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Photovoltaic thermal, (PV-T) collector is hybrid collector utilized to convert solar rays to usable electrical as well as thermal energy. Lately, the research field on PV-T has focused on enhancing the PV-T collector efficiency via substituting conventional fluids as heat transfer medium with different types of nanofluid. This paper investigated the outcome of a mixture of hybrid nanofluid on useful outcome energy and the gained efficiency of PV-T collector by using a specific fractions of Al2O3-SiC-TiO2 nano particles with water as a cooling fluid. The work showed that at a mixture ratio of volume fraction of ternary hybrid nanofluid with an equal proportion of each component (0.4 vol. fraction), the electrical as well as the thermal efficiencies of PV-T collector at using Al2O3-SiC-TiO2)/water nanofluid are12.83% and 78.7%, respectively. Also, the cells temperatures drop by 15ᵒC with a volume flow-rate 4 L/m of Al2O3-SiC-TiO2/water nanofluid. This study concludes that by utilizing Al2O3-SiC-TiO2/water nanofluid an overall maximum thermal efficiency could reach to 85.3%, and this present 39.7% enhancement the collector performance compared to using pure water. A 42% improvement in electrical efficiency was also observed compare to that of uncooled PV panel efficiency. [ABSTRACT FROM AUTHOR]

The experimental process carried out in this paper is to determine the convection heat transfer coefficient, overall heat transfer coefficient, and nanofluid heat transfer rate based on DWCNT (double-wall carbon nanotube) nanotubes applied to a shell and tube heat exchanger. The advantage of using DWCNT nanoparticles is the high thermal conductivity value. The volume fractions of nanoparticles were 0.1%, 0.3%, and 0.5% with the addition of PVP surfactant. Experimental tests were conducted to determine the heat transfer performance applied to a shell and tube type heat exchanger with upright baffles. This study aims to improve the heat transfer performance by utilizing nanofluids based on DWCNTs nanoparticles. As a result, using DWCNT nanofluids instead of base fluids increases the convective heat transfer coefficient values and overall heat transfer. The increase in the volume fraction of DWCNTs nanoparticles is also accompanied by an increase in the heat generated. The highest thermal conductivity was obtained by adding 0.5% volume of DWCNTs nanoparticles, which was 0.640 W/m.K. The highest heat transfer rate was produced by adding 0.5% volume fraction and 0.02% PVP with a result value of 70.191 W. [ABSTRACT FROM AUTHOR]

This paper aims to improve the thermal performance of Closed loop pulsating heat pipe (CLPHP) with nanofluid fused with refrigerants. In this paper, the thermal studies were carried out by SWCNT and MWCNT nanofluids fused with R-134a. Experimentation was conducted at 10W heating power and 90° inclination angle, temperature difference from evaporator and condenser were validated. Results indicate that using nanofluid fused with R-134a, could improve the thermal performance of heat pipes. And the readings were taken every two minutes. And the obtained result was plotted to and the result shows the addition of CNT nanofluid to the refrigerant improves the Thermal performance of the closed-loop heat pipe (CLPHP). Compare to SWCNT, MWCNT with R-134a shows better heat transfer and improve the cooling capacity. [ABSTRACT FROM AUTHOR]

Extracting clean Energy through different technologies and producing electricity has played a major role nowadays due to constant growing energy consumption because of increase in population as well as deteriorating effect on atmosphere due usage of fossil fuels. To have an efficient clean energy technology has become the necessity of time. Application of solar thermal energy as Solar cooker, Solar dryer, Solar Water Heater, Solar desalination etc, are widely used in industry and domestic applications. Among these different application of Solar Thermal Energy, Evacuated Tube Collectors are used extensively so far as it proposes less convection losses which arise in solar concentrators from the movement of air over hot receiver surfaces. It is found that use of nanofluid for the thermal performance enhancement of Evacuated tube collector using heat pipe significantly changed scenario of using ETC. With this paper various characteristics of using nano fluid with Evacuated tube collector has been critically reviewed for the thermal performance enhancement of ETC with effect of parameters like weight fraction, filling ratio, type of nano particle. [ABSTRACT FROM AUTHOR]

