PROPAGATION PROCESSES OF NEWLY DEVELOPED PLASMA JET IGNITER

Ogawa, Masaya,Sasaki, Hisatoshi,Yosgida, Koji,Shoji, Hideo,Tanaka, Hidenori The Korean Society of Automotive Engineers 2002 International journal of automotive technology Vol.3 No.1

In plasma jet ignition, combustion enhancement effects occur toward the plasma jet issuing direction. Therefore, when the igniter is attached at the center of a cylindrically shaped combustion chamber, plasma jet should issue toward the round combustion chamber wall. The plasma jet igniter that had an annular circular orifice has been developed. The purpose of this study is to elucidate the relationship between the newly developed plasma Jet igniter configuration and combustion enhancement effects. In this newly developed plasma Jet igniter, flame front wrinkle appears on the flame front and flame propagates rapidly. Plasma Jet influences on the flame propagation far long period when the plasma jet igniter has issuing angle 90 degrees and large cavity volume, because the plasma jet only lasts several ms. However, in the early stage of combustion, flame front area of issuing angle 45 degrees is larger than that of 90 degrees, because the initial flame kernel is formed by the plasma jet.

Research on the reaction progress of thermodynamic combustion based on arc and jet plasma energies using experimental and analytical methods

김권세,최두석 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.4

Plasma energies are a promising technique to increase IC engine performance, expend lean burn flame area, reduce exhaust gas, and enhance engine power. In particular, SI engines using combustion process can obtain the positive air, fuel and ignition sources, and international research organizations are intensively conducting research on new combustion in order to increase the performance for IC engines regarding solution methods that could ensure more stable combustion energies. These authors were conducted on arc and jet plasma energies in order to improve the reaction progress of thermodynamic combustion, where the unburned process in chemical state was changed from plasma signal, density, flame, temperature, and velocity, through experiment and analysis at rarefied mixture values of air and fuel excess ration ( f ) from air and C 3 H 8 after transmitting with discharge energies based on arc and jet plasma sources. Experimental and analytical methods were transmitted as high 1.2 J energy, where the strength of plasma volume was discharged between positive and negative electrodes to arc plasma, and jet plasma was monitored from reaction progress results as transmitting as 2.03 J energy higher than arc energy in order to have characteristics of directivity. Experimental and analytical conditions were set equally for combustion mixture ratio, which was changed at rarefaction from initial pressure of 4 bar, plasma duration 0.0015 s, plasma plug gap 1 mm, and mass fraction ( f ) 1.0, 1.2, 1.4 and 1.6. Reaction progress results were noticeable in that jet plasma was influenced more by fast advantages to expend the laminar flame with various waves in an unburned process than arc plasma of combustion response time from thermal diffusion with transient temperature change, plasma volume energy, and jet plasma had more advantages for rarefied combustion state from various energies as changed mass fraction rates ( f = 1.0, 1.2, 1.4 and 1.6) by initial jet. Consequentially, density result is noticeable in that jet plasma was quickly changed by a chemical equilibrium of density higher than arc plasma energy.

Comparison of characteristics of atmospheric pressure plasma jets using argon and helium working gases

Javanmard Sara,Pouryoussefi Sohrab Gholamhosein 한국물리학회 2023 Current Applied Physics Vol.46 No.-

Dielectric Barrier Discharge (DBD) plasma jets have been studied extensively in recent years because of their wide range of applications. In this work, we studied the performance of a DBD cold atmospheric pressure plasma jet with neutral argon gas experimentally and compared the produced DBD argon plasma with the helium jet in an equivalent operation. We investigated the effect of applied voltage, flow rate, and electrodes configurations on the argon and helium plume length and analyzed the physical parameters of the plasma plume, including discharge voltage, average gas, temperatures of the discharge gap, and jet velocity in plasma-on mode via Pitot glass tube as a speedometer. The results showed that by increasing any of the applied voltage or the flow rate at low values in different electrodes arrangements, plumes shape are more homogeneous and their length increases, but the helium plasma plume is transient from laminar to turbulent flow mode at higher flow rates. The temperatures of the discharge gap between the electrodes and their surroundings in the argon jet had a large increase over the helium jet in an equi-operational. Speedometer results show that plasma discharge affects the speed of argon jet more than helium.

