Numerical Heat Transfer and Pressure Drop Studies of Turbulent Al2O3 - Ethylene Glycol/Water Nanofluid Flow in an Automotive Radiator Tube

2015 ◽  
Vol 787 ◽  
pp. 152-156 ◽  
Author(s):  
N. Mohanrajhu ◽  
K. Purushothaman ◽  
N. Kulasekharan
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Ethylene Glycol ◽  
Base Fluid ◽  
Unit Length ◽  
Thermal Characteristics ◽  
Turbulent Regime ◽  
Pumping Power ◽  
Numerical Heat Transfer ◽  
Nano Fluid

Automotive radiators use flattened tubes within which Ethylene Glycol (EG) and Water (W) based nanofluids flow to enhance the heat transfer. Computations were carried out to understand the flow and thermal characteristics of the Aluminium oxide based nanofluids, with EG:W ratio of 60:40 as the base fluid, flowing inside a flattened tube. The flow was maintained in the turbulent regime with the Reynolds number (Re) ranging from 5,000 to 14,000.Investigations were carried out for nano particle concentrations (φ) varying from 1% to 5% of the base fluid by volume. Computations were also carried out for a circular tube to study the influence of tube shape. The nanofluid with φ = 5% increased the Nusselt number values by 40% for the flattened tubes compared to the base fluid at Re =14,000. These estimates are done at constant flow Reynolds number in-line with literature, which necessitated increased inlet velocity, which meant increased pumping power. Pumping power increased with increase in φ and Re. For a constant pumping power per unit length (Pp) of 5W/m the values of average heat transfer coefficient () decreases with increase in φ. The values of for the 2% and 5% nano fluid were lower than the base fluid by 6% and 23.8% respectively. Nanofluid with φ = 1% alone showed a 1.2% higher value than the base fluid indicating the need of further exploration of φ in a closer range.

Numerical Investigation of a Confined Laminar Jet Impingement Cooling of Heat Sources Using Nanofluids

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Orkodip Mookherjee ◽  
Shantanu Pramanik ◽  
Uttam Kumar Kar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Base Fluid ◽  
Strong Dependence ◽  
Jet Impingement ◽  
Effective Density ◽  
Eckert Number ◽  
Maximum Temperature ◽  
Pumping Power

Abstract The thermal and fluid dynamic behavior of a confined two-dimensional steady laminar nanofluid jet impinging on a horizontal plate embedded with five discrete heating elements subjected to a constant surface heat flux has been studied for a range of Reynolds number (Re) from 100 to 400 with Prandtl number, Pr = 6.96, of the base fluid. Variation of inlet Reynolds number produces a significant change of the flow and heat transfer characteristics in the domain. Increasing the nanoparticle concentration (ϕ) from 0% to 4% exhibits discernible change in equivalent Re and Pr caused by the modification of dynamic viscosity, effective density, thermal conductivity, and specific heat of the base fluid. Considerable improvement in heat transfer from the heaters is observed as the maximum temperature of the impingement wall is diminished from 0.95 to 0.55 by increasing Re from 100 to 400; however, the result of increasing ϕ on cooling of the heaters is less appreciable. Self-similar behavior has been depicted by cross-stream variation of temperature and streamwise heat flux in the developed region along the impingement wall up to Re = 300 for ϕ=0% to 4%. But the spread of the respective quantities shows strong dependence on ϕ at Re = 300 with sudden attenuation in magnitude in the developed region of flow. Substantial influence of Re is evident on Eckert number and pumping power. Eckert number decreases, whereas pumping power increases with an increase in Re, and the respective variations exhibit correspondence with power fit correlations.

scholarly journals Experimental investigation of convective heat transfer using ethylene glycol-based nano-fluid

2021 ◽  
Vol 239 ◽  
pp. 00022
Author(s):  
Muhammad Shoaib Rafiq ◽  
Hafiz Muhammad Ali ◽  
Amir Sultan
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Heat Transfer Coefficient ◽  
Ethylene Glycol ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Turbulent Regime ◽  
Nano Fluid

Coolant plays important characteristic in automobile industry to prevent failure and damage by balancing the temperature. Due to this approach, coolants are being used as new thermal fluid to study the heat transfer coefficient performance. This study consists of an experimental investigation of internal convective heat transfer of 50:50 Water-Ethylene Glycol based Nano-fluid through a copper tube of 18mm external diameter and 16.5mm internal diameter and a test section of 1m in a fully turbulent regime. Total convective heat transfer coefficient of Nano fluid at three different volumetric concentrations of nanoparticles is estimated. Local convective heat transfer at eight different points along the tube at varying Reynolds number is also determined. At 0.15% volumetric concentration of SiO2 Nanoparticles (NPS) 29% increment in convective heat transfer coefficient (CHT) is observed. The decrease in the heat transfer rate is observed with changing distance axially. Particles disorganized movement of NPs and undulation in the fluid and increased in thermal conductivity of Nano fluid can be possible reason for extra ordinary change in heat transfer.

