Kazemi, Ahmad Norouzi, Mahmood Nejad, Ali Abbas Kim, Mirae Kim, Kyung Chun Kim, Seo Gyun 2024-01-19T08:34:21Z 2024-01-19T08:34:21Z 2023-09-07 2023-09 0263-8762 https://pubs.kist.re.kr/handle/201004/113320 This study experimentally examined the immiscible viscoelastic Saffman-Taylor instability (STI) in porous media. The viscoelastic displacing fluids are solutions of glycerin, water, and polyacrylamide with concentrations of 100, 200, and 400 ppm, and the immiscible displaced fluids are silicone oils with different viscosities. The viscosity of viscoelastic liquids is rather constant, so they could be considered Boger liquids The main innovative aspect of the present study is the analysis of the role and contribution of the first normal stress differ-ence and elongational viscosity in the immiscible viscoelastic displacement. In this study, instead of using the simple geometry of the Hele-Shaw cell, some more applied results for viscoelastic STI in the low permeability transparent packed bed porous media have been presented. Another novel aspect of the current study is the analysis of the effect of different parameters, such as elasticity, flow rate, and viscosity ratio, on the viscoelastic STI for the case of immiscible displacement, experimentally. The results of the injection of Boger li-quids were compared with the injection of equivalent Newtonian fluids to investigate the effect of fluid elasticity. Furthermore, the effects of flow rate and viscosity ratio on the flow instability were studied in detail by analyzing images of the propagation of finger-like patterns and the results of mixing length and sweep efficiency. The results indicate that the contribution of the first normal stress difference to the stabilizing effect of polymeric ad-ditives is less than 18% for the different scenarios of Boger liquid injection. Thus, the elongational viscosity of displacing fluid has the main role in enhancing the sweeping of the displaced phase. When decreasing the polymer concentration and increasing the flow rate, the contribution of the elongational viscosity on STI can become more important compared to the first normal stress difference. & COPY; 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved. English Institute of Chemical Engineers An experimental study on the role and contribution of the first normal stress difference and elongational viscosity in immiscible viscoelastic Saffman-Taylor instability Article 10.1016/j.cherd.2023.07.036 1 Chemical Engineering Research and Design, v.197, pp.211 - 227 Chemical Engineering Research and Design 197 211 227 N scie scopus 001051675200001 2-s2.0-85166631216 Engineering, Chemical Engineering Article VISCOUS FINGERING INSTABILITY MISCIBLE DISPLACEMENTS SIMULATION OPTIMIZATION STABILITY Saffman-Taylor instability Fingering Immiscible Porous media Glass beads Shear-thinning Polyacrylamide Sweep efficiency Mixing length