Effect of shear-thinning on the volume flow rate of power-law fluids in microchannels

This study investigates whether rotational shear inside micro-annular printheads could be used to increase the volumetric throughput of shear-thinning silicone elastomers under geometrically confined flow conditions. The focus is on the extrusion process in direct ink writing. Using CFD simulations, analytical baselines, and microfluidic experiments, we quantify how inner-cylinder rotation affects throughput and possible downstream effects of rotational pre-conditioning. The results show that even moderate rotation can increase volumetric flow at fixed pressure, but this effect depends strongly on geometry and pressure. This effect becomes less noticeable with shrinking annular diameters and saturates at high rotation speeds. The findings establish a baseline for additional research in high-resolution additive manufacturing of medical silicones.