The efficient cooling of high-density electronic systems is challenged by the increasing number of transistors in the processor chip. Conventional air cooling and indirect liquid cooling have reached their limits, and new cooling methods such as immersion cooling are being sought. There is disagreement among researchers on the evaluation of the exact heat transfer mechanism in immersion cooling, but the improvement in heat transfer coefficient is clear in the literature. Unlike single-phase immersion cooling systems, double-phased systems are restricted by coolant choices because, in addition to good dielectric strength, they also should have a lower boiling temperature which matches the safe operating temperature of electronic systems. The two-phase immersion cooling eliminates the requirement of active cooling components such as interface materials, heat sinks, and fans. The use of nanoparticles and nanofluids as heat transfer enhancement methods has been widely studied in the past. This review explores the possibility of using dielectric nanofluids for double-phase immersion cooling applications. The nanoparticle being considered for double-phase immersion cooling is diamond nanoparticles because of their high dielectric strength. The thermal conductivity measurement of nanofluids has been studied in detail by past researchers, of which prominent ones are discussed in this paper. Ease of availability is used as a criterion for identifying dielectric fluids that are compatible with double-phase immersion cooling. Various methods for improving the heat transfer rate in pool boiling are reviewed, with the majority of them focusing on the creation of additional nucleation sites and the acceleration of bubble departure. [ABSTRACT FROM AUTHOR]

Recently heat transfer enhancement utilizing double pipe heat exchangers had been a key of engineering research topic in different field. The present work illustrates how magnesium oxide nanofluid (MgO) affects the enhancement of heat energy exchange in a double pipe heat exchanger at different concentrations of nanoparticles. The governing equations of heat and fluid flow had been solved using ANSYS FLUENT based upon finite volume scheme. The temperatures for hot and cold streams at the inlet are 50 oC & 25 oC respectively. The volumetric flowrates for hot fluid (8-20) LPM and for cold fluid 8 LPM. The magnesium oxide nanoparticles MgO have concentrations range (0.125 % - 2%) by volume were implemented. According to the findings of the study implemented in sustainable applications and different industries fields, heat energy exchange rises when the volume concentration of nanoparticles increases also. Currently, there are several studies have been conducted to assess the consequence of nanofluid that enhancement heat energy exchange in the double pipe heat exchanger. The type and concentration of nanoparticles in the base fluid play important role in the enhancement of heat energy exchange. This paper illustrated the effect of increased magnesium oxide nanofluid MgO nanoparticles concentration on the heat energy exchange of a double pipe heat exchanger. [ABSTRACT FROM AUTHOR]

Nanofluid is a novel industrial fluid that has the potential to improve heat exchanger performance. This paper presents an experimental study on the forced convective heat transfer of a graphene oxide nanofluid composed of water/Ethylene glycol and various volume percentages of GO nanofluid (0.5–2) percent passing in a cylindrical shell and tube heat exchanger with various baffle angles. Counter flow is investigated in turbulent flow conditions. The influence of heat transfer rate, entropy development, and overall heat transfer coefficient in heat exchangers with various baffle angles. The above-stated factors of the heat exchanger were governed by conventional correlations using nanofluids. Among the different reformed baffle angles, cylindrical shape nanoparticles performed best in factors of heat transfer rate and overall heat transfer coefficient. The overall heat transfer coefficient of cylindrical shape particles with 120 baffle angle is found to be 15%, 24%, and 30% higher than 240, 360baffle angles, in consistent to 1.5 vol. percent of GO nanofluid. Heat transfer is also found to be greater for cylindrical shapes at 120baffle angle than for other baffle angles. Entropy development, on the other hand, decreases with increasing volume percentage for all baffle angles. [ABSTRACT FROM AUTHOR]

The existing study of the paper using chemical reaction examines the consequences of thermal and mass transferal on MHD Alumina nanofluid energy passed over an oscillatory plate by radiation. Using similarity transformations, the governing equations are reformed into dimensionless equations and solved through Laplace Transformation. The effects of parameters in radiation (R), Schmidt number (Sc), Prandtl number (Pr), magnetic parameter (M), chemical Reaction Parameter (Kc), solid volume fraction (ϕ), thermal Grashof number (Gr), mass Grashof number (Gc), phase angle (ω) are scrutinized in velocity, temperature, and concentration forms. The depicted charts are shown the enhancement of the velocity, temperature, and concentration. It observes that an increment of magnetohydrodynamic diminishes the velocity, an increment of thermal and mass Grashof number stand out towards the increase through the velocities, and increasing radiation reduces a temperature. An increment of Schmidt number diminishes the concentration of the Alumina nanofluid. The Concentration of the fluid decreases as an increment of chemical reactive parameters. The increment in time directs to increase the Nusselt number along with the Sherwood number. The skin friction Coefficient improvements with accumulative values of mass grashof number and radiation. [ABSTRACT FROM AUTHOR]

