Base Fluid Mixture Research Articles

Molecular simulations of increased thermal energy storage in metal–organic heat carriers with R1234ze(E)/R32 mixtures combined with IRMOF-1

Metal-organic heat carrier (MOHC) nanofluids offer a promising solution to enhance the efficiency of Organic Rankine Cycle systems. In this study, we developed a computational model to assess the thermal energy storage capacity of MOHC nanofluids using a base fluid mixture of R1234ze(E) and R32 refrigerants. Through Grand Canonical Monte Carlo and molecular dynamics simulations, we examined the adsorption characteristics, desorption heat, and thermodynamic properties of MOHCs. Our findings reveal that R32 molecules are preferentially adsorbed in IRMOF-1 compared to R1234ze(E), with adsorption selectivity of R32 over R1234ze(E) increasing under higher adsorption pressures. When the temperature during the endothermic process surpasses the phase transition point of the base fluid, the latent heat of phase transition can be fully exploited to enhance energy storage. Moreover, the inclusion of IRMOF-1 nanoparticles significantly improves the energy storage properties of both R32 and R1234ze(E), as well as their mixtures. The energy storage enhancement provided by IRMOF-1 is particularly pronounced under high working pressures and low temperature differences. These insights offer valuable guidance for selecting appropriate base fluids in MOHC systems, thereby optimizing the utilization of low-grade energy sources.

Unraveling heat transfer mechanisms in MoS 2/SO−water nanofluid for flow over a stretching cylinder

Nanofluids, advanced heat transfer fluids with improved thermophysical properties, have proven effective in enhancing the efficiency of various devices. Widely applied in electronic devices and automotive industry, consisting of nanoparticles and base fluids, serve as efficient coolants to optimize heat transfer performance. This article investigates the physical effects of magnetohydrodynamic (MHD) boundary layer flow of H 2 O base fluid over a stretched cylinder subjected to heat generation and thermal radiation. The present nanofluid investigation incorporate Mo S 2 nanoparticles into a base fluid mixture of SO / H 2 O . The mathematical model, employing similarity transformations, is developed, leading to the formulation of similarity equations. Simulations are conducted using MATLAB’s bvp4c solver to analyze the resulting flow patterns. Simulation results for various physical parameters demonstrate that the inclusion of hybrid nanoparticles in the fluid mixture significantly enhances heat transfer compared to the conventional nanofluids. Our finding highlights the necessity of considering hybrid nanoparticles over single-type counterparts for creating efficient thermal systems. Moreover, investigation underscores the vital role of hybrid nanofluids in fluid transmission, showcasing their ability to achieve higher temperature distribution.

Ionanofluid flow through a triangular grooved microchannel heat sink: Thermal heightening

With recent technological advances, thermal transport from different electronic and electrical devices is the most vital concern. The microchannel heat sink (MCHS) of liquid cooling is a useful device to remove over thermal load. Ionanofluid is a brand new and super potential cooling fluid for its ionic conductivity, non-flammability, negligible volatility, and high-level heat stability. In this research, the ionanofluid's velocity and thermal field characteristics through a triangular grooved MCHS are investigated using numerical tools. The combination of ionic liquid (IL) 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide [C4mim]NTf2 and propylene glycol (PG) is used as base fluid whereas graphene (G) and single-walled carbon nanotube (SWCNT) are chosen as hybrid nanoparticles to make the working ionanofluid. The governing equations of nonlinear partial differential equations describing the physical phenomena along with proper border settings are resolved by applying the finite element method (FEM). Different ratios of hybrid nanoparticles (G: SWCNT) like (1: 0, 1/3: 2/3, 1/2: 1/2, 2/3: 1/3, 0: 1) are suspended in the base fluid mixture. In addition, the base fluid mixture is assumed in different combinations of (IL: PG) as (100: 0, 50: 50, 0: 100). The numerical results are displayed in the forms of streamlines, isothermal lines, and rate of thermal transfer for the pertinent parameters namely forced convection (Re = 100–900) and solid concentration (φ = 0.001–0.05). Also, pressure drop, field synergy number, relative fanning friction feature, relative Nusselt number, and temperature enhancement efficiency are calculated. The results indicate that a higher heat transport rate is found using the IL-based ionanofluid with the highest solid concentration. Moreover, the higher forced convection enhances the thermal efficiency of MCHS. Two linear regression equations along with very good correlation coefficients have been derived from the numerical results.

