Harsha S V, Chandra Shekara G, Hemanth Kumar C, Mayur D H
{"title":"利用 LTNE 模型对纳米流体流经水平多孔通道的混合对流进行稳定性分析","authors":"Harsha S V, Chandra Shekara G, Hemanth Kumar C, Mayur D H","doi":"10.1007/s12217-024-10140-w","DOIUrl":null,"url":null,"abstract":"<div><p>The present article investigates the stability of the mixed convective flow of nanofluids through a horizontal porous channel under the influence of a constant pressure gradient, utilizing the local thermal nonequilibrium (LTNE) model. The governing equations are derived by integrating the Oberbeck-Boussinesq theory with the Darcy model for low-permeability porous media. Using linear stability theory, we formulate a generalized eigenvalue problem (GEP) in terms of non-dimensional parameters. The weighted residual Galerkin method (WRGM) is then employed to solve the GEP, and the results are compared analytically. The findings of this study reveal that a horizontal pressure gradient initiates convection in an oscillatory mode rather than a stationary one. We identify that the interphase scaled heat transfer coefficient, thermal diffusivity ratio, nanoparticle volume fraction, and horizontal pressure gradient collectively influence the onset of oscillatory convection. Notably, our investigation into Titanium Oxide (TiO<sub>2</sub>), Copper Oxide (CuO), and Aluminum Oxide (Al<sub>2</sub>O<sub>3</sub>) nanoparticles reveals that TiO<sub>2</sub> particles enhance the onset of convection compared to Al<sub>2</sub>O<sub>3</sub> and CuO, while CuO nanoparticles exhibit greater thermal stability. Further, the nonlinear stability analysis is performed using the method of lines in conjunction with regularization and finite difference schemes for spatial derivatives. The time evolution of all field variables is simulated through the visualization of streamlines and isotherms, providing a detailed representation of the system's dynamics. Additionally, the critical values of the Darcy-Rayleigh number are computed and compared for both linear and nonlinear stability analyses. The results demonstrate the equivalence of linear instability and nonlinear stability boundaries in the absence of a constant pressure gradient, whereas subcritical instability becomes apparent in its presence. These insights advance our understanding of mixed convective flows in porous media, with potential implications for various engineering and environmental applications.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 6","pages":""},"PeriodicalIF":1.3000,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Stability Analysis of Mixed Convection of Nanofluid Flow Through a Horizontal Porous Channel Using LTNE Model\",\"authors\":\"Harsha S V, Chandra Shekara G, Hemanth Kumar C, Mayur D H\",\"doi\":\"10.1007/s12217-024-10140-w\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The present article investigates the stability of the mixed convective flow of nanofluids through a horizontal porous channel under the influence of a constant pressure gradient, utilizing the local thermal nonequilibrium (LTNE) model. The governing equations are derived by integrating the Oberbeck-Boussinesq theory with the Darcy model for low-permeability porous media. Using linear stability theory, we formulate a generalized eigenvalue problem (GEP) in terms of non-dimensional parameters. The weighted residual Galerkin method (WRGM) is then employed to solve the GEP, and the results are compared analytically. The findings of this study reveal that a horizontal pressure gradient initiates convection in an oscillatory mode rather than a stationary one. We identify that the interphase scaled heat transfer coefficient, thermal diffusivity ratio, nanoparticle volume fraction, and horizontal pressure gradient collectively influence the onset of oscillatory convection. Notably, our investigation into Titanium Oxide (TiO<sub>2</sub>), Copper Oxide (CuO), and Aluminum Oxide (Al<sub>2</sub>O<sub>3</sub>) nanoparticles reveals that TiO<sub>2</sub> particles enhance the onset of convection compared to Al<sub>2</sub>O<sub>3</sub> and CuO, while CuO nanoparticles exhibit greater thermal stability. Further, the nonlinear stability analysis is performed using the method of lines in conjunction with regularization and finite difference schemes for spatial derivatives. The time evolution of all field variables is simulated through the visualization of streamlines and isotherms, providing a detailed representation of the system's dynamics. Additionally, the critical values of the Darcy-Rayleigh number are computed and compared for both linear and nonlinear stability analyses. The results demonstrate the equivalence of linear instability and nonlinear stability boundaries in the absence of a constant pressure gradient, whereas subcritical instability becomes apparent in its presence. These insights advance our understanding of mixed convective flows in porous media, with potential implications for various engineering and environmental applications.