The experimental process is carried out in this paper to determine the value of the convection heat transfer coefficient, overall heat transfer coefficient, and the rate of heat transfer for nanofluids based on DWCNTs (double-wall carbon nanotubes) nanoparticles which ar e applied to shell and tube heat exchangers. The advantage of using DWCNTs nanoparticles is the high thermal conductivity value. The volume fractions of nanoparticles were 0.1%, 0.3%, and 0.5%. Tests were carried out to determine the heat transfer performance applied to the shell and tube type of baffle and no-baffle heat exchanger tools. The purpose of this research is to improve the heat transfer performance by utilizing nanofluids based on DWCNT nanoparticles. The results show an increase in the value of the convection heat transfer coefficient and the overall heat transfer coefficient when using DWCNTs nanofluids rather than using base fluids. [ABSTRACT FROM AUTHOR]

The development of nanofluids continues to provide advantages in various applications mostly for heat transfer medium. However, the biggest challenge of nanofluids is their stability. Differences in density and van der walls force between particles cause the nanofluid tend to agglomerate. In that case, surface modification is needed to solve this problem. Currently, research developments focus on renewable materials due to the increased concern for environmental sustainability. Thus, the use of nata de coco bacterial cellulose (NDC) as an additive is a suitable candidate to investigate its characteristics. This paper demonstrates the characterization of NDC-ethanol based nanofluid with 2,2,6,6-tetramethyl-1-piperidinooxy (TEMPO) as the additives. The TEMPO acts to oxidize the cellulose, resulting in weakening the NDC's hydrogen bonds, transforming into an individualized nanofiber. The sample morphologies and stabilities were investigated with and without the addition of TEMPO. The NDC was suspended into TEMPO by a magnetic stirrer. Then the pH was adjusted to 7, and the wet NDC was dried for 24 h. High shear homogenization was conducted to reduce the particle size of the fibers. The samples were then stored in a desiccator and captured every 24 h. The sample with the addition of TEMPOs displayed better stability. This result could be considered as promising additives used in nanofluid applications. [ABSTRACT FROM AUTHOR]

Solar photovoltaic/thermal technology has been widely used in private and commercial buildings because it produces heat and electricity simultaneously. To improve the performance of PV/T systems, nanofluids are used as potential heat transfer because of their high thermal conductivity. This paper summarizes the thermophysical properties of nanofluids (thermal conductivity, thermal diffusivity, viscosity, density and specific heat), the effect of fluid flow configuration (spiral, straight, mesh), cross-sectional shape (rectangle and circle) on PV/T performance, to the application of nanofluids as PV/T coolants. The heat transfer from the back of the PV module was shown to increase with the increasing concentration of nanoparticles in the base fluid. The performance of nanofluids is also at ambient temperature because it affects the viscosity. The PV/T power generated by the addition of nanofluid cooling increased by 6%. In addition, differences in fluid flow configuration, type of nanoparticles, size of nanoparticles and ambient conditions affect the performance of PV/T. The rectangular shape is able to increase the electrical efficiency by 11.4%, while the circular cross-section is 6%. These are some of the key parameters for using nanofluids as coolants to improve the performance of PV/T systems. [ABSTRACT FROM AUTHOR]

The problem of developing alternative energy sources with high efficiency was posed back in the middle of the 20th century. One of the possible ways to solve it is the development of systems based on direct absorption solar collectors based on nanofluids. Systems of this kind are the most environmentally friendly and modern, the disadvantages of which include the complexity of maintenance and climatic restrictions of widespread use. The aim of this paper is to determine ways to increase the efficiency of heat transfer in systems for collecting and storing solar energy by means of mathematical modeling of heat and mass transfer processes in direct absorption solar collectors based on nanofluids. When constructing a mathematical model, the contributions of the diffusion and electrostrictive components were taken into account. A mathematical model of heat and mass transfer in a liquid-phase medium with nanoparticles under the action of a light field is investigated, taking into account one-dimensional concentration convection in the form of a boundary-value problem for a system of second-order partial differential equations. The reported study was funded by RFBR, project number 19-31-90070. [ABSTRACT FROM AUTHOR]