Investigation on ethylene glycol and glycerol mixture concentration dependent optical, dielectric, electrical, rheological, and thermophysical properties of EG+Gly/ZnO semiconductor nanofluids

Wide energy bandgap metal oxide nanomaterials containing semiconductor nanofluids (SNFs) are technologically established as advanced multifunctional materials for progress in high performance soft condensed devices. Therefore, to strengthen this field of materials, the present study reports in detail the optical, dielectric, electrical, rheological, and thermophysical properties of the SNFs based on ethylene glycol (EG) and glycerol (Gly) mixture of an entire concentration range (Gly volume fractions; 0.00, 0.25, 0.50, 0.75, and 1.00) with a fixed amount of zinc oxide (ZnO) semiconductor nanomaterial (0.05 wt%). These green-formulated EG + Gly/ZnO SNF materials showed a longer stability of the suspended nanoparticles in the highly viscous hydrogen bonded base fluid and exhibited an increase in absorbance with the decrease wavelength of visible range photons and the ZnO electronic transition at about 3.2 eV energy of ultraviolet radiations. Dielectric measurements over the 20 Hz–1 MHz range of these SNFs, at 298.15 K, explained a dominant contribution of the electrode and interfacial polarization processes at low frequencies and the molecular dipole polarization of static permittivity about 40 at the higher frequencies. Electrode polarization and conductivity relaxation times enhanced exponentially when the Gly concentration increased in the EG + Gly base fluid which governs the electrical conductivity decrement from 0.79 to 0.04 μS/cm for these SNFs. The rheological study explained the Newtonian characteristics of EG + Gly/ZnO nanofluids with their base fluid mixture concentration controllable dynamic viscosity in the wide range of 17–702 mPa s, at 298.15 K. The density, refractive index, ultrasound velocity, prominent acoustic parameters, and thermal conductivity are determined and discussed to explore the solid-liquid interaction and interfaces formed in these innovative SNF materials.

Analysis and numerical simulation of fractal-fractional order non-linear couple stress nanofluid with cadmium telluride nanoparticles

It is generally considered that fractal-fractional order derivative operators are highly sophisticated mathematical tools that can be applied in a variety of physics and engineering situations to obtain real solutions. By using fractal-fractional derivatives, we can simultaneously investigate fractional order and fractal dimension. Due to extensive applications of fractal-fractional derivatives, in the present article fractal-fractional order model of non-linear Couple stress nanofluid has been analyzed. The homogenous mixture of base fluid and nanoparticles has been formed by the uniform dispersion of cadmium telluride nanoparticles in mineral transformer oil. Primarily, the classical mathematical model has been formulated via relative constitutive equations and then generalized by using fractal-fractional derivative operator. This model has been numerically solved using Crank-Nicolson technique. Using numerical solutions, various graphs are plotted to analyze how physical parameters alter Couple stress nanofluid rheology. As can be seen from the graphical study, couple stress slows down fluid velocity. Adding cadmium telluride nanoparticles to transformer oil increased its efficacy by 15.27%.

Significance of the third‐order slip flow of graphene‐(100% water, 70% water + 30% ethylene glycol, and 50% water + 50% ethylene glycol) nanofluids flow over a stretching surface with a Cattaneo–Christov heat and mass flux model

