气泡对过滤介质的堵塞机理

过滤介质的透水实验表明 ,清洁过滤介质的透水速率随时间延长而降低。水中所溶解的气体会吸际于过滤介质的纤维表面 ,并将滤布的孔隙堵塞 ,从而使过滤介质的透水速率逐渐降低。过滤介质的孔隙越小 ,纤维的疏水性越强 ,此现象越明显。     

机织过滤介质的流体透过性研究

机织过滤介质透过度在测试过程中随时间具有渐变性，这是由于流体中的微气泡在介质孔隙壁上的析出而造成，在测试中以介质两侧压差达到稳定并持续不超过１０ｍｉｎ所得到的透过度作为介质透过度的真值在统计学上是完全合理的。影响透过度大小的因素主要包括介质纱线类型、组织结构、孔径和孔隙度以及纤维的润湿性等     

机织滤布的生产与使用

介绍了国外固液分离用机织滤布的生产与使用现状，分析了国外过滤介质孔径，开孔率，透水和透气性能等测定标准，对机织滤布的材料，织造，精整加工技术等的发展趋势进行了讨论了，并着重介绍了目前重点发展的单丝滤布，双层复合滤布和涂膜滤布。     

精密单丝滤布透水速率与截留精度的研究

为进一步了解液固分离用织造滤布的过滤性能,以液固分离用新型过滤介质精密单丝滤布为研究对象,对滤布结构、开孔大小、丝径、孔隙率等因素对透水速率的影响进行了理论分析与讨论;并采用国际标准规定的鼓泡孔径、透水速率和截留精度的测试方法,对几种精密单丝滤布的孔径大小、透水速率、截留精度、透水阻力、孔隙度、分离效率进行了实验测定;同时介绍了不同孔隙度及截留精度的测定方法和结果,并对截留精度经验计算进行了实验验证,对正确选择与科学使用过滤介质单丝滤布提供有益的参考。     

滤布的过滤性能试验研究

以4种常用工业滤布为过滤介质,分别进行了透过空气、清洁水和酞氰蓝染料悬浮液的渗透性试验,测得了滤布的透气阻力、透水阻力和透过悬浮液的过滤介质阻力,并推出了它们之间的关系。通过悬浮液的过滤试验,提出了一种理论预测滤布的颗粒截留能力的方法。     

新型微孔薄膜复合过滤介质的过滤性能研究

对新型微孔薄膜复合过滤介质的过滤性能进行了系统研究,并与传统机织滤布的相关性能进行了对比。研究结果表明：新型微孔薄膜复合过滤介质具有极高的固体截留率、良好的抗堵塞性能和较长的使用寿命;在试验所考查的范围内,过滤介质的过滤速度稳定,基本不受过滤时间的影响;滤液浊度较低,基本不超过50mg／L;新型微孔薄膜复合过滤介质卸饼率高;气压过滤时的气耗量仅是普通机织滤布的0．056～0．11倍。     

新型微孔薄膜复合过滤介质的研究开发

根据减小孔径和改善接触滤饼侧的过滤介质孔隙结构有利于减轻介质污染的原则，利用凝固涂层的方法开发出一种具有良好防污性能的微孔薄膜复合过滤介质。它是以常规机织滤布为基布，复合一层微孔薄膜而成的。该复合滤材的微孔膜具有良好的弹性和耐酸碱能力，且与基布黏合良好，膜表面平滑且具有可控疏水性。复合滤布的孔径为1．41～9．12μm，孔隙度为59．33％～79．84％。在过滤过程中，悬浮液中固体颗粒难以进入微孔薄膜复合过滤介质的孔隙中，介质的抗污染能力良好，滤液浊度小，过滤速度稳定，且气耗量低。     

机织滤布的堵塞及单丝滤布的开发应用

从机织滤布的材料性质、孔隙结构及加工工艺等方面出发,讨论了机织滤布的堵塞机理及规律,在此基础上,充分论证了单丝滤布是减轻滤布堵塞,延长滤布过滤周期,提高过滤指标和经济效益的最有效的措施之一,并给出了生产实例的对比     

