Dynamic Sealing Using Magnetorheological Fluids

Abstract

Micropumps are microfluidic components which are widely used in applications such as chemical analysis, biological sensing and micro-robots. However, one obstacle in developing micropumps is the extremely low efficiency relative to their macro-scale counterparts. This paper presents a dynamic sealing method for external gear pumps to reduce the volumetric losses through the clearance between the tips of gears and the housing by using magneto-rheological (MR) fluids. By mitigating these losses, we are able to achieve high efficiency and high volumetric accuracy with current mechanical architectures and manufacturing tolerances. Static and dynamic sealing using MR fluids are investigated theoretically and experimentally. Two Mason numbers M n (p) and M n (Ω) which are defined in terms of pressure gradient of the flow and velocity of the moving boundary respectively are used to characterize and evaluate the sealing performance. A range of magnetic field intensities is explored to determine optimal sealing effectiveness, where effectiveness is evaluated using the ratio of volumetric loss and friction factor. Finally, we quantify the effectiveness of this dynamic sealing method under different working conditions for gear pumps.

Ferrofluids and bio-ferrofluids: looking back and stepping forward

“…90%) by introducing a magnetorheological fluid between gear and housing providing an efficient dynamic sealing effect, without introducing larger friction, tighter manufacturing tolerances, or vulnerability to vibrations. 788…”

Study on Fatigue Strength of Main Anti-collision Structure of Main Pier

“…The advantages of water transportation are obvious [1][2][3][4][5][6][7]. First of all, the shipping cost is lower [8][9][10], the tonnage of shipping is larger, and the shipping cost and freight rate are lower than that of highway, so it has obvious advantages in bulk cargo transportation; Secondly, ship energy consumption is low [11][12][13]. Among all kinds of transportation modes, road transportation and civil aviation transportation are well-known transportation modes with low energy efficiency; Thirdly, with the rapid economic development of Zhongshan, Jiangmen and other places, and the continuous improvement of port facilities, the number of water transport ships will further increase.…”

A review on multi-physics numerical modelling in different applications of magnetorheological fluids

“…The performances of these applications are found to improve significantly due to the rapid, reversible and controllable characteristics of MR fluids (Wang and Liao, 2011). Examples of these applications are journal bearings (Bompos and Nikolakopoulos, 2011), hydraulic valves (Bullough et al, 2008; Nguyen et al, 2008), micro-pumps (Liang et al, 2018), smart clutches (Ellam et al, 2006; Zhang et al, 2019), rotary MR dampers (Deng et al, 2019; Wang et al, 2019), robotics (Hartzell et al, 2019; Hwang et al, 2019), energy harvesters (Deng and Dapino, 2015; O’Donoghue et al, 2016), rheometers (Allebrandi et al, 2020), human prosthesis (El Wahed and Wang, 2019), engines mounts (Do and Choi, 2015), and hybrid body armours (Son and Fahrenthold, 2012). So far, there have been fewer studies on the employment of MR fluids in these applications compared to research efforts on linear MR dampers (Galindo-Rosales, 2016).…”