共查询到15条相似文献,搜索用时 672 毫秒
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在实验室条件下利用组合式激波管设备,对运动状态下液体轴对称抛撒进行了实验研究。通过纹影装置获得其所形成雾化场的外形轮廓照片,测量获得了液核发生首次破碎的位置与对称轴之间的距离。通过对抛撒过程中R-T不稳定性与K-H不稳定性的分析认为,轴向气流作用下液体轴对称抛撒的首次破碎点与对称轴的距离主要由轴向气流的速度、轴向气流的密度、液体轴对称抛撒的出口速度、抛撒液体的表面张力系数、环形喷口的宽度等参数所决定。在此基础上,利用相似性理论和无量纲分析,获得了运动状态下液体轴对称抛撒首次破碎点与对称轴之间的距离与相关参数的无量纲关系式。 相似文献
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液体轴对称抛撒的实验研究是以云雾爆轰武器的研制为背景的。为了研究轴向气流作用下液体轴对称抛撒二次破碎所形成的雾化场特性,本文利用两台激波管并对之加以改造,成功地在实验室实现了轴向气流作用下液体的轴对称抛撒。为了研究其雾化场的远场特性,本文利用激光粒子测量仪获得了在不同实验工况和不同位置下的雾化场SMD分布曲线。实验数据表明,由于轴向气流速度的增加,液体破碎的Weber数得到了提高,导致二次破碎初期雾化场的SMD随之减小;随着抛撒驱动压力的提高,二次破碎初期雾化场的SMD也随之减小;在同一工况下,雾化场SMD随着测量位置与喷口距离的增加而变大。 相似文献
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液体环轴对称抛撒首次破碎的实验研究和稳定性分析 总被引:1,自引:1,他引:0
首次破碎是液体抛撒、破碎过程中一个非常重要的阶段.本文提出了一种新的实验设备,并通过在这套实验设备上的一系列实验,得到了在不同激波马赫数、不同的液体种类和不同的抛撒容量下液体首次破碎过程的照片.实验结果表明,在确定的抛撒条件下,液体环的失稳,即不稳定的发生、发展并最终导致液体环破碎的过程,是由于液体环运动的加速度改变方向而引起的 相似文献
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In this paper,based on ref[1],the axisymmetrical buckling of simply supportedcylindrical sandwich shells under the action of uniform axial load is solved by a rigorousmethod.The classical theory of shells is used for the two face sheets and the core isconsidered as a three-dimensional elastic body.A series of transcendental equations areobtained,from which the critical loads can be calculated by numerical methods.Numericalexamples are given to compare with the solutions of sandwich shell theories. 相似文献
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The breakup of a liquid droplet induced by a high speed gas stream is a typical multiphase flow problem. The shock/droplet
interaction is the beginning stage of the droplet breakup. Therefore, investigation of the shock/droplet interactions would
be a milestone for interpreting the mechanism of the droplet breakup. In this study, a compressible multiphase solver with
a five-equation model is successfully developed to study shock/water column interactions. For code validation, interface-only,
gas–gas shock tube, and gas–liquid shock tube problems are first computed. Subsequently, a planar shock wave interacting with
a water column is simulated. The transmitted wave and the alternative appearances of local high- and low-pressure regions
inside the water column are observed clearly. Finally, a planar shock wave interacting with two water columns is investigated.
In this work, both horizontal and vertical arrangements of two water columns are studied. It is found that different arrangements
can result in the diversity of the interacting process. The complex flow structures generated by shock/water column interactions
are presented by flow-visualization techniques.
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E. Movahednejad F. Ommi S. M. Hosseinalipour C. P. Chen S. A. Mahdavi 《Heat and Mass Transfer》2011,47(12):1591-1600
This paper describes the implementation of the instability analysis of wave growth on liquid jet surface, and maximum entropy
principle (MEP) for prediction of droplet diameter distribution in primary breakup region. The early stage of the primary
breakup, which contains the growth of wave on liquid–gas interface, is deterministic; whereas the droplet formation stage
at the end of primary breakup is random and stochastic. The stage of droplet formation after the liquid bulk breakup can be
modeled by statistical means based on the maximum entropy principle. The MEP provides a formulation that predicts the atomization
process while satisfying constraint equations based on conservations of mass, momentum and energy. The deterministic aspect
considers the instability of wave motion on jet surface before the liquid bulk breakup using the linear instability analysis,
which provides information of the maximum growth rate and corresponding wavelength of instabilities in breakup zone. The two
sub-models are coupled together using momentum source term and mean diameter of droplets. This model is also capable of considering
drag force on droplets through gas–liquid interaction. The predicted results compared favorably with the experimentally measured
droplet size distributions for hollow-cone sprays. 相似文献
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A. N. Alexandrou A. V. Bazilevskii V. M. Entov A. N. Rozhkov A. Sharaf 《Fluid Dynamics》2010,45(6):952-964
The breakup of liquid bridges under the action of capillary forces is used for studying the rheology of suspensions under
stretching. The experiments were performed with suspensions of finegrained (3–30 μm) sand in glycerin for sand volume fractions
up to 0.465. The bridge thinning process was registered using an electro-optical measuring device and videofilming. The results
were analyzed on the basis of a theory developed earlier for the thinning of a liquid bridge under the action of capillary
forces. It is found that, for fairly slow stretching realized in the initial stage of the thinning, the rheological behavior
of the suspensions considered agrees with the model of a Newtonian viscous fluid. Along with this, the measured effective
viscosity of the suspension turned out to be approximately two-fold greater than the suspension viscosity under shear. The
origin of this discrepancy is analyzed. With increase in the stretching rate, in the final stage of the thinning, the weakening
of the suspension occurs, which is manifested in the formation of a local rapidly thinning neck in the bridge, similar to
that observed in the breakup of plastic materials. 相似文献