Performance Of Heat Transfer Fluids Research Articles

Improvement of thermal performance through nanofluids in industrial applications: A review on technical aspects

Nanofluids (NFs) have emerged as a transformative technology in industrial heat transfer applications due to their demonstrably superior thermal properties compared to conventional fluids. These engineered suspensions of nanoparticles in base fluids, including oil, ethylene glycol, or water exhibit significant enhancements in both conductive and convective heat transfer mechanisms. Their high surface area-to-volume ratio translates to exceptional heat exchange potential, making NFs ideally suited for real-world engineering applications. The performance of heat-transfer fluids may be greatly enhanced by NFs. This paper presents a summary to address the special properties of NFs, including their methods of synthesis, heat transfer processes, improvement of conduction and convection heat transfer, and maximizing heat exchange potential because of their high surface area relative to their volume. This paper also reviews the stability of NFs and the various methods to study their stability and their thermophysical characteristics. Finally, applications of NFs in various areas and industries are described, along with suggestions for future research that would encourage the rapid commercialization of NFs.

Investigation of Various Cooling Nanofluids in a Partially Heated Horizontal Circular Tube

Enhancement of cooling performance of heat transfer fluids can contribute to downsizing of thermal systems. Analysis of thermal behavior of four cooling water based nanofluids (CuO, Al2O3, ZnO and SiO2) in a circular duct is carried. Modeling of heat transfer and fluid flow is based on 3D non-linear differential elliptical equations and finite volume method approach. The Brownian motion is considered in modeling of the nanofluid behavior. A code is developed based on SIMPLER and TDMA algorithms. Hydrodynamic and thermal fields are examined for nanoparticles volume fractions range 0% ≤ Φ ≤ 4% and spherical nanoparticles mean diameter in the range 27 nm ≤ dnp ≤ 78 nm. Results show that the local and circumferentially average Nusselt number increases with increasing the nanoparticles volume fraction and decreases with the nanoparticles size. The maximum local Nu is observed at the bottom of the duct. SiO2–water nanofluid shows the best thermal performance as well as the strongest secondary flow. Increasing the nanoparticles volume fraction increases the secondary flow strength. Using 4 vol.% nanoparticles of 27 nm mean diameter improves Nu by 12%, 7%, 5%, and 3.7% for SiO2, Al2O3, ZnO, CuO, respectively, when compared to the cooling performance of water alone.

Convective heat transfer performance of thermal oil-based nanofluids in a high-temperature thermohydraulic loop

Enhancing the performance of heat transfer fluids (HTF) is a key target for improving the efficiency of many industrial processes. Employing nanofluids for this purpose, by dispersing nanoparticles into the initial HTF to improve its thermo-physical properties, is one possible way to increase its heat transfer capacity. However, testing these properties at high temperature is not always easy. An experimental setup consisting of a thermohydraulic loop for high-temperature heat transfer measurements was developed in this work. The accuracy and repeatability of the measurements taken in the heat transfer loop were ensured. A nanofluid consisting of a commercial thermal oil, doped with Sn nanoparticles at 1 wt% and olive oil surfactant used to enhance colloidal stability, was tested and compared to the results obtained for the base fluid and the base fluid/stabiliser mixture employing their experimentally measured thermo-physical properties. The nanofluid generally enhanced the convective heat transfer coefficient in relation to the base fluid with enhancements of up to 7.23% at 200 °C and 9.43% at 140 °C vs. the pure base fluid.

The enhanced heat transfer of diathermic oil-based alumina-doped zinc oxide nanofluids for domestic solar heating systems

Doped material-based nanofluids, as an extension of single-phase nanofluids, expand the performance of heat transfer fluids. In this study, a new type of diathermic oil (DO)-based alumina-doped zinc oxide (AZO) nanofluids was prepared, and the thermophysical characteristics of nanofluids were analyzed. It could be found that the addition of new doped nanoparticles made up for the deficiency in the performance of DO as heat transfer fluid (HTF). Compared with the pure DO, the thermal conductivity of the AZO nanofluids (0.08 mass%) was increased by 8.125%. And the viscosity of nanofluids was decreased by 70% as the temperature increased. So as to further determine the application of nanofluids in the domestic heating system, the parameters of forced convection heat transfer in the tube were analyzed in this article. The convective heat transfer coefficient of AZO nanofluids increased with the increase in temperature. At 50 ℃, the convective heat transfer coefficient of 0.08 mass% AZO nanofluid reached the maximum of 5.49% compared with pure DO. More importantly, this research investigated the heat transfer benefits of using nanofluids in domestic solar heating systems. These promising results indicated that AZO nanofluids showed excellent properties at higher temperatures. It shows DO-based AZO nanofluids application potential in domestic solar heating systems.

