共查询到20条相似文献,搜索用时 203 毫秒
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集流伞作为仪器与套管形成环形空间的封隔部件,对测井资料的准确性起着至关重要的作用。但由于井底状况不佳、仪器起下时的摩擦或者操作不当,集流伞很容易破损漏失,导致测量不准甚至失败。本文主要针对可能影响测井资料的阻抗式过环空找水仪集流伞状态进行分析,并通过实验确定其影响因素,从而提出较为可行的解决方法与措施。 相似文献
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为便于取出微正挤压零件,设计了具有分瓣式结构的微正挤压凹模,并成功成形出最小挤出杆直径为0.25 mm的微正挤压件.采用扫描电子显微镜(SEM)及金相显微镜对微正挤压件的表面形貌及微观组织进行了观察。结果表明,随着挤出杆尺寸的减小或晶粒尺寸的增大,内外层材料的非均匀塑性变形程度增加;当挤出杆尺寸降低到亚毫米尺度时,微挤压成形件发生了一定弯曲;微正挤压件纵向和横向微观组织的非均匀分布表明,在微正挤压成形过程中材料在纵向和横向上都经历了严重的非均匀塑性变形.材料的非均匀塑性变形程度是随着挤出杆尺寸的减小或晶粒尺寸的增加而不断增加的. 相似文献
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《化工新型材料》2016,(3)
研究了晶须状碳纳米管导电纸作为集流极对锌锰电池放电性能的影响。使用晶须状碳纳米管(MWCNTs),通过抽滤法制备出碳纳米管纸,利用扫描电子显微镜(SEM)对碳纳米管导电纸进行表征。碳纳米管导电纸作为柔性锌锰电池集流体,正极极片采用二氧化锰为活性材料,负极采用金属锌为电极,使用计算机控制精密电池测试仪测试其电化学性能。实验表明,柔性锌锰电池具有良好的机械柔性,弯曲状依旧保持电压稳定。与采用石墨为集流体的传统锌锰电池相比,在0.3mA恒流放电的情况下,碳纳米管纸作为集流体,锌锰电池的放电时间增加了64.2%,比容量提高186%,比能量提高172%。碳纳米管纸作为集流体的柔性锌锰电池表现出极佳优越性,并且碳纳米管纸的密度对电池放电性能有着较大的影响。 相似文献
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目的 提高现有微成形工艺的可成形性,解决薄板易破裂等缺陷,探究薄板软模微拉深成形工艺的工艺参数对成形性的影响,致力于制造具有更大拉深比的微型杯件。方法 采用退火后的纯钛薄板作为原始板材,设计了薄板的软模微拉深成形模具进行实验。实验中探讨了工艺参数和材料参数对微型杯件极限拉伸比的影响。工艺参数包括压边力、橡胶性能和润滑方式,材料参数主要是晶粒尺寸。结果 通过控制压边力能够避免微拉深工艺中的缺陷。压边力过低会导致法兰区域起皱,压边力过高会导致上圆角部位破裂。采用刚度系数为72N/mm的压边弹簧能够有效避免起皱和破裂。选用硬度为65HA的聚氨酯橡胶能够成形出极限拉深比最大(为2.64)的纯钛微型杯件。软模微拉深工艺必须采用有效的润滑方式来提高板材的流动行为。采用蓖麻油润滑能够有效避免微型杯件的破裂缺陷。板材的晶粒尺寸对极限拉深比的影响是最强烈的。晶粒尺寸为8.4μm的纯钛薄板能够制造出极限拉深比为2.64的微型杯件,而随着晶粒尺寸的增大,微型杯件的极限拉深比显著下降。结论 通过软模微拉深工艺并且采用合适的工艺参数成功制备了极限拉深比为2.64的微型杯件,与现有工艺相比,所获得的微型杯件的极限... 相似文献
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Akira Ogawa Kazunori Nagasaki Kazuya Sugiyama 《Particulate Science and Technology》1994,12(3):243-269
A cyclone dust collector is a simple device with no moving parts, so it is applied in many industrial fields. However there is still no satisfied theory to estimate the collection efficiency for a given cyclone with high reliability since it is very difficult to predict the movement of the fine solid particles in the three dimensional turbulent rotational flows in the cyclone. A new model of the fractional collection efficiency including the diffusion effect of the solid particles and the decay effect of the tangential velocity of gas flow along the concave wall surface has been derived. In order to confirm this model, a simplified axial flow cyclone of body diameter D1 = 99 mm has been constructed and fly-ash particles were used as a test dust. The experimental results of collection efficiency were compared those predicted by the Ogawa model and the Fuchs model. 相似文献
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J. Launay N. Allanic P. Mousseau R. Muller R. Deterre 《International Journal of Material Forming》2014,7(2):197-205