AbstractCommon conductive fluids include coolants (water and ethylene glycol [EG]), lubricants (oils), polymer solutions, paraffin, and biofluids. Compared with conventional fluids, the nanofluids have superior thermophysical properties like heat transmission, thermal conductivity, viscosity, and thermal diffusion. Such types of nanofluids have many biomedical, industrial, and engineering applications due to their enhanced properties like vehicle cooling, industrial cooling, heat transfer, electronics cooling, nanocryosurgery, magnetic drugs, etc. Therefore, in this analysis, the authors have investigated the significance of thermal and mass transmission mechanisms of the nanofluids on convective motion that happens through a stretching sheet with velocity slips. The nanofluid flow includes water (H2O) and EG (C2H6O2) which are used as a mixture of base fluid (water, 70%water + 30%EG, 50%water + 50%EG) and graphene nanomaterials (graphene nanoparticle [GP]) are used as nanoparticles. The governing equations are transformed with the help of suitable similarity variables and then solved by the means of homotopy analysis method (HAM). Validation of the present analysis has been performed and has found great agreement with previous results. The effects of physical factors developed during partial differential equation (PDE)‐to‐ordinary differential equation (ODE) transformations on flow profiles have been presented. The results show that the enhancing nanoparticle volume fraction shrinks the velocity boundary layer thickness and reduces the velocity profiles, while the thermal and concentration boundary layer thicknesses enhance, which consequently augment the thermal and concentration profiles. Additionally, the increasing nanoparticle volume fraction improves skin friction, heat transfer, and mass transfer rates. The augmenting thermal and mass relaxation times factors reduce the thermal and concentration profiles. Additionally, the thermal relaxation time factor shows prompt effect for the case of Fourier's law and the concentration relaxation time factor shows prompt effect for Fick's model. It is also found that the variations in the flow profiles are always dominant for the water + GP nanofluid as compared to 70% W + 30%EG + GP and 50% W + 50%EG + GP.

Thermal performance of ternary-hybrid nanofluids through a convergent-divergent nozzle using distilled water - ethylene glycol mixtures

A computational analysis is conducted based on ternary-nanoparticles performance for base fluid mixture through a convergent-divergent (CD) nozzle. Since the thermal phenomena through a CD nozzle exposes many attention-grabbing performances, it deserves additional investigation for laminar flow characteristics. Using ternary-nanoparticles at different base fluid mixture makes the study more robust and interesting to analyze the real situation better. In this study, the properties of cobalt (Co), silver (Ag), and zinc (Zn) nanoparticles along with base fluid mixtures of distilled-water (DW) and ethylene glycol (EG) as (100:0), (60:40), (50:50), and (0:100), are employed. A wide range of inlet velocity, solid concentrations, nanoparticle size and magnitude of nanoparticle shape factor is considered in this research. The mixtures of nanoparticles are considered as a ratio of (0:1/2:1/2), (1/2:0:1/2), (1/2:1/2:0), (1/6:1/6:2/3), (1/6:2/3:1/6), (2/3:1/6:1/6) and (1/3:1/3:1/3). The mathematical model is formulated using Navier-Stokes equations, energy conservation with proper boundary conditions, and solved using finite element method. Among the considered base fluid mixtures, the highest heat transfer rate is obtained for EG-Co-Ag-Zn nanofluid. A relatively higher heat transfer rate is found for all base fluid mixtures with nanoparticles ratio (1/6:2/3:1/6) compared to other combinations. Furthermore, advanced rate of thermal transport is found using laminar shape nanoparticles.

Heat transfer and electrical discharge of hybrid nanofluid coolants in a fuel cell cooling channel application

Hybrid nanofluid coolants is a new approach for advanced thermal management of Polymer Electrolyte Membrane fuel cells. Due to the high electrical conductivity of nanofluids, electrical discharge when a nanofluid coolant is used in a fuel cell is a concern and needs to be fundamentally studied. The objective is to obtain experimental correlations between heat transfer and electrical discharge rates of a nanofluid coolant in the form of a novel electro-thermal transfer ratio as a reference for future progress. A hybrid of 1%v TiO2 and SiO2 nanoparticles dispersed in a water and ethylene glycol (40:60) base fluid mixture was tested. The heated surface temperatures of the cooling channel were at 60 °C and 70 °C while the electrical power was nominally discharged through the test section at 0.7 V and 3 A. Under laminar flow, the concurrent changes to the temperature profile and active current were observed. The cooling was improved for the 40:60 hybrid TiO2:SiO2 nanofluid coolant with an enhancement factor of up to 2 times while the measured electrical current was visibly lower than the nominal current. The electro-thermal transfer ratio reduced exponentially with Reynolds number, indicating that electrical discharge strength into the coolant reduced at higher flow rates compared to the rate of heat transfer. These preliminary findings provide a new improved perspective in the assessment of nanofluid coolants for fuel cell systems and electrically-active systems in general.

