A microchannel flow with presence of micro -post arrays on channel top wall

A microchannel flow is considered and the influence of the micro-post arrays and air trapped on velocity and temperature increase of the working fluid is examined experimentally and numerically incorporating 3-D sim-ulations. The channel bottom plate is considered to be smooth and hydrophilic, which moves with a constant velocity, while channel top wall is stationary and it has staggered arrangement of micro-post arrays with hy-drophobic wetting state. An experiment is carried out to validate velocity and temperature predictions while setting simulation conditions in line with the experiments. It is found that the flow field in top channel wall vicinity is influenced by the micro-post arrays; hence, wavy flow field is generated in this region. Flow circulation in the trapped air in between the micro-post arrays influences the heat transfer rates. The Nusselt number reduces slightly with increasing pitch size of the micro-post arrays. In addition, increasing the microchannel height lowers the Nusselt number. The pressure drop between the channel inlet and exit is influenced significantly by the micro-post arrays. Increasing pitch size of the micro-post arrays reduces the pressure drop; however, further increase of the pitch size beyond 12 ?m does not alter the pressure drop across the microchannel.

Automated summary

This study investigates the influence of micro-post arrays and trapped air on velocity and temperature increase of the working fluid in microchannel flow. Experimental results show that micro-post arrays affect the flow field near the channel top wall, while air trapped between the arrays influences heat transfer rates. Additionally, increasing the pitch size of the arrays decreases the Nusselt number, increasing the microchannel height lowers the Nusselt number, and the pressure drop is significantly influenced by the arrays.