The thermal and kinetic behaviour of an elastomer flow inside an extrusion die is numerically investigated. The aim is to control scorch arisen and reduce the heating time in the mould by using viscous dissipation phenomena in order to improve the rubber compound curing efficiency. A three dimensional model, using the particle tracking technique, is developed in order to get thermal, velocity and kinetic fields through the flow. Three common geometries of an elastomer forming process are modeled: a straight runner, a bend zone and a bifurcation. This simulation is applied on the case of an EPDM (ethylene propylene diene monomer) flow. The thermal and rheological properties are experimentally characterized. The influence of viscous dissipation on the reaction progress of the melt is studied on several process conditions. Many criterions relevant for thermal and cure homogeneity are proposed in order to quantify the performance of geometry modifications. 相似文献
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以0.02 mm厚的铜箔作为标示材料、1 mm和2 mm厚的2024铝合金薄板作为基材,采用不同的叠加方式组成叠层并进行搅拌摩擦焊接(Friction stir welding, FSW)试验,分析搅拌针端部挤压区塑性金属的流动行为及其对焊缝成形的影响。结果表明,在FSW焊接过程中,焊缝上部被塑化的金属不断地沿着搅拌针螺纹旋向往搅拌针端部迁移、长大,形成挤压区。此挤压区由位于搅拌针两侧的扩展区和位于搅拌针端面下方的变形区组成。其中,变形区的金属一部分来自从焊缝上部迁移而来的塑性金属;另一部分来自搅拌针端面下方母材经旋转摩擦作用而发生塑性变形的金属。挤压区塑性金属的流动方式分为轴向挤压迁移、水平摩擦迁移和绕流迁移三种。对厚板进行FSW焊接时,挤压区的塑性金属倾向以绕流迁移方式为主,导致焊缝内部形成疏松区或孔洞型缺陷。 相似文献
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D. McGlinchey A. Cowell J.R. Pugh E.A. Knight J. Xiang J. Li 《Particulate Science and Technology》2013,31(3):215-227
ABSTRACT An improved angle droplet collection efficiency model for the intermediate flow regime is presented in this paper, taking into account both inertial impaction and interception mechanisms. This model uses the equations of motion that has been derived by performing a force balance on a particle interacting with the flow field of a spherical collector. The fluid flow field around the collector is assumed to be the approximate solution as developed by Hamielec and Johnson for Reynolds numbers ranging between 10 and 80 and Tomotika and Aoi for Reynolds numbers less than 1.0. The results of this work indicate that the collection efficiencies calculated by using potential flow conditions may have overestimated the overall collection of particulate matter. It was identified that the transition from intermediate to potential flow occurs when the Reynolds number is about 80. The interpolation scheme for the single droplet collection efficiency proposed in this work can be used from Stokes flow to potential flow conditions including intermediate flow regime. 相似文献