Atmospheric Pressure Plasma Jet Composed of Three Electrodes: Application to Tooth Bleaching

Lee, Hyun Woo,Nam, Seoul Hee,Mohamed, Abdel-Aleam H.,Kim, Gyoo Cheon,Lee, Jae Koo WILEY-VCH Verlag 2010 Plasma Processes and Polymers Vol.7 No.3

<P>Three-electrode plasma jet system consisting of a perforated dielectric tube with two outer and one floating inner electrodes was developed and employed for tooth bleaching. Lowered gas breakdown voltage and increased discharge current were achieved by using the floating inner electrode. Optical emission spectra analysis showed that the rotational temperature of the second positive nitrogen bands was ≈290 K and vibrational temperature was ≈2 500 K, which means this plasma is in highly non-quilibrium state and nonthermal. The presence of excited He, N<SUB>2</SUB>, N<EM><SUB>2</SUB><SUP>+</SUP></EM> and O in the plasma plume was revealed. The plasma jet was used in combination with hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) to remove stains from extracted teeth stained by either coffee or red wine. Combining the plasma jet and H<SUB>2</SUB>O<SUB>2</SUB> improved the bleaching efficacy by a factor of 3.1 (coffee) and 3.7 (red wine) compared with using H<SUB>2</SUB>O<SUB>2</SUB> alone.</P><P> <img src='wiley_img_2010/16128850-2010-7-3-4-PPAP200900083-gra001.gif' alt='wiley_img_2010/16128850-2010-7-3-4-PPAP200900083-gra001'> </P> <B>Graphic Abstract</B> <P>An atmospheric pressure plasma jet has attracted great interest in biomedical applications thanks to its simplicity of the design and its diverse capabilities. This study proposed a design of a safe and reactive, nonthermal atmospheric pressure plasma jet, and demonstrated that the plasma jet enhanced the tooth bleaching effect. We expect that this study can contribute to widening the application field of atmospheric pressure plasma. <img src='wiley_img_2010/16128850-2010-7-3-4-PPAP200900083-content.gif' alt='wiley_img_2010/16128850-2010-7-3-4-PPAP200900083-content'> </P>

Electrical and Optical Characterization of Atmospheric-Pressure Helium Plasma Jets Generated With a Pin Electrode: Effects of the Electrode Material, Ground Ring Electrode, and Nozzle Shape

Hea Min Joh,Hae Ra Kang,Tae Hun Chung,Sun Ja Kim IEEE 2014 IEEE transactions on plasma science Vol.42 No.12

<P>This paper tests various design and operation parameters in atmospheric-pressure helium plasma jets generated with a pin electrode to provide a plasma environment well suited for material processing or biomedical applications. The effects of the pin electrode materials (Cu, W, and Al), the position, and the width of a ground ring electrode on the characteristics of the jets are studied. The inner quartz tube encompassing the pin electrode and two types of the outer quartz tubes (straight or tapered cylinder shape) are employed, and their effects are investigated. The electrical characteristics of the plasma jets are measured by current-voltage measurements and analyzed by the equivalent circuit model. The optical characteristics of the discharges are obtained by optical emission spectroscopy to identify various excited plasma species produced in the plasma jets. Optical emission spectra are also obtained at different positions along the coaxial direction. A variety of choices in design parameters and operation parameters are undertaken to determine optimal conditions and elucidate the properties of the plasma jets.</P>

Sterilization of Microbes by Using Various Plasma Jets

엄환섭,최은하,조광섭,홍용철 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.6

Sterilization of various microbes was carried out by using several plasma jets. Argon plasma jets penetrate deep into ambient air and create a path for oxygen radicals to sterilize microbes including spores. A sterilization experiment with bacterial endospores indicates that an argon-oxygen plasma jet very effectively kills endospores of Bacillus atrophaeus (ATCC 9372), thereby demonstrating its capability to clean surfaces and its usefulness for reinstating contaminated equipment as free from toxic biological agents. The key element of the sterilization is oxygen radicals. The penciltype configuration produces a long, cold plasma jet capable of reaching 3.5 cm and having various excited plasma species shown through the optical emission spectrum. Operation of an air plasma jet at 2 W in a pencil-type electrode provides an excellent opportunity for sterilization of microbes. An electron microscope was used to observe the effects of the plasma on bacterial cell morphology. Transmission electron micrographs showed morphological changes in E. coli cells treated with an atmospheric plasma at 75 W for 2 min. The treated cells had severe cytoplasmic deformations and leakage of bacterial chromosome. The chromosomal DNA was either attached to the bacterial cells or released freely into the surrounding medium. The results clearly explain the loss of viability of bacterial cells after plasma treatment.

EFFECT OF THE PLASMA JET IGNITION AND FLAME KERNEL UNDER THE COMBUSTION PROCESS IN A CONSTANT VOLUME COMBUSTION CHAMBER

최문석,이경태,김권세,최두석 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.4

This work is to study the plasma application using a capacitive discharge ignition capable of using the plasma jet which belongs to the non-thermal plasma physic. A plasma-jet spark plug was designed to combine a discharge chamber including an insulator and expanding the plasma area. The nonresistance was applied to acting the interference suppression of a plasma-jet spark plug to ensure the high energy generated at a DC-DC converter. An ANSYS FLUENT program was used to conduct analyzing combustion progress. The combustion simulation model is composed of configurations of a spark plug, a lambda sensor, and an internal combustion chamber. Resultantly, the minimum value of the combustion pressure is verified at λ = 1.6, and the plasma jet has higher values in the order of 2, 3, and 4 bar than the conventional models due to having a fast reaction. Consequently, the plasma jet has advantageous in combustion diffusivity in comparison to the conventional spark plug since the negative electrode of the cathode is not designed in front of a jet plug.