scholarly journals Performance Improvement of Base Fluid Heat Transfer Medium Using Nano Fluid Particles

2020 ◽  
Vol 23 (4) ◽  
pp. 235-243
Author(s):  
T. Sathish
Keyword(s):  
Heat Transfer ◽  
Performance Improvement ◽  
Base Fluid ◽  
Flow Problem ◽  
Thermal Characteristics ◽  
Nano Particles ◽  
Simulation Tool ◽  
Heat Transfer Medium ◽  
Nano Fluid ◽  
Nano Fluids

Base fluids like water, ethylene glycolandengineoilare conventionally used as a heat transfer medium. The performance of heat transferred is improved in the conventional fluids with the addition of Nano particles. Hence, this paper considers the forced conventional flow problem over the base fluid within a uniform heated tube placed on a wall. The analysis of heattransferco-efficientis done through a constant Reynoldsnumberfor both Nano and base fluid with a simulation tool. Further, a comparative analysis is carried out with heat transfer coefficient over the base and various Nano fluids. It is seen that the Nano fluids has a better performance due to its better thermal characteristics under standard conditions.

Laminar Forced Convection of Nanofluids in a Circular Tube: A New Nonhomogeneous Flow Model

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Saptarshi Mandal ◽  
P. S. Ghoshdastidar
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Base Fluid ◽  
Flow Model ◽  
Circular Tube ◽  
Average Heat Transfer Coefficient ◽  
Pumping Power ◽  
Average Heat ◽  
Nonhomogeneous Flow ◽  
Agglomeration Of Nanoparticles

Abstract In this paper, the local and average heat transfer coefficient enhancement or deterioration, and rise in pumping power in steady, laminar alumina–water, titania–water, and carbon nanotube (CNT)–water nanofluids flow in a horizontal circular tube subjected to constant heat flux at the outer wall have been investigated numerically based on a new variable property nonhomogeneous flow model which takes into account agglomeration of nanoparticles. The results have been compared with the published experimental results of Utomo et al. (Utomo, A. T. et al., 2014, “The Effect of Nanoparticles on Laminar Heat Transfer in a Horizontal Tube,” Int. J. Heat Mass Transfer, 69, pp. 77–91.) using various property models of thermal conductivity and viscosity, and for equal Reynolds number, equal inlet velocity, equal mass flowrate, and equal pumping power of nanofluid and base fluid. Stream function–vorticity–temperature formulation and finite difference method have been used. Using the same Reynolds number of nanofluid and base fluid gives much higher enhancement in average heat transfer coefficient as compared to other modes of comparison. Interestingly, the criterion of equal pumping power gives negative percent enhancement in the case of CNT–water nanofluid. The pumping power is found to rise for all three nanofluids. It is found that consideration of agglomeration of nanoparticles has produced improved accuracy in the numerical solution.

scholarly journals Numerical Investigation on Forced Hybrid Nanofluid Flow and Heat Transfer Inside a Three-Dimensional Annulus Equipped with Hot and Cold Rods: Using Symmetry Simulation

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1873
Author(s):  
Aysan Shahsavar Goldanlou ◽  
Mohammad Badri ◽  
Behzad Heidarshenas ◽  
Ahmed Kadhim Hussein ◽  
Sara Rostami ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Base Fluid ◽  
Thermal Characteristics ◽  
Reynolds Numbers ◽  
The Other ◽  
Heat Transfer Fluid ◽  
Hybrid Nanofluid ◽  
Cu Nanoparticles ◽  
Flow And Heat Transfer