Entropy generation on the variable magnetic field and magnetohydrodynamic stagnation point flow of Eyring–Powell hybrid dusty nanofluid: Solar thermal application

The prime intention of this study is to analyse the significance of the variable magnetic field and magnetohydrodynamic stagnation point flow of Eyring–Powell hybrid dusty nanofluid over a Darcy–Forchheimer sheet. The hybrid nanofluid was formulated by suspending the nanoparticles of copper ( Cu) and zirconium dioxide ( ZrO2) into a base fluid mixture of ( C2 H6 O2) ethylene glycol (50%) + ( H2 O) water (50%). The mixture of two different base fluid properties has notable results compared to using a single base fluid. Because when we used the mixture of both base fluids, we obtained better heat conductivity than pure ethylene glycol and a lower freezing point than water. Glycol water has several applications in solar heating installation and antifreeze in automobiles. The suitable self-similarity transformations are employed to convert the hybrid and dusty nanofluids transport equations into ordinary differential equations and then resolved using the Runge–Kutta fourth order with the shooting method in the MATLAB solver. The calculated results are plotted graphically through velocity, temperature, entropy generation, local skin friction coefficient and rate of heat transfer. The velocity profile enhances with the higher values of the Eyring–Powell fluid parameter. Entropy generation ( N G) and Bejan number ( Be) have an opposite nature on the Brinkman number ( Br). The rate of heat transfer rises for the higher values of the radiation parameter and opposite behaviour is observed to the magnetic field parameter. It is noticed that hybrid nanofluids have a higher heat transfer process than dusty nanofluids.

Free convection flow of a heterogeneous mixture of water and nano-encapsulated phase change particle (NEPCP) in enclosure subject to rotation

Free convective heat transfer in hybrid nanofluids inside differentially heated square enclosure is considered. The square enclosure executes a steady uniform counterclockwise angular velocity about its longitudinal. The enclosure was filled with a heterogeneous mixture of base fluid and nano-encapsulated phase change particle (NEPCP). The NEPCP core can absorb thermal energy on charging state or releases energy on discharging state. The governing equations are solved using the using FEM. The validity of the present code is verified by comparing its predictions to the results form literature. The main outcomes is that the rotation parameter affects the cell circulation number, number of inner vortices and its intensity. Using higher speed of rotation leads to less NEPCP undergoes phase change and retard heat transfer.

Promising use nanoparticles in the base fluid of a system (preparation, stability test and critical analysis): A review

In this paper, the mixing of nanoparticles and base fluid appears to have more remarkable result in the suitable system. Study on types and percentage of nanoparticles in solution is important to obtain optimum nanoparticles in the based fluid. Water, refrigerant, PAG (poly alkylene glycol) oil, POE (polyol ester) oil, and mineral oil are typical base fluids used by researchers. Nanoparticles are classified into four groups as metal (Al, Cu, Zn, Ni, Si, Fe), metal oxide (Al2O3, TiO2, SiO2), carbon (graphene, diamonds, and carbon nanotubes), and metal hybrid (Al2O3 + MgO, combination of 2 type nanoparticles). Various procedures can be conducted to produce nanofluid at a specific time. Analysis of mixture of base fluid and nanoparticles is generally done using visual inspection. Some results showed the high sedimentation immediately at the bottom layer of the solution; hence, dispersant's role in some mixture base fluid production is tremendously essential. In this review paper, the current research showed that different materials and processes of production nanofluid cause significant decrease of compressor's work and increase of absorbed heat in the evaporator, which is utilized in the vapor compression refrigeration system. However, more nanoparticles contained in the nanofluid did not guarantee the best result in the experiment. From this review, further experiments may obtain more suitable amount of nanoparticles and base fluids.

