quartz tube;

2 - induction coil;

3 - skin layer;

4 - Inductively Coupled Plasma;

7 - tangential gas feeder for swirl flow formation

Gas Circulation in Tube with SwirlGas Circulation in Tube with Swirl

Typical Flow Pattern in tube near a swirlerTypical Flow Pattern in tube near a swirler11-- tube with closed end; 2 tube with closed end; 2 –– swirler; 3 swirler; 3 –– peripheral vortex flow; peripheral vortex flow; 4 4 –– central zone of reverse flow; 5 central zone of reverse flow; 5 –– face circulation flowface circulation flow

5 4 132

Reverse Vortex FlowReverse Vortex Flow

First gas in

Second gas in

ReverseVortex flow- CircumferentialVelocity component

NozzleFor reverseVortex flow

Gas out

ReverseVortex flow- Axial velocitycomponent

Gas out

Reverse Vortex Stabilization of Reverse Vortex Stabilization of Microwave PlasmaMicrowave Plasma

a b

2

1

3

5

4

6

7

1- quartz tube of microwave plasma torch;

2 -original tangential gas feeder;

3 - hot plasma fluid;

4 - bulk steel plasma-chemical reactor;

5 - steel connecting cone

6 - water-cooled diaphragm;7 - additional tangential gas feeder

Numerical Simulation for 3.5kW Microwave Numerical Simulation for 3.5kW Microwave Plasma Stabilization with AirPlasma Stabilization with Air--Cooling WallsCooling Walls

Numerical Simulation for 3.5kW Microwave Numerical Simulation for 3.5kW Microwave Plasma Stabilization with Adiabatic WallsPlasma Stabilization with Adiabatic Walls

Results of Results of experiments and experiments and Simulation for Simulation for 3.5kW Microwave 3.5kW Microwave Plasma Plasma StabilizationStabilization

J, kJ/g 0

10

20

30

40

50

2’

Wt /Wp ,%

1 2 3 4

3’

3

1

2

FVS – diaphragm

+ reactor

FVS + diaphragm

+ reactor

FVS + diaphragm

- reactor

RVS + reactor

RVS + reactor

Full curves - experiments, broken curves - numerical simulations;

1, 2, 2’ – Forward Vortex Stabilization (FVS)

3 and 3’ – Reverse Vortex Stabilization (RVS)

Reverse vs. Forward Reverse vs. Forward Vortex Methods for Gas Flame Vortex Methods for Gas Flame

StabilizationStabilization

3

1

6

4

52

a b

1 – Quartz tube;

2 – Tangential Air Inlet;

3, 4 – Axial Fuel Gas Inlet

5 – Diaphragm;

6 – Flame Zone

Conventional and Reverse Vortex Conventional and Reverse Vortex Methods for 2kW Flame StabilizationMethods for 2kW Flame Stabilization

α ≈ 1 α ≈ 1.5

Argon ICP, Argon ICP, Plate Power Plate Power –– 16 kW16 kW(a) (a) –– RVS (b) RVS (b) –– FVSFVS

Argon Mass Flow 2.1 g/s 1.4 g/s Argon Mass Flow 2.1 g/s 1.4 g/s Plasma Jet Enthalpy 2.57 kJ/g 2.4 kJ/g Plasma Jet Enthalpy 2.57 kJ/g 2.4 kJ/g

a

b

SelfSelf--consistent Simulation of the Argon RVS ICP consistent Simulation of the Argon RVS ICP

SelfSelf--consistent Simulation of the Argon RVS ICP consistent Simulation of the Argon RVS ICP

Representation of current loop

Current loop method for E - field calculation

Vector potential

)(2

),( 0 kGrRIzrA

πµ

θ =

Experimental and Modeling Results for Experimental and Modeling Results for RVS ICP EfficiencyRVS ICP Efficiency

Efficiency

0

10

20

30

40

50

60

70

0 5 10 15 20 25 30 35 40

Wp

1.4

2.3

3.2

Modeling 1.4

Modeling 2.3

Modeling 3.2

Traditional Gliding ArcTraditional Gliding Arc

Point of DevelopedGliding Arc when Maximum Energy is Transferred

Gas inlet

Reactor

Point of Gliding Arc Ignition

Point of Total Extinction

R

DC Power Supply

Vo

J

l

Electrical scheme of the DC Gliding Arc.

Arc and Gliding Arc in “Tornado”Arc and Gliding Arc in “Tornado”Idea of formationIdea of formation

ReverseVortex flow

Spiral shape,Electrode 1

Electrode 2

Connection wireTo power supply

Plasma reactorPlasma reactor

Arc and Gliding Arc in “Tornado”Arc and Gliding Arc in “Tornado”RealizationRealization

Gliding Arc “Tornado”Gliding Arc “Tornado”Visualization of gas motion near the wallVisualization of gas motion near the wall

Gliding Arc “Tornado”Gliding Arc “Tornado”Electrode 2

Connection wireto power supply

Circular ringElectrode

Gas out

Spiral shapeElectrode

Free end of spiral electrode

Gliding Arc “Tornado”Gliding Arc “Tornado”From the Spiral to the RingFrom the Spiral to the Ring

Gliding Arc “Tornado”Gliding Arc “Tornado”Arc Column with different exposition timeArc Column with different exposition time

Gliding Arc “Tornado”Gliding Arc “Tornado”Evolution between two circular electrodesEvolution between two circular electrodes

Gas flow

Elongation of arc between parallel electrodes but with different gas flow velocities near the two electrodes

Specific Features of the Reverse Vortex FlowsSpecific Features of the Reverse Vortex Flows

Directional heat and mass transfer from the Directional heat and mass transfer from the periphery to the centerperiphery to the centerGasGas--dynamic insulation of the central zonedynamic insulation of the central zoneTrapping of the active gas species in the central zone Trapping of the active gas species in the central zone Convective heat and mass transfer inside the central Convective heat and mass transfer inside the central zone zone –– Method of nonMethod of non--equilibrium (equilibrium (transitional) transitional) plasmaplasma formationformation