Entropy Analysis of Nano fluid in Open Cell Copper Metal Foam

Abstract

Entropy analysis plays a crucial role in understanding the thermodynamic behavior and energy conversion processes in various thermal systems. Previous studies have explored various techniques, such as local and global entropy generation analysis and exergy analysis, to quantify entropy generation and identify optimization strategies. The research findings highlight the significance of entropy analysis in optimizing the performance of porous media-based systems in the presence of Nano fluids which enhance heat transfer. The study\'s findings show how entropy analysis might improve heat transfer by improving the functionality of systems based on porous media. With different pore densities (PPI = 10, 20, and 40), nanoparticle mass fractions (from 0.0 to 0.5 wt%), and Reynolds numbers (Re = 414-1119), the impact of metal foam on entropy formation was investigated. The total amount of nanofluids first decreases, then increases with an increase in mass fraction, and finally decreases with an increase in PPI. The least amount of total entropy is produced by nanofluids with = 0.3 wt% under PPI = 40. It demonstrates that in this ideal scenario, the irreversible loss between the route and the working fluid may be reduced, actively reducing the system\'s entropy generation.

Introduction

I. INTRODUCTION

In recent years, there has been a growing interest in utilizing Nano fluids as a heat transfer medium in thermal systems. Nano fluids, which are colloidal suspensions of nanoparticles in a base fluid, have demonstrated enhanced thermal conductivity [1-3] and convective heat transfer properties compared to traditional fluids [9]. Many researchers have developed some empirical formulas of thermal conductivity [4-7]. The detailed review of the research on the preparation methods and thermal property parameters of nanofluids was presented in the literature [8]. Moreover, when these Nano fluids flow through porous media, such as porous structures, their heat transfer characteristics further improve due to increased surface area and interaction with the porous matrix [10]. Further, the analysis of entropy in thermal systems is of utmost importance in various engineering applications, as it provides insights into the system's efficiency, irreversibility, and overall performance [11].

Understanding and quantifying the entropy generation and transfer mechanisms in thermal systems with Nano fluids flowing through porous media are crucial for optimizing the system's performance and identifying potential areas for improvement. Entropy analysis provides a comprehensive approach to assess the irreversibilities and energy losses within the system, allowing engineers to design more efficient and sustainable systems [12]. After the ground-breaking work of Bejan [11] many scholars re-examined porous systems from the second law perspective. Cong Qi, et al [13] investigated the effects of metal foams with pore densities (20, 30, 40 PPI) on the exergy and entropy of TiO2-water Nano fluids in a heat sink and experimentally studied it. Nano fluids with concentration of 0.3 wt% exhibited the highest exergy efficiency, and the metal foam with PPI = 40 showed the smallest entropy generation. M. Sheikholeslami, et al [14] numerically investigated the entropy behavior of Fe3O4-H2O flowing within a porous media under a magnetic force impact considering non-darcy model. The outputs of the simulations showed that increasing permeability makes Bejan number. to decline, boundary layer thickness enhances with a rise of Lorentz force. They also suggested formulas for the estimation of the Bejan number and average Nusselt number. A numerical study of mixed convective flow in porous cavity with Al2O3 Nano fluid in an inclined channel (inclination angle = 0º to 360º) was presented by S. Hussain, et al [15]. The average values of Nusselt number, Bejan number, total entropy generation, entropy generation due to fluid friction and heat transfer showed enhancement with an increase in the inclination angle and had a maximum values at 135º. The entropy generation analysis of three different nanofluids copper, alumina and titania in porous asymmetric micro channel was done by S. Noreen, et al [16]. The copper–water nanofluid and Al2O3 nanofluid showed same enhancement for total entropy generation and Bejan number (Be) while, total entropy generation and Be number of TiO2 nanofluid was lower than copper–water nanofluid and Al2O3 water nanofluid.

Although the carbon based nanoparticles have been used very rarely, Noreen S Akbar, et al [17] analyzed single-wall carbon nanotubes (SWCNT) nanoparticles with water as a base fluid through a ciliated porous medium by preparing mathematical model. An enhancement in Entropy generation was observed with rising values of both Brinkman number and Darcy number and was greater for SWCNT-nanofluids. Numerical investigation of Entropy generation due to conjugate natural convection–conduction heat transfer in a square domain was performed under steady-state condition [18]. The domain composed of square porous cavity heated by a triangular solid wall and saturated with a CuO–water nanofluid. It was found that the addition of nanoparticles increases the entropy generation, also the largest solid thickness and the lower wall thermal conductivity ratio manifest better thermal performance.

The various applications of graphene in different types of heat exchangers, electronic devices challenges and opportunities, by highlighting the advantages of using graphene was described by K. Natesan, et al [19]. An experimental investigation had been conducted for studying the effects of graphene nanofluids by M. Fares, et al [20] on the convective heat transfer in a vertical shell and tube heat exchanger. A maximum increase in the heat transfer coefficient of 29% was observed using 0.2% graphene/water nanofluids. Furthermore, the mean thermal efficiency of the heat exchanger was enhanced by 13.7%. To analyze thermo-physical properties of aqueous Graphene Nanoplatelet (GNP) at various mass concentrations of GNPs, an experimental investigation was performed within a microchannel at various heat flux and Reynolds number by M.M. Sarafraz et al [21]. The enhancement in the thermal performance of the system was attributed to the thermophoresis effect, Brownian motion and the enhancement in the thermal conductivity of the nanofluid due to the presence of the GNP nanoplatelets. These transport phenomenons (thermophoresis effect, Brownian motion) are well described by S. Belorkar, et al [22].

II. SPECIFICATIONS

Table I Specifications

III. EXPERIMENTAL SETUP

The four basic components of an experimental setup are a heating section, a flow section, a heat exchanger, and a data collection device. A heating section with the following outside measurements: 165*120*40 mm is made out of a fiber sheet that contains open-cell copper-porous metal foam.

Conclusion

Experimental investigation is being done on the entropy generation in thermal systems with copper metal foam that has a range of pore densities (PPI = 10, 20, and 40) and nanoparticle mass fractions (0.0 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, and 0.5 0.0 wt%). The following are some important conclusions: 1) According to the graph, frictional entropy generation in nanofluids is significantly higher than in pure water and grows with proportion. The formation of frictional entropy is greatly influenced by the Reynolds number. 2) The total amount of nanofluids first declines, then increases with an increase in mass fraction and decreases with an increase in PPI. The least amount of total entropy is produced by nanofluids with = 0.3 wt% under PPI = 40. 3) The frictional entropy generation of nanofluids increases with the increase of mass fraction and Reynolds number under the combined action of working fluid density and mass flow rate. 4) It shows that under this ideal circumstance, the irreversible loss between the channel and the working fluid can be decreased, which actively contributes to lowering the system\'s entropy creation. 5) According to the thermal entropy generation formula, the use of nanofluids can increase the convection heat transfer coefficient of the channel. This is because the thermal conductivity and Nusselt number product, which is also a manifestation of improved heat transport of nanofluids, can be raised in the denominator of the thermal entropy formula. 6) While increasing pressure drop, metal foam has a greater potential for heat transfer. 7) The following tasks entail examining the impact of the local metal foam filling and different rotation angles on the heat sink.

References

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Copyright

Copyright © 2023 Punit M. Bannagare, Prof. R S Mohod. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.