共查询到20条相似文献,搜索用时 25 毫秒
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S. A. Zhdan 《Combustion, Explosion, and Shock Waves》2003,39(4):458-463
The problem of a detonation wave propagating in a cylindrical column of a chemically active bubbly medium screened by a liquid from the tube walls is formulated and numerically solved within the framework of the Iordanskii–Kogarko two-phase model with allowance for energy dissipation due to acoustic radiation of bubbles. The wave structure of the reaction zone and the detonation velocity of the bubbly medium column are calculated. It is found that the self-sustaining wave can propagate with a velocity greater than the velocity of one-dimensional bubble detonation by a factor of 1.5–2.5. 相似文献
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Unsteady extraction from a system of semi-infinite capillaries to the flow of a fluid with a linear velocity gradient is studied. An assumption that the diffusion in the flow is a quasi-steady-state process is taken to obtain a linear equation for the local mass flux from the pore space, which involves fractional derivatives with respect to time and flow coordinate. Limiting solutions for the total diffusion flux at small and large times that cover the entire time interval are found. 相似文献
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Diffusion of a gas through a membrane 总被引:1,自引:0,他引:1
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A. N. Pavlenko N. I. Pecherkin V. Yu. Chekhovich V. E. Zhukov S. Sunder P. Houghton A. F. Serov A. D. Nazarov 《Theoretical Foundations of Chemical Engineering》2006,40(4):329-338
A large-scale experimental setup is designed to study the hydrodynamic parameters and the mass-transfer efficiency in a countercurrent flow of mixtures of Freon R21 and Freon R114 on structured packings in a column 0.9 m in diameter. The study deals with the local and integral parameters of separation of the mixture, the degrees of nonuniformity of the flow rates and concentration distributions of the liquid and vapor phases over a cross section and on the column wall, and the pressure difference while varying the number of packing layers and their rotation angle. The mass-transfer processes while independently varying the liquid and vapor flow rates over wide ranges are also investigated. Experimental data are presented to illustrate the effect of the operating parameters on the height of an equivalent theoretical plate, the relative pressure difference, and the distributions of the local parameters of the flows. 相似文献
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Interaction of an incident shock wave (with a rectangular or triangular profile behind its front) with a finite-width semi-infinite cloud of aluminum particles located in a channel along the plane of symmetry is numerically simulated. Shock-wave interaction with the leading edge of the cloud results in the formation of a vortex that leads to cloud dispersion. Reflection of the curved shock wave from the plane of symmetry may be regular or may include the formation of the Mach stem. If the cloud is loaded by a rather strong shock wave, a detonation wave is formed in the cloud. In this case, the flow is periodic, which is caused by passing of transverse waves and their reflection from the walls. 相似文献
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Dashkov G. V. Solodukhin A. D. Stolovich N. N. Fisenko S. P. 《Theoretical Foundations of Chemical Engineering》2003,37(1):82-87
The transient outflow of a liquid from a perforated horizontal tube as a result of abruptly applied constant pressure is studied theoretically and experimentally. Equations and a computer program are developed for estimating the parameters of such transient processes. Retardation of the liquid outflow is observed, and its mechanism is discussed. 相似文献
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The problem of reflection of shock waves and expansion waves from a rigid wall in a mixture of liquid iron and small molybdenum
crystals is considered. The study is performed within the framework of equilibrium and nonequilibrium approximations of mechanics
of heterogeneous media with different pressures of the components. The mathematical model is verified by fitting the dependence
of the equilibrium-frozen velocity of sound on the initial pressure in the mixture with available experimental data. In the
equilibrium approach, the dependence of the type of the reflected wave on the type of the incident wave is determined. Direct
numerical calculations within the framework of the nonequilibrium model of mechanics of heterogeneous media confirmed the
validity of the reflection chart obtained. The possibility of significant compacting of molybdenum particles in reflected
waves is revealed.
Translated fromFizika Goreniya i Vzryva, Vol. 36, No. 4, pp. 97–107, July–August, 2000.
