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71.
Analytical modeling was used to track the mudline displacement of a simulated fluid dispersion that underwent a simulated linear increase in the fluid viscosity as a function of time following an induction period. Modeling results indicate two regimes of settling behavior from the driving force of density differences between the particles and the fluid. A linear mudline movement was first determined in the regime of constant viscosity, and a logarithmic retarded mudline movement was numerically determined following a linear rise in fluid viscosity. The results show that the combination of settling and solidification leads to a transitional mudline movement similar to batch settling curves described by early settling theories.  相似文献   
72.
本文利用磁流变减振机理,去解决离心机由于非线性振动带来的减振困难问题。通过研究构建了磁流变减振器动力学模型,设计了离心机的磁流变减振器,运用模糊控制原理对磁流变减振器进行主动控制,通过计算机仿真,获得了较为满意的结果。  相似文献   
73.
根据两个相对运动的平行板的流体处于简单剪切流状态的原理,设计制作了滑动平板式多功能流变体屈服应力测试装置.该装置用步进电机驱动,用单片机对步进电机进行精确定位和调速,并且由力传感器和应变仪来测量切应力数值,可以分别用于电流变液、磁流变液以及电磁流变液的测试.测试结果说明,该装置测量各种流变液都是有效的和实用的,且能保证一定的测量精度.  相似文献   
74.
A non-Newtonian rheological model to investigate theoretically the effects of lubricant additives on the steady state performance of hydrodynamically lubricated finite journal bearings is introduced. In this model, the non-Newtonian behavior resulting from blending the lubricant with polymer additives is simulated by Stokes couple stress fluid model. The formed boundary layer at the bearing surface is described through the use of a hypothetical porous medium layer that adheres to the bearing surface. The Brinkman-extended Darcy equations are utilized to model the flow in the porous region. A stress jump boundary condition is applied at the porous media/fluid film interface. A modified form of the Reynolds equation is derived and solved numerically using a finite difference scheme. The effects of bearing geometry, and non-Newtonian behavior of the lubricant on the steady-state performance characteristics such as pressure distribution, load carrying capacity, side leakage flow, and coefficient of friction are presented and discussed. The results showed that lubricant additives significantly increase the load carrying capacity and reduce both the coefficient of friction and the side leakage as compared to the Newtonian lubricants.  相似文献   
75.
油膜水滴是使用冷空气、微量可自然降解油剂和少量水,经复合喷雾法形成可自然分解的、新型绿色切削液.与传统切削液相比,油膜水滴在保护环境,节省资源等方面有很大的优势.通过车削试验,比较和分析不同冷却润滑条件下刀具磨损和已加工表面质量,揭示出雾状油膜水滴绿色切削液的优越性.  相似文献   
76.
Metalworking fluids(MWFs) are classified as hazardous substances. Due to the characteristics of the stable oil–water emulsions, it requires more costly and complicate treatment techniques to remove oil from spent MWFs. Metal organic frameworks(MOFs) are a porous network material used to remove contaminants from environment. One of the most prominent of MOFs is HKUST-1 or Cu-BTC. In this study, the Cu-BTCs were prepared by solvothermal method in various conditions and used as absorbent for removing oil micelles in MWF emulsion. The particle size of all synthesized Cu-BTCs ranged from ≈80 to 400 nm. The ability of all synthesized Cu-BTCs to remove oil micelle was greater than 95% in 60 min, while the capacity of GAC was obtained the result for only 6.8%. The maximum adsorption capacity(q _(max)) of oil micelles on Cu-BTCs was 1666.7 mg·g~(-1). The highest removal capacity of oil micelles in MWF emulsion is greater than 99% in 24 h by using Cu-BTCs washed with either butanol or ethanol.  相似文献   
77.
赵春伟  彭向和 《功能材料》2012,43(15):2098-2101
采用ANSYS有限元软件,计算了磁流变液单链在剪切过程中的力学特性,并以此为基准分别与基于简化偶极子模型和基于不简化偶极子模型的结果进行了比较。结果表明,简化偶极子模型在描述磁流变液力学特性方面具有较高的精度,但由其得到的剪切屈服应力略低于有限元计算结果。这对于改进偶极子模型以建立磁流变液性能更精确快捷的多层次描述方法,进而设计高性能磁流变液具有重要的意义。  相似文献   
78.
79.
In this study, the analysis of nonlinear stability with viscoelastic ferromagnetic fluids as working media is performed by finite-amplitude perturbations. The solution of the resulting nonautonomous system of the Lorenz model (generalized Khayat–Lorenz model of four modes) is obtained numerically to measure the amount of heat transport. The effects of elastic parameters, Prandtl number, modulation parameters, buoyancy magnetic parameter, and nonbuoyancy magnetic parameter on heat transport are studied. Heat transport is quantified through the average Nusselt number, which is determined by solving the scaled Lorenz model. As limiting cases of the study, the results of Newtonian, Maxwell, Rivlin–Ericksen fluids are determined. The results obtained have been presented graphically.  相似文献   
80.
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