Actuation Mechanism of Microvalves: A Review

Abstract

The microvalve is one of the most important components in microfluidics. With decades of development, the microvalve has been widely used in many industries such as life science, chemical engineering, chip, and so forth. This paper presents a comprehensive review of the progress made over the past years about microvalves based on different actuation mechanisms. According to driving sources, plenty of actuation mechanisms are developed and adopted in microvalves, including electricity, magnetism, gas, material and creature, surface acoustic wave, and so on. Although there are currently a variety of microvalves, problems such as leakage, low precision, poor reliability, high energy consumption, and high cost still exist. Problems deserving to be further addressed are suggested, aimed at materials, fabrication methods, controlling performances, flow characteristics, and applications.

Effect of Blade Outlet Angle on the Flow Field and Preventing Overload in a Centrifugal Pump

“…The uniformity of the turbulence distribution reflects the number of vortices in the fluid and the amount of viscous dissipation. A larger turbulent kinetic energy indicates larger turbulent vortices [ 36 ]. Flow separation does not necessarily occur in areas with large turbulent kinetic energies, but occurs in areas with large rates of change in the turbulent kinetic energy and mainly occurs near the blade working surface.…”

Amplified piezoelectrically actuated on-chip flow switching for a rapid and stable microfluidic fluorescence activated cell sorter

“…Compared to many other m-FACS systems, our ow switching based m-FACS device takes advantage of a new fast valving mechanism, which is simple in structure, reliable in ow control, and cost-effective in fabrication and implementation (more than 1 000 000 times valving have been successfully performed so far, using single setup). Overcoming problems of many other microvalves, 51 in addition to cell sorting, the proposed rapid valving principle could further expand its application to many other areas.…”

“…50 However, problems such as complex structure, high cost and leakage are still existing and preventing piezoelectric microvalves from being applied in m-FACS systems. 51 In this work, we demonstrate a new design of amplied piezoelectrically actuated microvalve and applied it to demonstrate an on-chip ow switching based sorting mechanism. A bifurcately congurated microuidic chip and displacement ampliers for piezoelectric actuators have been developed for the construction of the m-FACS system.…”

Numerical Calculation of Energy Performance and Transient Characteristics of Centrifugal Pump under Gas-Liquid Two-Phase Condition

“…It is of great practical value to study the distribution and the mechanism of a gas-liquid two-phase flow in centrifugal pumps, which is especially crucial in the fields of petroleum exploitation, natural gas transportation, and chemical industry [8][9][10]. He et al [11] and Ge et al [12] proposed the numerical simulation method of Computational Fluid Dynamics (CFD) and Population Balance Modeling (PBM) coupling to numerically calculate a gas-liquid two-phase flow on a centrifugal pump, and the numerical simulation results matched the experimental results well, which led to the conclusion that the method is superior to the Eulerian-Eulerian model.…”