• Title/Summary/Keyword: Supersonic Plasma

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Experimental Analysis of a Supersonic Plasma Wind Tunnel Using a Segmented Arc Heater with the Power Level of 0.4 MW (0.4 MW 급 분절형 아크 히터를 이용한 초음속 플라즈마 풍동 특성 실험)

  • Kim, Min-Ho;Lee, Mi-Yeon;Kim, Jeong-Soo;Choi, Chea-Hong;Seo, Jun-Ho;Moon, Se-Yeon;Hong, Bong-Guen
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.9
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    • pp.700-707
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    • 2013
  • Experimental analyses on a supersonic plasma wind tunnel of CBNU (Chonbuk National University) were carried out. In these experiments, a segmented arc heater was employed as a plasma source and operated at the gas flow rates of 16.3 g/s and the total currents of 300 A. The input power reached ~350 kW with the torch efficiency of 51.4 %, which is defined as the ratio of total exit enthalpy to the input power. The pressure of plasma gas in the arc heater was measured up to 4 bar while it was down to ~45 mbar in a vacuum chamber through a Laval nozzle. During this conversion process, the generated supersonic plasma was expected to have a total enthalpy of ~11 MJ/kg from the measured input power and torch efficiency. In addition to the measurement of total enthalpy, a cone type probe was inserted into the supersonic plasma flow in order to estimate the angle between shock layer and surface of the probe. From these measurements, the temperature and the Mach number of the supersonic plasma were predicted as ~2,950 K and ~3.7, respectively.

Numerical analysis of plasma effect on fluid flow in a supersonic flow (플라즈마에 의한 초음속 유동 변화 해석)

  • Park, Sul-Ki;Cho, Hyung-Hee;Song, Ji-Woon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.05a
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    • pp.369-372
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    • 2009
  • A numerical analysis of the effect of plasma on flow characteristics in supersonic flow is studied. It is shown that change of direction and velocity magnitude of flow is appeared different in relative direction of plasma and fluid flow. The case of that direction of electrons, which are same with flow direction, the flow is accelerated, and the case of opposition, the flow is decelerated.

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Supersonic Mach Disk Characteristics in a Plasma Wind Tunnel (플라즈마 풍동의 초음속 마하 디스크 특성)

  • Chinnaraj, Rajesh Kumar;Oh, Philyong;Choi, Seongman
    • Journal of the Korean Society of Propulsion Engineers
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    • v.23 no.1
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    • pp.61-70
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    • 2019
  • A primary investigation on the underexpanded flow generated in a 0.4 MW class high enthalpy supersonic arc-heated plasma wind tunnel is conducted experimentally. The diameter and the position of the Mach disk from the nozzle exit is measured for overall pressure ratios ranging from 200 to 30. The empirical correlations for Mach disk diameter and position are determined which show very good agreement with experimental results.

Forced Ignition Characteristics with a Plasma Jet Torch in Supersonic Flow (초음속 유동장 내 플라즈마 토치를 사용한 강제 점화 특성)

  • Kim, Chae-Hyoung;Jeung, In-Secuk;Choi, Byoung-Il;Kouchi, Toshinori;Masuya, Goro
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.04a
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    • pp.363-366
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    • 2011
  • Mixing and combustion experiments with a vent slot mixer were performed in Mach 2 supersonic wind tunnel. Helium and hydrogen gases each were used for the mixing and the combustion experiment with a plasma jet (PJ) torch. The vent slot mixer holds plenty of fuel in the downstream mixing region, even though the fuel is transversely injected. In case of the combustion, the injected fuel is ignited by the PJ torch, and then unburned mixture is burned by shock-induced combustion downstream. Thermal choking in the combustor leads to shock trains in the isolator, causing the unstable combustion.

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Fundamental Experiments of Drag Reduction for a High Speed Vehicle Using Plasma Counterflow Jets (플라즈마 분사장치를 활용한 초고속 비행체의 항력감소 기초 실험)

  • Kang, Seungwon;Choi, Jongin;Lee, Jaecheong;Huh, Hwanil
    • Journal of the Korean Society of Propulsion Engineers
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    • v.21 no.6
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    • pp.57-63
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    • 2017
  • In this study, the fundamental test for drag reduction is carried out by using a plasma generator. Fundamental test setup is constructed of visualization and drag measurement system. The schlieren technique is used to visualize the plasma counterflow in supersonic flow. The penetration of the plasma jet and the change of the flow structure are observed through visualization results. Load cell is used to confirm possibility of drag reduction. Results show that drag was reduced by 6.2% using plasma jet in supersonic flow.

