atmospheric pressure plasma sources for environmental ... · pdf fileatmospheric pressure...

Atmospheric pressure plasma sources for

environmental application Vitas Valinčius

P L A S M A P R O C E S S I N G L A B O R A T O R Y

Plasma Technologies as a tool for environment protection

International workshop, St. Petersburg, 21 March 2012

Contents

TEMA B5-16-133-3.5-G GALUTINĖ ATASKAITA

Introduction; Principles of plasma generation Range of plasmas as function of electron temperature (eV) Distribution of electric discharges Dielectric barrier discharge (DBD) Corona discharge Radio frequency (RF) plasmas Microwave plasma Hollow cathode discharge Gliding arc discharge Electron beam generated plasma ARC discharge Linear plasma torch and its operating principle Schematic presentation of linear plasma torch Classification of linear plasma sources Variety of plasma torches Main scheme of atmospheric pressure plasma system DC plasma sources AC plasma sources Prevailing processes in arc discharge channels of plasma generator

Main equations of electric arc plasma Modeling of processes in electric arc plasma torches Energy balance of plasma torch Characteristics of DC arc plasma sources

Energy characteristics of the arc in plasma torches with interelectrode inserts Distribution of parameters in exhaust plasma jet Samples



Introduction

Plasma sources are systems in which electric energy is converted into thermal energy by means of the generation of Joule heat in the discharge channel or chamber. Heating of the gas in these systems takes place mainly as a result of heat conductivity, convective heat exchange and radiation between the arc, gas flow and the walls. Plasma technology processes take place at high temperatures of gas flows created by the specific equipment. Usually, gas retains its dielectric properties there, however, with certain amount of electrons it becomes a conductor and a suitable power source creates in it the electric current, even electric arc discharge. Temperatures in low temperature plasma generators (PG) vary from 500 to 30000 K depending on pressure, gas composition, and current. Complex electric, chemical and thermal processes take place in the electric discharges flown past by gas. The application of the electric arc in removal of pollutants is caused by: – high concentration of energy in the small volume of plasma; – high rate of the chemical reactions, so that it is possible to produce high-productivity apparatus-reactors; – reliability and stability of operation of equipment; – the possibility of stationary heating of the gas to the mean mass temperature up to 15·103; – high efficiency of the transformation of electrical energy into thermal; – the possibility of heating of a wide range of gases and mixtures; – possibility automation and optimization of controlling the regime of the processes; – small amount and small material consumtion of plasma technology.



Principles of plasma generation •Direct current discharge (DC); •Alternating current (AC) (HZ); •Pulsed DC discharge (kHz); •Radio-frequency discharge (MHz) - sustained by two electron heating mechanisms: ohmic heating and stochastic heating; •Microwave discharge (GHz); •Laser plasma (PHz).

Plasmas are generated: •by electrode surface phenomena; •by supplying energy to a neutral gas causing the formation of charge carriers; •by collision of particles in gas. (Sufficiently energetic to disrupt the internal electronic structure of the particles and, in particular, may result in the production of free electrons and ions. Nearly all gases are highly ionized at temperatures of about 20,000K. Way to supply the energy to a neutral gas: i) thermal energy (exothermic reactions, compression), ii) beams of charged particles (electron and laser beams), iii) applying an electric field to a neutral gas, charge carriers accelerated in the electric field couple their energy into the plasma via collisions with other particles.





Range of plasmas as function of electron temperature (eV)

Thermal plasma (Quasi-equilibrium plasma) Te ≈ Ti ≈ Tg ≤ 2×104 K

ne ≥ 1020 m-3

Arc plasma, plasma torches, RF inductively

coupled discharges

Non-Thermal plasma (Non-equilibrium

plasma)

Te >> Ti ≈ Tg = 300…103 K

ne ≈ 1010 m-3

Glow, corona, direct barrier discharge,

atmospheric pressure plasma jets,

hollow cathode discharges, electron

beams, microwave and etc.



Volt-amperic characteristics of low-pressure gas electric discharge regions

•Dielectric barrier discharge (DBD); •Corona discharge; •RF plasmas (capacitively, inductively); •Microwave discharge; •Hollow cathode discharges; •Gliding-Arc discharges; •Electron beams; •Water plasmas.

