挡板式泡沫发生器内部流场分析

泡沫发生器是产生泡沫流体的设备,其发泡的基本原理是将空气引入发泡剂溶液中。应用数值模拟与PIV实验相结合,研究不同挡板角度对泡沫发生器内部气液两相流流动影响规律。该研究为疏松砂岩油藏冲砂洗井作业提供指导,为后续泡沫发生器结构设计提供理论依据。     

井下泡沫发生器内流场数值模拟及结构优选

井下泡沫发生器的应用可以避免泡沫从地面注入井下过程中的消泡问题,改善泡沫驱油的效果。但是由于井下径向空间有限,其内部泡沫发生结构的设计受到诸多因素的限制。应用Fluent软件,对射流挡板式、螺旋挡板式和螺旋搅拌式3种不同的井下泡沫发生结构进行了内部流场的数值模拟,对比分析了流场的迹线、速度分布、气液相分布和压力分布情况。结果表明:螺旋搅拌式发泡结构对气液相的掺混效果较好,压力损失小,为所研究的最佳井下泡沫发生结构。     

一种污染土壤异味高效阻隔系统的开发与应用

介绍了一种污染土壤异味快速、高效阻隔系统,该系统集泡沫发生器、发电、供气、药剂储存及自动化控制等功能于一体;其特殊设计的泡沫发生器,强化了发泡过程,所发泡沫更细腻、均匀、稳定,喷洒范围更广;优选的配套设备保证了发泡过程的平稳性和连续性。     

射流式泡沫发生器内部流场的数值模拟

通过数值模拟方法,运用FLUENT模拟射流式泡沫发生器内部气液两相流流场运动规律,并分析不同气液比对泡沫发生器内部气相体积分布影响。结果显示,不同气液比情况下,射流式泡沫发生器内气液两相流的静压和速度分布表现不同。该成果为疏松砂岩油藏以及油田冲砂洗井作业提供指导,为后续射流式泡沫发生器结构设计提供理论依据。     

电炉粉尘造泡沫渣过程中FeO的还原与炉渣发泡行为

在实验室研究了循环利用电炉粉尘造泡沫渣过程中,FeO还原速度的影响因素,同时分析了 FeO 还原速度与炉渣发泡高度的关系. 结果表明,随着粉尘和煤粉加入量增加以及反应温度提高,渣中FeO的还原速度加快;渣中FeO被固体碳还原的反应为表观一级反应;渣中FeO还原反应速率常数与泡沫渣的最大发泡高度存在很好的相关性,还原速度增加,泡沫渣的最大发泡高度也随之提高.     

泡沫金属亲疏水性对T型小通道气液两相流相分离特性影响研究

小通道填充泡沫金属成为近几年强化换热方向的研究热点。以空气和水为工作介质,将PPI为10和20的泡沫金属分别填充到截面为2.5 mm×2.5 mm的T型小通道内,改变泡沫金属的亲疏水性,分别研究弹状流和环状流下气液两相表观流速及亲疏水性对相分离的影响机制。比较亲水、疏水处理及未处理这三种泡沫金属的分离特性发现：无论是弹状流还是环状流,分离效果最好的是亲水处理后的泡沫金属,其次是未经处理的泡沫金属,而进行疏水处理后的分离效果最差,填充泡沫金属的T型通道相分离效果要明显好于未填充的通道。对于亲疏水处理过的T型通道,无论是弹状流还是环状流,T型小通道内侧支管气相采出分率占优,液相采出分率随着液体表观速度的增加而降低,但气相表观速度对液相采出分率影响很小。而泡沫金属PPI的减小会降低气相采出分率,使分配效果更加趋近于均匀分布线。     

HO-PDMS改性酚醛泡沫材料的性能研究

研究了低聚羟基封端聚硅氧烷(HO-PDMS)改性酚醛泡沫的性能,考察了HO-PDMS含量对改性酚醛泡沫表观密度、吸水率、压缩强度和阻燃性的影响。结果表明:含10%HO-PDMS改性酚醛树脂制成的泡沫压缩强度达到336 k Pa,是改性前的1.9倍左右;泡沫的阻燃性随HO-PDMS含量的增加而下降,在HO-PDMS含量为25%时,泡沫的氧指数仍保留在40%以上;改性泡沫的表观密度随增韧剂含量的增加而增加;HO-PDMS的添加有效降低了酚醛泡沫的吸水率。     

泡沫相部分水平泡沫分离塔强化分离牛血清蛋白的工艺研究

为了加强泡沫相排液,提高目的产物的富集比,设计了一种新型泡沫分离塔即泡沫相部分水平泡沫分离塔.以传统泡沫相垂直泡沫分离塔为对照塔,以牛血清蛋白(BSA)为体系,考察了表观气速、装液量、物料初始浓度和初始pH对牛血清蛋白(BSA)富集比和回收率的影响.结果表明泡沫相部分水平泡沫分离塔有效减小了泡沫相排液的阻力,提高了BS...     

