受局部热非均衡模型影响的双扩散浮力驱动纳米悬浮的热性能和不可逆性分析

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering Pub Date : 2024-10-15 DOI:10.1016/j.csite.2024.105294

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引用次数: 0

摘要

事实上，由于多孔材料中两种成分（固体和纳米流体）之间存在显著的温度差异，局部热平衡（LTE）并不适用于核反应堆、电子设备、空间装置、地热工程和高导电性泡沫。上述实际应用中可能会出现局部热不平衡（LTNE）的情况。鉴于上述相关性，本研究探讨了 LTNE 模型对装有 TiO2-H2O 纳米流体的流体饱和多孔容器内双扩散自然对流（DDNC）的影响，并在 Forchheimer-Brinkman 扩展达西介质中设置了四个冷却和热通道。动量、热量和质量方程采用有限元法求解。分析了多孔结构中两种成分（纳米流体和固体）的不可逆性。分析结果表明，介质孔隙率的增加会促进流体循环。随着雷利数和介质孔隙率的增加，流体摩擦熵 EnFF,T 显著降低了 1514.16 % 和 872.97 %。很明显，Nuloc,nf、Nuave,nf、Nuloc,s&Nuave,s 会随着浮力和导热率、间隙固体/流体传热系数的增加而显著提高。

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Analysis of thermal performance and irreversibility of double-diffusive buoyancy-driven nano-suspension subject to local thermal non-equilibrium model

In fact, local thermal equilibrium (LTE) would be unsuitable when it comes to nuclear reactors, electronic equipment, space devices, geothermal engineering, and high-conductivity foams, due to prominent temperature discrepancy between the two constituents (solid and nanofluid) in porous material. Local thermal non-equilibrium (LTNE) situation may be considered in above real world applications. In view of above relevance, the effects of LTNE model on double-diffusive natural convection (DDNC) within a fluid-saturated porous container loaded with the TiO₂-H₂O nanofluid and emplacing four cooling and hot channels in Forchheimer-Brinkman-extended Darcy medium have been investigated in the present study. The momentum, heat and mass equations are solved by finite element method. Irreversibility in the two constituents (nanofluid and solid) of the porous structure has been analyzed. The significant outcomes are that fluid circulations enhance due to rise in porosity of the medium. Fluid friction entropy

E n_{F F, T}

ameliorates significantly by 1514.16 % and 872.97 % with increase in Rayleigh number and porosity of the medium. It is clear that

N u_{l o c, n f}, N u_{a v e, n f}

N u_{l o c, s} & N u_{a v e, s}

enhance significantly with rise of buoyancy and thermal conductivity ratio, interstitial solid/fluid heat transfer coefficient.

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来源期刊

Case Studies in Thermal Engineering Chemical Engineering-Fluid Flow and Transfer Processes

CiteScore

8.60

自引率

11.80%

发文量

812

审稿时长

76 days

期刊介绍： Case Studies in Thermal Engineering provides a forum for the rapid publication of short, structured Case Studies in Thermal Engineering and related Short Communications. It provides an essential compendium of case studies for researchers and practitioners in the field of thermal engineering and others who are interested in aspects of thermal engineering cases that could affect other engineering processes. The journal not only publishes new and novel case studies, but also provides a forum for the publication of high quality descriptions of classic thermal engineering problems. The scope of the journal includes case studies of thermal engineering problems in components, devices and systems using existing experimental and numerical techniques in the areas of mechanical, aerospace, chemical, medical, thermal management for electronics, heat exchangers, regeneration, solar thermal energy, thermal storage, building energy conservation, and power generation. Case studies of thermal problems in other areas will also be considered.