In this paper, conjugate heat transfer in turbulent flow horizontal combined with slot jet impinging on several hot sources utilizing hybrid nanofluid has been analyzed numerically using k-w SST with low-Re correction turbulence model. In the current study the governing equations were solved by employing Ansys Fluent 14.5 program. Several variables such as streamline, isotherm contours, average Nusselt number (Nu) are analyzed for multiple Reynolds number ratio (α), nanoparticle volume fraction (φhnf) and position of the slot jet. The steady, turbulent, forced convection, incompressible, and Newtonian flows were chosen to analyze the flow and heat transfer properties. The findings concluded that the heat transfer rate was enhanced by raising the α and φhnf. The addition of an impinging jet to the higher wall of the channel containing the hot sources significantly enhances heat transfer rate, specifically when the impinging jet is located on the first source. A comparison between mono nanofluid and hybrid nanofluid was performed. Results indicated that hybrid nanofluid with 30 % CNT (Carbone nanotube) of the nanoparticles' total volume fraction improves the heat transfer rate better than mono nanofluid. A strong consensus has been reached with the experimental findings available in the literature. [ABSTRACT FROM AUTHOR]

The main intention of the study is to solicit the heed towards the field of heat transfer by exploring the demand and challenges of nanofluids. In the ongoing trend, many industries are giving paramount importance to the ultra-smart cooling techniques, in which nanofluids were employed as the cooling medium. Nanofluids provide the best cooling rates and reserve the maximum efficiency in many industries. Little while ago, nanofluids have been inseminated by adding two or more nanomaterials. Many types of nanomaterials in different forms and with unique properties were widely available to enhance the respective abilities of the nanofluids. The motto of the paper is to elaborate the influence of nanomaterials when infused into conventional fluids for numerous applications. The entire paper provides the detailed information about the types of nanomaterials available in different forms, properties, their preparation, and the corresponding variations when they are incorporated with conventional fluids are presented. The influencing factors like shape, size and concentration have been elaborated and the evolution methods for the proper settlement of the nanomaterials have been discussed. [ABSTRACT FROM AUTHOR]

In this paper, a numerical study has been conducted on the heat transfer of non-Newtonian nanofluid (Copper-Water) in a vertical rectangular cavity in the presence of a horizontal or angular magnetic field. The numerical simulation has been accomplished using the graphics process unit (GPU) accelerated multiple-relaxation-time (MRT) lattice Boltzmann method. A modified power-law model has been employed to characterize the non-Newtonian fluid behavior. The simulation presented in this paper spans a range of power-law index (0.6 ≤ n ≤ 1.0), Hartmann number (0 ≤ Ha ≤ 50) and nanoparticle volume fraction (0 ≤ φ ≤ 0.05). Results indicate that an increment of the power-law index leads to reduce the heat transfer rate from the hot walls. The heat transfer rate also drops when the Hartmann number is incremented. Moreover, augmentation of the volume fraction of nanofluids can enhance the average Nusselt number. Finally, the average Nusselt number increases when the magnetic field is applied at a different angle instead of 0°. [ABSTRACT FROM AUTHOR]

Since the 1990's, nanofluids have been one of the abundantly preferred newcomer technology invented to assist in electronic and heat transfer purposes. Their thermophysical properties and heat transfer performance make nanofluids highly demanded to overcome the current issues in the world. In this paper, a vast number of applications using nanofluids are reviewed as well as an epitome on the challenges in their respective areas. Additionally, recent research papers for specific applications of nanofluids in improving heat transfer efficiency were outlined while the experimental and theoretical methods were discussed in the articles and journals is summarized in this paper including the effects of thermal properties on the performance of nanofluids. In a nutshell, this review of experimental research extracted from most recent papers, published from 2011 to 2016, is a review on the latest updates in the nanofluids and heat transfer community to help anyone in concern of the topic and enough information to select nanofluids based on their needed applications. [ABSTRACT FROM AUTHOR]

