{"title":"幂律流体在轴向变化几何形状填充毛细血管中的自发渗吸","authors":"Shabina Ashraf , Karan Gupta","doi":"10.1016/j.jnnfm.2025.105442","DOIUrl":null,"url":null,"abstract":"<div><div>Imbibition of wetting fluids in confined pore spaces is a ubiquitous phenomenon in nature. Several attempts have been made to understand the invasion of Newtonian fluids in capillaries. The imbibition of non-Newtonian fluids, however, is relatively less explored owing to the dynamic shear rate during the imbibition process. In this work, we develop equations governing the displacement of one power-law fluid with another power-law fluid in axially diverging and converging capillaries. Using lubrication approximation, the governing equations in one-dimension are developed to model the advancing interface with time for various combinations of shear-thinning, shear-thickening, and Newtonian fluids. For this imbibition phenomenon, we explore the effect of imbibing and residing fluid power-law indices, their time scales, interfacial properties, and the impact of the geometric parameters. The developed equations serve as a comprehensive mathematical model, and the self-imbibition relations available in literature can be retrieved from the developed model by considering special cases. We also identify early and late regimes of flow where the viscous resistance of either the imbibing or the residing fluid dominates the imbibition. This study will help design geometrical parameters for pore space with desired flow properties, and has wide applications in microfluidics.</div></div>","PeriodicalId":54782,"journal":{"name":"Journal of Non-Newtonian Fluid Mechanics","volume":"343 ","pages":"Article 105442"},"PeriodicalIF":2.8000,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Spontaneous imbibition of power-law fluids in filled capillaries of axially varying geometries\",\"authors\":\"Shabina Ashraf , Karan Gupta\",\"doi\":\"10.1016/j.jnnfm.2025.105442\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Imbibition of wetting fluids in confined pore spaces is a ubiquitous phenomenon in nature. Several attempts have been made to understand the invasion of Newtonian fluids in capillaries. The imbibition of non-Newtonian fluids, however, is relatively less explored owing to the dynamic shear rate during the imbibition process. In this work, we develop equations governing the displacement of one power-law fluid with another power-law fluid in axially diverging and converging capillaries. Using lubrication approximation, the governing equations in one-dimension are developed to model the advancing interface with time for various combinations of shear-thinning, shear-thickening, and Newtonian fluids. For this imbibition phenomenon, we explore the effect of imbibing and residing fluid power-law indices, their time scales, interfacial properties, and the impact of the geometric parameters. The developed equations serve as a comprehensive mathematical model, and the self-imbibition relations available in literature can be retrieved from the developed model by considering special cases. We also identify early and late regimes of flow where the viscous resistance of either the imbibing or the residing fluid dominates the imbibition. This study will help design geometrical parameters for pore space with desired flow properties, and has wide applications in microfluidics.</div></div>\",\"PeriodicalId\":54782,\"journal\":{\"name\":\"Journal of Non-Newtonian Fluid Mechanics\",\"volume\":\"343 \",\"pages\":\"Article 105442\"},\"PeriodicalIF\":2.8000,\"publicationDate\":\"2025-06-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Non-Newtonian Fluid Mechanics\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0377025725000618\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MECHANICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Non-Newtonian Fluid Mechanics","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0377025725000618","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MECHANICS","Score":null,"Total":0}
Spontaneous imbibition of power-law fluids in filled capillaries of axially varying geometries
Imbibition of wetting fluids in confined pore spaces is a ubiquitous phenomenon in nature. Several attempts have been made to understand the invasion of Newtonian fluids in capillaries. The imbibition of non-Newtonian fluids, however, is relatively less explored owing to the dynamic shear rate during the imbibition process. In this work, we develop equations governing the displacement of one power-law fluid with another power-law fluid in axially diverging and converging capillaries. Using lubrication approximation, the governing equations in one-dimension are developed to model the advancing interface with time for various combinations of shear-thinning, shear-thickening, and Newtonian fluids. For this imbibition phenomenon, we explore the effect of imbibing and residing fluid power-law indices, their time scales, interfacial properties, and the impact of the geometric parameters. The developed equations serve as a comprehensive mathematical model, and the self-imbibition relations available in literature can be retrieved from the developed model by considering special cases. We also identify early and late regimes of flow where the viscous resistance of either the imbibing or the residing fluid dominates the imbibition. This study will help design geometrical parameters for pore space with desired flow properties, and has wide applications in microfluidics.
期刊介绍:
The Journal of Non-Newtonian Fluid Mechanics publishes research on flowing soft matter systems. Submissions in all areas of flowing complex fluids are welcomed, including polymer melts and solutions, suspensions, colloids, surfactant solutions, biological fluids, gels, liquid crystals and granular materials. Flow problems relevant to microfluidics, lab-on-a-chip, nanofluidics, biological flows, geophysical flows, industrial processes and other applications are of interest.
Subjects considered suitable for the journal include the following (not necessarily in order of importance):
Theoretical, computational and experimental studies of naturally or technologically relevant flow problems where the non-Newtonian nature of the fluid is important in determining the character of the flow. We seek in particular studies that lend mechanistic insight into flow behavior in complex fluids or highlight flow phenomena unique to complex fluids. Examples include
Instabilities, unsteady and turbulent or chaotic flow characteristics in non-Newtonian fluids,
Multiphase flows involving complex fluids,
Problems involving transport phenomena such as heat and mass transfer and mixing, to the extent that the non-Newtonian flow behavior is central to the transport phenomena,
Novel flow situations that suggest the need for further theoretical study,
Practical situations of flow that are in need of systematic theoretical and experimental research. Such issues and developments commonly arise, for example, in the polymer processing, petroleum, pharmaceutical, biomedical and consumer product industries.