Enhancement of heat and mass transfer characteristics of metal hydride reactor for hydrogen storage using various nanofluids

The execution of metal hydride reactor (MHR) for storage of hydrogen is greatly affected by thermal effects occurred throughout the sorption of hydrogen. In this paper, based on different governing equations, a numerical model of MHR filled by MmNi4.6Al0.4 is formed using ANSYS Fluent for hydrogen absorption process. The validation of model is done by relating its simulation outcomes with published experimental results and found a good agreement with a deviation of less than 5%; hence present model accuracy is considered to be more than 95%. For extraction or supply of heat, water or oil is extensively used in MHR during the absorption or the desorption process so as to improve the competency of the system. Since nanofluid (mixture of base fluid and nanoparticles) has a higher heat transfer characteristics, in this paper the nanofluid is used in place of the conventional heat transfer fluid in MHR. Further the numerical model of MHR is modified with nanofluid as heat extraction fluid and results are presented. The Al2O3/H2O, CuO/H2O and MgO/H2O nanofluids are selected and simulations are carried out. The results are obtained for different parameters like nanoparticle material, hydrogen concentration, supply pressure and cooling fluid temperature. It is seen that 5 vol% CuO/H2O nanofluid is thermally superior to Al2O3/H2O and MgO/H2O nanofluid. The heat transfer rate improves by the increment in the supply pressure of hydrogen as well as decrement in temperature of nanofluid. The CuO/H2O nanofluid increases the heat transfer rate of MHR up to 10% and the hydrogen absorption time is improved by 9.5%. Thus it is advantageous to use the nanofluid as a heat transfer cooling fluid for the MHR to store hydrogen.

A critical review of drilling mud rheological models

Drilling mud is a mixture of base fluid and other materials combined in specified amounts for the purpose of cleaning a drilled well. Some of its functions during drilling include but are not limited to the following: cuttings transport, cooling and lubrication of drillstring, consolidating wellbore walls and controlling formation pressure. These functions are executed concurrently. In order to improve the drilling process, a robust mud rheological model is needed to capture the dynamics of the mud flow. This work synthesises an appreciable amount of studies on the modelling of oil well drilling mud rheological properties. While a substantial number of models have impacted the literature, to the best of our knowledge, a critical appraisal of these models has not. Furthermore, there is little or no literature review of the knowledge gained from these models to date. A lot can be gleaned by concentrating on the former; principal of which would be relevant for deepening knowledge on the subject. Hence, an attempt has been made to orient the contents of this review towards critiquing the extant models and charting a new course for future studies. This is what makes this study novel and serves as its major contribution. To enable an understanding of the subject, some consideration of theoretical information has been put in place. The general ‘filter’ for inclusion of models in the current review has been that the model should (1) have been published in peer-reviewed journal papers or conference proceedings and (2) the model is specifically for predicting drilling mud rheological properties (plastic and apparent viscosity, yield point and gel strength) and not crude oil or oil well cement rheology. The review highlights what algorithms were used, their relative successes, limitations, performance as well as input parameters which aided in estimating mud rheological properties. For convenience and ease of reference, these models are organised chronologically in simple tables. Results of the bibliometric survey show that though there are numerous modelling approaches in the literature, artificial neural network was the most popular algorithm among researchers. It is also noticed that fuzzy logic theories and a fusion of traditional sensors and machine learning algorithms are recently gaining traction in their use. Furthermore, it is also observed that while yield point, plastic and apparent viscosity are widely modelled, little attention is given to the gel strength. This review constitutes the first critical compilation on a broad range of models applied to estimating mud rheological properties with the aim of supplying vital elements necessary for an improved understanding of the concept of mud rheology. Despite the authors’ effort at being comprehensive, the list of models in this work is far from exhaustive. Nonetheless, the consolation is that it has captured the majority of mud rheological properties models in the literature. The information contained in this review is intended to be of assistance to researchers and the drilling community in the making of technically correct and cost-effective decisions on mud rheology.

Dynamics of Marangoni convection in hybrid nanofluid flow submerged in ethylene glycol and water base fluids

This research article communicates with the study of hybrid base fluids with suspension of copper nanoparticles. Additionally effects of mixed convection and MHD are also considered. Here ethylene glycol and water are used as a base fluid and nanoparticles of copper are suspended in it. Usually H2O, C2H6O2 or Ethylene glycol are used as a single base fluids when we do a mixture of base fluid and nanoparticles. But here we have used the ethylene glycol+water as base fluids which combines the properties of both fluids and we get much better result as compared to by using single base fluid. Because when we used the mixture of both we get higher thermal conductivity than pure ethylene glycol and lower freezing point as water. Glycoled water have many applications in transfer medium in solar heating installation and as a antifreezer in cars. Governing equations are formed after applying order of approximation. Transformations are utilized for non-dimensionalization of governing equations and NDSolve method is used to construct the physical results. For different values of pertinent parameters the results of velocity, temperature and Nusselt number are seen through graphs.