A 3D computational fluid dynamics method is used in the current study to investigate the hybrid nanofluid (HNF) flow and heat transfer in an annulus with hot and cold rods. The chief goal of the current study is to examine the influences of dissimilar Reynolds numbers, emissivity coefficients, and dissimilar volume fractions of nanoparticles on hydraulic and thermal characteristics of the studied annulus. In this way, the geometry is modeled using a symmetry scheme. The heat transfer fluid is a water, ethylene–glycol, or water/ethylene–glycol mixture-based Cu-Al2O3 HNF, which is a Newtonian NF. According to the findings for the model at Re = 3000 and ϕ1 = 0.05, all studied cases with different base fluids have similar behavior. ϕ1 and ϕ2 are the volume concentration of Al2O3 and Cu nanoparticles, respectively. For all studied cases, the total average Nusselt number (Nuave) reduces firstly by an increment of the volume concentrations of Cu nanoparticles until ϕ2 = 0.01 or 0.02 and then, the total Nuave rises by an increment of the volume concentrations of Cu nanoparticles. Additionally, for the case with water as the base fluid, the total Nuave at ϕ2 = 0.05 is higher than the values at ϕ2 = 0.00. On the other hand, for the other cases, the total Nuave at ϕ2 = 0.05 is lower than the values at ϕ2 = 0.00. For all studied cases, the case with water as the base fluid has the maximum Nuave. Plus, for the model at Re = 4000 and ϕ1 = 0.05, all studied cases with different base fluids have similar behavior. For all studied cases, the total Nuave reduces firstly by an increment of the volume concentrations of Cu nanoparticles until ϕ2 = 0.01 and then, the total Nuave rises by an increment of the volume concentrations of Cu nanoparticles. The Nuave augments are found by an increment of Reynolds numbers. Higher emissivity values should lead to higher radiation heat transfer, but the portion of radiative heat transfer in the studied annulus is low and therefore, has no observable increment in HNF flow and heat transfer.

CFD study of slot jet impingement heat transfer with nanofluids

2015 ◽  
Vol 230 (2) ◽  
pp. 206-220 ◽  
Author(s):  
Rabijit Dutta ◽  
Anupam Dewan ◽  
Balaji Srinivasan
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Base Fluid ◽  
Volume Fraction ◽  
Jet Impingement ◽  
Pumping Power ◽  
Inlet Velocity ◽  
Impingement Heat Transfer

We present a numerical investigation of hydrodynamic and heat transfer behaviors for Al2O3–water nanofluids for laminar and turbulent confined slot jets impingement heat transfer at nanoparticle volume fractions of 3% and 6%. A comparison of the nanofluid with the base fluid has been performed for the same Reynolds number and same jet inlet velocity. A single-phase fluid approach was used to model the nanofluid. Further, the thermo-physical properties of nanofluid were calculated using a recent approach. For the same value of Reynolds number, maximum increase in the average heat transfer coefficient at the impingement plate was found to be approximately 27% and 22% for laminar and turbulent slot impingements, respectively, for 6% volume fraction of nanofluid as compared to that of water. However, the pumping power curve showed a steep increase with the volume fraction with nearly five times increase in the pumping power observed for 6% volume fraction nanofluid. Further, the energy-based performance was assessed with the help of the performance evaluation criterion (PEC). PEC values indicate that nanofluids do not necessarily represent the most efficient coolants for this type of application. Moreover, at the same jet inlet velocity, a reduction in the heat transfer coefficient of 7% and 20% was observed for nanofluid as compared to base fluid for laminar and turbulent flows, respectively.

scholarly journals Thermal and Fluid Dynamic Performance Comparison of Three Nanofluids in Microchannels Using Analytical and Computational Models

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 754
Author(s):  
Dustin R. Ray ◽  
Roy Strandberg ◽  
Debendra K. Das
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Aluminum Oxide ◽  
Copper Oxide ◽  
Wall Temperature ◽  
Base Fluid ◽  
Fluid Dynamic ◽  
Convective Heat Transfer Coefficient ◽  
Pumping Power ◽  
Flux Boundary Condition

The fluid dynamic and thermal performance of three nanofluids containing aluminum oxide, copper oxide, and silicon dioxide nanoparticles dispersed in 60:40 ethylene glycol and water base fluid as a coolant in a microchannel heatsink are compared here by two methods. The first is a simple analytical analysis, which is acceptable for very low nanoparticle volumetric concentration (1–2%). The second method is a rigorous three-dimensional finite volume conjugate heat transfer and fluid dynamic model based upon a constant heat flux boundary condition, which is applicable for cooling electronic chips. The fluids’ thermophysical properties employed in the modeling are based on empirically derived, temperature dependent correlations from the literature. The analytical and computational results for pressure drop and Nusselt number were in good agreement with the nanofluids showing a maximum difference of 4.1% and 2.9%, respectively. Computations cover the practical range of Reynolds number from 20 to 200 in the laminar regime. Based on equal Reynolds number, all of the nanofluids examined generate a higher convective heat transfer coefficient in the microchannel than the base fluid, while copper oxide provided the most significant increase by 21%. Based on the analyses performed for this study, nanofluids can enhance the cooling performance of the heatsink by requiring a lower pumping power to maintain the same maximum wall temperature. Aluminum oxide and copper oxide nanofluids of 2% concentration reduce the pumping power by 23% and 22%, respectively, while maintaining the same maximum wall temperature as the base fluid.

