共查询到19条相似文献,搜索用时 125 毫秒
1.
2.
3.
采用交错均匀网格、全隐欧拉后差格式,对二维轴对称等离子体电弧进行随时间演化的数值模拟.得到了平衡时的稳态温度场、电流场和随时间演化的气流速度场.发现其中有周期性传播的磁流体激波,激波速度各点不等,约为700~1000m/s,这与实验观测到的等离子体电弧不稳定性现象是一致的
关键词: 相似文献
4.
在静电磁流体方程基础上提出了柱状放电电弧等离子体的磁螺旋不稳定性的一种新的线性分析方法。通过数量级分析得到了简化扰动能量方程。数值研究了外加轴向磁场、输入功率和弧柱半径外管壁半径相对大小等对电弧不稳定性的影响。 相似文献
5.
��������ƽ����������о� 总被引:1,自引:0,他引:1
研究了滑动弧放电过程中电参数的变化,并对滑动弧等离子体中的非平衡度和各个参数之间的关系进行了讨论。应用双通道电弧模型,对电弧在气流作用下运动规律进行了数值模拟,模拟所得的结果有助于分析滑动弧非平衡等离子体的产生机理。 相似文献
6.
在静电磁流体方程基础上提出了柱状放电弧等离子体的磁螺旋不稳定性的一种新的线性分析方法。通过数量级分析得到了简化扰动能量方程。数值研究了外加轴向磁场、输入功率和弧柱半径外管壁半径相对大小等对电弧不稳定性的影响。 相似文献
7.
8.
滑动弧等离子体的电弧温度场、电场和导电区域尺寸是确定电子温度、电子密度、化学反应速率以及能量效率的重要参数.对气流量为1.43 L/min和6.42 L/min时50 Hz交流滑动弧放电的电参数进行了测量;用瞬态的电弧模型描述滑动弧的能量传递,并用近似的介质电导率和热扩散系数对模型进行简化,解决了由于电弧结构变化所导致的移动边界问题;模拟求得等离子体的电弧结构、电场强度和动态温度场等参数的演化.其中,电弧电场的模拟值与实验值基本符合,计算得到电弧轴心温度可以达到5700—6700 K.研究结果表明,气流直
关键词:
滑动弧等离子体
温度场
电场强度
导电半径 相似文献
9.
10.
11.
The onset current of the helical instability of wall stabilized arcs can be determined by a theoretical model from a dimensionless function which is only dependent on the power input and a factor containing the gas properties and the arc conductance. The model describes the onset current of the instability in hydrogen and nitrogen as function of the tube diameter and of the pressure. Questions of restabilization are discussed. 相似文献
12.
The paper analyses the hydrodynamic instability of a flame propagating in the space between two parallel plates in the presence of gas flow. The linear analysis was performed in the framework of a two-dimensional model that describes the averaged gas flow in the space between the plates and the perturbations development of two-dimensional combustion wave. The model includes the parametric dependences of the flame front propagation velocity on its local curvature and on the combustible gas velocity averaged along the height of the channel. It is assumed that the viscous gas flow changes the surface area of the flame front and thereby affects the propagation velocity of the two-dimensional combustion wave. In the absence of the influence of the channel walls on the gas flow, the model transforms into the Darrieus–Landau model of flame hydrodynamic instability. The dependences of the instability growth rate on the wave vector of disturbances, the velocity of the unperturbed gas flow, the viscous friction coefficients and other parameters of the problem are obtained. It is shown that the viscous gas flow in the channel can lead, in some cases, to a significant increase in instability compared with a flame propagating in free space. In particular, the instability increment depends on the direction of the gas flow with respect direction of the flame propagation. In the case when the gas flow moves in the opposite direction to the direction of the flame propagation, the pulsating instability can appear. 相似文献
13.
The results of theoretical and experimental studies of collective processes in helical electron beams in gyrotron-type devices are generalized. Main attention is paid to low-frequency oscillations associated with the development of instability in the space charge trapped between the cathode and the magnetic mirror. The mechanism of evolution of instability is substantiated and the effect of oscillations on the main parameters of the electron flow determining its quality is analyzed. Data on the suppression of low-frequency oscillations and resulting enhancement of the gyrotron efficiency are considered. 相似文献
14.
A novel CO2 laser tube which forms a helical axial gas flow is designed. The influences of such a flow on the output laser beam is discussed. 相似文献
15.
A novel CO_2 laser tube which forms a helical axial gas flow is designed. The influences of such a flow on the output laser beam is discussed. 相似文献
16.
This paper presents the experimental technique and results of tests on a half-scale sector model of a steam generator helical coil tube bank. A series of tests was performed: (1) bench tests of a single helical tube in air; (2) tests of the sector model in air; (3) tests of the sector model in stationary water to determine natural frequencies and damping; (4) tests in flow. The experimental results reveal the general characteristics of the sector model and provide the information for the design evaluation of a helical tube array to avoid detrimental fluidelastic instability. 相似文献
17.
Stability of the combined flow of liquid film and turbulent gas is studied theoretically for an arbitrary angle between the directions of gas flow and gravity force. The three-dimensional wave flow of the film is described on the basis of integral approach and quasilaminar model of the turbulent gas flow. Increment and phase velocity of waves are calculated for the case of a vertical film and horizontal gas flow depending on the direction of their propagation. According to calculations, the cross gas flow increases the instability area significantly as well as the range of directions for propagation of the fast growing perturbations on the film surface. 相似文献
18.
B. Dipierro M. Abid 《The European Physical Journal B - Condensed Matter and Complex Systems》2012,85(2):69
Using linear instability theory and nonlinear dynamics, the Rayleigh-Taylor instability
of variable density swirling flows is studied. It is found that the flow topology could be
predicted, when the instability sets in, using a function χ dependent on
density and axial and azimuthal velocities. It is shown that even when the inner
axial-flow is heavier than the outer one (a favorable case for the development of the
Rayleigh-Taylor instability thanks to the centrifugal force) the instability is not
necessarily Rayleigh-Taylor-dominated. It is also shown that when the Rayleigh-Taylor
instability develops, it is helical. 相似文献
19.
This paper reports an analysis of the experimental results on how the threshold electric field intensity required to excited helical instability of a semiconductor plasma in wafers of p-silicon depends on the magnitude of magnetic induction. Also cited are data on the dependence of the threshold frequency on electric field intensity. The variations of the amplitude of the alternating current, caused by the development of helical instability, with electric field intensity and magnetic induction well above the instability excitation threshold are examined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 54–60, August, 1991. 相似文献