Stagnation point flow of radiative Oldroyd-B nanofluid over a rotating disk

Background: Nanofluids are known for better heat transfer characteristics in many heat exchanger devices due to their enhanced heat transfer abilities. Recently, scientists give the idea of nanofluid which is the mixture of base fluid and solid nanoparticles having very small size. For physical phenomenon of conventional fluids by mean of suspensions of nanoparticles in base fluids and prompted produce a new composite known as “nanofluids”. These composite contain the nanoparticles with 1–100 nm sized which are suspended in the base fluids. Here we have considered a subclass of non-Newtonian fluid called Oldroyd-B fluid. The fluid motion over the disk surface is produced due to the rotation as well as radially stretching of disk. Further, the impact of non-linear thermal radiation and heat generation/absorption is introduced to visualize the heat transfer behavior. The convective boundary is also taken into consideration in order to investigate the fluid thermal characteristics. The novel features of thermophoresis and Brownian motion during the nanoparticles movement in fluid motion are studied with revised Buongiorno model. The physical problem is modeled with the concept of classical Fourier’s and Fick’s laws. The von Karman variables are used to convert the partial differential equations (PDEs) into non-dimensional ordinary differential equations (ODEs).Method: The system of governing ordinary differential equations (ODEs) with boundary conditions (BCs) are highly non-linear in nature. To handle these non-linear ODEs, we use a numerical technique called BVP Midrich scheme which uses the midpoint method to acquire the numerical solution of the governing problem. The solutions of the governing problem are obtained by utilizing Maple software.Results: Effect of different involved controlling parameters on the velocity profiles, temperature and concentration distributions are analyzed graphically. Additionally, the numerical data for local Nusselt and Sherwood numbers are also tabulated. The reduction in heat transfer rate at the wall is noticed against thermoporesis and Brownian motion parameters, respectively. The concentration gradient at the wall reduces with an increment in mass transfer parameter.

Numerical investigation of heat transfer enhancement of a water/ethylene glycol mixture with Al2O3–TiO2 nanoparticles

This paper presents a numerical study of a four-component hybrid nanofluid consisting of binary nanoparticles, Al2O3 and TiO2, dispersed into a double base fluid mixture of water and ethylene glycol. The nanofluid were modeled as a single phase fluid with volume concentrations of 2.5% Al2O3–1.5% TiO2 and 5% Al2O3–3% TiO2 respectively. The nanoparticles are suspended in a double base fluid of water and ethylene glycol mixture with a 70:30 vol ratio. The simulations were conducted for turbulenct flow through a pipe at working temperatures of 293 K and varying Reynolds numbers (7800–2000). Constant heat flux of 129,983 W/m2 heat flux was applied to the pipe wall. The thermal conductivity was enhanced by 24% and 11% at concentrations of 5–3% and 2.5–1.5%, respectively. While, viscosity of hybrid nanofluids was rising up to 70% and 67% at the same concentration. The avarage heat transfer coefficient of Al2O3–TiO2 hybrid nanofluids were enhanced with increase of temperature and volume concentration. It was noted that the maximum heat transfer enhancement is 52% higher than the base fluid for a volume concentration of 5–3%. There is a slight increase in the friction factor of Al2O3–TiO2 hybrid nanofluids with higher volume concentration.

Using statistical and optimization tools for determining optimal formulations and operating conditions for Al2O3/(EG + Water) nanofluids for cooling system

In this research, Al2O3/Ethylene Glycol-water (40%–60%), Al2O3/EG-water (20%–80%) and Al2O3/EG-water (60%–40%) nanofluids have been optimized in various volume fractions and temperatures for heat transfer functions. The volume fractions between 0 and 1.5% and the temperatures between 20 °C and 60 °C were considered as designing variables, while the goal was reducing the dynamic viscosity and increasing thermal conductivity of nanofluids. Modeling the goal functions was conducted by presenting mathematical correlations for the viscosity and thermal conductivity of the mentioned nanofluids in terms of temperature and volume fraction. The modeling was performed by Non-dominated Sorting Genetic Algorithm (NSGA-II) so in order to obtain the optimal points of the designing, mathematical correlations were connected to optimization algorithm. By performing optimization, the optimal points were obtained for all the nanofluids for each volume fraction and temperature. These points showed the highest heat transfer coefficient and the lowest viscosity. In order to use the results of this study, some correlations were presented for the most optimal nanofluids. Through utilizing these correlations, a designer can determine the best temperature, volume fraction, and percentage of base fluid mixture according to his need and the significance of each of the goal functions.