Demand of today's era for effective and efficient thermal systems has been increasing day by day. Several modifications are obligatory to fulfil the necessities of high heat transfer. Nanofluids are used instead of conventional fluids for the betterment of heat exchange devices. Stability of nanofluids plays vital role for their proper working in thermal systems. In this article, various stability evaluation and enhancement techniques are described in major part. To gain important indicative information about stability of nanofluids, various stability evaluation methods like sedimentation, zeta-potential, spectral absorbance and electron microscopy are deliberated. For improving stability of nanofluids, various stability enhancement techniques such as ultra-sonication, surfactant addition, surface modifications of nanoparticles and pH change are also described in this paper. To minimize pressure losses, to find optimum concentration of nanoparticles, long term stability and to explore hybrid nanofluids are some of the future research should be discovered. These are some of the technical challenges associated with nanofluids need to be solved for their better industrial applications. [ABSTRACT FROM AUTHOR]

Experimental results and investigation of parabolic trough solar receiver with various nano-fluids and same nanofluids with different base fluids and without nanofluid are reviewed in this paper. Utilization of different nanofluids in enhancement of heat transfer, properties of nanofluid with respect to several parameters associated with heat trapping and thermal performance enhancement of trough collector with nanofluid & without nanofluid are analyzed in detail. [ABSTRACT FROM AUTHOR]

Heat transfer effects on radiative nanofluid through an plate which is inclined in nature under the effects of MHD, Heat source and sink with the boundary condition of non-uniform surface temperature is discussed in this paper with the nanoparticles of Copper and silver. Basic governing equations are numerically solved using MATLAB R2014a by admitting crank Nicolson's method of finite difference which is implicit in nature. The results are discussed by the mean of graphs. Nanofluid consists of silver nanoparticle along with water as base fluid is more reacting than the Nanofluid consists of Copper along with water as base fluid. [ABSTRACT FROM AUTHOR]

Steady flow of a viscous, incompressible, electrically conducting, and chemically reacting nanofluid over a stretching sheet, with melting, in the presence of an applied transverse magnetic field is investigated. Using adequate similarity transformations non-linear partial differential equations, governing to the problem, are transformed into non- linear ordinary differential equations and then solved using bvp4c (Matlab's boundary value problem solver). A comparison is also done to validate the numerical results obtained in the present paper with the existing literature. Numerical results of velocity, temperature, and species concentration are depicted graphically. Numerical values of skin friction coefficient, Nusselt number, and Sherwood number are presented in tabular form. Such nanofluid flows find applications in heat transfer processes, pharmaceutical processes, domestic refrigerators, heat exchanger, engine cooling, vehicle thermal management etc. [ABSTRACT FROM AUTHOR]

Continuous technological development in automotive industries has increased the demand for high efficiency engines. Optimizing design and size of a radiator in order to reduce a vehicle weight is a requirement for making the world green. Using of fins is one of the techniques to increase the cooling rate of the radiator. However, traditional approach of enhancing the cooling rate by using fins and microchannels has already showed to their limit. Furthermore, heat transfer fluids such as water and ethylene glycol have very low thermal conductivity. As result there is an urgency for new and innovative heat transfer fluids for increasing heat transfer rate in an automotive cooling circuit. Nanofluids represent potential substitute of conventional coolants in engine cooling system. In this paper a cooling circuit is modelled in TRNSYS (version 17) and investigated in transient regime. The circuit is composed by a heating system, a pump and a heat exchanger. The heat exchanger represents a car radiator in the circuit. The nanofluid is a mixture of water and Al2O3 nanoparticles. The study is conducted for three different engine operating conditions (Low, Medium and High) and different volume concentrations of nanoparticles. [ABSTRACT FROM AUTHOR]

In this paper, the problem of natural convective heat transfer in a right triangular cavity filled with nanofluids using nonhomogeneous dynamic model is investigated numerically. The inclined wall of the cavity is maintained at constant cold temperature, left vertical wall is adiabatic whereas the bottom wall is considered as uniformly heated. The cavity is permeated by an inclined uniform magnetic field and the effects of gravity, Brownian motion and thermophoresis are incorporated into the nanofluid model. Governing partial differential equations are developed and solved them using the finite element simulation with Galerkin’s weighted residual technique. Comparison with previously published works is performed and very good agreement is obtained. The computations are carried out for different values of the model parameters and the results are displayed graphically in the form of isotherms. Moreover, the average Nusselt number from the bottom heated wall is presented in a tabular form for 10 types of nanofluids. The result shows that the rate of heat transfer of Fe3O4-H2O nanofluid is much higher than that of other 9 types of nanofluids which are studied in the present analysis. [ABSTRACT FROM AUTHOR]

