Effects of salinity on the onset of elastic turbulence in swirling flow and curvilinear microchannels

Abstract

Elastic turbulence, which is sensitive with geometry and polymer itself, is capable of leading to improved performance of mixing, hear transfer and even oil recovery. Recently, the rheological properties of polymer solutions showed significant effects on the onset of elastic turbulence or instability. However, the variations of rheological properties based on polymer sensitivities such as salinity and its corresponding effects on the elastic turbulence have not been investigated. This work investigates systematically the effects of salinity on the onset of elastic turbulence in both swirling flow and curvilinear microchannels. The variations of statistical properties, such as probability distribution functions and spectra profiles of inject power, were analyzed for characterization. The onset conditions of elastic turbulence are postponed by high salinity, which was consistent with the mixing performance in curvilinear microchannel. A salinity independent power-law exponent at values of-4.3 was observed in fully developed elastic regime for all of polymer solutions. Particularly, the diffusion of fluorescein at low flow rate in microchannel is possible due to the existence of steady secondary flow before the onset of elastic instability.

Short and long-range cyclic patterns in flows of DNA solutions in microfluidic obstacle arrays

“…Our results are in agreement with studies showing an increased degree of elastic effects with reduced salt 40,49 and polymer concentrations. 28 Interestingly, Gulati et al observed no vortex formation at 40 μg mL −1 λ DNA but increasing vortex formation with higher Wi (corresponding to the Deborah number used in our work) for 400 μg mL −1 λ DNA, similar to the lack of waves for our 50 μg mL −1 sample but waves occurring at C ≥ 100 μg mL −1 .…”

Surface functionalized Fe3O4‐polyacrylamide dispersion for improved oil recovery at harsh conditions

“…It is known that most oil reservoirs consist of significant divalent ions such as strontium, barium, magnesium, and calcium [82][83][84] with reservoir temperature up to 120 C. 27,37 These conditions significantly reduced the applicability of injected dispersions during oil recovery due to the lack of stability caused by particle aggregation/agglomeration. Most recent research on nanotechnology-enhanced EOR focused on the effect of salinity and/or temperature without investigating the impact of surface functionalization and their influence on stability.…”