Mitigation of clogging in a microfluidic array via pulsatile flows

Clogging is a common obstacle encountered during the transport of suspensions and represents a significant energy and material cost across applications, including water purification, irrigation, biopharmaceutical processing, and aquifer recharge. Pulsatile pressure-driven flows can help mitigate clogging when compared to steady flows. Here, we study experimentally the influence of the amplitude and the frequency of pulsation on clog mitigation in a microfluidic array of parallel channels using a dilute suspension of colloidal particles. We combine flow rate measurements with direct visualizations at the pore scale to correlate the observed clogging dynamics with the changes in flow rate. We observe that the rearrangement of particles when subject to a dynamic shear environment can delay the clogging of a pore or even remove an existing clog. However, this benefit is drastically reduced at too low frequencies as the pulsatile timescale becomes too large compared to the timescale associated with the clogging. Our experiments also reveal that large amplitude pulsations, which result in periodic flow reversal, can accelerate the clogging of the system through the interaction of adjacent pores. The present study demonstrates that pulsatile flows are a promising method to delay clogging at both the pore and system scale.