Nanofluids can be considered to be the next-generation heat transfer fluids as they offer exciting new possibilities to enhance heat transfer performance compared to pure liquids. In this paper preparation of Ethylene Glycol (EG) based graphite nanofluid by two step method using PVP as surfactant is studied. Four different volume concentrations of 0.05%, 0.2%, 0.86% and 2% nanoparticles are suspended in the EG base fluid by ultrasonication for 5 hours. The effect of shear rate from 10-100s-1 on viscosity of nanofluid is performed at a fixed temperature. The nanoparticle size considered for analysis of viscosity is <50nm. Further, the thermal conductivity of prepared nanofluid is estimated at a constant temperature for nanoparticle size of <50nm and <100nm. From this complete investigation it is concluded that the viscosity of nanofluid increased with change in volume concentration. Thermal conductivity ratio has shown a linear improvement with increasing volume concentration of nanoparticle. Particle size shows an influence on thermal conductivity variation along with volume concentration. [ABSTRACT FROM AUTHOR]

Coagulation of the dispersed nanoparticles in the base fluid diminishes its thermo-physical and transport properties, leading to its low performances as a heat transfer medium for thermal applications. In this paper, Al2O3- water and CuO - water nanofluids were synthesized using NaOH, NH4OH and acetic acid as surface charge modifiers to improve the stability of the prepared nanofluids. The stability of the suspended nanoparticles was evaluated using, scanning electron microscope (SEM), transmission electron microscope (TEM), and optical microscope (OP). The results showed that Al2O3-water nanofluid stabilized at low pH value of 4.59 (within the acidic region) while CuO-water nanofluids showed poor stability compare to Al2O3-water nanofluid. It is a well-known fact that if the pH of a nanofluid is significantly less or substantially more than the isoelectric point (IEP), better stability will be observed. Therefore, by adjusting the pH of the suspension away from IEP, the repulsive force of the particles in the suspension become stronger, making the nanofluid stable. [ABSTRACT FROM AUTHOR]

This paper presents a numerical research for Cu-nanofluid flow and heat transfer due to a vertical semi-infinite plate at uniform wall temperature embedded in a porous medium. Unlike most classical works, in this paper the thermal conductivity is assumed to vary as a linear function of temperature. Bifurcation solutions established by means of the similarity transformation and shooting technique. Moreover, for some domains of parameters, the associated transfer characteristics, the major and minor differences between the constant thermal conductivity model and this paper are analyzed. [ABSTRACT FROM AUTHOR]

In this paper, a problem of two-dimensional MHD nanofluid flow and heat transfer over a curved surface is discussed. Flow is generated by a curved surface which is stretched nonlinearly. Nanofluid comprises water as base fluid and Copper(Cu) and silver(Ag) as nanoparticles. The system of nonlinear ordinary differential equations is attained from the partial differential equations by employing appropriate similarity transformations. The nonlinear system of equations is solved numerically using the bvp4c tool of the MATLAB software. The impact of relevant parameters like power-law indices, dimensionless radius of curvature, volume fraction and Hartmann number on temperature and velocity profile are studied and presented graphically. With the increase in the value of curvature parameter temperature and velocity profiles decreases. Also, there is an enhancement in the temperature profile when nanoparticle volume fraction is increased. Moreover, with the increment in the value of Hartman number velocity and surface heat transfer rate reduces.To examine the skin-friction coefficients and local Nusselt number, numerical computations are performed. A comparison is done with the published work to validate the numerical results. [ABSTRACT FROM AUTHOR]

Nanofluid is becoming a promising heat transfer fluids due to its improved thermo-physical properties and heat transfer performance. Micro channel heat transfer has potential application in the cooling high power density microchips in CPU system, micro power systems and many such miniature thermal systems which need advanced cooling capacity. Use of nanofluids enhances the effectiveness of t=scu systems. Computational Fluid Dynamics (CFD) is a very powerful tool in computational analysis of the various physical processes. It application to the situations of flow and heat transfer analysis of the nano fluids is catching up very fast. Present research paper gives a brief account of the methodology of the CFD and also summarizes its application on nano fluid and heat transfer for microchannel cases. [ABSTRACT FROM AUTHOR]

