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2015),"Surface and wear mechanisms analysis of phosphorous-free and conventional engine lubricants on cylinder liner and piston rings surfaces", Industrial Lubrication and Tribology, Vol. 67 Iss 5 pp. 441-448 http://dx.(2015),"A new logarithmic profile model and optimization design of cylindrical roller bearing", Industrial Lubrication and Tribology, Vol. 67 Iss 5 pp. 498-508 http://dx.If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -The purpose of this publication is to determine the influence of selected factors on the durability and the tightness of ferrofluid seals working in water environments. Ferromagnetic fluid (FF) seals are one of the most common applications of magnetic fluid. New applications can be developed by extending the capabilities of these seals in fluid environments, especially in water. Design/methodology/approach -Tests were performed using ferrofluids with differing physical properties like density, dynamic viscosity and saturation magnetization. Working conditions, such as water pressure and peripheral speed, were taken into account. Findings -A mathematical description which allows the selection of an appropriate ferrofluid and the determination of the operating parameters of an FF seal was developed. Originality/value -This study concerns the influence of peripheral speed, water pressure and magnetic fluid properties on seal tightness.

Magnetic fluid seals are among the most common applications of ferrofluids. In such seals, the torque friction results only from the internal friction in the fluid and there is no direct contact between seal elements. Despite this, the heat generated during operation can be significant due to the low volume of the ferrofluid in the seal and high rotational speeds. The difficulty in calculating the torque friction is because the ferrofluid is a non-Newtonian fluid and changes its viscosity under the influence of a magnetic field. In order to measure torque friction in magnetic fluid seals, a special test stand was built. Tests were performed at different rotation speeds, different temperatures, and two seal stage geometries (rectangle and trapezoid). Numerical simulations were performed to determine the magnetic field distribution in the seal. Dynamic viscosity under the influence of the magnetic field was measured on a rotary rheometer. Mathematical models were compared with laboratory results. The results obtained from the calculations in some cases gave overstated values almost twice in value. An additional correction in the case of ferrofluid viscosity is proposed.

Magnetic fluid seals are among the most common ferrofluid applications. One interesting area is the use of numerical simulations to determine the critical pressure, which is a basic parameter determining the possible range of seal operating pressures. The purpose of this study is to present the method of critical pressure calculations in magnetic fluid seals based on magnetic field numerical simulations, which will provide better results than the methods used previously. It is a relatively simple method and can help to reduce the difference between simulations and experiments. Different seal stage shapes, such as symmetric trapezoidal, asymmetric trapezoidal, and rectangular, were taken into account. The research shows that an increase in the magnetic fluid volume applied at the seal stage and a magnetic saturation increase in the seal gap allow the manufacturing inaccuracy influence to be reduced, meaning that the difference between the simulation and experiment results is smaller. In addition, in this paper, the pressure transfer mechanism between liquid rings of the multistage seal is analyzed to show its influence on the critical pressure value calculated based on simulations.