{"title":"Heat transfer enhancement for electro-thermo-convection of FENE-P viscoelastic fluid in a square cavity","authors":"Bo Guo , Rong Liu , Xinhui Si","doi":"10.1016/j.ijheatmasstransfer.2024.126390","DOIUrl":null,"url":null,"abstract":"<div><div>This study numerically investigates the heat transfer enhancement for viscoelastic electro-thermo-convection in a two-dimensional differentially heated cavity with injection from below. The flow motion is assumed to be incompressible, which is driven by the Coulomb force and the thermal buoyant force. The polymers are described by the FENE-P model which exhibits typical shear-thinning and elastic properties. Based on the extensibility parameter (<span><math><mi>L</mi></math></span>), the cases are divided into several scenarios, corresponding to weak elasticity with strong shear-thinning, moderate elasticity with moderate shear-thinning, and strong elasticity with weak shear-thinning, respectively. We find that the competition between the shear-thinning and elasticity dominates the flow state and heat transport. The shear-thinning effect tends to facilitate heat transfer, while its elastic properties tend to decrease it. In the scenario of weak elasticity with strong shear-thinning (<span><math><mrow><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>10</mn></mrow></math></span>), the polymer additives significantly improve the heat transfer enhancement (HTE) of the electric field as the polymer viscosity ratio (<span><math><mi>β</mi></math></span>) decreases or Weissenberg number (<span><math><mrow><mi>W</mi><mi>i</mi></mrow></math></span>) increases, where the maximum HTE reaches around 92.1%. The amount of HTE first increases rapidly with <span><math><mrow><mi>W</mi><mi>i</mi></mrow></math></span> but then remains almost constant once a critical <span><math><mrow><mi>W</mi><mi>i</mi></mrow></math></span> is exceeded. However, the HTE significantly decreases in the scenario of strong elasticity with weak shear-thinning (<span><math><mrow><mn>300</mn><mo>≤</mo><mi>L</mi><mo>≤</mo><mn>1000</mn></mrow></math></span>) since the elasticity dominates over the shear-thinning. These heat transfer performances are then corroborated with the boundary layer and kinetic energy budget analysis.</div></div>","PeriodicalId":336,"journal":{"name":"International Journal of Heat and Mass Transfer","volume":"236 ","pages":"Article 126390"},"PeriodicalIF":5.0000,"publicationDate":"2024-11-08","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/S0017931024012195","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
This study numerically investigates the heat transfer enhancement for viscoelastic electro-thermo-convection in a two-dimensional differentially heated cavity with injection from below. The flow motion is assumed to be incompressible, which is driven by the Coulomb force and the thermal buoyant force. The polymers are described by the FENE-P model which exhibits typical shear-thinning and elastic properties. Based on the extensibility parameter (), the cases are divided into several scenarios, corresponding to weak elasticity with strong shear-thinning, moderate elasticity with moderate shear-thinning, and strong elasticity with weak shear-thinning, respectively. We find that the competition between the shear-thinning and elasticity dominates the flow state and heat transport. The shear-thinning effect tends to facilitate heat transfer, while its elastic properties tend to decrease it. In the scenario of weak elasticity with strong shear-thinning (), the polymer additives significantly improve the heat transfer enhancement (HTE) of the electric field as the polymer viscosity ratio () decreases or Weissenberg number () increases, where the maximum HTE reaches around 92.1%. The amount of HTE first increases rapidly with but then remains almost constant once a critical is exceeded. However, the HTE significantly decreases in the scenario of strong elasticity with weak shear-thinning () since the elasticity dominates over the shear-thinning. These heat transfer performances are then corroborated with the boundary layer and kinetic energy budget analysis.
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