中子辐照对硅橡胶泡沫材料性能的影响

研究了中子辐照对化学交联剂交联的开孔硅橡胶泡沫材料压缩及拉伸性能的影响。简要分析了中子辐照后材料性能发生变化的原因。研究结果表明,化学交联剂交联硅橡胶泡沫材料经中子辐照后,可发生二次交联,使硅橡胶泡材料泡沫材料的表观密度,凝胶质量分数,拉伸 扯断伸长率增大,而对压缩性能的影响较小;硅橡胶泡沫材料中子辐照前后的热重分析曲线存在明显的差异,但热降解速度无显变化,只是中子辐照后,材料的分解温度升高,加     

短玻璃纤维、K_2Ti_6O_(13)晶须改性酚醛泡沫的性能研究

分别利用K2Ti6O13晶须、短玻璃纤维对酚醛泡沫(PF)进行改性,并制备了不同短玻璃纤维含量的酚醛泡沫,考察了不同改性方法对酚醛泡沫的表观形貌、力学性能和保温性能的影响。表观形貌结果表明,添加4%K2Ti6O13晶须可以显著改变酚醛泡沫的表观形貌,使得泡孔更规则、均匀。力学性能测试表明,短玻璃纤维含量在8%以内,压缩强度和弯曲强度都随着短玻璃纤维含量的增加而增大;短玻璃纤维和短玻璃纤维/4%K2Ti6O13晶须可以显著提高酚醛泡沫的压缩强度和弯曲强度,压缩强度和弯曲强度最高分别提高了126%和208%;加入短玻璃纤维稍稍提高了酚醛泡沫的导热系数,降低了酚醛泡沫的保温性能;加入相同量的短玻璃纤维,短玻璃纤维/4%K2Ti6O13晶须改性的酚醛泡沫相比于短玻璃纤维改性酚醛泡沫具有更高的压缩强度、弯曲强度和保温性能。     

Behavior of sandwich structures and spaced plates subjected to high‐velocity impacts

This work evaluates the behavior of sandwich and spaced plates subjected to high‐velocity impacts. The sandwich structures were made of glass/polyester face‐sheet and a PVC foam core. The spaced plates were made of two plates of the same material of the sandwich face‐sheet at a distance equal to the core thickness. The residual velocity, the ballistic limit, and the damage area were selected to compare the response of both structures. The residual velocity and ballistic limit was very similar in both cases. Nevertheless, the damage area of sandwich structures and spaced plates differed due to the dissimilar properties between the sandwich core and the air inside of the spaced plates. An analytical model, based on energy criteria, was applied to estimate the residual velocity of the projectile, the absorbed energy by each face‐sheet, and the ballistic limit in the spaced plates. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Synthesis and characterization of elastomeric polyurea foam

Polymeric foams are ubiquitous in impact mitigation for civilian and military applications; the performance in such loading scenarios can be elucidated through quasi-static and dynamic mechanical testing. The present study reports on the complex microstructure of newly synthesized polyurea foams exhibiting a hierarchical structure consisting of large perforated semi-closed spherical cells with a mean diameter of 370 ± 162 μm surrounded by smaller closed, spherical cells with size distribution of 69 ± 18 μm. The stress–strain curves were used to calculate the basic mechanical properties and to predict the dynamic behavior of the foams. Nonlinear regression and finite element analyses were used to calibrate the Ogden hyperfoam model to explicate the hyperelastic behavior. The performance of the polyurea foam was found to outperform a benchmark foam in nearly all the elastic and energy absorbing properties. For example, one variation of the newly synthesized foam stored nearly doubled the energy of the benchmark foam while being 12% lighter. Low-density polyurea foam was found to decelerate an incoming impact mass with a minimum G-level that was nearly one third lower than the higher density polyurea and benchmark foams. In all, the behavior of the foam is dependent on the parameters of the fabrication process. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48839.     

Investigation and Development of Epoxy Foams

The development of low toxicity rigid epoxy foams as an alternative to polyurethane foams for electronics encapsulation is described. The basic foam components - epoxy resin, hardener, accelerator, blowing agent and surfactant - are blended to form a two part system which is mixed and foamed when required. Each foam component is selected for its contribution to the foaming reaction and the final foam properties. The balance of component miscibility, viscosity, reaction rate and exotherm determine foam quality. Foam properties are affected by (1) density (2) cell structure and (3) the molecular structure of the reactants. Initial foam development utilised epoxy/amine chemistry and produced two foams, Feldex F3 and F4. Subsequently, use of a more reactive polymercaptan hardener improved foam strength and process times, resulting in Feldex F5 and F6 which have been used successfully to prepare quality mouldings and encapsulated electronics. Recently, development has been extended to new areas of application, e.g. high temperature foams. The mechanical, electrical, thermal and chemical properties of the best epoxy foams have been evaluated; selected results are reported. The epoxy foams developed offer low density, high strength, low dielectric constant and loss tangent, high volume resistivity, good thermal insulation, low corrosivity and low toxicity. In addition, epoxy foams soften in acetone, an advantage over their polyurethane counterparts since encapsulated electronics may be retrieved without employing corrosive solvents. (Feldex is a registered trade mark of THORN EMI Electronics.)     