新型微孔薄膜及其复合过滤介质基本性能研究

介绍了利用凝固涂层的技术研制出综合性能良好的微孔薄膜复合过滤介质,其中的薄膜具有良好的弹性,能完全匹配基布的各种力学形变。且与基布黏合良好。说明了微孔薄膜的孔径可以人为控制,随不同的制膜条件孔径一般在1．41～9．12μm范围内变化,薄膜的孔隙度最小不低于52％,以及具有良好的耐酸碱能力和可控疏水性;同时,复合过滤介质的抗拉强度主要由基布承担,基布复合微孔薄膜后的经向、纬向断裂强度仅提高1．75％和2．38％,经向、纬向断裂伸长率提高7．14％和6．26％;复合滤布表面平整光滑,其最大静摩擦系数小于常规的机织滤布,且具有较高的透水能力。     

单丝与复丝机织过滤介质流体透过性对比研究

研究了单丝和复丝机织过滤介质对流体的阻力特性、透过度及其与滤材孔径和孔隙度的经验关系。结果表明,过滤介质对流体的阻力可以分为粘性阻力和惯性阻力两类;阻力的大小可以用阻力因子来反映;机织过滤介质阻力因子与雷诺数的关系为f=1.2393/N_(Re)+0.0098(单丝)和f=2.1024/N_(Re)+0.008947(复丝);透过度与介质的孔径、孔隙度的关系为B_F=60.09d_b~(0.152)ε_m~(0.324)(单丝)和B_F=5.11×10~(-5)d_b~(1.678)ε_m~(2.341)(复丝)。     

过滤介质的发展、精度表征与正确使用(Ⅰ)

阐述了新型织造滤布、金属和陶瓷过滤介质、选择性过滤介质及含催化剂过滤介质等的发展状况,对过滤介质的标准和透过度模型的研究进行了简单介绍,并阐述了过滤介质过滤精度的表征方法和存在的问题。同时针对目前存在的问题,对过滤介质的正确选择、使用,提出了一些看法。     

机织滤布的透水性能研究

对不同材质、不同纤维类型和不同编织方法的滤布的透水性能进行了研究,分析了诸因素对滤布透水性能的影响,研究结果对今后实际作业中滤布选型有一定的参考价值。     

操作温度对褶皱型不锈钢编织型过滤器阻力特性的影响

Effect of working temperature on the resistance characteristic including the permeability coefficient and the pressure drop evolution of a pleated stainless steel woven filter with a nominal pore size of 0.5 μm has been studied. The permeability coefficient was obtained based on the pressure drop data and the Darcy’s law. In three filtration experiments, pure carbon dioxide at 283 K, nitrogen at 85 K and liquid helium at 18 K are adopted, respectively. It is found that the permeability coefficient decreases at the working temperature due to the cold shrink of the filter element at cryogenic temperature. Then, two kinds of feed slurries, mixture of liquid nitrogen and solid carbon dioxide at 85 K, and mixture of liquid helium and solid nitrogen at 18 K, flow into the filter cell. The solid particles are deposited on the filter surface to form a filter cake and the purified liquid flows through the filter. It is found that the pressure drop evolution shows the same trend on these two temperatures, which can be divided into three stages with high filtration efficiency, indicating the feasibility of the filter for cryogenic application. However, variant cake resistances are obtained, which is resulted from the different interactions between solid particles in the feed slurry at lower working temperature.     

The structure and permeability of the disordered layer prepared by freeze-casting

Asymmetric ceramic membranes with disordered layer prepared by directional freeze-casting can be used as filter materials. However, there are few research achievements on the structural and permeability of disordered layers. Here, we obtained alumina asymmetric ceramic membranes with different disordered layer by adjusting the amount of alumina in the ceramic slurry. The results show that there are two kinds of structures in the disordered layer: spherical micropores and interconnected meshy pores, which lead to the change of airflow state. With the increase of the alumina content, the pore size of the disordered layer decreases and the network structure becomes complex, resulting in the decrease of the velocity of the inertial flow. The filter resistance of disordered layer increases obviously, but its proportion in the total filter resistance increases first and then decreases. The permeability is related to the pore size, specific surface area and channel complexity of the membrane.     

