离心泵内小间隙环流瞬态流体力计算

基于湍流润滑理论建立小间隙环流数学模型,计算层流假设时层流、过渡流及湍流3种流态下环流内压力分布情况,并与实验结果进行对比.结果显示采用层流模型进行计算时,层流工况下求得结果与实验吻合很好,但当雷诺数增加导致小间隙环流发展至过渡态及湍流状态时,数值计算结果与实验结果相比有较大偏差.利用几种典型湍流模型及过渡流模型对数值结果进行修正,修正后的数值结果与实验结果吻合较好;引用过渡区域摩擦因子对模型进行修正后的计算结果可修正采用层流模型和湍流模型时产生的误差,更接近于实验结果.针对离心泵启动的瞬态过程,求解考虑转子涡动角速度及涡动幅值变化时小间隙环流内压力分布,结果显示,涡动角速度及涡动幅值的变化对环流内正压区及负压区分布均有明显影响.     

粘弹性流体旋转流实验研究

利用粒子图像测速仪(PIV)对圆筒形容器内有自由表面变形的粘弹性流体旋转流动进行了实验研究.旋转流动由等速旋转的容器底面来驱动.实验工质为CTAC(十六烷基三甲基氯化铵界面活性剂)水溶液.测量了水、40×10-6、60×10-6和200×10-6CTAC水溶液在弗鲁德数为2.59至16.3范围内的旋转流动.PIV用来测量子午面内的二次流场,并从PIV图像中抽取自由面高度.结果表明在相似的弗鲁德数下,相比于水流CTAC水溶液旋转流动自由表面中心处的凹陷深度降低,随着溶液浓度或粘弹性升高,子午面内右上角的惯性涡被压缩且强度变得越来越弱.通过与水流动比较并做力平衡分析,定量估算了CTAC水溶液的第一正应力差或弱粘弹性.     

声控磁控两相流流型的实验研究

研究了在两端开放的水平管中，磁流体在磁场和声场的共同作用下的流型，结果表明在两端开放的水平管中磁性粒子在高振动频率小振幅时出现驻波状集聚，在低振动频率大振幅时出现均相。     

Modeling study on fluid flow and inclusion motion in 6-strand bloom caster tundishes

The behavior of fluid flow and particle motion in a 6-strand bloom caster tundish was investigated by a water model and numerical simulation. Compared with a device without flow control, the tundish with flow control has an important effect on the fluid flow pattern and inclusion removal. It is revealed that by non-isothermal process, which is real production condition, the fluid flow in tundish shows a strong buoyancy pattern, which drives particles to move upwards. The particle removal was quantitatively studied by mathematical and physical simulations.     

MHD three-dimensional flow of Jeffrey fluid with Newtonian heating

The magnetohydrodynamic（MHD） three-dimensional flow of Jeffrey fluid in the presence of Newtonian heating is investigated. Flow is caused by a bidirectional stretching surface. Series solutions are constructed for the velocity and temperature fields. Convergence of series solutions is ensured graphically and numerically. The variations of key parameters on the physical quantities are shown and discussed in detail. Constructed series solutions are compared with the existing solutions in the limiting case and an excellent agreement is noticed. Nusselt numbers are computed with and without magnetic fields. It is observed that the Nusselt number decreases in the presence of magnetic field.     

非牛顿流体管道流动方程及其近似解

为准确计算非牛顿流体充填料浆在不同工况条件下的充填流量和沿程阻力并以之指导充填工程实践,对非牛顿流体充填料浆在管道内的流动行为进行了研究.首先根据流变学以及流体力学理论,对充填料浆在管道内的流动状态进行分析,确定了非牛顿流体管道输送的层流临界条件;然后推导出近似管道流量方程,大幅度的降低了计算量、简化了计算过程;最后根据所构建的非牛顿流体管道流量方程组和近似管道流量方程组,以铜矿选厂全尾砂和325普通硅酸盐水泥制备了固体质量分数为71%、水泥掺量为11%的非牛顿流体充填料浆进行了环管试验,并分别以精确解法和近似解法对其屈服应力τ_B、稠度系数K和幂率指数n进行了计算. 研究结果表明:试验料浆在管道半径R为0.75 m、管道总长L为26 m及压差ΔP分别152 376、132 219、109 576 Pa时,流量Q分别为119.6、73.1、24.3 m³/h;基于试验结果以精确解法所求解的τ_B为128.098 3 Pa、K为0.450 6、n为1.109 7,以近似解法所求解的τ_B为138.965 2 Pa、K为1.244 4、n为0.905 7;以方程可视化方法绘制的三维图像对比证明精确解法和近似解法所求得的管道流量数值大小基本一致,且有相似的变化规律,证明了近似管道流量方程的准确性;因此,非牛顿流体管道流动方程及其近似解适用于非牛顿流体管道输送工程实践,是白金汉（Buckingham）流动方程和泊肃叶定律（Poiseuille law）的有力补充.     

