Wu Chengkang
Chinese Academy of Sciences
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Publication
Featured researches published by Wu Chengkang.
Plasma Science & Technology | 2006
Lin Lie; Wu Bin; Yang Chi; Wu Chengkang
A gliding arc discharge plasma and its characteristics are described. Analysis of the production principle of the plasma is presented. Some experimental results about two novel types of the gliding arc plasma generator have been obtained. These types of gliding arc plasma are potentially usable in the chemical industry and environmental engineering.
Chinese Physics Letters | 2005
Pan Wenxia; Li Teng; Meng Xian; Chen Xi; Wu Chengkang
The arc-root attachment on the anode surface of a dc non-transferred arc plasma torch has been successfully observed using a novel approach. A specially designed copper mirror with a boron nitride film coated on its surface central-region is employed to avoid the effect of intensive light emitted from the arc column upon the observation of weakly luminous arc root. It is found that the arc-root attachment is diffusive on the anode surface of the argon plasma torch, while constricted arc roots often occur when hydrogen or nitrogen is added into argon as the plasma-forming gas.
Plasma Science & Technology | 2000
You Hui; Yan Wen-zi; Wu Chengkang
The dual-jet plasma generator is composed of two plasma torches from which the outgoing jets form a passage for electrical current with the plasma volume in the form of a Y-shaped stream. Due to this special configuration of the arc, the plasma flow field could have certain special characteristics, which make it promising for some applications such as gas heating and materials processing. In this paper, a three-dimension numerical calculation is carried out to simulate the flow field of the plasma jet. The simulation of flow field by the SIMPLE algorithm is based on a model of high-temperature gas flow with turbulence, coupled with the equation of electric field. The result of simulation reveals a complicated flow character in the dual jet, and shows that the shape of the high temperature volume in the flow field is nearly straight and agrees with the photograph of the arc. Effects of varying the angle between jets are also studied. These results can help to understand the behavior of the flow field for its future usage.
Chinese Physics Letters | 2009
Pan Wenxia; Li Teng; Wu Chengkang
An arc-heated thruster of 130–800 W input power is tested in a vacuum chamber at pressures lower than 20Pa with argon or H2-N2 gas mixture as propellant. The time-dependent arc voltage-current curve, outside-surface temperature of the anode nozzle and the produced thrust of the firing arcjet thruster are measured in situ simultaneously, in order to analyze and evaluate the dependence of thruster working characteristics and output properties, such as specific impulse and thrust efficiency, on nozzle temperature.
Plasma Science & Technology | 2007
Pan Wenxia; Meng Xian; Li Teng; Chen Xi; Wu Chengkang
Results observed experimentally are presented, about the DC arc plasma jets and their arc-root behaviour generated at reduced gas pressure without or with an applied magnetic field. Pure argon, argon-hydrogen or argon-nitrogen mixture was used as the plasma-forming gas. A specially designed copper mirror was used for a better observation of the arc-root behaviour on the anode surface of the DC non-transferred arc plasma torch. It was found that in the cases without an applied magnetic field, the laminar plasma jets were stable and approximately axisymmetrical. The arc-root attachment on the anode surface was completely diffusive when argon was used as the plasma-forming gas, while the arc-root attachment often became constrictive when hydrogen or nitrogen was added into the argon. As an external magnetic field was applied, the arc root tended to rotate along the anode surface of the non-transferred arc plasma torch.
Plasma Science & Technology | 2006
Pan Wenxia; Meng Xian; Wu Chengkang
Arc voltage fluctuations in a direct current (DC) non-transferred arc plasma generator are experimentally studied, in generating a jet in the laminar, transitional and turbulent regimes. The study is with a view toward elucidating the mechanism of the fluctuations and their relationship with the generating parameters, arc root movement and flow regimes. Results indicate that the existence of a 300 Hz alternating current (AC) component in the power supply ripples does not cause the transition of the laminar plasma jet into a turbulent state. There exists a high frequency fluctuation at 4 kHz in the turbulent jet regime. It may be related to the rapid movement of the anode attachment point of the arc.
Plasma Science & Technology | 2001
Meng Xian; Pan Wenxia; Zhang Wenhong; Wu Chengkang
By using steady and transient methods, the total heat fluxes and the distributions of the heat flux were measured experimentally for an argon DC laminar plasma jet impinging normally on a flat plate at atmospheric pressure. Results show that the total heat fluxes measured with a steady method are a little bit higher than those with a transient method. Numerical simulation work was executed to compare with the experimental results.
Plasma Science & Technology | 2010
Pan Wenxia; Huang Heji; Wu Chengkang
A 1 kW-class arcjet thruster was fired in a vacuum chamber at a pressure of 18 Pa. A gas mixture of H2 : N2 = 2.8:1.5 in volume at a total flow rate of 4.3 slm was used as the propellant with an input power fixed at 860 W. The time-dependent thrust, nozzle temperature and inlet pressure of the propellant were measured simultaneously. Results showed that with the increase in nozzle temperature the thrust decreased and various losses increased. The physical mechanisms involved in these effects are discussed.
Chinese Physics Letters | 2008
Huang Heji; Pan Wenxia; Wu Chengkang
Arc root motions in generating dc argon-hydrogen plasma as reduced pressure are optically observed using a high-spped video camera. The time resolved angular position of the arc root attachment point is measured and analysed. The arc root movement is characterized as a chaotic and jumping motion along the direction on the anode surface.
Plasma Science & Technology | 2001
Lin Lie; Wang Boyi; Wu Chengkang
A kind of plasma spraying torch with a hollow cathode is described in this paper. The plasma torch can be used for axial powder injection in plasma spray studies. The arc characteristics of the plasma torch with various gas flowrates, different gas media, are presented. The mathematical modeling and computational method are developed for predicting the temperature and velocity field inside the plasma torch.