Visualization and quantification of forced in-plane flow through deformed porous media

Fluid flow in liquid molding processes and in other applications involving porous media is often characterized with a permeability tensor and modeled by d'Arcy's law. The permeability is a sensitive function of pore structure, which, in deformable materials, is influenced by compression and extension. The majority of previous permeability measurements on composite reinforcement fabrics did not account for deformations imposed on them by corners and curves in the mold. In the present study, transparent molds were designed with a single 90° bend in which the gap between plates was held constant throughout the flow path. Thus, the effects of fabric curvature on permeability were investigated independently of the effects of fabric compression in the thickness direction. A new experimental system was developed to visualize and quantify fluid flow in fabrics mounted in transparent molds. The reported measurements were conducted with fluid flowing through a (vertical) flat region of fabric, around the 90° curve, and then along a second (horizontal) flat region. Permeability was found to be reduced by the imposed curvature for a nonwoven polyester and three-dimensional woven glass fabric. We were able to quantify the effect of curvature on permeability for the former, but not for the latter because of an enduring, dominant nonlinear entrance resistance. For the glass, comparison of two flow rates indicates that the faster flow is characterized by a two stage filling process, whereas, at the slower rate, the liquid front fills all pores at the same time.     

Pore network modeling of permeability for textile reinforcements

The homogenized permeability of textile reinforcement is computed using pore network modeling. The model takes as input a 3D image of the reinforcement, reduced to an array of points, each of them having a binary value designating whether the point lies inside a yarn or in a pore. The array can be acquired by X‐ray micro‐computerized tomography. The calculations proceed in two steps. First, the 3D image is analyzed to create a representation of the pores in the reinforcement by a system of interconnected pipes. Each pipe is characterized by its hydraulic resistance. Then the hydraulic resistance of the system of pipes is computed using the Kirchoff theory to yield a value for homogenized permeability of the reinforcement. The model is applied to a glass woven laminate, producing results in good agreement with experimentally measured values.     

平面三向织物增强橡胶复合材料撕裂性能研究

研究了平面三向织物及其增强橡胶复合材料的撕裂性能,分别对预切口平行于平面三向织物中某一组纱线和平行于平面三向织物中相邻两组纱线角平分线方向2种情况下的撕裂性能进行研究,并与平纹织物增强橡胶复合材料进行了对比.结果表明,平面三向织物及其增强橡胶复合材料的撕裂过程可分为初始阶段、预切口张开阶段和撕裂口扩展阶段等3个阶段,分...     

立体打印机织物基本组织

以3ds Max软件为平台,采用Peirce圆形理论模型,结合NURBS曲线建模方法,根据控制点坐标确定出机织物基本组织中的纱线轴线路径,通过对纱线截面"放样"、"复制"等操作,得到机织物平纹组织、1/3↗右斜纹组织的三维模型。以柔性聚乳酸耗材为打印材料,通过熔融层积成型(FDM)技术,在3D打印机中对建立的机织物基本组织模型进行立体打印,得到了立体打印的机织物组织。     

渐变系列色织床上用品面料的设计与织造

以25 tex×2涤纶纱为原料,采用联合组织、平纹组织、缎纹组织,织物经纬密度均为273根/10 cm、经纬紧度均为50%,结合色彩流行趋势进行色彩设计,并通过CAD模拟、小样织机织造,设计并织造出黄色渐变、红色渐变、蓝紫渐变、沙滩渐变4种床上用品面料。设计织造的4种面料都具有良好的视觉效果和手感,满足了床上用品面料舒适美观的要求。