旋转气流下AOD熔池内流体流动和混合特性的水模拟研究

在以足够高的运动相似性对双枪呀吹非旋转气流１８ｔ ＡＯＤ炉内流体流动和混合特性水模拟研究的基础上，对采用套管式螺旋板型喷枪时ＡＯＤ熔池内流体流动和混合特性作了水模拟研究，所用喷枪的中心管（主枪）内置有一厚度为０．２ｍｍ的黄铜质螺旋型板条，相应的螺距为４６．５７ｍｍ，环缝（副枪）与原模型喷枪相同。考察耻旋转射流下吹气量和枪间夹角的影响及螺旋型喷枪对实际过程的适用性。结果表明，在相同的吹气量下，与非旋     

两相泥石流的非恒定特性研究

按照运动机理和泥沙粒径组成的不同,泥石流可分为一相泥石流和两相泥石流。两相泥石流是水和泥沙混合液体与石块构成的固体之间有明显的相对运动的泥石流。两相泥石流在山区沟谷中分布更为广泛,本文针对两相泥石流的非恒定运动过程展开实验研究。实验发现两相泥石流的运动过程具有明显的间歇特征,龙头的运动和停滞呈现间歇式分布。泥石流在停滞过程中,水流或泥沙悬浮液携带石块在前部堆积使得龙头高度和坡度逐渐增大,当坡度达到临界值时,泥石流向下游运移,龙头高度和坡度进而减小,当龙头坡度减小到一定值时,泥石流进入下一个停滞阶段,等待上游泥沙的补给和能量的聚集。两相泥石流龙头后部水流断面平均速度>颗粒断面平均速度>龙头速度,水流速度是颗粒速度的2～3倍,水流通过颗粒不断的将能量传递给龙头用来克服龙头相对较大的阻力。本文通过两相泥石流的实验,研究了间歇流动的形成发展过程,通过分析建立了相应的的力学模型。     

Experimental study on microcapsule fluid oscillating heat pipe

In this experiment,a four-turn oscillating heat pipe(OHP)is made of copper tube with an inner diameter of 1.3mm,and an outer diameter of 2.5mm.A series of experiments are performed to investigate the startup characteristics of OHP,and the effects of different working fluids(FS-39E microcapsule fluid,pure water,ethanol),different liquid filling rates(40%—80%)on the heat transport capability of OHP in vertical bottom heat mode.The results show that the startup of OHP is relative with liquid filling rate,therm...     

Experimental investigations on the fluid flow mechanism in porous media of enhanced oil recovery by alkli/surfactant/polymer flooding

Nowadays, most oil fields in China are in the later period of production, and the water cut increases rapidly with even over 80 percent. It is hard for the water flooding tech- nique to meet the needs of oil fields production. Thus, it is inevitable to develop new oil production techniques to replace water flooding. ASP flooding is a new technique which is developed out on the basis of alkali flooding, surfactant flooding and polymer flood- ing in the late 1980s. ASP flooding synthetically m…     

多旋流烧嘴加热炉内冷态流场的数值模拟研究

在任意拉格朗日－欧拉（ALE）框架下，采用有限体积法开发了三维非定常流体流动的数值计算程序，利用该程序对包钢多旋流平焰烧嘴步进式加热炉内的冷态流动场分布进行了计算模拟，并与无旋流烧嘴加热炉内场进行了比较，发现多旋流烧嘴加热炉内的流场分布更加合理，且与生产中所观察到的情况一致，对生产实际有重大的指导意义。     

电流变流体可变阻尼对系统振动的影响

利用等效线性化的方法分析了电流变流体的等效阻尼、等效刚度及其对系统振动特性的影响。对具有电流变流体的阻尼器的振动响应进行了数值计算。结果表明:利用电流变流体的可变阻尼对系统的振动具有明显的抑制作用。控制电场强度可以控制系统的阻尼,电场强度的增加可导致峰值频率的增加及共振峰值的减小。     

Validation of the numerical simulation of fluid flow in the continuous casting tundish

The 3-dimensional fluid flow in a water model of the continuous casting tundish is simulated with the k-ε two-equation turbulence model. The methods to decide the size of wall-adjacent grids and the effects of residuals and mesh size on the simulation accuracy are discussed. The current investigation concludes that the following condition should be satisfied to get accurate enough simulation results: (1) If the dimension of the domain is in the order of cubic meters, the average size of cells in the mesh system should be at least smaller than 30 mm; (2) The normalized non-scaled residual should be reached at least smaller than 10^-4.     