This work was performed within the framework of the Integration Project No. 97-24 of the Siberian Division of the Russian
Academy of Sciences. 相似文献
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Phase studies on a mixture of two polymers are presented, one of which is mesomorphic. We have systematically examined the influence of the molecular weight of the flexible polymer (including the oligomers) and of the semi-flexible polymer. In addition to the effect of the molecular weight, specific interactions are important for compatibility and formation of a homogeneous mesomorphic phase. The nature of this phase is demonstrated to be cholesteric and the pitch is determined. 相似文献
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Measured propagation speeds are given for the combustion front in a blind gap in a condensed substance, which are related to gap height and mean pressure. The front may propagate monotonically, which is characteristic of relatively high pressures and wide gaps, or as a result of additional burning foci arising at a certain distance from the main front. At low pressures and particularly with small gap heights, the front propagates in an unstable fashion over the surface.Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 28, No. 4, pp. 49–53, July–August, 1992. 相似文献
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Continuous Detonation of a Subsonic Flow of a Propellant 总被引:13,自引:0,他引:13
The principal possibility of organizing controlled combustion of a subsonic flow of a propellant in longitudinal pulsed and spin detonation waves is experimentally verified. Conditions and reasons for the existence of detonation waves are considered. 相似文献
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利用MAP装置改产S-NPK是MAP产品结构调整的方向之一,着重介绍KCI低温转化、混倒中和的工艺特点、主要设备选型和总结运行情况,并对存在问题提出改进措施。 相似文献
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Particle flows formed from shaped charges with a combined steel liner consisting of a hemisphere and a cylinder with a hemispherical part of degressive thickness (decreasing from top to bottom) were investigated by flash radiography. It has been found experimentally that the change from a constant to a degressive thickness of the hemispherical part increases the velocity of the head part of the liner jet formed during its compression, which is subsequently separated upon collapse of the cylindrical part. The maximum particle velocity obtained as a result of separation in the experiments was 8.6 km/s. 相似文献
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《Desalination》2007,202(1-3):351-360
The effect of different hydraulic cleaning methods was investigated in terms of flux decline and resistance using the cross-flow UF unit. The use of varied production intervals, varied ratios of periodic relaxation and the use of a periodic high-rate crossflow were investigated.This cleaning method of relaxation followed by high-rate crossflow mainly removed the resistances of the concentration polarization and gel layer compared with weak adsorption resistance. The cleaning protocol utilizing a periodic relaxation step and/or a periodic increased cross-flow rate at a decreased pressure can lead to productivity improvements and an increase in the operational lifetime of the membrane. If the optimal frequency and duration of the cleaning step (1 h production–60 s relaxation–60 s crossflow) is used, a net productivity increase of 14.8% is achievable and a significant extension to the membrane's life results. However, a critical point of different cleaning intervals did exist. Utilizing the optimized periodic cleaning techniques developed in this study allows higher recovery rates for ultrafiltration to be achieved, without the problems of increased flux decline normally experienced when operating with high recovery rates. 相似文献
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圆球在大空间均匀来流下的绕流特性已得到了广泛的研究,但是壁面对圆球绕流特性的影响还未清楚。通过实验方法研究了与壁面接触的静止圆球在明渠流中的绕流特性,重点关注了圆球后尾迹的特性。研究发现,圆球尾迹存在三种状态:稳定状态、非稳定对称状态和非稳定非对称状态。当Re<150时,尾迹呈稳定状态,尾迹关于垂直于壁面的平面对称;当150<Re<400时,尾迹呈对称状态,Reynolds数较高时,圆球后存在规则的、周期性的涡脱落,Strouhal 数为0.26~0.33,脱落涡关于垂直于壁面的平面对称,此时尾迹功率谱的频带分布较宽;而当Re>400时,圆球后的涡脱落不再对称,尾迹随着Reynolds数的增大呈现混沌特征。 相似文献