Distribution of electric discharges



Characteristics of DBD: •Te >> Ti = Tg = 300…103 K; •Capacitive electric load: low Power Factor in the range of 0.1 to 0.3; •High ignition voltage 1 - 10 kV; •Huge amount of energy stored in electric field – requirement of energy recovery; •Voltages and currents during discharge event have major influence on discharge behavior (filamented, homogeneous); •Low density of electrons with high kinetic energy.

Application: •Generation of UV-radiation (indirect). (Ozone for industrial scales. Ozone, e.g. air and water treatment); •modification (cleaning) of the surfaces of materials (e.g. polymers, semiconductors etc.); •semiconductor manufacturing, germicidal processes; •high-power CO2 lasers typically used for welding and metal cutting; •pollution control. •Medicine (plasma medicine) (bio-medical applications such as sterilization of implants and surgical instruments, therapeutic applications without affecting tissue and even stimulating tissue regeneration); •Water treatment (direct) (emove chlorine organic compounds used for removal of bacteria and organic contaminates in drinking water supplies; treatment of public swimming pools and baths, aquariums); •Industry (textile industry to modify the surface properties of the textile to improve wettability, improve absorption of dyes, sterilization); •Treatment of waste water after technological process of any field of industry; •Removal of VOCx and NOx/SOx from flue gases; •Agriculture. Reduction of odours.

Dielectric barrier discharge (DBD)



Corona discharge

Applications: •Production of ozone; •Sanitization of water; •Removal of unwanted volatile organics, such as chemical pesticides, solvents, or chemical weapons agents; •Scrubbing particles (particulate matter) from air streams; •Surface treatment for tissue culture; •Air ionizers; •Surface treatment of materials to change properties (adhesiveness, hardness etc.).

Advantages: •High removal efficiency; •Low energy yields; •Low investment and operational costs compared to other technologies; Disadvantages:

•Audible noise; •Power loss; •Electromagnetic interference; •Ozone production; •Insulation damage of devices; •Purple glow; •Static electricity discharge.



Radio frequency (RF) plasmas (capacitively, inductively)

•Capacitively coupled discharges, ‘E’ •Inductively coupled discharges, ‘H’

Application: •deposition of thin-films, •plasma etching and sputtering of insulating materials •microfabrication of an integrated circuit manufacturing industries for plasma enhanced chemical vapor deposition (PECVD) •lighting applications (electrodeless discharge lamps) •mass spectrometric analysis and some environmental applications for ozone production

Advantages: •low plasma loss and better ion generation efficiency; •simplicity of the concept, no requirements for DC magnetic fields Disadvantages:

•Higher sputter-contamination, •UV-damage and heating of neutrals at the substrate. Multipole magnets can be used to increase radial plasma uniformity. The planar coil can also be moved close to the wafer surface, resulting in near-planar source geometry, having good uniformity properties, even in the absence of multipole confinement.



Microwave plasma

Three types of microwave plasma reactors: • closed structures, • open structures, and • resonance structures with a magnetic field

Application: • semiconductor and optical component production • device for etching or deposition, because it is clean and has high chemical reactivity. • ion production, • atomization and light, and • excitation source in ion bombardment, • nitrification and solar lamps as well as • analytical chemistry

It can be applied also for waste treatment, such as decomposition and detoxification of detrimental gases (chlorofluorocarbon and nitrogen oxides) from industrial facilities and cars, and for the surface treatment and the electromagnetic coating at atmospheric pressure



Hollow cathode discharge

Applications: •plasma processing (ion etching, thin film deposition, surface treatment); •ion gas lasers and spectroscopic analysis, where the hollow cathode is used as an emission source, allowing direct excitation and analysis of samples; •as a light source in absorbtion spectrometry; •environmental applications, such as conversion of gases. The 100 % conversion rate of NO was achieved in NOx + N2 system



Gliding arc discharge

Main advantages: •near atmospheric pressure; •energy of the electrons is much higher than that of the heavy species; •simplicity of the power supply system; •intermediate system between thermal and non-thermal discharges; •environmentally much cleaner than mechanical and wet chemical processes; •fast processing; •low cost.

Application: •useful in many industrial applications; •coating, painting, dying, etc.; •plasma based surface treatments;

Disadvantages: •plasma is weakly ionized; •characterized by the lack of local thermodynamic equilibrium;



Electron beam generated plasma

Application: •material processing; •etching; •deposition and surface treatment; •flue gas treatment of power plants; •pollution removal.

Advantages:

•high removal efficiency;

•no need for treatment of waste water;

•no expensive catalysts;

•wasteless process, useable by-products as fertilizers;

•dry process;

•simple facility construction;

•pollutants removal efficiency: 90 % SO270 % NOx

•economical competiveness.

