Influence of feature size of micro-scale channel on ink flow characteristics

Under the micro-scale condition,feature size of the channel is one of the main factors influencing the fluid flow characteristics. In printing process,ink thickness in the extrusion zone formed by two ink rollers may reach micron scale. Compared with macroscopic fluid,the velocity field and the pressure field of fluid may change when the feature size of fluid channel reaches micron scale. In order to control printing quality,it is necessary to research the influence of feature size on ink flow characteristics in micro scale. This paper analyzes it in theory,and then numerical simulation of an ink flow model with different feature sizes is carried out in no slip condition. The influence of the feature size on the ink flow characteristics and the wall shear force are obtained. Besides,the ink flow model with different feature sizes is simulated numerically in slip condition,and the influence of feature size on ink flow characteristics is obtained. Finally,by comparing and analyzing the above results,it can be concluded that both the ink velocity and pressure at the inlet of the extrusion zone are inversely proportional to the feature sizes whether in slip condition or not. And the ink velocity in slip condition is larger than that without slip,the pressure at the inlet of the extrusion zone is less than that in no slip condition. Within the micro-scale range,the ink velocity difference between the two conditions cannot be ignored. Therefore,it is necessary to consider slip when analyzing the influence of feature size of micro-scale channel on ink flow characteristics.     

聚合物熔体在U形截面流道中的流动模型

根据流变学原理，在圆形截面流道流动模型的基础上，采用截面面积等效法，从理论上建立了聚合物熔体在U形截面流道中流动时剪切速率、流率和压力降之间的关系式。这些模型可用于计算机仿真U形流道充填的研究。     

非牛顿粘性流体薄板流的数学模型

建立了描述非牛顿粘性流体薄板流的数学模型，给出了单口浇注过程注射压力计算公式，并讨论了充分发展的矩形薄板流问题解的存在唯一性及求解方法．     

筛套环空砾石层压降的简化计算模型

在砾石充填井筛套环空砾石层的压降计算中 ,将液流简化为单向流或径向流计算得到的压降与实际值相差较大 ,描述这种发散流的Yildiz等人的模型比较复杂 ,且求解困难 ,不便于应用。因此 ,提出一种砾石层压降的简化计算方法 ,即将环空砾石层中的发散流简化为锥形流 ,根据Forchheimer方程导出计算压降的新公式。计算结果表明 ,锥形流模型与Yildiz等人的模型计算结果非常接近 ,并且应用更简便。分析结果还表明 ,油井产量以及射孔孔径和孔密度是影响砾石层压降的重要因素。     

气—液—固三相并流体系的流型识别

三相并流的流型与系统的动态特征有关。本文将压力信号的检测分析应用于三相并流的流型研究．根据球振动模型的能量分析导出识别模型，同时给出识别参数—压力振动能的概念和表达式，通过信号分析实现模型的量化．结果表明，流型转变时，压力振动能变化显著而有规律，依之判别三相并流流型效果显著；适用于三相并流时传质、传热、气含率及压降等研究的分区。     

三维水墨动画创意与制作新技术——以作品《中国风》为例

为了提高三维水墨动画创意与制作技术水平，以荣获全国二等奖的原创三维水墨动画作品《中国风》为例，介绍了一种三维水墨动画制作新技术：即使用3dsMax软件和FumeFX插件，将建好的三维模型赋予水墨特效，并使用后期特效软件After Effects制作运动镜头效果．与传统制作技术相比，该技术能在运动镜头中更好地表现水墨的晕染和流动感，减少了制作工序，提高了技术含量．     

基于动态纹理和粒子系统的喷泉模拟

喷泉效果可以大大增强虚拟现实系统的沉浸感.粒子系统是实现喷泉效果的有效方法,但该方法由于需要大量三角形单元的绘制,会降低虚拟现实系统的实时性.这里采用矢量控制法来建立粒子系统喷泉模型,然后渲染成一定幅数的连续图像,将这些图像作为贴图,同时采用billboard技术和动态纹理技术实现纹理喷泉的绘制,既保证了系统的真实感,又提高了系统的实时性.     

基于两相流EWF模型的样品表面相变行为及液膜变化的CFD预测

提出了一种利用两相流Eulerian Wall Film ( EWF)模型和自定义结露量公式相结合来预测样品表面相变行为及液膜变化的方法。首先利用自搭建环境实验箱开展结露物理实验,并分别基于两相流EWF模型与单相流模型进行仿真实验。结果表明,相对于单相流模型,EWF模型因考虑了相变过程而能够更加精确地模拟样品表面相变行为。然后通过自定义公式计算所得结露量与实测结露量的对比,验证了所提出结露量公式的正确性。最后在模拟与实测的温湿度曲线以及结露量吻合较好的前提下,模拟了样品表面液膜变化过程,过程中液膜呈现的形态与物理实验中原位摄像系统捕捉到的液膜形态初步吻合。     

内流式锥阀液动力的理论探讨

文中指出一般内流式锥阀流体力分析中选用一个控制体积的不足，选取了阀腔上、下流两个控制体积，运用两次动量变化的概念，得到新的内流式锥阀液动力理论方程。为了实用方便，文中给出了一种近似计算公式。     

Analysis of ink flow channel between two rotating ink rollers

In order to research how the size of the ink flow channel is affected by the interaction of adjacent ink areas,according to the method of fluid-solid interaction,this paper analyzes the size of the ink flow channel of two ink rollers' rotation.Firstly,this paper simulates the situation of only one ink area.Secondly,this paper simulates the situation of five adjacent ink areas.Then,through comparing the simulation results of two above situations,it' s obvious that the interaction of adjacent ink areas has big effects on the ink pressure and the size of ink flow channel.At last,this paper gets the main factor that affects the size of ink flow channel in the different situations.