Heat generation is an inevitable phenomenon during machining. To eradicate heat oriented detrimental effects like surface burning, tool wear and so on- different types of cooling system are being used. Traditional flood cooling method is the most widely used technique; however the consumption rate of coolant is very high. Moreover, if it is not deposited or recycled properly, it may also cause environmental hazard. Minimum Quantity Lubrication (MQL), on the other hand, sprays lubricant which decreases the frictional force and heat produced during machining. Nanofluid MQL is the incorporation of especially engineered nanoparticles into the lubricant that increases the heat carrying capacity. In this paper, four manufacturing processes (grinding, turning, milling, and drilling) and the effect of using nanofluid MQL in them are studied and summarized. Parameters that are considered in this study are cutting force, surface roughness, machining temperature, tool wear and environmental aspects. It can be observed that using nanofluids in an optimized manner can be beneficial to the machining processes because of their superior characteristics. [ABSTRACT FROM AUTHOR]

In this paper, the problem of magnetohydrodynamic (MHD) boundary layer flow and heat transfer of a nanofluid with the influences of the chemical reaction and thermal radiation over an exponentially shrinking sheet is studied numerically. The model used for the nanofluid is called the Buongiorno model which incorporates the effects of the Brownian motion and thermophoresis. The governing dimensionless ordinary differential equations are solved using the bvp4c method. The effects of the magnetic field parameter, thermal radiation parameter and chemical reaction parameter on the velocity, temperature and concentration profiles of the nanofluid over an exponentially permeable shrinking sheet are discussed and presented through graphs and tables. [ABSTRACT FROM AUTHOR]

In this paper, we have considered the unsteady magnetohydrodynamic squeezing axi-symmetric flow of water-nanofluid through saturated porous medium between two parallel disks. The equations for the governing flow are solved by Galerkin optimal Homotopy asymptotic method. The effects of non-dimensional parameters on velocity, temperature and concentration have been discussed with the help of graphs. Also we obtained local Nusselt number and computationally discussed with reference to flow parameters. [ABSTRACT FROM AUTHOR]

In this paper, the boundary layer magnetohydrodynamics (MHD) flow of Williamson nanofluids over a stretching sheet with Newtonian heating in the presence of thermal radiation effect is analyzed. Using a similarity transformation, the governing equations are reduced to a set of nonlinear ordinary differential equations (ODEs). These equations are solved numerically using a shooting method. The effects of Williamson parameter, magnetic parameter, radiation parameter, Prandtl number, Lewis number, Schmidt number, heat capacities ratio, thermophoretic diffusivity and conjugate parameter on velocity, temperature and concentration fields are shown graphically and discussed. It is found that the rate of heat transfer is higher for Williamson nanofluids compared to the classical viscous fluid. Also, the comparisons with existing results are provided in the literature. [ABSTRACT FROM AUTHOR]

In this paper, the effects of Brownian motion, thermophoresis, chemical reaction, heat generation, magnetohydrodynamic and thermal radiation has been included in the model of nanofluid flow and heat transfer over a moving surface with variable thickness. The similarity transformation is used to transform the governing boundary layer equations into ordinary differential equations (ODE). Both optimal homotopy asymptotic method (OHAM) and Runge-Kutta fourth order method with shooting technique are employed to solve the resulting ODEs. For different values of the pertinent parameters on the velocity, temperature and concentration profiles have been studied and details are given in tables and graphs respectively. A comparison with the previous study is made, where an excellent agreement is achieved. The results demonstrate that the radiation parameter N increases, with the increase in both the temperature and the thermal boundary layer thickness respectively. While the nanoparticles concentration profiles increase with the influence of generative chemical reaction γ<0, while it decreases with destructive chemical reaction γ> 0. [ABSTRACT FROM AUTHOR]

The problem of natural convective heat and mass transfer in a triangular enclosure filled with nanofluid saturated porous medium in presence of heat generation has been studied in this paper. The bottom wall of the cavity is heated uniformly, the left inclined wall is heated linearly and the right inclined wall is considered to be cold. The concentration is higher at bottom wall, lower at right inclined wall and linearly concentrated at left inclined wall of the cavity. The governing equations are transformed to the dimensionless form and solved numerically using Galerkin weighted residual technique of finite element method. The results are obtained in terms of streamline, isotherms, isoconcentrations, Nusselt number (Nu) and Sherwood number (Sh) for the parameters thermal Rayleigh number (RaT), Heat generation parameter (λ) and Lewis number (Le) while Prandtl number (Pr), Buoyancy ratio (N) and Darcy number (Da) are considered to be fixed. It is observed that flow pattern, temperature fields and concentration fields are affected by the variation of above considered parameters. [ABSTRACT FROM AUTHOR]

