【作者】 国亚东；

【导师】 陈照波； 姜洪源；

【作者基本信息】 哈尔滨工业大学 ， 机械设计及理论， 2010， 博士

【摘要】 由不锈钢丝编织压制成型制作的金属橡胶(Metal Rubber,简称MR)多孔材料兼有金属和橡胶的双重特性,在高低温、腐蚀等恶劣环境均保持阻尼、过滤、抗噪、隔热、密封等一系列优异特性,在航空、航天和空间技术领域有较大的潜在应用价值。金属橡胶多孔材料液体过滤特性及试验研究是金属橡胶技术研究领域的一个重要组成部分,由于金属橡胶过滤元件具有制备工艺简单独特、承载能力高、耐高低温和大温差性能强、对于流体流速及压力波动具有自动吸收及调节能力、孔隙度分布范围广且具有可设计性等特点,因此,金属橡胶过滤材料及过滤装置等在航空航天、国防及民品特殊工况具有广泛用途。金属橡胶在特种环境下所具有的优良过滤性能是其它相关产品无法比拟的,俄罗斯对此有成功的应用及研究经验。资料表明,我国对金属橡胶技术的研究尚处于专项研究阶段,主要集中于金属橡胶材料在阻尼减振、密封及吸声降噪等领域的应用。为了填补国内目前对此类新型材料在过滤方面的有关技术空白,本论文对金属橡胶多孔材料的内部孔隙组织结构特性及其过滤相关技术进行开创性研究,为金属橡胶多孔材料过滤技术的广泛应用奠定理论及试验基础。本文详细地综述了课题研究的背景及国内外研究现状,阐述了金属橡胶多孔材料用于过滤领域的可行性及鲜明特点。深入研究了表征金属橡胶多孔材料孔隙特征的几个重要因素:孔隙度、当量直径、最大孔隙直径和孔径分布规律等。推导出金属橡胶滤材平均孔隙度、最小孔隙度计算式和孔隙度计算的动态模型;借助于毛细管模型,获得了金属橡胶滤材的当量直径(水力直径)的表达式;对金属橡胶滤材内部孔隙结构适当简化基础上,采用统计学方法推导出金属橡胶滤材最大孔径的理论公式,并利用气泡试验孔径测定法加以验证。结果表明,该公式准确地反映出金属橡胶滤材最大孔径的影响因素及其相互关系;基于平面随机分割理论(Poisson Polyhedron Theory),推导出金属橡胶滤材的理论孔径分布。并采用压汞法对金属橡胶滤材孔径分布进行试验测定,结果表明试验结果与理论公式符合较好。以流体的流量连续性方程为基础,推导出圆柱形金属橡胶过滤材料雷诺数的计算公式。并利用金属橡胶过滤材料雷诺数,采用理论与试验相结合的方法,建立了金属橡胶过滤材料的压力损失精确计算公式。基于达西定律和流体介质渗流速度的理论公式,推导出金属橡胶过滤材料渗透系数的计算公式。对不同结构参数的圆柱形金属橡胶过滤元件进行了大量的多次通过试验,获得了孔隙度、金属丝直径和试件成型厚度对过滤效率和过滤压降的关系曲线。对环形与圆柱形金属橡胶滤材的过滤性能进行了对比试验研究,结果表明在较低孔隙度时,金属橡胶滤材过滤性能不受其结构形式的影响,而在较高孔隙度时,环形金属橡胶滤材远高于圆柱形金属橡胶滤材的过滤效率。开展了组合金属橡胶滤材过滤性能的试验研究,结果表明,组合金属橡胶滤材具有更加优异的过滤性能,在过滤效率相同的情况下,组合金属橡胶滤材过滤压降较低,流体的通过性能更好,在达到极限压降前能够容纳更多的污染物,滤材使用寿命大为延长,过滤性能得到了充分的发挥。通过理论推导与试验研究,建立了金属橡胶滤材过滤精度的理论公式,确定了孔隙度、金属丝直径与过滤精度的函数关系。同时,成型厚度对金属橡胶滤材过滤精度有着重要的影响,增加金属橡胶滤材厚度有利于获得稳定的过滤精度值。分析了悬浮颗粒及液体的物理性质对金属橡胶滤材过滤性能的影响。运用经典过滤机理,从微观上分析了金属橡胶多孔过滤材料捕获颗粒的机制。更多还原

