共查询到20条相似文献,搜索用时 203 毫秒
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理论分析了射流抛光的紊动冲击射流特点,构建了射流抛光的垂直冲击射流模型和斜冲击射流模型。根据射流抛光冲击射流的特点,比较各种流体模型后,采用RNG k-e 模型应用于射流抛光模型的计算。利用计算流体力学理论的二阶迎风格式对抛光模型方程离散,用SIMPLEC数值计算方法对射流抛光过程的紊动冲击射流和离散相磨粒分布进行数值模拟,得到了射流抛光过程的连续流场和离散相磨粒与水溶液的耦合流场,同时计算出了抛光液射流在工件壁面上的压力、速度、紊动强度、剪切力分布和磨粒体积质量分布,分析了垂直射流抛光模型和斜冲击射流抛光模型紊流流场的特点。 相似文献
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为了提高电磁被动装甲对聚能射流的防护能力,利用叠加原理和磁流体线性不稳定理论,在轴向脉冲电流作用下建立了射流运动线性扰动控制方程,并对射流箍缩和扭曲不稳定性增长率随粘性、时间的变化规律进行了分析,得到了射流不稳定增长率和射流的变形规律,并利用数值方法得到了射流变形的计算公式。最后通过直径39.2mm破甲弹进行静破甲试验,通过后效板射流入射孔的大小验证了脉冲电流对射流的箍缩作用;利用具有初始弯曲、直径为1.75mm铜丝模拟了脉冲电流对射流的扭曲作用,通过铜丝的变形验证了脉冲电流对射流的扭曲作用。实验结果证实了理论分析的正确性。 相似文献
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自由表面磁流体射流不稳定性分析(Ⅱ) 总被引:1,自引:0,他引:1
用微分解析方法分析了自由表面磁流体射流在两个非均匀、相互垂直的横向磁场中的稳定性行为。获得了在给定射流初始速度分布和磁场分布条件下射流的速度空间分布表达式;分析了射流扭转及向外溅射的位置。 相似文献
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光学窗口长期处于水下环境中容易滋生水生物,水生物的附着影响光学窗口的观察与使用。为抑制或去除附着水生物,采用水下高速射流的方法。水下射流不同于空气中射流,由于环境水的作用会有很大的能量消耗,而目标前射流的流场对清洗效果具有十分重要的影响,故而进行水下射流流场分析和试验研究。通过水下射流流场分析,获得目标前的流场参数。根据流场分析结果,设计了水下射流装置。水下射流装置由潜水电机、泵、喷管和控制箱组成。运用试验装置进行了水下射流试验,取得了喷口前300 mm处2.2 m/s的流速。运用水下射流装置定期对处于水下环境的光学窗口进行水下射流可以去除初期附着的水生物和污垢,也可以抑制水生物生长,保持光学窗口的洁净。 相似文献
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用微分解析方法分析了自由表面磁流体射流在两个非均匀、相互垂直的横向磁场中的稳定性行为。获得了在给定射流初始速度分布和磁场分布条件下射流的速度空间分布表达式;分析了射流扭转及向外溅射的位置。 相似文献
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Yu. G. Gubarev 《Technical Physics》2011,56(3):345-350
The problem of linear stability of steady-state axisymmetric shear jet flows of an inviscid ideally conducting incompressible
liquid with a free surface and “frozen-in” azimuthal magnetic field is analyzed. The sufficient conditions for theoretical
(on semi-infinite time intervals) and practical (on finite time intervals) instability of these flows relative to small axisymmetric
long-wave perturbations are obtained by the direct Lyapunov method. An a priori lower estimate indicating (at least) an exponential
increase with time of small perturbations under investigation is constructed in the case when these conditions are valid for
theoretical as well as practical instability. In addition, an illustrative analytic example of steady-state flows under investigation
and small axisymmetric long-wave perturbations superimposed on them is constructed (according to our estimate, these perturbations
increase with time). 相似文献
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利用COMSOL Multiphysics软件实现磁场、导电流体、氚输运的多物理场耦合,研究了在强磁场下3维方管中锂铅流体内的氚输运及其分布。通过计算得到,锂铅流体在平行磁场方向的导电壁侧形成了射流,而在哈德曼壁侧及流体的芯部区域流动滞缓;射流的强对流效应使得在导电壁侧具有较低的氚浓度,而在哈德曼壁面侧及流体芯部具有较高的氚浓度累积,形成了不对称的氚浓度体分布。 相似文献
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介绍了在核工业西南物理研究院的液态金属实验回路(LMEL)上获得的几种可供液态偏滤器-限制器系统选用的液体自由表面的磁流体动力学(MHD)效应不稳定性的实验结果。实验发现:自由表面射流在穿越梯度横磁场时射程变短、截面变扁平,但MHD效应稳定,调节射流与磁场的夹角可以控制射流的流动特性;自由表面膜流MHD效应存在三种现象,即层流、溪状流和湍流。层流是由多束射流打到固体表面产生的(简称“射-膜流”),从MHD效应角度考虑,“射-膜流”将是四种可选液态偏滤器-限制器系统的液体自由表面形式中最佳的选择。同时,探讨了从物理的角度来理解四种自由表面形式的MHD效应的现象。 相似文献
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B. V. Perepelitsa 《Journal of Engineering Thermophysics》2018,27(2):196-201
Presented are results of visual studying the structure of a round minijet flowing into the atmosphere exposed to an acoustic field. The studies were performed with the laminar jet flow. According to the photo and video recording of the flow pattern we revealed characteristic features of the jet structure in the acoustic field. Characteristic vortex structures and zones with intensive turbulent mixing were detected in the flow.We revealed the process of formation of vortex structures in a laminar jet under the action of the acoustic field, vibrational and rotational jet flows at the outlet of the pipe 1.35 mm in diameter. The present study is a continuation of the research on a minijet structure in an acoustic field [13]. 相似文献
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A visual study of underexpanded plasma jet was conducted to reveal the detailed behavior in the strong magnetic field. The