水基泡沫的稳定性评价技术及影响因素研究进展

综述了当前比较常用的和新开发的泡沫稳定性评价技术,评述了水基泡沫稳定性的影响因素,并对改变泡沫稳定性的途径进行了探讨,同时展望了有关泡沫稳定性研究的发展方向。     

夹芯板材用硬质酚醛泡沫性能的研究

对用于夹芯板材的硬质酚醛泡沫的发泡过程进行了研究。讨论了发泡温度、固化剂和发泡剂对泡沫体性能的影响。结果表明:反应温度控制在70℃～80℃,固化剂用量控制在16%～20%,得到的泡沫体均匀细腻,综合性能好。     

酚醛泡沫的制备

研究了两种酚醛泡沫的制备, 一种是用加热法制备酚醛泡沫, 另一种是尿素改性酚醛泡沫的制备。实验表明, 用加热方法制备的酚醛泡沫, 压缩强度较常温发泡提高一倍左右, 吸水率降至原来的一半, 导热系数由原来的００３３ Ｗ／ ｍ · Ｋ 降至００２８ Ｗ／ ｍ· Ｋ, 泡沫均匀、细腻。尿素改性酚醛泡沫, 其性能介于加热发泡和常温发泡两种酚醛泡沫之间, 但可降低成本。二者在管道保温领域具有广阔的应用市场。     

Fabrication and overcoating of divinylbenzene foam shells using dual initiators

Divinylbenzene (DVB) shells with a density of about 100 mg/cc were produced using a dual‐thermal initiator system. New high‐gain designs for direct‐drive ignition at the National Ignition Facility and the OMEGA laser facility at the Laboratory for Laser Energetics require low‐density foam shells such as these. Previous research using a single initiator system produced fragile DVB shells that cracked or imploded during the fabrication process. The dual‐initiator DVB system used in the present study enabled the shells to be robust enough to produce a high yield of intact shells. The two thermal initiators used were azobisisobutyronitrile (AIBN) and another azo‐type initiator, V‐70. The DVB shells were 800–3500 μm in diameter, with shell wall thickness 7%–10% of the diameter. Because the foam shells were porous, a full‐density permeation barrier of poly(vinyl phenol) was developed and deposited on the shells using two techniques to enable the shells to retain gas. The initial results show that the permeation barrier was pinhole free and could hold the gas in a gas‐filled shell. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2523–2529, 2006     

Nanoporous Ag and Pd foam: Redox induced fabrication using electrochemically deposited nanoporous Cu foam with no need to any additive

A simple, rapid and green method for fabrication of nanoporous metal (Ag and Pd) foams using electrochemically deposited nanoporous copper foam is presented. Ideally direct electrochemical formation of Ag and Pd foam structures without any additive reagent does not lead to a desired result; however, indirect fabrication starting from electrochemically fabricated Cu foam seems promising. Highly porous copper foam is fabricated electrochemically at a copper sheet and in turn serves as a hard template and a redox inducer for the deposition of Ag or Pd. The redox induced replacement of copper foam with Ag or Pd is done via simple immersion of as-fabricated nanoporous copper foam in cation aqueous solutions of Ag or Pd. The surface morphology of the as-fabricated foam is characterized by scanning electron microscopy (SEM), EDX and X-ray diffraction. The hydrogen evolution reaction is investigated as an example to demonstrate the electrocatalytic ability of as-fabricated foams.     

HCFC-141b发泡剂制备的半硬质聚氨酯整皮泡沫

采用氢氟氯烃1，1－二氯－1－一氟乙烷（简称HCFC－141b)代替一氟三氯甲烷（简称CFC－11）作发泡剂帛得具有臻密表皮层的半硬质聚氨酯整皮泡沫塑料，采用扫描电子显微镜观察了两种发泡剂帛得材料的内部泡孔结构，比较了两者的力学性能，结果表明；采用HCFC－141b代替CFC－11可以帛得性能良好的半硬质聚氨酯整皮泡沫塑料。     

硬质泡沫橡胶浮子的试制

针对泡沫浮子的使用要求，筛选出了用于制备泡沫橡胶浮子的配方体系，通过实验确定出了3种不同发泡剂的泡沫橡胶浮子的配方，比较了垂直自由发泡法、垂直加压发泡法和水平加压发泡法的优缺点。