Enhancement of Thermal Properties of Fluids With Dispersion of Various Types of Hybrid/Nanoparticles

The main aim of the present research is to enhance the thermal properties of fluids with a dispersion of various types of hybrid/nanoparticles which has the capability of improving heat transfer properties. Thermal conductivities of Nanofluids are probably higher as compared with conventional fluids. The use of metal nanoparticles has not been intensely investigated for heat transfer applications due to a lack of stability. Research hard work has been equally put forth to improve the active performance of heat transfer fluid (HTF) through the use of hybrid nanomaterial. The particularly higher surface-to-volume ratio of nanomaterial makes them properly promote nucleation and heat switch in PCM. The right choice and training of nanomaterials pave the manner for achieving superior thermal conductivity, specific heat, and heat transfer ordinary performance of hybrid nanofluids. Nanomaterials, organized in splendid systems collectively with nanotubes, nanorods, nanoparticles, etc. would possibly display off awesome thermo-bodily factors while dispersed in heat transfer fluid (water). Therefore, various hybrid/nanoparticles have synthesized the usage of the sol-gel approach. Synthesized Nanomaterials are to be tested for XRD, SEM to recognize the crystalline structure, length, form, etc. The ultrasonic process needs to be performed during the dispersion of nanoparticles in HTF for uniform dispersion and to avoid agglomeration. Then nano-based fluids are characterized to study Physical, thermal properties. The nanofluids are tested using Fourier Transformer Infrared Spectrometry (FTIR) to check chemical compatibility between HTF and nanoparticles, later a thermal conductivity analyzer is used to verify thermal conductivity of various hybrid/nano-based fluids. A thermogravimetric analyzer (TGA) is used to check the commencement and end of decomposition temperature of various hybrid/nano-based fluids. Later several experimentations are carried out using shell and tube type heat exchanger to study heat transfer characteristics of various hybrid/nanofluids. The results from various characterization techniques and experimentation are analyzed for optimizing the nanoparticles type and proportions used in HTF for proposing in practical applications.

Study of flow uniformity within convergent microchannels with a circular manifold

Velocity distribution among microchannels has a significant effect on the cooling performance of heat transfer fluids in contact with the heat sinks. In this study, a novel circular manifold’s practical role in the fluid distribution and flow uniformity among microchannels is investigated. Twenty microchannels are placed around the circular manifold as their cross section varies with convergence or divergence angles ranging from 0 to 10°, leading to the Reynolds numbers of 10, 88, 300, 500, and 1000. The influence of the manifold geometry, microchannel characteristics, and Reynolds number on flow uniformity is investigated. The results reveal that the maximum flow uniformity is obtained for four inlets around the manifold and an outlet in its center where the convergence angle of microchannels is 6°.

JATROPHA OIL WITH IRON NANOPARTICLES APPLICATION IN DRILLING PROCESSES

A performance of heat transfer fluids has a substantial influence on the size, weight and cost of heat transfer systems, therefore, a high-performance heat transfer fluid is very important in many industries. Over the last decades, nanofluids have been developed. According to many researchers and publications on nanofluids, it is evident that nanofluids have a high thermal conductivity. The aim of this experimental study was to investigate the change of the workpiece temperature during drilling using Jatropha oil with iron nanoparticles and water with iron nanoparticles as lubricating and cooling fluids. These experiments were carried out with samples of nanofluid with different nanoparticles volume ratio, such as samples JN1, JN5 and JN10 of iron nanoparticles in the base Jatropha oil with a nanoparticle volume fraction of 1 %, 5% and 10% respectively and samples WN1, WN5 and WN10 of iron nanoparticles in the base water with a nanoparticle volume fraction of 1 %, 5% and 10% respectively.

Influence of Al2O3 nanoparticles on the stability and viscosity of nanofluids

Improving the performance of heat transfer fluids is becoming significantly important. One of the most effective methods for increasing thermal conductivity is the addition of solid nanoparticles to fluids. The molecular dynamics simulation method has the proper ability to diagnose the stability of fluids. This method can be used with a view to the low cost and high repeatability as a suitable method for studying different materials. In this study, the stability and viscosity of the nanofluid at different percentages of base fluid [water–ethylene glycol (EG)] in contact with Al2O3 nanoparticles, was investigated by molecular dynamics simulation with using some analyzes such as total energy, kinetic energy, radial distribution function diagrams and dispersion diagrams. The results show that, the stability of Al2O3 is better where the percentage of water in the base fluid is higher. The molecular dynamics simulation properly predicts the nanofluid viscosities in all concentrations, temperatures and for each base fluid. The maximum discrepancy between experimental and simulation results is 15.1% at 40 °C for 0.5% Al2O3 nanoparticles in the water–EG (60:40) mixture. The obtained results can provide useful understanding of the structural and transport properties of nanofluids, not only in the EG–water nanofluids, but also in other types of nanofluids.

