共查询到18条相似文献,搜索用时 531 毫秒
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作者分别用圆形和方形爆轰管,通过改变惰性气体的比例和圆锥管道的锥角,对H2-O2和C2H2-O2系统进行了爆轰临界直径的实验研究,得到了不同稀释浓度下方管中爆轰波熄灭的临界直径,验证了Mitrofanov.V.V.和Soloukhin,R.I.以前得到的结果(dc/=10),也得到了圆锥管道中不同锥角对临界直径的影响(dc/-),并用流管理论对实验结果作了初步的分析。 相似文献
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对136组不同炸药的爆轰产物压力-粒子速度实验数据进行分段拟合,得到一个过C-J点的爆轰产物Hugoniot经验关系;对该经验关系进行Riemann积分,得到一个描述爆轰产物压力相对比容关系的爆轰产物等熵状态方程,该方程的参数仅为炸药的初始比容和C-J状态量,与传统经验等熵状态方程相比,不需要进行实验标定,因此可节约标定方程的实验成本和计算成本。为验证方程的合理性,采用该方程在压力相对比容平面上给出了Comp-B、HMX、PETN、ANFO、TNT以及LX-14炸药的爆轰产物等熵膨胀曲线,发现与采用JWL状态方程给出的相应炸药爆轰产物等熵膨胀曲线符合较好。 相似文献
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采用频散可控的耗散格式(DCD),求解Euler方程和一种改进的二阶段化学反应模型,
对氢氧反向-正向双爆轰驱动段激波管进行了数值模拟. 计算结果表明:当辅驱动段与主驱动
段初始压力比小于临界值时,Taylor波仍会出现,但波扇夹角较单一前向爆轰驱动段小,入
射激波马赫数衰减率变小;当初始压力比等于临界值时,主驱动段中的Taylor波完全被消除,
入射激波马赫数不再衰减. 当初始压力比大于临界值时,在主驱动段中能产生过驱动爆轰波,
不仅Taylor波被完全消除,而且驱动能力较单一前向爆轰驱动段强. 相似文献
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建立了描述可燃粉全-氧气混合物爆轰波的一维两相反应流模型,用MacCormack有限差分格式求解了控制方程,成功地模拟了玉米粉-氧气混合物在氢-氧爆轰驱动下爆轰波的传播过程,其数值结果在接近稳态爆轰区时与实验规律有良好的一致性。 相似文献
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建立了描述可燃粉全-氧气混合物爆轰波的一维两相反应流模型,用MacCormack有限差分格式求解了控制方程,成功地模拟了玉米粉-氧气混合物在氢-氧爆轰驱动下爆轰波的传播过程,其数值结果在接近稳态爆轰区时与实验规律有良好的一致性。 相似文献
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金属射流失稳断裂的理论分析 总被引:2,自引:0,他引:2
基于Hamilton原理,提出一个包含射流强度、剪切、应变率效应、动力学黏性、表面张力和速度梯度等多因素耦合的金属射流拉伸运动方程,具体分析了各种失稳因素,并由数值解定量给出其影响大小,以及最不稳定波长与初始应变率乘积\lambda_{m}\dot{\varepsilon}_{0} 值的变化范围;给出了射流断裂的时间判据和近似理论公式,计算得到的 t_{b}-\dot{\varepsilon}_{0}曲线与射流实验点、Chou\&Carleone拟合公式三者符合较好. 相似文献
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An analytical solution is given for a time-decay Rankine vortex profile due to viscous effects. The vortex filament is assumed
to be isolated, strong, concentrated and having zero-meridional flow (i.e. radial and axial velocities are equal to zero).
Zero-meridional renders the governing equations for an unsteady, incompressible and axisymmetric vortex in a simple form.
Based on the tangential momentum equation, the spatial-temporal distributions of the swirl velocity are given in terms of
Fourier-Bessel series by using separation of variables technique. A general formula is derived by total differentiation of
the swirl velocity with respect to time, depicting the viscous dissipation for Oseen and Taylor-like vortex profiles. This
analysis is validated by comparison with previous experimental data.