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折叠管作为平行流冷凝器的重要组成部分,具有良好的极限承压能力使其逐步替代传统挤压管。本文对折叠管承压能力展开机理研究、仿真及实验分析。通过实验数据拟合得到折叠管材料应力应变数值曲线,将材料参数导入ANSYS建立折叠管爆破仿真模型,此模型仿真爆破值与实验爆破值21.9 MPa相符,通过实验对比验证了模型结果可靠性。基于对折叠管的理论分析,设计一种内插翅片双片式的新型微通道折叠管,通过仿真模型分析其内外壁厚等参数对极限承压能力的影响,得出在内片壁厚0.08 mm、外片壁厚0.2 mm、19孔时综合性能最优,相比于普通微通道管,新型折叠管体积减少了35%,极限承压值增加30%。新型折叠管不仅节约材料成本,使扁管结构更加紧凑,还具有优异的极限承压性能。 相似文献
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The influence of particle properties on slug flow conveying was experimentally examined by using polyethylene particles of different densities from 825 kg/m3 to 945 kg/m3 in a horizontal pipeline 5.5 m in length, inside diameter of 32 mm, for air speeds below 8 m/s. It was found that hardness affects the slug flow conveying in such a way that for soft particles lower limiting velocity as well as boundary air velocities for suspension flow and slug flow increases. Additionally, it was found that the frictional characteristics of a particle influence its flow pattern. Also, there are two types of slug flow, that is, a solitary slug flow and a consecutive slug flow. In a solitary slug flow, there is at most only one plug in the pipeline. In a consecutive slug flow, the particles are conveyed continuously as slugs. There is always at least one slug in the pipeline. 相似文献
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The influence of particle properties on slug flow conveying was experimentally examined by using polyethylene particles of different densities from 825 kg/m3 to 945 kg/m3 in a horizontal pipeline 5.5 m in length, inside diameter of 32 mm, for air speeds below 8 m/s. It was found that hardness affects the slug flow conveying in such a way that for soft particles lower limiting velocity as well as boundary air velocities for suspension flow and slug flow increases. Additionally, it was found that the frictional characteristics of a particle influence its flow pattern. Also, there are two types of slug flow, that is, a solitary slug flow and a consecutive slug flow. In a solitary slug flow, there is at most only one plug in the pipeline. In a consecutive slug flow, the particles are conveyed continuously as slugs. There is always at least one slug in the pipeline. 相似文献
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基于链化模型的磁流变弹性体磁致效应影响因素分析 总被引:2,自引:1,他引:2
磁流变弹性体是磁流变材料中新的一员,它是由可磁化的铁磁性颗粒和橡胶基在外加磁场下固化而成的,固化后铁磁性颗粒在基体中形成链状等有序结构,因此其力学、电学、磁学等性质可由外加磁场控制.目前限制磁流变弹性体的大规模应用的一个重要因素是其磁致效应还不能够满足工程需要,制备出具有更大磁致效应的磁流变弹性体材料是当前的紧迫任务之一.在磁流变弹性体链化模型的基础上,引入斜链夹角的正态分布,采用偶极子法从理论上分析了诸多因素对磁流变弹性体磁致效应的影响,包括颗粒链的初始倾斜角、外加磁场强度、剪应变大小等,为材料的制备和性能的优化提供理论上的帮助. 相似文献
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为了研究胶粉加工参数对活化胶粉/丁苯橡胶(SBR)复合改性沥青性能的影响,得到胶粉的最佳加工参数,采用废食用油来活化胶粉,选取不同掺配比例(胶粉质量∶废食用油质量)、加热温度、加热时间制备活化胶粉,复配SBR制备复合改性沥青。通过沥青常规性能试验、旋转薄膜加热试验(RTFOT),对复合改性沥青的高温性能、低温性能、黏度、存储稳定性和抗老化性能进行分析研究。结果表明:胶粉加工参数对复合改性沥青的综合性能影响显著;胶粉的最佳加工参数建议为掺配比例1∶1、加热温度160℃、加热时间90min;复合改性沥青的常规性能与90#基质沥青相比提升显著且优于SBR、活化胶粉改性沥青。 相似文献