Multiphase modeling approach for ionic liquids (ILs) based nanofluids: Improving the performance of heat transfer fluids (HTFs)

Ionic liquids (ILs) based nanofluids was recently being considered as a heat transfer augmentation method via improving the thermal properties of heat transfer fluids (HTFs). In this study, the thermal performance of ionic liquids (ILs) based nanofluids in a circular tube was numerically analyzed using (i) a continuum based model and an (ii) eulerian based two phase model. For the continuum model, we considered ILs based nanofluids as a mixture averaged single fluid. The eulerian based model connected with two fluids multiphase model which emphasizes the dynamics of interaction between the nanoparticles and the base fluid. The study was carried out for ILs based nanofluids: a mixture of 1-butyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl} imide ([C4mim][NTf2]) ILs and Al2O3 nanoparticles. The numerical model was validated against the experimental data for ILs based nanofluids and the Shah’s equation for base ILs. The results showed that the overall heat transfer coefficient increases significantly for ILs based nanofluids for a range of Reynolds numbers. The results also suggested that the two phase eulerian model was more reliable than continuum based model for predicting the heat transfer performance under such a configuration. A parametric analysis of nanofluids volume fraction and heat flux were also analyzed. Finally, an empirical model was proposed in this study to analyze the heat transfer performance of ILs based nanofluids under laminar flow conditions.

Thermophysical properties and stability of carbon nanostructures and metallic oxides nanofluids

A pioneer idea for increasing the thermal performance of heat transfer fluids was the use of ultrafine solid particles suspension in the basefluid. Nanofluids, synthesized by mixing solid nanometre-sized particles at low concentrations with the basefluid, were used as a new heat transfer fluid which developed a remarkable effect on the thermophysical properties and heat transfer coefficient. For any nanofluid to be usable in heat transfer applications, the main concern is its long-term stability. In this investigation, pentaethylene glycol-treated graphene nanoplatelets (PEG-GnP), pentaethylene glycol-thermally treated graphene (PEG-TGr), Al2O3 and SiO2 were synthesized. The thermophysical properties of PEG-GnP, PEG-TGr, Al2O3 and SiO2 were measured experimentally by using different devices and equipment. Dispersion stabilities of carbon-based nanofluids and metallic oxides nanofluids were observed for 30 days, and the results showed the higher dispersibility of the nanofluids in an aqueous media with very low sedimentation. Thermal conductivity, viscosity and density were increased, while specific heat decreased as mass concentration increased. The temperature effect on the nanofluids was directly proportional to their thermal conductivity and inversely to the viscosity, density and specific heat.

Nanofluids Application in the Drilling Process

A high performance of heat transfer fluid has a great influence on the size, weight and cost of heat transfer systems, therefore a high-performance heat transfer fluid is very important in many industries. Over the last decades nanofluids have been developed. According to many researchers and publications on nanofluids its evident that nanofluids are found to exhibit enhance thermal conductivity. The aim of this experiment was to investigate the change of workpiece temperature during drilling using Jatropha oil with nanoparticle and water with iron nanoparticle as lubricating and cooling fluids. These experiments were carried out with samples of nanofluid with different volume ratio. Samples JN1, JN5 and JN10 of iron nanoparticles in the base Jatropha oil with iron volume fraction 1%, 5% and 10% respectively. Samples WN1, WN5 and WN10 of iron nanoparticles in the base water with iron volume fraction 1%, 5% and 10% respectively. The work arises from the projects which were realized at University J. E. Purkyně, Faculty of Mechanical Engineering, in cooperation with Namibia University of Science and technology, department of Mechanical Engineering.

Performance of heat transfer fluids with nanographene in a pilot solar collector

A pilot scaled solar collector was used to compare different heat transfer fluids, with a radiation source of a 1000 W halogen lamp, real time acquisition with a multiplexer and a Pt100 temperature control. The heat transfer fluid studied was a mixture of water and ethylene glycol 30% (w/w) with three different concentrations of nanographene (0.05, 0.08, 0.10 wt.%). The concentration that showed better results was used in a real test situation, without addition of dispersive agents. For both situations we report a higher efficiency of the collector, without visible clogging problems, due to the low nanomaterial concentration used.