The problem of steady laminar boundary layer flow over a fixed or moving flat surface by considering the effect of internal heat generation is studied in this paper. By using a similarity transformation, the partial differential equations are transformed into ordinary (similarity) differential equations. The transformed equations are solved numerically for copper, Cu nanoparticles, in the water based fluid with Prandtl number Pr = 6.2. These equations along with the corresponding boundary conditions are solved numerically using a numerical bvp4c Matlab program. The effects of internal heat generation on the velocity and the temperature profiles are illustrated. The results also indicate that the dual solutions exist when the surface and the free stream move in opposite directions. [ABSTRACT FROM AUTHOR]

Transport phenomena in porous media have received considerable attention due to an increasing interest in geothermal processes, chemical catalytic reactors, waste storage (especially geological or ocean storage of carbon dioxide), etc. Among others, oil industry has shown an increasing interest in studying diffusion phenomenon. Nanofluid is a term used to describe the suspension of low concentration of metallic and non-metallic nanoparticles in a base fluid. The size of a nanoparticle ranges from 10 to 100nm, and the conventional fluids used are water, ethylene glycol (C2H6O2) or engine oil. Various studies have proven that nanoparticles improve the heat transfer of a base fluid. However, using various nanofluids it has been shown that the results could vary depending on different initial concentrations. The main objective of this paper is to study the diffusion and the thermodiffusion effect in a nanofluid for different fluid/porous media configurations. In this configuration, a liquid layer surrounds a porous layer. The full Brinkman equation coupled with the heat and mass transfer equations have been solved numerically for the porous layer using the finite element technique. The full Navier stokes equation coupled with heat and mass transfer equations have been solved for the liquid layer using the finite element method. A constraint between the liquid and porous layer has been applied to ensure heat flow and mass transfer continuity is maintained. A square cavity filled with hydrocarbon nanofluid of a mixture of fullerene-toluene with varying concentration of fullerene has been subject to different heating conditions. The entire cavity has been considered to be fully wetted with nanofluid. Results have confirmed that in the presence of a nanofluid a heat transfer enhancement is present up to certain initial concentration of the fullerene. The heat convection coefficient has been found to be 16% higher when a nanofluid is used as the working fluid. [ABSTRACT FROM AUTHOR]

In this paper, the stability analysis of the two-dimensional boundary layer flow and heat transfer of a copper (Cu)- water nanofluid past a permeable moving flat plate in the presence of a co-flowing fluid is theoretically investigated. The governing partial differential equations are first transformed into ordinary differential equations before they are solved numerically using bvp4c function in Matlab. The numerical results for the skin friction coefficient, the local Nusselt number and the local Sherwood number, as well as the velocity, temperature and nanoparticle volume fraction profiles are obtained, presented and discussed in detail for a range of various governing parameters. The numerical results indicate that dual solutions exist when the plate and the free stream move in the opposite directions. The time-dependent version of the problem is then considered to produce linearize eigenvalue problem which are then solved numerically using bvp4c function in Matlab. The stability analysis is carried out to show which branch solutions are stable and physically realizable. [ABSTRACT FROM AUTHOR]

The magnetohydrodynamic (MHD) stagnation point flow and heat transfer of an electrically conducting nanofluid over a nonlinear stretching/shrinking sheet is studied numerically. Mathematical modelling and analysis are attended in the presence of viscous dissipation. Appropriate similarity transformations are used to reduce the boundary layer equations for momentum, energy and concentration into a set of ordinary differential equations. The reduced equations are solved numerically using the built in bvp4c function in Matlab. The numerical and graphical results on the effects of various parameters on the velocity and temperature profiles as well as the skin friction coefficient and the local Nusselt number are analyzed and discussed in this paper. The study discovers the existence of dual solutions for a certain range of the suction parameter. The conducted stability analysis reveals that the first solution is stable and feasible, while the second solution is unstable. [ABSTRACT FROM AUTHOR]