【Abstract】 The Metal Rubber(MR) porous material compacted by stainless steel thread is possessed of dual properties of metals and rubber. It can keep a series of excellent performances such as damping, filter, noise reduction, heat insulation and sealing even under rugged environment of high and low temperature and erosion, so it boasts the great potentiality in the field of aviation, aerospace and interspace. Liquid filtration properties and experimental study of the MR porous material become an important component of MR technology. Because of the simple and unique fabrication process, the high carrying capability, the strong capability of resisting large temperature difference as well as the devisable characteristics of automatic absorption and good adjustment when fluid velocity and pressure were fluctuant and of the large distribution range of porosity, the MR filtering materials and filtering device are widely utilized in the domain of aviation, national defense and the special condition of civilian products. The MR porous material is in the possession of excellent filtering capability which other interrelated material are unmatched to, and Russian made it successful utilized and researched. Data shows that Chinese study on the MR technology is still in special research where attention is mainly focused on the application field of damping and vibration reduction, sealing and noise absorption. In order to make up the lack technology of new material about its filtration, the pioneering study was made about inner pore structure and filtering technology of the MR porous material, which provided theoretical and experimental foundation for its large use.The background of the issue and the research situation home and abroad was detailed introduced in this paper where the feasibility and distinct characteristic of the using of the MR porous material in the filtering domain was also stated. Several important factors affecting the pore character of the MR porous material was deeply studied such as the porosity, equivalent diameter, the pore maximum diameter and the distribution range of pore diameter. The main results are as followings: the calculating formula of average and minimum porosity and the dynamic formula of porosity were deduced. By means of the capillary model, the equivalent diameter(hydraulic diameter) formula of the MR porous material was obtained. On the basis of reasonable simplification of inner pore structure, the theoretical formula describing maximum pore size of MR filtering material is derived by statistical method and was proved by bubble test pore size. The results show that the formula precisely illustrates the influencing factors on maximum pore size of MR and their interrelation. With the help of Poisson Polyhedron Theory, theoretical pore size distribution of MR was worked out and was verified by mercury porosimetry method. The experimental results are well matched to the theoretical formulas.Based on the flow continuity equation of fluid, the Reynolds Equation of cylindrical MR filtering material was done. Precise formula of pressure loss was deduced using Reynolds Equation of MR filtering material in terms of combining the theory and the experiment. On account of Darcy law and the formula of fluid seepage velocity, theoretical formula of permeability coefficient was figured out.Relation curves of the porosity, thread diameter and the thickness of formed specimen to the filtering effectiveness and the filtering pressure-drop were obtained from a large number of successful experiments on elements of cylindrical MR filtering material with different structural parameters. There was a compared study on filtering capacity of annular and cylindrical MR filtering material, the results of which show that filtering capacity of the MR is not affected by its structural form at low porosity and while on high porosity filtering effectiveness of annular MR filtering material is higher than that of cylindrical MR filtering material. Combined MR was researched through doing experiments and the result indicates its filtering capacity is better than the others. At the same filtering capacity, combined MR filtering material is in the nature of lower filtering pressure-drop, better fluid traffic ability, containing more contamination before reaching its ultimate pressure-drop and of longer working life so that it was capable of giving full play of its filtering capability. The theoretical formula describing filtering precision of MR was obtained from theoretical deducing and experimental study so that function of porosity, thread diameter and filtering precision was determined. Meanwhile, the formed thickness had great effect on filtering precision of MR filtering material and the thickness addition helped filtering effectiveness tend to a stabilized value.The filtration mechanism of the MR porous filtering material was analyzed, which will provide the reference for the understanding of the performance of the MR filtering. The mechanics balance equations were established considering the suspended particle deposition, the dispersion and the migration during the filtration process. The decision condition of the particle disperses and the migration were given, and the force and the moment that carries in the particle are analyzed one by one. The decision condition of the motive particle deposition, the dispersion and the migration were given in the paper.更多还原