Viscoelastic effects of immiscible liquid–liquid displacement in microchannels with bends

The displacement flow of an organic Newtonian fluid by a pure viscoelastic aqueous solution is experimentally investigated inside circular microchannel 200 μm. Displacement commonly encountered in many industrial applications, from cleaning and decontamination to enhanced oil recovery. In this study, with no shear-thinning properties (known as Boger fluid) made up polyethylene oxide, glycol, zinc chloride used displace immiscible liquid (silicone oil). results were compared against those similar density viscosity the one. High-speed imaging track both residual film thickness phase interface deformations during displacement. It found that displacing produces thinner displaced fluid, particularly at high capillary numbers. A correlation proposed for thickness, which includes Weissenberg number case. After front, becomes unstable two modes instability identified. case are core shifting, also present case, periodic elastic stresses Additionally, shape interfacial instabilities switches freely asymmetric axisymmetric ones throughout flow. frequency increases rate. was bends downstream observation point affect instabilities.