</p></div>\",\"PeriodicalId\":707,\"journal\":{\"name\":\"Microgravity Science and Technology\",\"volume\":\"36 6\",\"pages\":\"\"},\"PeriodicalIF\":1.3000,\"publicationDate\":\"2024-10-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Microgravity Science and Technology\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s12217-024-10140-w\",\"RegionNum\":4,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENGINEERING, AEROSPACE\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microgravity Science and Technology","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s12217-024-10140-w","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, AEROSPACE","Score":null,"Total":0}
Stability Analysis of Mixed Convection of Nanofluid Flow Through a Horizontal Porous Channel Using LTNE Model
The present article investigates the stability of the mixed convective flow of nanofluids through a horizontal porous channel under the influence of a constant pressure gradient, utilizing the local thermal nonequilibrium (LTNE) model. The governing equations are derived by integrating the Oberbeck-Boussinesq theory with the Darcy model for low-permeability porous media. Using linear stability theory, we formulate a generalized eigenvalue problem (GEP) in terms of non-dimensional parameters. The weighted residual Galerkin method (WRGM) is then employed to solve the GEP, and the results are compared analytically. The findings of this study reveal that a horizontal pressure gradient initiates convection in an oscillatory mode rather than a stationary one. We identify that the interphase scaled heat transfer coefficient, thermal diffusivity ratio, nanoparticle volume fraction, and horizontal pressure gradient collectively influence the onset of oscillatory convection. Notably, our investigation into Titanium Oxide (TiO2), Copper Oxide (CuO), and Aluminum Oxide (Al2O3) nanoparticles reveals that TiO2 particles enhance the onset of convection compared to Al2O3 and CuO, while CuO nanoparticles exhibit greater thermal stability. Further, the nonlinear stability analysis is performed using the method of lines in conjunction with regularization and finite difference schemes for spatial derivatives. The time evolution of all field variables is simulated through the visualization of streamlines and isotherms, providing a detailed representation of the system's dynamics. Additionally, the critical values of the Darcy-Rayleigh number are computed and compared for both linear and nonlinear stability analyses. The results demonstrate the equivalence of linear instability and nonlinear stability boundaries in the absence of a constant pressure gradient, whereas subcritical instability becomes apparent in its presence. These insights advance our understanding of mixed convective flows in porous media, with potential implications for various engineering and environmental applications.
期刊介绍:
Microgravity Science and Technology – An International Journal for Microgravity and Space Exploration Related Research is a is a peer-reviewed scientific journal concerned with all topics, experimental as well as theoretical, related to research carried out under conditions of altered gravity.
Microgravity Science and Technology publishes papers dealing with studies performed on and prepared for platforms that provide real microgravity conditions (such as drop towers, parabolic flights, sounding rockets, reentry capsules and orbiting platforms), and on ground-based facilities aiming to simulate microgravity conditions on earth (such as levitrons, clinostats, random positioning machines, bed rest facilities, and micro-scale or neutral buoyancy facilities) or providing artificial gravity conditions (such as centrifuges).
Data from preparatory tests, hardware and instrumentation developments, lessons learnt as well as theoretical gravity-related considerations are welcome. Included science disciplines with gravity-related topics are:
− materials science
− fluid mechanics
− process engineering
− physics
− chemistry
− heat and mass transfer
− gravitational biology
− radiation biology
− exobiology and astrobiology
− human physiology