Chainarong Buttapeng

Annealing of metal wire by atmospheric pressure discharge plasma

A manufacturing process of fine wire is mainly consisted of 3 following processes. 1) The drawing process, 2) The cleaning process, and 3) The annealing process. In this study, the possible application of atmospheric pressure dielectric barrier discharge plasma to the annealing of metallic wire was examined and presented. The main purposes of the study are as followings; 1) to investigate the annealing effect by using the plasma, 2) to examine the surface cleaning effect for the cylindrical object by the atmospheric pressure plasma. In the previous study, it was shown that the annealing of wire was possible by the plasma. Then, it was shown that surface cleaning was also possible by the plasma exposure. From these results, the possibility of the rationalization of fine wire manufacturing process was able to be shown.

The Effects of Swirl Vane for Disk MHD Accelerator

The purposes of current study are to compare the performances with-and-without inlet swirl of the Disk MHD Accelerator, and to find out its effects. With an inlet swirl, results of calculation show that it is able to improve the MHD compression. In case of the swirl ratio of -1.0, a maximum velocity of about 3100 m/s is obtained. These are because of the influence of the electric field that is caused by the strong Lorenz force Fr and the counter clockwise of the gas flow uθ. Nomenclature u = gas velocity, m/s E = electric field, V/m j = current density, A/m 2 σ = electrical conductivity, S/m β = Hall parameter ρ = gas density, kg/m 3 B = magnetic flux density, T T = temperature, K PL = pressure loss, Pa QL = thermal loss, W CP = specific heat at constant pressure, J/kg/K CV = specific heat at constant volume, J/kg/K ES = total enthalpy, J/m 3 R =

Performance evaluation of disk MHD accelerator with nozzle and diffuser

The channel shape of disk MHD accelerator is so unique for the propulsion system, and it has some advantages for the acceleration. This work is to evaluate the performance of disk MHD accelerator with nozzle and diffuser. Q1D program is used as an analysis program. As results, radial gas velocity is increased up to 3,100 (m/s) at the middle of diffuser. In addition the velocity is suddenly decreased, and gas pressure gained at the close to channel inlet at the same time. This phenomenon is called as MHD compression whose reason was the interaction of Lorenz force, in particularly much Hall current density is done. And the work of diffuser could show the recovering of the gas pressure about 0.01(MPa) from the back side to the exit of the diffuser. Therefore electrical conductivity in the diffuser was increased.

Introduction to Pulsed Power Producing Pulsed Ion Beam- Driven Ablation Plasma for Space Propulsion Applications

This paper presents the modest results of ablation plasma and its behavior. This ablation plasma is produced by irradiating a 50-µm-Al foil with a pulse ion beam generated by a pulsed power generator. This kind of pulsed power generator reveals the significant weakness of its weight if the study is to apply to space propulsion. The modest technology using a more compact pulsed power generator is introduced. To investigate the feasibility of ablation plasma produced by this compact pulsed power system, a one-dimensional hydrodynamic model is employed to clarify the ablation plasma formation process and its properties when a pulsed ion beam interacts with an Al target. Physical parameters in terms of ablated plasma temperature, pressure, and the energy deposition distributions are presented. The plasma velocity, as well as its momentum-producing capability, is also investigated.

Efficiency of Ablation by Pulsed Ion Beam and Propulsion Performance

This paper presents the hydrodynamic efficiency of ablation plasma produced by pulsed ion beam based on the ion bea m and solid fuel target interaction. We used a one -dimensional hydrodynamic model, which mostly focused on an ion beam energy deposition phenomena and analyze it as a rocketlike model to explain and examine hydrodynamic variables. These variables were esti mated by the concept of ablation driven implosion in terms of ablated mass fraction, ratio of target velocity, and ablation velocity and thrust efficiency. Hydrodynamic efficiency of 17.5% by means of thrust conversion efficiency was achieved. The results show maximum energy efficiency of the ablation process (ablation efficiency) of about 70% meaning the efficiency with which pulsed ion beam energy E ionbeam is converted into exhaust kinetic energy in the solid fuel material. Moreover, propulsion performanc e with specific impulse of 3600 s was briefly reviewed. An effect of an ablation depth to hydrodynamic efficiency was also tested.

Closed cycle MHD power generation system driven by nuclear reactor for space exploration

For deep space explorations, we have to develop high-efficiency, high-reliability and high-performance electric power generation system. In this paper, a closed cycle magnetohydrodynamic (CCMHD) power generation system directly driven by a nuclear fission reactor (NFR) was proposed and investigated. Output electric power level is multi-MWe. Particularly, influence of the number of compressor stages, the regenerator efficiency and the radiator temperature on total plant efficiency and on specific mass (kg/kWe) was analyzed. Proposed system was expected to provide over 55% of total plant efficiency with the radiator temperature of 300 K. The estimated specific mass was about 2/spl sim/3 (kg/kWe) for 2 MWe output and 1/spl sim/2 (kg/kWe) for output power over 3 MWe level.

Behavior of Ablation Plasma Produced by Pulsed Ion Beam

Thin film production, flyer acceleration, and space propulsion system using ablation plasma produced by an intense pulsed ion beam have been studied. To control the generation of ablation plasma to adequate conditions is a key point for these applications. We studied the behavior of ablation plasma and target by a simple basic numerical hydrodynamic model. This paper discussed the ion beam irradiated angle and target materials effect to behavior of ablation plasma by comparison of numerical results to experimental ones. We could recognize that to change ion beam irradiation angle could affect plasma pressure and mass of ablated plasma without changing temperature significantly. Target materials changed velocity distribution of ablation plasma number density, electron number density, and temperature. Moreover, velocity distribution of ablation plasma number density was almost agreed well with an experimental data at various target materials.

Application of Ablation Acceleration by Pulsed Ion Beam to Space Propulsion

Our recent advanced research into ablation plasma acceleration produced by the irradiation of an intense pulsed ion beam has focused on ablation propulsion as a possible application to interplanetary missions. For this purpose, a one-dimensional hydrodynamic model, based on the interaction between target material and ion beam irradiation has been numerically analyzed the fundamental study of flyer acceleration in both flyer velocity and ablation plasma pressure. The results were in fairly good agreement with previous experimental data with a maximum flyer velocity of 8 km/s and maximum ablation pressure of about 80 GPa instantly reached at the ion beam energy density is 4 kJ/cm. From these results, two propulsion performance indicators namely thrust of 2000 N and specific impulse of 5000 seconds are estimated for space propulsion respectively. Here, we obtained energy transfer efficiency about 10%. In addition, this paper presents the factors effect these indicators and we have found that changing acceleration voltage of ion beam, energy density, power, and the duration of ion beam irradiation can control both performances. Total energy density affects specific impulse whereas beam power influences thrust and flyer acceleration. Furthermore, the latest results confirm that controlling acceleration voltage relates directly not only to system capability but also economy.