Disadvantages:

Needs of ammonia



ARC discharge

Application: •welding; •cutting; •metallurgy industry; Thermal arc discharge plasma can be applied: •industrial scale applications; •as processing medium with one of the highest energy densities; •plasma spraying for production of hard coatings with good resistance properties; •production of catalytic materials; •destruction of hazardous waste; •plasma treatment of medical waste; •other wide range of applications (production of mineral fiber, sterilization, plasma pyrolysis, producing synthetic gas, etc.). Advantages: •high processing rates; •high fluxes of radical species, the potential for smaller installations; •wide choice of reactants; •high chemical reactivity; •high quench rates; •short residence time of treated materials. of organic materials.

Disadvantages:

•Erosion of the electrodes.

•Arc flash.

•Consumes quite lot electricity.

•Noise.

Simplified schematic presentation of linear plasma torch

Linear plasma torch and its operating principle

Principal scheme of linear plasma torch and distribution of energy characteristics along the chamber axis. 1 – boundary layer; 2 – arc zone; 3 – thermal layer; 4 – cold medium; Ei – specific energy generation; Q – specific heat flux to the walls



Schematic presentation of linear plasma torch



Classification of linear plasma sources



Variety of plasma torches

A few schemes of plasma torches with the self-setting arc length. a) the single-chamber torch with an internal flat end electrode; b) two-chamber torch with an internal flat end electrode; c) single-chamber torch with a cup-shaped internal electrode; d) two-chamber torch with a cylindrical tubular internal electrode [1]



Main scheme of atmospheric pressure plasma system



DC plasma sources

Linear plasma sources: •Plasma sources with hot cathode; •Plasma torches with the self-setting arc length •Single-chamber plasma torches; •Two-chamber plasma torch with an extended arc; •Multichamber plasma torches; •Plasma sources with step-formed anode; •Stabilization of electric arc in the arc chamber; •Plasma torch with the mean arc length fixed with a ledge

Samples of DC plasma torches;



AC plasma sources

The scheme of the AC plasma torch and operating principle;

Three-phase plasma torches; Three-phase plasma torches with the triangle-

type connection; Design of plasma generator; Specific features of the gas flow in arc

discharge channel; Specific features of burning arc in al channel;

Diagram of AC plasma torch

AC plasma torches are not yet used widely. This is caused by the fact that the application of alternating current is associated with additional difficulties caused by the variability with time of the electrical parameters of the power source and associated mainly with: 1) ensuring continuous arcing at alternating current in the transition of current through zero in the linear plasma torches; 2) noncorrespondence of the form of the current and voltage curves, reducing the coefficient of utilisation of the power of the power source; 3) the variability of the supply of energy in time in the single-phase system; 4) the need to ensure uniform phase loading and using three-phase current for supplying the power; 5) with the presence in the certain systems of three-phase plasma torches of during measurements 4) noisy operating.



Prevailing processes in arc discharge channels of plasma generator

Main equations of electric arc plasma; Effect of electromagnetic forces on the formation of plasma flows in arcs; Nonequilibrium processes in arc discharge plasma;

Behaviour of arc in the turbulent flow;

The high-pressure electric arc plasma is characterized by a complicated complex of mutually related gas-dynamic, thermal and electromagnetic processes. In a general case, it is described by a system of equations of radiation magnetic gas dynamics (MGD), including the laws of conservation of mass, pulse and energy, and the equations of electrodynamics and radiation transfer. It is assumed that the following hypotheses are fulfilled: – continuity of the medium according to which any infinitely small volume of the medium is occupied by the matter; – the ideal nature of the electric arc plasma.

the continuity equation (conservation of mass)

the equation of motion (conservation of pulse)

the energy equation



Processes in arc channel

Maxwell equations

Ohm law

Shunting

Scheme of shunting in DC PT with cylindrical anode. 1 – arc; 2 – long-scale shunting; 3 ,4 – small-scale shunting



Modeling of processes in electric arc plasma torch

Similarity criteria of electric arc processes; Physical meaning of similarity criteria; Methods for determining similarity criteria;

