共查询到19条相似文献,搜索用时 93 毫秒
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润滑油的压粘系数和固化压力是弹流理论应用于摩擦学工程设计的关键试验数据。本文报道了20种国产润滑油的压粘系数和其中16种润滑油的最小固化压力的测定结果,并对不同油田的基础润滑油、不同化学结构的合成润滑油和不同用途的工业润滑油的压粘系数和固化压力进行了分析比较。 相似文献
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作者研制了一台可测试润滑油在高压下的粘度和密度的落柱式高压粘度装置。本装置采用了新型高压粘性动密封和新型高压流变平垫静密封,经1200MPa试压、1000MPa压力下48小时保压和使用试验证明均无泄漏。用本装置所获得的压粘数据的重现性好、灵敏度高、可比性强。 相似文献
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温压炸药的爆炸涉及到起爆、爆轰、冲击波的传播与反射、多相湍流和多模化学反应等, 是一个多尺度、多物质、多因素、多物理场耦合过程, 深化温压炸药高效释能的关键基础理论, 揭示温压爆炸的反应机理并有效控制和利用是温压武器创新发展的关键科学问题, 对高威力温压炸药的配方设计、温压武器的研制和使用具有重要指导意义. 本文描述了温压爆炸的基本原理, 讨论了温压炸药的概念和内涵, 从炸药种类、释能特点、能量构成、爆炸反应机制、爆炸效应增强机理、杀伤机制等方面阐述了温压炸药的特征, 分析了温压炸药有限空间内部爆炸威力的评估方法以及温压炸药的研发状况, 并提出了相关发展建议, 以期为高威力温压炸药的设计、温压弹的研制及毁伤评估提供指导. 相似文献
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温压炸药坑道内爆炸冲击波的数值模拟研究 总被引:1,自引:0,他引:1
基于二次反应理论,采用AUTODYN程序对温压炸药(RDX/AP/AL/粘合剂=20/43/25/12,质量比)坑道内爆炸冲击波进行了数值模拟研究。将温压炸药与传统炸药TNT的计算结果进行了比较,结果表明:①在爆炸近区,温压炸药比TNT的爆炸冲击波超压峰值低。但在爆炸远区,温压炸药的爆炸冲击波超压峰值则逐渐超过了TNT,最高达到了TNT的1.48倍;温压炸药爆炸冲击波的冲量峰值始终高于TNT,约为TNT的1.33~1.43倍。②最小二乘拟合得到了温压炸药坑道内爆炸冲击波超压峰值随距离衰减的计算公式,具有一定参考价值。 相似文献
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构筑了轴向解析、周向有限元压力分布的一维变粘度场有限宽轴承模型。在绝热边界条件下,忽略泊肃叶流项对速度的影响,不考虑温度轴向变化并沿油膜厚度方向积分,三维能量方程可降阶为平均温度场只沿周向分布的一维形式,结合滑动轴承非线性油膜力的一维直接解法,能量方程与雷诺方程可分别求解,既考虑了温粘效应对滑动轴承非线性动力学性能的影响,又提供了无需迭代直接确定油膜破裂边界和求解非线性油膜力的快速新方法。作为应用,针对进油槽位于水平两侧的椭圆瓦轴承进行了动力润滑热效应分析,与工程数据比较,计算结果吻合,证明该模型合理,适用于工程上多瓦轴承的分析计算。 相似文献
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HKD-1型航空润滑油特征剪切应力及有效粘压系数确定的研究 总被引:2,自引:0,他引:2
在球盘式拖动力试验机上,对HKD-1型航空润滑油进行拖动力测量,给出了根据拖动力试验曲线的非线性上升段确定润滑油有效粘压系数和特征应力的方法,对HKD-1型航空润滑油在试验条件下的粘压系数和特征应力进行分析,并建立了其计算公式.结果表明:特征应力和有效粘压系数的求解方法简单合理,其计算公式的拟合精度较高,可为轴承动态特性设计提供计算依据;随着接触压力、入口油温和滚动速度增加,HKD-1型航空润滑油的特征应力增大,其粘压系数减小;滚动速度对特征应力和粘压系数的影响小于接触压力和入口油温. 相似文献
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温压炸药能量输出结构的初步研究 总被引:3,自引:0,他引:3
为了研究温压炸药后燃反应及其对空中爆炸冲击波的影响规律,采用实验和数值模拟相结合的方法对温压炸药能量输出结构进行了初步研究。结果表明,距爆心较近时冲击波压力时程曲线上呈现两个峰值,而在较远处则存在较宽的正压作用区,该炸药正压作用区冲量为相同质量TNT的约1.6~1.8倍。并根据JWL-Miller模型参数得出后燃反应释放的能量占总能量的约1/3,以及非理想组分反应度随时间的变化关系,在完全燃烧的理想情况下,后燃持续时间可达400ms。说明温压炸药中铝粉等高能添加剂的后燃反应对增强冲击波效应和提高炸药做功能力有显著贡献。 相似文献
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油-气润滑系统工作过程中,润滑油膜受微油滴冲击和压缩空气扰动影响易形成气泡夹带现象,气泡夹带行为将对壁面润滑油膜层的形成及流动过程产生重要影响。基于VOF数值模拟方法,对含气泡油膜沿倾斜壁面的流动行为进行研究,考察了气泡的存在对油膜形态和流动速度的影响规律,以及气泡破裂阶段空腔邻域内流体压力变化特性。研究表明,油膜夹带气泡的形变和迁移诱发气泡周围微流场的速度扰动现象,导致气液界面处产生非均匀速度梯度分布,进而引发油膜表面的形态波动。气泡发生破裂时,油膜空穴部位发生明显的正负压力波动现象,气泡附近壁面将承受一定的交变载荷作用。 相似文献
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《Particuology》2023
Aiming at improving the capture performance of internal vortex electrostatic cyclone precipitator (ECP), a theoretical model with mechanics-electric-magnetic coupling was established, the collection efficiency of magnetic confinement ECP under different working voltages was simulated, and the influence of magnetic flux intensity on the removal performance of submicron particles was explored. Results show that the number of particles escaped from the cyclone is greatly reduced after the introduction of magnetic field and electric field, indicating that charging effect and magnetic confinement are more conductive to trap submicron particles in the internal vortex ECP. The lower the working voltage is, the worse the charging lifting effect is, but the stronger the magnetic confinement characteristics are. Furthermore, the contributions of charging effect to collection efficiency and magnetic confinement characteristics are more obvious at a weaker magnetic flux density. The research results can provide a practical new idea for the innovative design of ECP. 相似文献
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Numerical investigation on the influence of surface texture on the performance of hydrodynamic journal bearing 总被引:1,自引:0,他引:1
Many researchers have adopted various techniques for improving the performance characteristics of journal bearing. Apart from
other parameters, incorporation of different forms of surface texture (sinusoidal, dimple, spherical etc.) on bearing or shaft
