共查询到20条相似文献,搜索用时 93 毫秒
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针对磁流体在磁场中粘度测试的特殊性,研制了一种新型的旋转法磁流体粘度测试实验台,该实验台可通过测试带动工作气隙内磁流体作旋转剪切运动所需的力矩来推算得出磁流体的粘度,满足磁流体在磁场中的粘度测试要求。利用所设计的实验台对矿物油基Fe3O4磁流体的粘度进行了测试,研究了外加磁场、温度及磁流体中磁性颗粒含量对其粘度的影响规律。结果表明:磁流体的粘度随着外加磁场强度的增加而增大,当磁场强度增大到一定程度时,其粘度变化逐渐趋缓;随着温度的升高,磁流体的粘度呈不断下降趋势,在有外加磁场作用情况下,其粘度下降的幅度要远大于无外加磁场作用的情况;随着磁流体中所含磁性颗粒质量分数的增加,其粘度逐渐增大,当磁性颗粒质量分数小于30%时,粘度增加缓慢,但当质量分数超过30%以后,粘度则急剧增大。 相似文献
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建立了磁流体滑动轴承的弹流润滑数学模型,利用考虑热效应的Renolds方程,采用多重网格法、多重网格积分法和逐列扫描法,对磁场作用下的水基磁流体润滑滑动轴承的弹流性能进行数值分析。对比了有无磁场作用下的水基磁流体弹流润滑数值模拟结果,并探讨了磁感应强度对其膜厚和压力的影响。结果表明,在有磁场作用的条件下,不同磁粉体积分数下的水基磁流体的润滑膜膜厚比没有磁场作用时有所增加,但压力没有明显变化;在不同磁感应强度条件下,随着磁感应强度的增加,水基磁流体润滑膜厚增加,压力没有明显变化。 相似文献
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油气润滑系统广泛应用于高速滚动轴承,油气润滑条件下轴承温升特性与温度场分布是影响轴承极限转速与动态工作稳定性的重要因素.基于高速滚动轴承摩擦学与两相流理论,以角接触球轴承为研究对象,建立了油气润滑条件下轴承与流体域之间的流固耦合模型.利用流体仿真软件Fluent对油气润滑条件下高速角接触球轴承与流体之间的传热方式及温度场分布进行了数值模拟分析,得到了轴承与轴承腔体的温度场分布.并进一步研究了供油量、润滑油粘度、轴承转速和载荷对轴承温升的影响,得到了油气润滑参数等与轴承温度场热平衡之间的关系.结果 表明:轴承转速与径向载荷是影响高速滚动轴承生热量与温升的主要因素,轴承内部温度场分布不均匀,对于特定工况存在最佳供油量与润滑油黏度使轴承温升最小. 相似文献
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介绍了磁悬浮电主轴单元的工作原理,以5.5kW电主轴单元为例,利用ANSYS软件对其径向磁轴承磁场进行了有限元分析.找出其系统磁场分布的变化规律和影响因素.分析表明:在主轴正常悬浮且单边气隙值取0.3±0.004mm,主轴支承处轴颈圆度取0.003mm,径向磁轴承磁极内圈圆度取0.007mm时,磁路磁漏不影响控制系统的性能,主轴实际中心线距理想位置的最大偏移量为0.0025mm,可满足精密机床主轴径向旋转精度性能要求.研究结果为磁悬浮电主轴单元的径向支承结构的优化设计提供了理论依据. 相似文献
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A controllable and variable magnetic field was got by improving the oil cup of a MS-800 four-ball tester. By this improved four-ball tester, the tribological properties of Mn0.78Zn0.22Fe2O4 magnetic fluid in the magnetic field were tested. The worn surfaces of the steel balls lubricated with 6 wt% Mn0.78Zn0.22Fe2O4 magnetic fluid under different magnetic fields were observed by using a scanning electron microscope (SEM), while the elemental compositions of the wear scars were analyzed by means of energy dispersive spectrometry (EDS). It was found that the Mn0.78Zn0.22Fe2O4 nanoparticles had a diameter about 20 nm. Under magnetic field, the 46# turbine oil containing 6 wt% Mn0.78Zn0.22Fe2O4 nanoparticles showed much better friction-reducing and anti-wear abilities compared with lubrication without magnetic field. The worn surface, lubricated by 6 wt% Mn0.78Zn0.22Fe2O4 magnetic fluid lubricated under the effect of magnetic field, is smooth and the plowing is almost disappeared. Moreover, it is found that 22 mT magnetic induction is the optimum magnetic induction. Form theory study we found that under the effect of magnetic field, the bearing capacity increasing with the increasing of magnetic induction. When the eccentricity is small, the side leakage is highly decreased. 相似文献
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Wang Zhaoxia Zhang Weimin Liu Hongguang 《Frontiers of Mechanical Engineering in China》2008,3(2):222-225
The magnetic leakage field distribution resulting from linear defects of a tube sample in the geomagnetic field is modeled
according to the magnetic dipole theory. The formula to compute the normal component of the weak magnetic field is deduced
based on the spatial distribution of the magnetic dipole. The shape and characteristics of the zero line (an important criterion
for magnetic memory testing) of the normal field is analyzed under different longitudinal magnetizations. Results show that
the characteristics of the zero line should be considered when the metal magnetic memory testing method is used to find and
locate the defect.
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Translated from Transactions of Beijing Institute of Technology, 2007, 27(147): 395–398 [译自: 北京理工大学学报] 相似文献
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The magnetic leakage field distribution resulting from linear defects of a tube sample in the geomagnetic field is modeled according to the magnetic dipole theory. The formula to compute the normal component of the weak magnetic field is deduced based on the spatial distribution of the magnetic dipole. The shape and characteristics of the zero line (an important criterion for magnetic memory testing) of the normal field is analyzed under different longitudinal magnetizations. Results show that the characteristics of the zero line should be considered when the metal magnetic memory testing method is used to find and locate the defect. 相似文献
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磁流体-泡沫金属减振器磁场强度有限元分析 总被引:1,自引:1,他引:1
磁流体-泡沫金属减振器与单纯磁流体减振器相比具有适用于更宽频率范围振动的控制并且可提供较大可控阻尼力的特点.在磁流体-泡沫金属减振器的设计与制造中,其内部磁场分布规律是影响减振效果的一个重要因素.为了探讨其磁场分布规律及影响因素,利用ANSYS软件对该新型减振器的磁场进行有限元分析,结果表明,在新型减振器的活塞外圆柱表面开环槽可以提高阻尼通道内的磁场强度,且适当地增加所开环槽的数量可使阻尼通道内的磁场强度提高幅度增大.该研究结论对磁流体-泡沫金属减振器的设计与制造具有一定的参考价值. 相似文献
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