{"title":"Thermal design of a non-isothermal microfluidic channel for measuring thermophoresis","authors":"Namkyu Lee , Simone Wiegand","doi":"10.1016/j.ijheatmasstransfer.2024.125871","DOIUrl":null,"url":null,"abstract":"<div><p>Thermophoresis describes mass transport in a non-isothermal temperature field and thus provides a fundamental understanding of the behavior of colloidal particles. Various methods have been proposed for measuring the Soret coefficient, a representative value of thermophoresis. In particular, microscopic channels are an emerging method as they shorten the equilibrium time and allow direct observation of the particles. However, little emphasis has been placed on the simultaneous consideration of fluid dynamics, heat transfer, and mass transfer characteristics within the microfluidic channel, despite the simultaneous presence of natural convection and thermodiffusion phenomena. In this study, we present a novel approach to address this gap by introducing a <em>figure of merit</em>, which incorporates essential parameters to accurately characterize a specific cell configuration. This <em>figure of merit</em> allows for the identification of a reliable measurement range in a microfluidic channel with a temperature gradient, while accounting for fluid dynamics, heat transfer, and mass transfer characteristics. The proposed approach is validated through rigorous simulations and experiments, enabling an evaluation of the impact of <em>figure of merit</em>-derived parameters on the measurement channel. The findings from our study demonstrate that the <em>figure of merit</em> serves as a representative measure for stable thermophoretic measurements in a microfluidic channel. Moreover, we propose a threshold value that signifies the transition from a diffusion-dominant to a convection-dominant field.</p></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":null,"pages":null},"PeriodicalIF":5.0000,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Heat and Mass Transfer","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0017931024007026","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Thermophoresis describes mass transport in a non-isothermal temperature field and thus provides a fundamental understanding of the behavior of colloidal particles. Various methods have been proposed for measuring the Soret coefficient, a representative value of thermophoresis. In particular, microscopic channels are an emerging method as they shorten the equilibrium time and allow direct observation of the particles. However, little emphasis has been placed on the simultaneous consideration of fluid dynamics, heat transfer, and mass transfer characteristics within the microfluidic channel, despite the simultaneous presence of natural convection and thermodiffusion phenomena. In this study, we present a novel approach to address this gap by introducing a figure of merit, which incorporates essential parameters to accurately characterize a specific cell configuration. This figure of merit allows for the identification of a reliable measurement range in a microfluidic channel with a temperature gradient, while accounting for fluid dynamics, heat transfer, and mass transfer characteristics. The proposed approach is validated through rigorous simulations and experiments, enabling an evaluation of the impact of figure of merit-derived parameters on the measurement channel. The findings from our study demonstrate that the figure of merit serves as a representative measure for stable thermophoretic measurements in a microfluidic channel. Moreover, we propose a threshold value that signifies the transition from a diffusion-dominant to a convection-dominant field.
期刊介绍:
International Journal of Heat and Mass Transfer is the vehicle for the exchange of basic ideas in heat and mass transfer between research workers and engineers throughout the world. It focuses on both analytical and experimental research, with an emphasis on contributions which increase the basic understanding of transfer processes and their application to engineering problems.
Topics include:
-New methods of measuring and/or correlating transport-property data
-Energy engineering
-Environmental applications of heat and/or mass transfer