水电站越坝气流及雾流降雨试验研究

以二滩水电站为背景对越坝气流与雾流降雨进行了试验研究,分析了来流条件和泄流方式对越坝气流回流区长度的影响。试验所得雾流降雨范围与原型观测成果近似一致,初步表明通过采用人工水雾形成雾源,在风洞中进行雾流降雨范围的模拟是可行的。     

Numerical simulation of fluid flow in a reheating furnace with multi-swirling-burners

A general numerical simulating program for three-dimensional (3-D) and time-dependent fluid flow for a reheating furnace with multi-swirling-burners has been developed based upon an arbitrary Lagrangian-Eulerian scheme (ALE) with the finite volume method. The parameters of fluid flow in a reheating furnace with multi-swirling-burners was calculated and the 3-D velocity distributions were obtained. The design of the burners was optimized for forming better swirling flow. The simulation shows that the fluid flow in the reheating furnace with the optimized burners is reasonable.     

EDM混粉工作液过滤装置及其工艺流程

提出一种新型电火花加工工作液过滤装置,介绍其循环处理系统及工艺流程.该液循环处理系统可以实现:①混粉电火花加工时,可分离出混粉工作液中80%以上的加工渣,实现混粉加工在线除渣;②更换混粉工作液或从混粉加工向普通加工转换时,可分离粉末添加剂和加工渣,实现工作液的再次利用;③普通电火花加工时,可将加工渣从工作液中分离,实现普通工作液在线除渣.     

Linearization and analytic solution of fluid dynamics of cell two-phase flow

Linearized equations of fluid dynamics of cell two-phase flow for one-dimensional case are proposed. Based on the equations, an analytic solution is derived, in which the frequency of wave is observed. The frequency formula consists of all important parameters of the fluid dynamics. In our observation, the group velocity and phase velocity of the motion of wave propagation are explicitly exhibited as well.     

均匀流场中三维陷落腔流激振荡实验研究

针对均匀流场中,三维等高型陷落腔因分离流而产生的流激振荡问题,开展了系列的实验研究.实验过程中,主要考虑来流攻角为0时,流速变化(Re=2.06×105~1.16×106)对三维陷落腔流激振荡特性的影响.同时,分别测量了三维腔体侧壁周向及垂向流体压力,分析了腔体内稳态压力和脉动压力的周口、垂向分布规律及腔口剪切层自持振荡特性.实验结果表明:均匀流场中三维陷落腔内部压力分布复杂,且当雷诺数大于某值时腔体内稳态压力全都呈现出负压,同时腔口随边处存在着较大的脉动压力,且脉动压力随相对高度增加而减小,但腔口导边及侧面处的脉动压力随相对高度增加而增大.剪切层自持振荡频率的无量纲数St数随Re变化为一常数值,但其值略大于气流场中二维陷落腔的St数.     

泄洪闸三维流态CFD优化分析

采用最新CFD方法对具体工程泄洪闸水流流态进行模拟分析.先给出了数学模型和计算方法;然后结合模型实验成果,用CFD详细分析了泄流能力与水面线、压力、流速等流场参数的规律性,弄清了不良流态的原因;进而提出加大侧墙弧度以消除吸气漩涡及加大孔口断面避免脱流的措施,通过3个方案对比分析验证了其效果,并得出最佳方案的泄流能力、进水口流态及泄槽内流态、压力和速度的分布规律.     

Experimental study on visualization of the flow field in microtube

Fluid flow in microtubes and microchannels has emerged as an important area of re-search. Because advances in microelectro-mechanical systems (MEMS) and other mi-crotechnologies involving fluid transport require the use of microfluidic components, which are often interconnected by tubes and channels. Up to now, many researches es-pecially on experimental studies have been performed to clarify the heat and mass transport characteristics in the microtube and microchannels. Wang and Peng[1] exp…