images of the jet were taken by a digital single-lens reflex camera through viewing windows. The distribution of optical intensity
obtained from the raw data was compared to that of the typical emission line intensity. The profile of the optical intensity
agrees well with that of the emission intensity. It is illustrated that the typical structure of underexpanded jet such as
Mach disk is also affected obviously by the magnetic field. The radial distribution of number density was determined by using
the image analysis based on the Abel-inversion. The converted data clarify the jet behavior that is hidden on the ordinary
observation. The density obtained from numerical analysis for a simple gas was also compared with the number density. It is
confirmed from the comparison with numerical results that the radial profile of number density can be utilized for understanding
the plasma jet behavior under the strong magnetic field. 相似文献
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The influence of a transverse magnetic field on the jets of an impulse discharge was investigated. It was found that the jet trajectories show a curvature. The amount of the curvature depends on the pressure, the magnetic field intensity, the discharge current, the material and the polarity of the electrodes. The curvature of the jets was explained as a result of the action of forces arising in a plasma flow through a magnetic and electric field; their analysis was carried out on the bases of a MHD model. On hand of a derived solution, a possible influence of the jets on the origin of a retrograde motion is discussed. It is shown that the existence of certain discharge parameters and of a certain magnitude of the magnetic field brings about, in a plasma flying through a magnetic field, an induction of fields and currents under the action of which, on the one hand, the plasma itself flows in a retrograde direction and, on the other hand, there are influenced the trajectories of the carriers (particularly those of ions) of the current in the channel of discharge in front of the cathode spot. The proposed model of the retrograde motion is discussed and compared to the known results. 相似文献
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Keidar M. Beilis I.I. Boxman R.L. Goldsmith S. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(4):580-585
The plasma jet focusing and voltage distribution in the interelectrode gap of a vacuum arc with a ring anode and subjected to an axial magnetic field were studied theoretically. A two-dimensional model was developed based on the free plasma jet expansion into vacuum, and the steady-state solution of the fully ionized plasma in the hydrodynamic approximation was analyzed. It was found that the imposition of an axial magnetic field reduces the radial expansion of the plasma jet. The characteristic jet angle decreases from about 40° in the zero magnetic field case and approaches a value of about 20° with a 0.02 T magnetic field. The arc voltage consisting of the cathode drop, the plasma voltage drop, and anode sheath drop increased, with the imposition of a magnetic field, and decreased with the anode length. The model was compared to experimental measurements of the vacuum arc voltage behavior in an axial magnetic field, and good agreement was found 相似文献
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Magnetic field generation in shear flows of an incompressible viscous conducting medium across the flux lines of the initial field created in them is considered in the framework of the plane 1D problem of magnetohydrodynamics. The conditions of free slip and “sticking” are stipulated at the boundary between the flows. The variations of the magnetic field and velocity of shear flow occurring in the moving medium correspond to an Alfven wave “spreading” during its propagation due to dissipative processes in the medium associated with its viscosity and electrical resistance. It is shown that a high-rate shear of metals under explosive or impact loading may lead to generation of megagauss magnetic fields. 相似文献