Abstract
Although roughness is negligible for laminar flow through tubes in classic fluid mechanics, the surface roughness may play an important role in microscale fluid flow due to the large ratio of surface area to volume. To further verify the influence of rough surfaces on microscale liquid flow and heat transfer, a performance test system of heat transfer and liquid flow was designed and built, and a series of experimental examinations are conducted, in which the microchannel material is stainless steel and the working medium is methanol. The results indicate that the surface roughness plays a significant role in the process of laminar flow and heat transfer in microchannels. In microchannels with roughness characteristics, the Poiseuille number of liquid laminar flow relies not only on the cross section shape of the rough microchannels but also on the Reynolds number of liquid flow. The Poiseuille number of liquid laminar flow in rough microchannels increases with increasing Reynolds number. In addition, the Nusselt number of liquid laminar heat transfer is related not only to the cross section shape of a rough microchannel but also to the Reynolds number of liquid flow, and the Nusselt number increases with increasing Reynolds number.
Highlights
Microscale heat transfer and fluid flow are widely present in micro-electromechanical systems [1], chip laboratories [2, 3], biomedical testing [4], microelectronic chip cooling [5], fuel cells [6], microreactors, and other frontier scientific and technological fields [7, 8]. e research in this field is of great importance at the scientific level for exploring the law of microscale heat and mass transfer
For fluid flow in conventional channels, Poiseuille number is just dependent on the shape of the cross section of the channel according to the theory of classical fluid mechanics [24, 25]
With an increase in the Reynolds number, the roughness results in an increase in the Poiseuille number of liquid laminar flow in the microchannels, indicating that the laminar flow characteristics in rough microchannels differ from those in conventional microchannels
Summary
Microscale heat transfer and fluid flow are widely present in micro-electromechanical systems [1], chip laboratories [2, 3], biomedical testing [4], microelectronic chip cooling [5], fuel cells [6], microreactors, and other frontier scientific and technological fields [7, 8]. e research in this field is of great importance at the scientific level for exploring the law of microscale heat and mass transfer. The effect exerted on heat transfer and fluid flow in microchannels by surface roughness is becoming increasingly prominent [9, 10], and the influence mechanism has attracted attention around the world [9, 11]. The role of rough surfaces in microscale heat transfer and flow has not been fully revealed. E MEMS microchannel heat sink was initially proposed by Tuckerman and Pease [12] in the early 1980s. It possesses the advantages of small size, more area for heat transfer in a limited volume, which contributes to a comparably large heat transfer coefficient.
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