A NUMERICAL STUDY ON JET IMPINGEMENT OF PULSED PLASMA DISCHARGE ON A FLAT PLATE (벽면에 충돌하는 펄스 플라즈마 제트 유동특성에 대한 수치적 연구)

  • Kim, K.;Kwak, H.S.;Park, J.Y.
    • Journal of computational fluids engineering
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    • v.14 no.1
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    • pp.70-77
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    • 2009
  • In this study, time-dependent numerical analysis was carried out to investigate the plasma jet impingement on a flat plate, and a compressible form of two-dimensional inviscid gas dynamics equations were solved using the flux corrected transport algorithm. The mathematical modeling of Joule heating in the polycarbonate capillary bore and the mass ablation from the bore wall was incorporated in the numerical analysis and the series of computation was performed for three cases depending on the distance of the opposing plate from the capillary exit. The computational results reveal that the presence of the opposing plate does not affect the flow conditions inside the capillary when compared to the case of open-air plasma discharge. In the exterior region, the flow structure shows the typical supersonic underexpanded jet which consists of the strong Mach disk in front of the opposing plate and the barrel shock at the side of the jet. It is found that the shock evolution becomes more quasi-steady when the plate distance decreases. Also, the effects of the distance between the capillary bore exit and the opposing plate on the flow conditions along the opposing plate are investigated and the pressure variation on the plate shows more complicated interaction between the plasma discharge and the opposing plate when the location of plate becomes closer to the capillary exit.

COMPUTATIONAL MODELING AND SIMULATION OF METAL PLASMA GENERATION BETWEEN CYLINDRICAL ELECTRODES USING PULSED POWER (펄스파워를 이용한 실린더형 전극간 금속 플라즈마 생성현상의 전산유동해석)

  • Kim, K.;Kwak, H.S.;Park, J.Y.
    • Journal of computational fluids engineering
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    • v.19 no.4
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    • pp.68-74
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    • 2014
  • This computational study features the transient compressible and inviscid flow analysis on a metallic plasma discharge from the opposing composite electrodes which is subjected to pulsed electric power. The computations have been performed using the flux corrected transport algorithm on the axisymmetric two-dimensional domain of electrode gap and outer space along with the calculation of plasma compositions and thermophysical properties such as plasma electrical conductivity. The mass ablation from aluminum electrode surfaces are modeled with radiative flux from plasma column experiencing intense Joule heating. The computational results shows the highly ionized and highly under-expanded supersonic plasma discharge with strong shock structure of Mach disk and blast wave propagation, which is very similar to muzzle blast or axial plasma jet flows. Also, the geometrical effects of composite electrodes are investigated to compare the amount of mass ablation and penetration depth of plasma discharge.

Performance Characteristics of 0.4 MW Class Arc-Heated Plasma Wind Tunnel (0.4 MW 급 아크가열 플라즈마 풍동의 성능특성)

  • Oh, Philyong;Chinnaraj, Rajesh Kumar;Hong, Seong Min;Shin, Eui Sup;Choi, Seong Man
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.5
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    • pp.115-124
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    • 2018
  • Thermal protection materials (TPMs) are very crucial for the survival of any re-entry space vehicles. One of the systems used for rigorous validation of TPMs is an enhanced Huel type segmented arc-heated plasma wind tunnel. A 0.4 MW class arc-heated plasma wind tunnel has been constructed at Chonbuk National University which is capable of producing high enthalpy supersonic flow. In this paper we have studied the characteristics of plasma flow according to power and mass flow parameters.

Simulation of Capacitively Coupled RF Plasma; Effect of Secondary Electron Emission - Formation of Electron Shock Wave

  • Park, Seung-Kyu;Kim, Heon-Chang
    • Journal of the Semiconductor & Display Technology
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    • v.8 no.3
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    • pp.31-37
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    • 2009
  • This paper presents one and two dimensional simulation results with discontinuous features (shocks) of capacitively coupled rf plasmas. The model consists of the first two and three moments of the Boltzmann equation for the ion and electron fluids respectively, coupled to Poisson's equation for the self-consistent electric field. The local field and drift-diffusion approximations are not employed, and as a result the charged species conservation equations are hyperbolic in nature. Hyperbolic equations may develop discontinuous solutions even if their initial conditions are smooth. Indeed, in this work, secondary electron emission is shown to produce transient electron shock waves. These shocks form at the boundary between the cathodic sheath (CS) and the quasi-neutral (QN) bulk region. In the CS, the electrons emitted from the electrode are accelerated to supersonic velocities due to the large electric field. On the other hand, in the QN the electric field is not significant and electrons have small directed velocities. Therefore, at the transition between these regions, the electron fluid decelerates from a supersonic to a subsonic velocity in the direction of flow and a jump in the electron velocity develops. The presented numerical results are consistent with both experimental observations and kinetic simulations.

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Combustion Characteristics Study using Hyper-mixer in Low-enthalpy Supersonic Flow (하이퍼 혼합기를 사용한 저엔탈피 초음속 유동장 내연소 특성 연구)

  • Kim, Chae-Hyoung;Jeung, In-Seuck
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.6
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    • pp.75-80
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    • 2013
  • In this study, a forced ignition method with a plasma jet torch is studied in Mach 2 laboratory scaled wind-tunnel. The hyper-mixer is used as a mixer. For two normal injection cases, the one is collided against a wedge plate of the hyper-mixer and the other is directly injected into the cold main flow. For the first case, the hyper-mixer disperses the injected fuel, leading to the mixing enhancement. Furthermore, the fuel-air mixture is provided into the plasma hot gas, which enhances the combustion performance. However, the direct injection into the main flow method spends amount of fuel without ignition in the cold supersonic flow. In the end, for the forced combustion, it is important to supply the fuel-air mixture into the heat source.