Numerically investigation on heat transfer and Pressure drop behavior of MWCNT nanofluid in MCHS

Background/Objectives: To find the best method for nanofluid stability or increment in heat transfer enhancement and terminating pressure drop. Methods/Statistical analysis: Nanofluids have big problem regarding its own preparation or stability. Here is details which can prevent both of problem. This paper based on a work which is able to prevent nanofluids stability problem or pressure drop problem in MCHS. Findings: MCHS vary from 2 cm to several feet or meter because its depends on the requirement of work. The design procedure is complex because of its diameter vary in micro-meter, but it can be designed for our requirement easily. Traditionally we utilized water, ethylene-glycol & some special kind of oils. But, with the large demand in obligation of working efficiency nanofluids were produced which are colloidal mixture of base fluid with nanoparticles. Nanofluids have truly developed the heat transfer characteristics of base fluids & hence are great base to overall working efficiency of the system. But along with advantages it also has quite a few disadvantages to which are stability, limitation to the volumetric concentration addition process of manufacturing and most of all economics of production. Improvements/Applications: They can also be used for wide range of applications such as in the chemical industry, food processing industry, refrigeration industry, computer technology industry, automobile industry, aerospace industry, power plant, mechanical industry etc. Keywords: Heat Transfer, Micro Channel Heat Sink, Pressure Drop, MWCNT’S

Turbulent combined forced and natural convection of nanofluid in a 3D rectangular channel using two-phase model approach

The nanofluid is a mixture of base fluid and solid nanoparticles in nanosize. The heat transfer generated by the nanofluid is more than the base fluid and its lowering pressure drop, which is why its use is increasing. In this paper, the effect of volume fraction, aspect ratio and diameter of the nanoparticles on the turbulent mixed convection in a three-dimensional rectangular channel is numerically investigated. The boundary conditions are constant heat flux, and governing equations are numerically solved by the mixture model. Base fluid in this study, water and aluminum oxide are used as nanoparticles. In this study, all physical properties are considered constant and the effects of volume fraction, aspect ratio and diameter of the particles on the thermal and hydrodynamic parameters of the fluid were studied.

Properties of glycerol and ethylene glycol mixture based SiO2-CuO/C hybrid nanofluid for enhanced solar energy transport

Hybrid nanofluids are a novel class of colloidal fluids which have drawn significant attention due to potential tailoring of their thermo-physical properties for heat transfer enhancement by a combination of more than one nano-additive to meet specific requirements of an application. In the present work, ceramic copper oxide/carbon (SiO2-CuO/C) nanoparticles in 80:20 (wt%) composition were prepared by ultrasonic-assisted wet mixing technique. The hybrid nanofluid was formulated by dispersing the nanoparticles into a base fluid mixture of 60:40 (% by mass) glycerol and ethylene glycol (G/EG) using the two-steps method. The influence of nanoparticles on the augmentation of specific heat, thermal conductivity and viscosity was examined in the volume concentration range of 0.5–2.0% in the temperature range of 303.15–353.15K. The results demonstrate that the synthesized SiO2-CuO/C hybrid nanoparticles enhanced the thermo-physical properties of the base fluid mixture which is higher than using SiO2 alone. In the case of SiO2–G/EG nanofluid, the specific heat capacity decremented by a maximum value of 5.7% whereas the thermal conductivity and viscosity incremented by 6.9% and 1.33-times as compared with G/EG at maximum volume concentration of 2.0% at a temperature of 353.15K. Comparatively, a reinforcement of 80% SiO2 with 20% CuO/C in G/EG mixture led to thermal conductivity and viscosity enhancement by 26.9% and 1.15-times, respectively with a significant reduction of specific heat by 21.1%. New empirical correlations were proposed based on the experimental data for evaluation of thermophysical properties.