Liquid flow through converging microchannels and a comparison with diverging microchannels

Abstract

Diverging and converging microchannels are becoming an important part of microdevices. In this work, an experimental study of liquid flow through converging microchannels is performed and analyzed using results from 3D numerical simulations. Converging microchannels of various configurations: hydraulic diameter (118–177 µm), length (10–30 mm) and convergence angle (4°–12°) are used to measure the pressure drop for a volume flow rate range of 0.5–5 ml min−1 (8.33 10−6–8.33 10−5 kg s−1) using deionised water as the working fluid. It is observed that the pressure drop in a converging microchannel varies non-linearly with the volume flow rate, and inversely with the convergence angle and hydraulic diameter. An equivalent hydraulic diameter is introduced in order to predict the overall pressure drop through the converging microchannel using the established theory for straight microchannels. The equivalent hydraulic diameter of the converging microchannel lies at 1/3.6th of the total length from the narrowest width of the microchannel; compared with 1/3rd for the diverging microchannel. A comparative analysis of flow through diverging and converging microchannels is also performed. It is shown that fluidic diodicity varies asymptotically with the angle and length of microchannels, whereas it increases with the volume flow rate. A theoretical expression for diodicity is also derived. The maximum fluidic diodicity is found to lie between 1.2 and 1.3. The data presented in this work is of fundamental importance and can help in optimizing the design of various microdevices.

Three-dimensional numerical study of flow physics of single-phase laminar flow through diamond (diverging–converging) microchannel

“…δ = 0.5 (symmetric diamond microchannels). That is, in this study we are not considering asymmetric diamond channel to avoid the asymmetric transfer characteristic of a flow passage, or fluidic diodicity [12].…”

“…given case, the characteristic location is obtained at 1/7th of the total length of the microchannel from inlet. This can be explained by diodicity (D) [12] of the microchannel.…”

“…The fundamental flow phenomenon in non-uniform microchannel differs substantially from its uniform cross-section counterpart [9,10]. Diverging-converging microchannels (diamond) are characteristic nonuniform channels and flow in diamond microchannels have numerous applications in medicine, engineering and biology, such as in heat transfer enhancement [11], flow rectification [12], DNA stretching [13], micromixer [14][15][16], particle separation [17], etc. These applications require a thorough, fundamental understanding of the flow physics in diamond microchannels especially from the viewpoint of design optimization.…”

A review of liquid flow and heat transfer in microchannels with emphasis to electronic cooling

“…The shapes of the intermediate side walls in serpentine and raccoon channels are indicated in figure 11. Duryodhan et al [157][158][159] performed experiments involving flow through straightwalled straight-axis microchannels of single unit of converging, diverging or converging-diverging passage under relatively low wall heat flux in the range of 0.3 to 9.5 W/cm 2 . The last one of these three studies clearly established the necessity of conjugate heat transfer modeling for numerical analysis.…”

The flow and heat performance of tree-like network heat sink with diverging–converging channel

“…It is obvious that most of the attention on tree-like network was given to uncover physics of fluid flow through microchannel with uniform cross-section, while flowing through non-uniform microchannels has not received sufficient attention. Diverging-converging micro-channels (diamond) are characteristic non-uniform channels and have numerous applications in medicine, engineering andbiology, such as in flow rectification [17], DNA stretching [18],particle separation [19]. Some studies are carried on flow in diverging-converging channels [20][21][22].…”