Heat transfer and second law analysis of ethylene glycol based ternary hybrid nanofluid under laminar flow

2021 ◽  
pp. 1-45
Author(s):  
Lingala Sundar ◽  
Kottutu V.V. Chandra Mouli ◽  
Zafar Said ◽  
Antonio C.M. Sousa
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Ethylene Glycol ◽  
Physical Properties ◽  
Friction Factor ◽  
Base Fluid ◽  
Hybrid Nanofluid ◽  
Pumping Power ◽  
Thermo Physical Properties

Abstract Experiments were conducted to evaluate the thermal and frictional entropy generation and exergy efficiency of rGO-Fe3O4-TiO2 hybrid nanofluid in a circular tube under laminar flow. The ternary nanoparticles are synthesized using the sol-gel technique and characterized by XRD, SEM, and FTIR. The stable ethylene glycol based ternary hybrid nanofluid were prepared and thermo-physical properties, heat transfer, friction factor, and pumping power at various particle weight concentrations (0.05% to 0.2%) and Reynolds number (211 to 2200) were investigated. Enhancement in the thermal conductivity and viscosity of 10.6% and 108.3% at ψ = 0.2% and at 60°C over the base fluid were obtained. Similarly, Nusselt number is enhanced to 17.78%; heat transfer coefficient is enhanced to 24.76%; thermal entropy generation is reduced to 19.85%; exergy efficiency enhancement of 6.23% at ψ = 0.2% and at Re = 1548 is achieved. The pressure drop, pumping power, and friction factor is augmented to 13.65%, 11.33%, and 16% at ψ = 0.2% and at Re = 221.1 over the base fluid. The overall thermal performance of the system is enhanced to 14.32%. New equations are modeled to evaluate the thermo-physical properties, Nusselt number, and friction factor.

Numerical Investigation of Fluid Flow and Heat Transfer in Finned Micro-Channels with Nanofluids

2015 ◽  
Vol 813-814 ◽  
pp. 723-728
Author(s):  
Deepak Kumar ◽  
D.P. Mishra
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Wall Temperature ◽  
Transfer Rate ◽  
Base Fluid ◽  
Thermal Characteristics ◽  
Mixed Flow ◽  
Nano Fluid ◽  
Flow And Heat Transfer ◽  
Micro Channels

Conservation equations of mass, momentum and energy have been solved using Fluent 14 to compute the Nusselt number and wall temperature of a finned rectangular Micro-channel for a laminar flow for water and nanofluids under mixed flow condition. Alumina based water is considered as nano fluid for the present investigation. It has been found from the numerical investigation that as the percentage of alumina is increased in the base fluid (water) the heat transfer rate is increased. It has been found that the wall temperature decreases with increase in fin number. The heat transfer is found to be more in rectangular shaped fin compared to any other shape both for the water and nanofluid. In addition to thermal characteristics, the variation of pressure drop for different fin number has also been investigated.

scholarly journals Effects of Nanofluid Flow in Micro channel Heat Sink for Forced Convection Cooling of Electronics Device: A Numerical Simulation

2019 ◽  
Vol 9 (2) ◽  
pp. 5230-5243
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Ethylene Glycol ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Base Fluid ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Pumping Power ◽  
Cooling Of Electronics

computational study is carried out on a rectangular microchannels heat sink using nanofluids flow for cooling of electronics device under uniform heat flux condition. In the present investigation water, ethylene glycol and a mixture of ethylene glycol (20%wt) and water are considered as base fluids with varying concentration of five different nanoparticles includingAl2O3 , TiO2 , CuO, SiO2 and ZnO. Numerical computations are performed using ANSYS Fluent software by considering the single phase model and results are validated with available experimental and numerical data. Further parameters like thermal resistance, pumping power, local heat transfer coefficient and temperature variation of IC chip are presented and analysed. It was noted that with addition of nanoparticles there is sharp increment in local heat transfer coefficient and decrements in local thermal resistance compared to base fluid but at same time viscosity of fluid increases that provide more drag or pressure drop which ultimately increases the pumping power. 𝑪𝒖𝑶-Water nanofluid of concentration 1% and 4% give large improvement in heat transfer parameters and at the same time there is little enhancement in pressure losses or pumping power also it has less cost and more stability in base fluid as compared to other nanofluids.

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