Measurement of optical signals as a plasma propagation in the atmospheric pressure plasma jet columns

김윤중,한국희,진세환,최은하,엄환섭,조광섭 한국물리학회 2014 Current Applied Physics Vol.14 No.12

The propagation of plasma jets with argon gas is characterized in terms of two factors, the effect of electric field distribution along the tube and the effect of voltage polarity, from the observed results of optical signals along the entire column of plasma. The optical signal of plasma propagates from the high electric-field region of high-voltage electrode toward the low field region of the open air-space, regardless of the polarity of the voltage. The optical intensity and the propagation velocity are higher for the positive voltage than for the negative voltage. Moreover, the length of plasma plume exited from the end of the glass tube into the open air is shorter for the negative voltage. When the optical intensity is strong enough, a secondary peak signal follows the primary peak. In the plasma column on the inside of the glass tube, the optical intensity and the propagation velocity depend on the strength of the electric field; they are both high at the high-field region of voltage terminal and decay toward the end of the tube. The velocity is as fast as 104 m/s at the high-field region and slows down to 103 m/s at the low-field region of the glass-tube end. However, the plasma accelerates drastically to be (104e105) m/s after exiting the glass tube toward open air, even though the electric field is a quite low and thus the optical signal decays low before fading out. The experimental observations present in this report are explained with the propagation of the plasma diffusion waves.

Propagation of Plasma Diffusion Wave According to the Voltage Polarity in the Atmospheric Pressure Plasma Jet Columns

Guangsup Cho,Yun-Jung Kim,Eun Ha Choi,Han Sup Uhm IEEE 2014 IEEE transactions on plasma science Vol.42 No.11

<P>Propagation of optical signals measured along the atmospheric plasma-jet column according to the operational voltage polarity is analyzed with the electrostatic plasma-diffusion wave in terms of the characteristic speeds of plasma fluids, such as the plasma drift u<SUB>d</SUB>, the gas flow u<SUB>b</SUB>, and the plasma diffusion u<SUB>n</SUB>. For the positive voltage, the ion wave propagates with the wave-packet velocity of u<SUB>g</SUB> ~ c<SUB>s</SUB><SUP>2</SUP>/u<SUB>n</SUB>, where c<SUB>s</SUB> is the acoustic velocity along the whole column of plasma jet without any restrictions. The electron wave propagates backward with the group velocity of electron drift with u<SUB>g</SUB> ~ -u<SUB>ed</SUB> toward the high voltage electrode right after passing of the frontline of ion wave-packet. For the negative voltage, the ion wave propagates on the high ionization column with the wave-packet velocity of u<SUB>g</SUB> ~ c<SUB>s</SUB><SUP>2</SUP>/u<SUB>n</SUB>. The electron wave propagates forward while its propagation mode varies from the group velocity of u<SUB>g</SUB> ~ c<SUB>s</SUB><SUP>2</SUP>/u<SUB>n</SUB> on a region of high electric field to the velocity of electron drift with ug ~ +u<SUB>ed</SUB> on a low field region.</P>

Measurement of optical signals as a plasma propagation in the atmospheric pressure plasma jet columns

Kim, Y.,Han, G.H.,Jin, S.,Choi, E.H.,Uhm, H.S.,Cho, G. Elsevier 2014 CURRENT APPLIED PHYSICS Vol.14 No.12

The propagation of plasma jets with argon gas is characterized in terms of two factors, the effect of electric field distribution along the tube and the effect of voltage polarity, from the observed results of optical signals along the entire column of plasma. The optical signal of plasma propagates from the high electric-field region of high-voltage electrode toward the low field region of the open air-space, regardless of the polarity of the voltage. The optical intensity and the propagation velocity are higher for the positive voltage than for the negative voltage. Moreover, the length of plasma plume exited from the end of the glass tube into the open air is shorter for the negative voltage. When the optical intensity is strong enough, a secondary peak signal follows the primary peak. In the plasma column on the inside of the glass tube, the optical intensity and the propagation velocity depend on the strength of the electric field; they are both high at the high-field region of voltage terminal and decay toward the end of the tube. The velocity is as fast as 10<SUP>4</SUP> m/s at the high-field region and slows down to 10<SUP>3</SUP> m/s at the low-field region of the glass-tube end. However, the plasma accelerates drastically to be (10<SUP>4</SUP>-10<SUP>5</SUP>) m/s after exiting the glass tube toward open air, even though the electric field is a quite low and thus the optical signal decays low before fading out. The experimental observations present in this report are explained with the propagation of the plasma diffusion waves.