Thermophysical and rheological properties of water-based graphene quantum dots nanofluids

Application of the suspended solid particles in the base fluids is one of the novel methods to increase the thermal performance of heat transfer fluids. However, the major problems with this technique are the short time colloidal stability, low thermal conductivity of additive as well as significant negative effects on rheological properties once loading nanoparticles. The present study explores, for the first time, the impacts of graphene quantum dot (GQD) on the colloidal stability and thermophysical properties of water-based GQD suspensions as a new generation of heat transfer fluid. To this end, amine-treated GQD (A-GQD) were synthesized with a novel method. Surface functionality groups on A-GQD were analyzed by XPS. Atomic-force microscopy (AFM), UV–vis spectrometry, zeta potential and average particle size techniques have been used in order to measure and evaluate the colloidal stability, size and thickness of A-GQD. After applying A-GQD as an additive, colloidal stability results indicate no sedimentation after a 30-day period. In addition, all the thermophysical properties e.g. thermal conductivity, density and viscosity were measured experimentally. The viscosity of the water-based A-GQD samples was tested at various shear rates, concentrations and temperatures. Further, it has shown that by loading A-GODs in the water, the increasing rate of the density and viscosity is not significant. Interestingly, the water-based A-GQD nanofluids at very low concentration significantly increase the thermal conductivity in comparison with that of pure water.

INVESTIGATION OF THERMO‐PHYSICAL PROPERTIES OF DIATOMITE/WATER NANOFLUID

In this study, the thermo physical properties of the nanofluid obtained with prepared solution by adding as basic fluid 1.3% the diatomite nanoparticles into water were determined. Many researchers are working to improve the performance of heat transfer fluids. One of the methods used, if we want to increase the overall thermal conductivity of the fluid, the high thermal conductive materials such as metal oxides, metals and carbon should be added to heat transfer fluids as nano‐sized particles. In this study, specific heat capacity, thermal conductivity and viscosity of nanofluid obtained with diatomite nanoparticles in order to increase the fluid's thermal performance and not found in the literature were investigated experimentally.

Stability and thermophysical properties of non-covalently functionalized graphene nanoplatelets nanofluids

A pioneering idea for increasing the thermal performance of heat transfer fluids was to use ultrafine solid particles suspended in the base fluid. Nanofluids, synthesized by mixing solid nanometer sized particles at low concentrations with the base fluid, were used as a new heat transfer fluid and developed a remarkable effect on the thermophysical properties and heat transfer coefficient. For any nanofluid to be usable in heat transfer applications, the main concern is its long-term stability. The aim of this research is to investigate the effect of using four different surfactants (sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB), and gum Arabic (GA)), each with three different concentrations, and five ultrasonication times (15, 30, 60, 90, and 120min) on the stability of water-based graphene nanoplatelets (GNPs) nanofluids. In addition, the viscosity and thermal conductivity of the highest stability samples were measured at different temperatures. For this aim, nineteen different nanofluids with 0.1wt% concentration of GNPs were prepared via the two-step method. An ultrasonication probe was utilized to disperse the GNPs in distilled water. UV–vis spectrometry, zeta potential, average particle size, and Transmission Electron Microscopy (TEM) were helpful in evaluating the stability and characterizing the prepared nanofluids. TEM and zeta potential results were in agreement with the UV–vis measurements. The highest nanofluid stability was obtained at 60-min ultrasonication time. The prepared water-based pristine GNPs nanofluids were not stable, and the stability was improved with the addition of surfactants. The presence of SDBS, SDS, and CTAB surfactants in the nanofluids resulted in excessive foam. The best water-based GNPs nanofluid was selected in terms of better stability, higher thermal conductivity, and lower viscosity. From all the samples that were prepared in this research, the (1–1) SDBS–GNPs sample with 60-min ultrasonication showed the highest stability (82% relative concentration after 60days), the second better enhancement in the thermal conductivity of the base fluid (8.36%), and nearly the lowest viscosity (7.4% higher than distilled water).

Heat transfer during cryopreservation by perfusion through the vascular system

An analytical study was performed to determine whether it is possible to uniformly freeze or thaw biological tissue by perfusion with a fluid that transfers heat along the vascular system. A simple criterion was developed to evaluate the thermal performance of heat transfer fluids. The results show that fluids that have been considered in the past for heating or cooling by perfusion are unable to transfer heat uniformly through the tissue.

Characterization of potential thermal degradation products from the reactions of aqueous ethylene glycol and propylene glycol solutions with copper metal

Aqueous solutions of ethylene glycol and propylene glycol are common heat transfer fluids for solar collector systems. Thermal oxidative degradation produces organic acids which, in turn, generate copper salts through reaction with copper containment systems. Copper (II) salts of the organic acids which may be generated as the result of the degradation of the ethylene glycol and propylene glycol were prepared by reacting aqueous solutions of the acids with copper (II) carbonate. Infrared spectra and X-ray diffraction peak spacings and intensities are presented for the salts. These spectra may be useful in analyzing the servive performance of heat transfer fluids used in solar collector systems.