Method of generalization of experimental results

Solution of equations given in previous is complex one and is not exact enough. This is characteristic for a long arc in turbulent flow because of the lack of pulsation characteristics. Therefore, application of methods of similarity theory for this case is of great importance. Similarity criteria of the physical processes may be established using - theorem or the analysis of equations describing the process. Similarity theory is successfully applied for formation of the criteria equations used in investigations of the electric arc [1-3]. In addition to the classic gas dynamics similarity criteria, the following are used:

aVM /

/Re Vd

a/Pr

Mach number

Reynolds number

Prandtl number

The new criteria appear as a result of equation analysis. They are as follows: the electric field strength

IEdN /2

1

3

022 /( dVHIN

the electric field strength

Reynolds magnetic number dVIBN 2

3 /

energy

dKn e / Knudsen number



Modeling of processes in electric arc plasma torch

If more values are known additional parameters are used: l/d, L/L0, T/T0, p/p0, G/G1 and so on. CVCs type – dependence of voltage drop on gas amount, on pressure and so on – are important for experimental investigations of PG. Changes in the morphology of electrodes due to material lose by erosion during operation of PG or the motion of cathode spot didn’t take into account. For PG with the dynamic arc stabilization (when for arc rotation electromagnets are not used) with gas being homogenous and temperature, geometric and dynamic similarity maintained, the electric field strength and energy criteria are most important. For the PG with fixed arc length, where arc length is determined by shunting, usage of the energy, Reynolds and Knudsen criteria is recommended [2]:

)Re,,( 21 KnNfN

It was established that Kn-1 pd, while

dG /Re

Electric characteristics of the linear, sectional or step anode fixed PG are generalized as follows [4]:

rk

nm

dlpdd

G

Gd

IA

I

Ud)/()(

2

PG performance can be evaluated by its efficiency indicating what part of generated energy is transferred to gas:

)(UIGH

Generalization of the TC of PG is similar to generalization of the electric characteristic:

2

2

2221r

k

nm

d

lpd

d

G

Gd

IB

This value may be represented by the Stanton number Std

l41



Parameter Linear plasma generator

Two chamber Three chamber

Power, P (kW) 33-78 40-94

Arc current, U (A) 175-245 175-285

Arc voltage, I 160-335 200-360

Cooling water flow rate, Gv (kg s-1) 0.16-0.18 0.16-0.18

Water temperature increment (deg):

plasma torch

cathode

ignition section

neutrode

anode

15-23

1.1-1.53

1.08-2.16

-

13.0-19.3

18-38

1.004-1.75

1.15-3.0

2.2-6.0

13.7-27.3

Source gas flow rate (kg s-1):

cathode, G0

neutrode, G1

anode, G2

0.54-1.0

-

1.85-7.6

0.54-1.2

1.2-3.6

1.0-3.0

Plasma jet average mass

temperature Tf (K)

3460-5200 3480-5170

Plasma jet velocity, w (m s-1) 350-1000 500-1000

Efficiency, η 0.58-0.78 0.6-0.77

Reaction chamber diameter (10-3

m):

d1

d2

d3

4.0

8.0

12.0

4.0

8.0

12.0

Section length (10-3 m):

l1

l2

l3

13.0

-

64.0

13.0

26.0

56.0



Characteristics of DC arc plasma sources

Energy characteristics of the arc in plasma torches with interelectrode inserts

12,0

1

5,02

G

G

d

I

Gd

Ic

I

Udm

Energy balance of plasma torch; Characteristics of DC arc plasma sources;

Energy characteristics of the arc in plasma torches with interelectrode inserts; The characteristics of the arc in the axial gas flow; Electrical characteristics of plasma generator; Variation of arcing voltage by the gas-dynamic effect; Generalized voltage-current characteristics of the arc in different gases; Distribution of the strength of the electrical field of the arc in a long cylindrical channel;

150

200

250

300

150 170 190 210 230 250

I, A

U, V

1

2

3

4

5 6

The CVC as function of total air flow rate G: 1 – 3.0; 2 – 3.4; 3 –

4.0; 4 – 5.17; 5 – 7.5; 6 – 7.15

10-3 kg s-1.



