Parallel Simulation of 3-D Turbulent Flow Through Hydraulic Machinery

Parallel calculational methods were used to analyze incompressible turbulent flow through hydraulic machinery. Two parallel methods were used to simulate the complex flow field. The space decomposition method divides the computational domain into several sub-ranges. Parallel discrete event simulation divides the whole task into several parts according to their functions. The simulation results were compared with the serial simulation results and particle image velocimetry (PIV) experimental results. The results give the distribution and configuration of the complex vortices and illustrate the effectiveness of the parallel algorithms for numerical simulation of turbulent flows.     

偏置式垂直转子微小型泵内的黏性流动

为研究垂直转子微小型泵的内部黏性流动,根据偏置于两平板间的转子两端剪切力不平衡的原理,设计了一种偏置式垂直转子微小型泵,并利用粒子成像测速(PIV)技术对泵体内部的黏性流动进行了可视化量测。根据N-S方程对微小型泵的内部粘性流动进行了数值模拟计算。用这2种方法均得到了泵体内部的流线分布、泵体出口端面的平均速度和体积流量与Reynolds数的关系曲线。比较和分析结果表明:当Reynolds数小于100时,泵体出口端面的平均速度、体积流量与Reynolds数基本成正比关系;随着Reynolds数的减小,流体的黏性作用相对增大,垂直转子微小型泵可对流体进行更加有效的输送。     

用动理学方法推导空化流的控制方程

为了更合理地描述两相空化流,推导出物理意义清晰的控制方程是非常必要的。采用微观动理学方法,对描述空化流相空间中分子或颗粒速度分布函数守恒规律的Boltzmann方程分别取零次矩和一次矩,分别得到两相空化流的连续方程和动量方程。其中,用动理学方法可直接推导出泡径变化引起的质量、动量传递,并推导出相间碰撞积分项。对推导所得控制方程的分析表明,微观动理学方法能够描述相颗粒间的相互作用及相颗粒运动的微观特性,从而能够更好地模拟和认识空化流。     

TF513石钢炼铁技术的进步0048

ＴＦ５１３石钢炼铁技术的进步００４８［刊］／吴玉林…（石家庄钢铁厂）∥炼铁──１９９５，１４（２）．３３～３６总结了石钢近年来炼铁技术的进步。具体是：改善原料条件，提高烧结机产量约２６％；优化焦炭结构，配加１０％～２０％的澳块矿，减少土烧结构和土焦入...     

高线吐丝机调整对圈形的影响及对策

阐述了吐丝机的工作原理及工作中存在的问题，对影响高速线材圈形质量的原因进行了较为详尽的分析，通过对吐丝机及吐丝管进行针对性的工艺革新和调整，有效地改善了高速线材的圈形质量。     

Three-Dimensional Simulation of Unsteady Flow in a Model Francis Hydraulic Turbine

For Francis hydraulic turbines, unsteady flow caused by vortex ropes in the draft tube leads to a problem of stability in operation. The unsteady flow field ef a model Francis hydraulic turbine was simulated under part-load operation. A sliding mesh model was used to calculate a time-accurate solution for the strong rotor-stator interactions between the runner and guide vanes, and the draft tube. Based on threedimensional incompressible Reynolds averaged Navier-Stokes equations and on a renormalization group k-ε turbulence model, spatial discretizatien was obtained by using the finite volume method with unstructured grid elements, and a second order fully implicit scheme was applied for time. Pressure fluctuations in the draft tube were recorded and analyzed via a fast Fourier transform calculation. The results were compared with the experimental data, and shew that the vertex rope in the draft tube and the induced pressure fluctuations are well simulated.     

离心泵全三维流场的大涡数值模拟

通过使用FLUENT软件的大涡模拟模型及多重参考坐标系，计算单级蜗壳式离心泵包括导入管、叶轮及泵壳在内的全三维湍流场．发现泵叶轮内各通道的流量、流速及压力等分布有显著差别，流动呈现明显的非对称性，泵内流动旋涡一般出现在叶轮叶片工作面上．文中还将泵性能的预测值与实测值作了对比，验证了计算结果的有效性．     

对旋式轴流泵全流道三维定常紊流场的数值模拟

为研究对旋式轴流泵的内部流场特性及前后叶轮之间的流场干涉情况,应用标准k-ε紊流模型和SIMPLEC算法进行了定常三维紊流流场的数值模拟,得到了叶片吸力面与压力面、过渡干涉面、全流道下4个轴向位置的径向剖分面和3个径向位置轴向剖分的周向截面的压力分布及等值线图。应用数值模拟的结果能够获得前置叶轮、后置叶轮及整个泵各自的外特性,还可以帮助直观地认识对旋式轴流泵内部流动的耦合与干涉机理,指导水力模型设计。     

PIV Experimental Investigation on the Flow in a Model of Closed Pump Sump

Vortices in the flow of a pump sump present an important problem in pump station operation. In the present study, the flow patterns in two model pump sumps with specially designed structures are analyzed using the particle image velocimetry (PIV) technique. The data is analyzed to reveal a number of parameters including the internal flow field with velocity distribution, the streamline distribution, and the turbulent kinetic energy. The analysis certifies that a modified pump with added T-type baffle below the sump exhibits good performance for realistic working conditions.