A Deformation of a Mercury Droplet under Acceleration in an Annular Groove

Abstract

Microelectromechanical system (MEMS) liquid sensors may be used under large acceleration conditions. It is important to understand the deformation of the liquid droplets under acceleration for the design and applications of MEMS liquid sensors, as this will affect the performance of the sensors. This paper presents an investigation into the deformation of a mercury droplet in a liquid MEMS sensor under accelerations and reports the relationship between the deformation and the accelerations. The Laminar level set method was used in the numerical process. The geometric model consisted of a mercury droplet of 2 mm in diameter and an annular groove of 2.5 mm in width and 2.5 mm in height. The direction of the acceleration causing the droplet to deform is perpendicular to the direction of gravity. Fabrication and acceleration experiments were conducted. The deformation of the liquid was recorded using a high-speed camera. Both the simulation and experimental results show that the characteristic height of the droplets decreases as the acceleration increases. At an acceleration of 10 m/s2, the height of the droplet is reduced from 2 to 1.658 mm, and at 600 m/s2 the height is further reduced to 0.246 mm. The study finds that the droplet can deform into a flat shape but does not break even at 600 m/s2. Besides, the properties of the material in the domain surrounding the droplet and the contact angle also affect the deformation of the droplet. This work demonstrates the deformation of the liquid metal droplets under acceleration and provides the basis for the design of MEMS droplet acceleration sensors.

Formation of Mercury Droplets at Ambient Conditions through the Interaction of Hg(II) with Graphene Quantum Dots

“…9 Very recently, it has been shown that a Hg droplet can deform into a flat shape but does not break even at an acceleration rate of 600 m/s 2 . 10 The last 2 decades witnessed an enormous number of publications on synthesis and applications of metallic nanoparticles particularly Au, Ag, and other noble metals. 11−15 However, Hg is not the choice of metal for the researchers in the design of synthesis and applications because of its toxicity.…”

“…The Hg liquid expands and contracts while varying the temperature due to its high coefficient of expansion and surface tension. , Although cinnabar (HgS) is the major source for the production of metallic Hg, it is also available in small quantities in other minerals, such as corderoite (Hg 3 S 2 Cl 2 ), livingstonite (HgSb 4 S 7 ), montroydite (HgO), and calomel (HgCl). , Another interesting property of Hg is its tendency to coagulate in droplets because of its high surface tension which leads to a great decrease in its evaporating surface. , As a result, its atmosphere life-time is ∼6–24 months which is relatively long in contrast to its ionic species . Very recently, it has been shown that a Hg droplet can deform into a flat shape but does not break even at an acceleration rate of 600 m/s 2 …”

A Capacitive MEMS Inclinometer Sensor with Wide Dynamic Range and Improved Sensitivity

“…Compared with solid-state beam sensors, MEMS sensors that use metal droplets as sensitive elements have the advantage of having a high resistance ability for overload [7][8][9]. Droplets will only be squeezed and deformed under a large acceleration and will soon return to the initial shape after the acceleration is released [10]. By taking advantage of this, Park first proposed a MEMS liquid droplet inclinometer sensor with a mercury droplet as a sensitive element [11].…”