Low-order modeling of resonance for fixed-valve micropumps based on first principles

Abstract

Micropumps that utilize fixed-valves, i.e., valves having no moving parts, are relatively easy to fabricate and inherently reliable due to their simplicity. Since fixed-valves do not close, pumps based on them need to operate in a well-designed resonant mode in order to attain flow rates and pressures comparable with other designs. However, no methodology currently exists to efficiently investigate all the design parameters including valve size to achieve optimal resonant response. A methodology that addresses this problem is 1) the determination of optimal parameters including valve size with a low-order linear model capable of nonempirical prediction of resonant behavior, and 2) the independent determination of the best valve shape for maximal valve action over a target Reynolds number range. This study addresses the first of these two steps. The hypothesis of this study is that the resonant behavior of a fixed-valve micropump can be accurately predicted from first principles, i.e., with knowledge only of geometric parameters and physical constants. We utilized a new low-order model that treats the valves as straight rectangular channels, for which the unsteady solution to the Navier-Stokes equations is exact and with which the problem was linearized. Agreement with experiment using pump-like devices with valves replaced by straight channels was found to be excellent, thereby demonstrating the efficacy of the model for describing all aspects of the pump except actual valves. Agreement with experiment using pumps with Tesla-type valves was within 20 percent. With such accuracy and without the need for empirical data, the model makes possible reliable, efficient investigation and optimization of over 30 geometric and material parameters.

A Digitally Controllable Polymer-Based Microfluidic Mixing Module Array

“…Because microfluidic devices are required to be transparent and chemically inert for many bio-optical detection applications, we chose PMMA as the major structural material. Multiple mixing modules, which each contained two vortex micropumps, two Tesla valves [35,36] and an active micromixer (Figure 2(a)), were fabricated in a single microfluidic device using our process described in Methods; and a fabricated microfluidic device (top view dimensions: 42.5 mm × 60 mm) integrated with three mixing modules is shown in Figure 2(b). Each module was utilized to supply a chemical or reagent with a regulated concentration of the additive components.…”

“…It should be mentioned that the Tesla microvalves (Figure 2(c)) located at the channel sections between the pumps and the mixers were applied to reduce potential backward flow since the backward fluidic resistance of the Tesla valve was comparatively higher than the forward one [36]. We performed computational analysis on the fluid flow in a Tesla valve to verify the flow resistance in different flow directions using commercially available software (COMSOL Multiphysics, COMSOL, Burlington, MA, USA).…”

A Glucose Biofuel Cell Equipped in the Fluid Reservoir of a Polyimide Diaphragm Micropump

“…Micropumps fabricated with MEMS technology have been considered for use in such fuel transport mechanisms [16][17][18][19][20][21][22][23][24][25][26][27]. Liu et al reported polyimide (PI) diaphragm micropumps (15 × 15 mm 2 ) fabricated using MEMS technology [22].…”

An Integrated Pumping and Mixing Device

“…Furthermore, the soft diaphragm is compatible with the pumping of a liquid because liquid flow has high resistance and high kinetic energy. The flow rectification principles of valveless micropumps are usually based on the modification of the physical properties of fluids (5) or on flow-directing effects such as those found in diffuser elements (6)- (8) and Tesla elements (9) . Recently, a new channel structure to rectify flow without valves has been proposed (10)- (12) .…”