Dusty plasma actuators: “Powder-phobic” walls to mitigate clogging in granular flows

Abstract

Clogging is a thornier problem for many production environments run by granular flows. The cure? Purging and cleaning the pipelines continuously. Although simple and certainly effective, such mechanical operations indicate that there is no pat answer to this challenge. Yet, stopping the line jeopardizes the reliability and predictability of production environments — two pivotal concerns for many industrial sectors, such as new energy systems based on granular media.

Here, we propose the use of electric forces to clear the granular material adhered to the pipeline walls. The charge injected from the electrodes is transferred to the grains that eventually repel each other and the electrodes. To that end, we used a dielectric barrier discharge setup, with fine powders settling on the surface. Experiments monitored the powder mass ejected from the surface, exploring the role of the particle size (from 15 to 80 microns) and the frequency of the electric signal (from 2 to 500 Hz).

The results left no doubt about the potential of these settings. All the tests, irrespective of the frequency and particle sizes, led to clean surfaces with no trace of particles — as general trend, higher frequencies result in faster cleaning. Particle size also plays a role; it modulates the powder removal rate. Importantly, we found an operational regime for frequencies of the electric stimulus around 100 Hz in which all the powder samples were thrust efficiently (in a minimal time window) and homogeneously (within similar time windows, regardless of the particle size).

Undoubtedly, the practicality of using electrical forces to prevent particles from adhering to the pipeline walls opens new avenues for designing robust and reliable pumping systems — a long-standing demand for an ample palette of engineering processes that require transporting and storing cohesive granular media.