The English text was polished by Yunming Chen. 相似文献
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An analytical solution is given for a time-decay Rankine vortex profile due to viscous effects. The vortex filament is assumed to be isolated, strong, concentrated and having zero-meridional flow (i.e. radial and axial velocities are equal to zero). Zero-meridional renders the governing equations for an unsteady, incompressible and axisymmetric vortex in a simple form. Based on the tangential momentum equation, the spatial-temporal distributions of the swirl velocity are given in terms of Fourier-Bessel series by using separation of variables technique. A general formula is derived by total differentiation of the swirl velocity with respect to time, depicting the viscous dissipation for Oseen and Taylor-like vortex profiles. This analysis is validated by comparison with previous experimental data. 相似文献
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假设纤维方向角沿层合板的长度方向线性变化,研究了变角度纤维复合材料层合斜板的颤振.通过坐标变换将斜板变换为正方形板,采用层合板表面连续变化的速度环量来模拟空气对其的作用,速度环量分布利用Cauchy积分公式计算.建立了系统的Lagrange方程并采用Ritz法得到了层合板的自振频率和颤振/不稳定性分离临界速度.通过数值算例验证了本文模型和方法的正确性和收敛性,分析了各个铺层内纤维方向角的变化对自振频率和颤振/不稳定性分离临界速度的影响.研究结果表明,通过纤维的变角度铺设,可有效地提高层合板的基频和颤振/不稳定性分离临界速度.经合理设计的变角度复合材料层合板具有抑制颤振的作用. 相似文献
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D. Moreno-Hernández B. Barrientos-García H. J. Puga-Soberanes C. Pérez-López F. Mendoza-Santoyo 《Experimental Mechanics》2006,46(4):491-502
The Proper Orthogonal Decomposition (POD) method and the Galerkin projection are applied to study vibrations on an aluminum
square plate. Data from the plate vibrations were obtained using a Laser Vibrometer and the Fringe Projection technique. The
vibrations, within the range 100 to 5,000 Hz, on the metal plate were produced with an electrodynamical shaker. Due to the
symmetrical nature of the plate, the vertical displacement velocity measurements were taken only on a rectangular grid of
7×8 points. The vertical displacement velocity measured at different locations and times, was synchronized with a full-field
instantaneous image of the plate obtained from the Fringe Projection technique. The plate vibration measurements were used
to calculate its eigenfunctions and the eigenvalues. It was found that a large fraction of the total energy of the vibration
is contained within the first two POD modes. The essential features of the vibration are thus described by only the first
two eigenfunctions. A reduced order model for the dynamical behavior is then constructed using the Galerkin projection of
the equation of motion for the vertical displacement of a plate. 相似文献
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F.D. Bennett 《International Journal of Non》1977,12(5):285-292
A refraction law for the velocity at an oblique shock in a compressible fluid is derived in dyadic form similar to that for refraction of light rays at an interface. The shock tensor embodies only the assumptions of conservation of mass and equality of tangential velocity components. Given the shock inclination and density ratio, a quadratic equation in the ratio of the flow speeds can be found with flow turning angle as a parameter. Analysis of the two solutions shows that they lie on a circle in the polar plane, a result independent of the equation of state or other conservation laws. If the density ratio is allowed to vary, a pencil of circles is generated in the hodograph plane ; or, equivalently a right, elliptic cone with two nappes appears in the three-space formed when the density ratio coordinate is added at right angles to the hodograph plane. The further requirements that momentum and energy be conserved taken together with weak restrictions on the functional form of the equation of state are sufficient to permit the development of a general theory of shock polars. The allowed shock states are seen to lie on the space curve formed by intersection of a surface called the Hugoniot cylinder with the elliptic cone. The projection of this space curve on the hodograph plane is the shock polar. The theory is applied to the special case of a polytropic gas by way of illustration. 相似文献
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《Particuology》2023
In response to the divergent understanding of double inlet cyclone performance in the literature, the effect of inlet volute wrap angle on the performance and flow field of double inlet cyclone separator was studied by Computational Fluid Dynamic (CFD) method. The results showed that the inlet volute wrap angle can affect the comparison results of the single and double inlet gas cyclones with the same total inlet cross-sectional area and velocity. 0° and 90° volute double inlet improved the efficiency mainly by separating particles below 10 μm, while 180° volute double inlet had no separation advantage for any particles, so the symmetrical double inlet does not always improve the efficiency, and the appropriate inlet volute wrap angle should be selected according to the actual situation, otherwise, the expected performance requirements of the symmetrical double inlet cyclone cannot be achieved. Compared with the flow field, it is found that the inlet volute wrap angle changed the tangential velocity of the symmetrical double inlet cyclone separator, thus changing the performance. 相似文献