Investigating the Potential Drag Reduction and Thermal Transport Improvement in Textured Microchannels

Over the past few decades, microscale duct flow has been the key element for many applications, such as drug delivery and microelectronics cooling. To enhance the performance of such systems and to save more energy, looking for new ways to control the hydrodynamic and thermal characteristics of the microchannel flow has been of great interest lately. The aim of this research is to gain a better understanding of the flow physics within microchannels with microtextured walls. Therefore, a set of numerical study has been conducted on the combined effect of flow and heat transfer for spanwise rectangular trenches. The surface microstructures increase the wetting surface area, which is supposed to increase friction (skin drag). Recirculation produced inside the grooves, on the other hand, aids in increasing main flow slippage and lowering pressure drop along the microchannel. It is also worth noting that recirculation creates a negative pressure difference in the opposite direction of the flow (pressure drag). The geometrical parameters of the trenches have a significant impact on the trade-off between the drag reducing and drag increasing factors in textured microchannel flow, which is addressed in this research. Furthermore, the textures disrupt the thermal boundary layer, which can boost thermal transport through recirculation mixing. However, the stagnant fluid trapped within the grooves has weak convective heat transfer. So far, the results have been promising and a drag reduction of about 25% has been reported for wide trenches at low Reynolds numbers. Thermal transport enhancement is also possible for some tested geometries when the flow has not achieved the thermally fully development.

Design and Analysis of Microchannel for Plasma Separation from Blood

Microchannel device is important and having great use in field of biological research. The micro channels having some advantages like reduction in the sample processing time, consumption of costly reagents and sample volumes. The current work for microchannel is based on the Zwiefach- fung bifurcation law which used to study for separation process. The microchannel based plasma separation is far better and rapid than conventional plasma separation techniques like centrifugation, filtration. Microchannel flow simulation is carried out using CFD software. The analysis is done for different type channel with combination of various sets of different shape and size of obstacles placed along the channel walls. For this analysis we used computational fluid dynamic tool known as COMSOL MULTIPHYSICS 5.0, to study different configurations on pressure and velocity drop. Also, the effect of geometry, cross sectional area are studied. While analysis different obstacles placed along the channel like rectangular, semicircle and triangular are used. The analysis is done for each shape obstacle and observation are recorded while analysis it is observed of that pressure is decreases with increase in number of obstacles.