Numerical and Experimental Investigation of AC Electrothermal Flow Pumping in Microfluidic Devices: Influence of Electrode Pair Count on Velocity

In recent years, there has been significant interest in the use of alternating current electrothermal (ACET) flow in microfluidics due to its ease of use and ability to provide precise results. This research aims to examine the effect of various parameters on the ACET pumping of fluid within microchannels. These parameters include electrode pair sizes (both wide and narrow), channel height, gap between electrode pairs, applied voltage, and the number of electrode pairs in a microchannel. Numerical simulations are conducted to achieve these objectives, and experimental tests are carried out to validate the numerical results. The Design Expert software is utilized to optimize and reduce the number of simulation runs, which are performed using a newly developed ACET solver in OpenFOAM. Furthermore, a global correlation is derived between the outlet ACET flow velocity and the other parameters involved in the problem. Additionally, an ACET test device is constructed to experimentally validate the accuracy of the results obtained by a novel developed solver in OpenFOAM. The results indicate that for microchannels with the desired dimensions, the maximum flow velocity agrees well with the numerical solution in the same region. It is observed that increasing the gap between small and large electrodes by three times reduces the flow velocity by 40 %, while increasing the size of the small electrode by four times reduces the flow velocity by 288 %. Moreover, increasing the height of the microchannel up to a certain amount leads to a 40 % increase in the flow velocity, beyond which the flow velocity remains almost constant.