Thermal characteristics of the arc in plasma torches with interelectrode inserts (example)

Heat exchange of the electrical arc in the turbulent gas flow with the walls of the discharge chamber; Heat losses in the discharge chamber of the plasma torch with the interelectrode insert; Heat losses in the plasma torch with gas vortex stabilization of the arc; Integral thermal characteristics of plasma torches with the self-setting and fixed arc length; Generalized thermal characteristics of the arc in different gases;

Thermal efficiency of the plasma torch with the inter-electrode insert

0.6

0.65

0.7

0.75

0.8

170 190 210 230 250

I, A

12

34

5

6

10 9

10 3

3 . 10 9 4 . 10 8

1 2

B

I 2

/Gd

PG efficiency in dependence on air flow rate: 1 –

3.0; 2 – 3.4; 3 – 4.0; 4 – 5.17; 5 – 7.5; 6 – 7.15x10-3 kg s-1

10-3 kg s-1

Generalized PG efficiency. 1 – with additional and

2 – without additional section. Here

95.0

02

2.0

2

12.0

1 )/)(/()/()/)(/)1( dldIdGGGB

95.0

2.012.0

1

8.02

)/(1

dlI

d

d

G

G

G

Gd

Ic

without intermediary section c 0.68

95.0

3.012.0

1

3.02

)/(1

dld

G

G

G

Gd

Ic

with intermediary section c 0.71

10-4



Profiles of plasma jet velocity; Axial distribution of plasma jet velocity; Profiles and axial distribution of plasma jet temperature and enthalpy; Fluctuations and turbulence in plasma jet;

Distribution of electron temperature

Distribution of parameters in exhaust plasma jet



1,0E+16

3,0E+16

5,0E+16

7,0E+16

9,0E+16

0 1 2 3 4 5

x/d

ne,

m-3

Variation of electron (1,2) and thermodinamical gas temperature (3) in plasma jet generated by PT of different construction and capacity: 45 ir 35 kW 1 and 2 – respectively

Axial distribution of electron density

Profiles of electron temperature at x/d: 1 – 0, 2 – 2, 3 – 4, 4 – 6

Profiles and axial distribution of electron temperature plasma jet



Indirect environmental application of DC arc plasma generators

Realization of plasma processes and deposition of coatings employing flow kinetic energy; The barrier coatings (oxides and nitrides) deposited on the surface of construction materials;

The unified plasma torch for spraying



The scheme of plasma equipment

Plasma torch

Plasma equipment in operation

Plasma equipment for deposition of catalytic coatings

Plasma torch charakteristics

Plasma sources



Plasma equipment in operation



Destruction of hazardous substances



References 1. Zhukov M. F., Zasypkin I. M. Thermal Plasma Torches - 2006 - 720 2. Ambrazevicius A. Heat transfer during quenching of gases. Vilnius,1983. - 192 p. 3. Valinčiūtė V., Kėželis R., Valinčius V., Valatkevičius P., Mėčius V. Heat transfer in a plasma jet reactor for melting and melt fibrillation of hard

ceramics // Heat transfer research. ISSN 1064-2285. 2008. Vol. 39, Iss. 7, p. 609-618. 4. Valinčius V., Snapkauskiene V., Kėželis R., Valinčiūtė V., Mėčius V. Preparation of insulating refractory materials by plasma spray technology

// Journal of High Temperature Material Processes. ISSN 1093-3611. 2006. Vol. 10. P. 365-378. 5. Akdoğan E., Çökeliler D., Marcinauskas L., Valatkevičius P., Valinčius V., Mutlu M. A New method for immunosensor preparation: atmospheric

plasma torch // Surface and Coatings Technology. ISSN 0257-8972. 2006. Vol. 201, P. 2540-2546. 6. Marcinauskas L., Grigonis A., Valinčius V., Valatkevičius P. Surface and structural analysis of carbon coating produced by plasma jet CVD //

Materials science. ISSN 1392-1320.2007. Vol. 13, No. 4, p. 269-272. 7. Valinčius V., Kėželis R., Valatkevičius P., Milieška M. Melting and conversion into fibre dolomite and quartz sand mixtures by means of plasma

spraying // Изв.вуз.Физика. 2007.№ 9, с.441-444. 8. Marcinauskas L., Valinčius V., Grigonis A., Valatkevičius P. Structure of carbon films deposited at atmospheric pressure // Proceedings

international conference BALTRIB' 2007, Kaunas, Lithuania, November 21-23, 2007. Lithuanian University of Agriculture, 2007. ISSN 1822-8801, p. 151-155. [ISI Proceedings]

9. Valinčius V., Marcinauskas L., Grigonis A., Valatkevičius P. Effect of Ar/C2H2 ratio on deposition of carbon films by plasma jet chemical vapour deposition // Изв.вуз.Физика. ISSN 0021-3411. 2007. № 9, с. 413-416. [INSPEC]

10. Marcinauskas L., Valinčius V., Valatkevičius P., Grigonis A. Vienkamerinio linijinio plazmos generatoriaus, kaitinančio vienatomes ir dvitomes dujas, charakteristikų tyrimas // Energetika. 2006. Nr. 1. P. 36-41.