also helps to increase the load carrying capacity and reduce the friction coefficient etc. in the journal bearing. Present
study investigates the influence of different forms of surface texture on finite journal bearing which has been considered
in the form of negative texture (micro cavities) at different locations of bearing surface. The Governing equations are solved
numerically through finite difference approach for analysis of texture effects on bearing characteristics. It has been observed
that the presence of micro cavities at different locations of bearing surface help in enhancing the bearing performance. It
has also been found that the negative half wave texture enhances the bearing performance more in comparison to full wave texture
on bearing surface. 相似文献
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The primary goal of this paper is to study film cooling performance for a cylindrical hole with plasma aerodynamic actuation. The simulation model of plasma aerodynamic actuation on improving film hole cooling effectiveness was established. The heat effect of plasma aerodynamic actuation model was taken into consideration. It was firstly found that the velocity and blowing ratio greatly affect the film cooling effectiveness. Then, position, power input, and the number of plasma actuators were particularly investigated. 相似文献
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IntroductionThenumericalsimulationoftheevolutionaryhistoryofthebasinisconductedacordingtothemechanismofpetroleumgeologyandmec... 相似文献
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Numerical investigation of the influence of incidence angle on asymmetrical turbine blade model showerhead film cooling effectiveness 总被引:2,自引:0,他引:2
The influence of various incidence angles on film cooling effectiveness of an axial turbine blade cascade with leading edge ejection from two rows of cooling holes is numerically investigated. The rows are located in the vicinity of the stagnation line. One row is located on the suction side and the other one is on the pressure side. The predicted pressure field for various blowing ratios (M = 0.7, 1.1 and 1.5) is compared with available experimental results at the design condition. Moreover, the effect of various incidence angles (?10°, ?5°, 0°, 5° and 10°) at three blowing rates is investigated by analyzing the results of both laterally averaged and area averaged values of adiabatic film cooling effectiveness. Numerical results indicate that the incidence angle can strongly affect the thermal protection of the blade at low blowing ratio but becomes less dominant at high blowing ratio. In fact, for the low blowing ratio, a small change in the incidence angle that relates to the design condition can deeply affect the thermal protection of the blade, which is evident from the laterally and area averaged film cooling effectiveness distributions. 相似文献
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The importance of the lift force acting on the dispersed phase in the boundary layer of a laminar gas-particle dilute mixture
flow generated by a shock wave is investigated numerically. The particle phase is supposed to form a continuum and is described
by an Eulerian approach. The ability of the Eulerian model to simulate particle flows and the importance of the two-way coupling
are proven by comparison with experimental data as well as with the numerical results from schemes based on a Lagrangian approach.
The models used for the lift force are discussed through comparisons between numerical and experimental results found in the
literature. Some results about the formation of a dust cloud are numerically reproduced and show the major role of the lift
force. Simulations of two-dimensional two-phase shock tube flows are also performed including the lift force effects. Although
the wave propagation is weakly influenced by the lift force, the force modifies substantially the dynamics of the flow near
the wall.
Received 17 February 2000 / Accepted 30 November 2000 相似文献