11. Valatkevičius P., Valinčius V. Žematemperatūrinės plazmos ir jos technologijų tyrimai Lietuvos energetikos institute // Lietuvos mokslas 2006. P. 294 – 316..

12. Valinčius V., Valatkevičius P., Kėželis R. Plazminis įvairių pavojingų atliekų nukenksminimas // Energetika 2006. Nr.3. P. 51 – 60.



13. Grigaitienė V., Valinčius V., Kėželis R. Measurement and numerical simulation of two-phase plasma flow in plasma spray process // Radiation interaction with material and its use in technologies 2008: international conference, Kaunas University of Technology, September 24-27, 2008. Kaunas: Technologija, 2008. ISSN 1822-508X, p. 62-65. 15. Marcinauskas L., Valinčius V., Grigonis A., Valatkevičius V. Application of plasma spray technology for carbon films production // Энергоэффективность-2007: материалы конференции, Киев, 15-17 октября 2007. Киев, 2008. ISSN 2070-4399, p. 1-14. 16. Valinčius V., Valatkevičius P., Valinčiūtė V. Low temperature plasma and plasma processing in Lithuanian Energy institute // Энергоэффективность-2007: материалы конференции, Киев, 15-17 октября 2007. Киев, 2008. ISSN 2070-4399, p. 1-14. 17. Valatkevičius P., Marcinauskas L., Valinčius V. Surface modification of steel alloys by nitrogen-hydrogen plasma // International Conference Plasma Physics and Plasma Technology PPPT-5, Minsk. Belarus, September 18-22, 2006 contributed papers. Volume II (section 4-6). 18. Ambrazevičius A., Valatkevičius P., Valinčius V. The application of the new plasma technology in Lithuania // International Conference of Plasma Physics and Plasma Technology PPPT-5, Minsk, Belarus, September 18-22, 2006 contributed papers. Volume II (section 4-6) 4 p. 19. Marcinauskas L., Grigonis A.,Valinčius V., Valatkevičius P. Influence of the hydrogen and plasma forming gases on the carbon coatings deposited from saturated and unsaturated hydrocarbons // International Conference on Radiation Interaction with Material and it suse in Technologies. ISSN 1822-508X. Kaunas, Lithuania, 28-30 September, 2006. P. 233 – 235. 20. Brinkienė K., Česnienė J., Kėželis R., Mečius V., Zunda A. Effect of plasma parameters on wear properties of zirconia coatings // Progress by corrosion control EUROCORR 2007 : the European corrosion congress, Freiburg im Breisgau, Germany, September 9-13, 2007. Germany, 2007, p.1-5. 21. Kėželis R., Brinkienė K., Mėčius V., Čėsnienė J., Žunda A. Characterization of tribological properties of plasma sprayed ceramic coatings // Proceedings international conference BALTRIB' 2007, Kaunas, Lithuania, November 21-23, 2007. Lithuanian University of Agriculture, 2007. ISSN 1822-8801, p. 146-150. 22. Valinčius V., Valatkevičius P., Kėželis R.,. Marcinauskas L. Application of plasma spray technology in the synthesis of micro-and nanostructured surfaces and composites // Dusty plasmas in applications :proceedings of 2nd international conference on the physics of dusty and burning plasmas, Odessa, Ukraine, August 26-30, 2007.Odessa, 2007, p.152-156. 23. Valinčiūtė V., Kėželis R., Valinčius V., Valatkevičius P.., Mečius V. Heat transfer in plasma jet reactor for melting and melt fibrillation of hard ceramics // Advances in heat transfer : proceedings of the Baltic heat transfer conference, Saint-Petersburg, Russia, September 19-21, 2007. St Petersburg : Saint -Petersburg State Polytechnical University, 2007. Vol. 2. ISBN 5-7422-1592-4, p. 580-588. 24. Marcinauskas L., Grigonis A., Valatkevičius P., Šablinskas V. Formation of carbon coatings employing plasma torch from argon-acetylene gas mixture // Proceedings of SPIE : Advanced optical materials, technologies, and devices, Vilnius, Lithuania, August 27-30, 2006. USA, 2007. ISSN 0277-786X, p. 1-7.



THANK YOU!

atmospheric pressure plasma sources for environmental ... · pdf fileatmospheric pressure...

Documents