Preparation Of Nanofluids Research Articles

Experimental study on preparation of nanoparticle-surfactant nanofluids and their effects on coal surface wettability

To improve the efficiency of coal seam water injection, the influence of nanofluids on coal surface wettability was studied based on the nano drag reduction and injection enhancement technology in the field of tertiary oil recovery. The composition optimization and performance evaluation of nanofluids with nano-silica and sodium lauryl sulfate as the main components were carried out, and the effects of the nanofluid with the optimal ratio on coal wettability were studied through spontaneous upward imbibition experiments. The results show that the composite nanofluid has a lower surface tension, and the lowest value of the interfacial tension is 15.79 mN/m. Therefore, the composite nanofluid can enhance the wettability of coal. However, its effects on coal samples with different metamorphic degrees is different, that is, low rank coal is the largest, middle rank coal is the second, and high rank coal is the least. In addition, a functional relationship between time and imbibition height is found for pulverized coal with different particle sizes. When the particle size of pulverized coal is 60–80 mesh, the wettability of nanofluid to coal is best. The findings in this paper provide a new perspective for improving the water injection efficiency for coal seams with low permeability.

Preparation of Hybrid Nanofluids, Their Thermophysical Properties, and Stability Parameters

Preparation of Hybrid Nanofluids, Their Thermophysical Properties, and Stability Parameters

A Comprehensive Review on Efficiency Enhancement of Solar Collectors Using Hybrid Nanofluids

Because of its potential to directly transform solar energy into heat and energy, without harmful environmental effects such as greenhouse gas emissions. Hybrid nanofluid is an efficient way to improve the thermal efficiency of solar systems using a possible heat transfer fluid with superior thermo-physical properties. The object of this paper is the study the latest developments in hybrid applications in the fields of solar energy systems in different solar collectors. Hybrid nanofluids are potential fluids with better thermo-physical properties and heat transfer efficiency than conventional heat transfer fluids (oil, water, ethylene glycol) with single nanoparticle nanofluids. The research found that a single nanofluid can be replaced by a hybrid nanofluid because it enhances heat transfer. This work presented the recent developments in hybrid nanofluid preparation methods, stability factors, thermal improvement methods, current applications, and some mathematical regression analysis which is directly related to the efficiency enhancement of solar collector. This literature revealed that hybrid nanofluids have a great opportunity to enhance the efficiency of solar collector due to their noble thermophysical properties in replace of conventional heat transfer working fluids. Finally, some important problems are addressed, which must be solved for future study.

Hybrid nanofluids flow and heat transfer in cavities: a technological review

ABSTRACT The urgent and indispensable need to develop new methods of enhancing heat transfer efficiency to improve energy devices’ performance cannot be overlooked in this era of green energy and sustainable technologies. Nanofluids research has proliferated in the past decade, and reports indicate that nanofluids can be used for heat transfer applications in engineering and in general and/or commercial industries. Nanofluid is the dispersion of nanoparticles with high thermal conductivity in common working fluids. Nevertheless, a growing area of research in recent years has involved using two or more nanoparticles in a base fluid, known as hybrid nanofluids. Studies show that hybrid nanofluids exhibited better thermal and rheological characteristics than mono nanofluids. In addition, many researchers have reported on the thermal-fluid behaviors of nanofluids in comparison with hybrid nanofluids on natural convection in cavity flows. This review discusses hybrid nanofluids preparation, stability analysis and characterization, thermal properties and heat transfer characteristics in cavities. Furthermore, hybrid nanofluids demonstrated better heat transfer characteristics than mono nanofluids or conventional fluids even if more research is needed in terms of hybrid nanofluids preparation, stability, characterization and applications.

Comparison of Different Empirical Models for Analysing the Thermal Conductivities of Various Materials for Use in Nanofluid Preparation

For over the past ten years, various empirical models have been studied for analysing the thermal conductivity of different materials. In this analysis, different empirical correlations and models of thermal conductivity have been compared. The thermal conductivities of four types of oxide materials (SiO2, TiO2, CuO, Al2O3) and MWCNTs with volume fractions from 0.5 to 5% in a temperature range of 273–373 K and various nanoparticle shapes were compared. The results illustrated that the thermal conductivity of nanofluids based upon various nanoparticles increased with increasing volume fraction. In comparison, the effective thermal conductivity of nanofluids based on MWCNTs was enhanced much more than that of other types of nanofluids. Furthermore, Maxwell’s model was considered the basis for predicting the effective thermal conductivity of nanofluids. According to the basic models, a new correlation was proposed for predicting the effective thermal conductivity as a function of temperature and nanoparticle volume concentration. The nanoparticle shape has a great impact on the thermal conductivity of nanofluids. Regarding the precise heat transfer enhancement, the analysed nanofluids are suggested to be heat carriers in thermal systems, particularly solar thermal collectors. Typically, the use of nanofluids in solar thermal collectors improves the thermal efficiency of collectors in terms of the precise heat transference of nanofluids.

A Systematic Review on Promising Development of Palm Oil and Its Nanofluid as a Biodegradable Oil Insulation Alternative

This review is conducted following a systematic approach by adopting the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and using reliable and trustworthy databases, namely, IEEE <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Xplore</i> , Science Direct, and Scopus, with Google Scholar as an additional database. This review has divided into three subsections. The first subsection shows the major publications searching for palm oil (PO)-based as an alternative to biodegradable oil insulation. The second subsection discusses the research trends on PO replacing mineral oil. Finally, the third subsection discusses the development and progress of PO-based nanofluid (NF) as a future substitute for biodegradable oil insulation and the types of analyzes conducted in the studies. This part contains 11 subsubsections, namely: 1) types of PO used; 2) tests of PO as an insulating liquid; 3) properties of PO as an insulating liquid; 4) thermal aging; 5) water content; 6) dissolved gas analysis; 7) selection of nanoparticles; 8) preparation of PO-based NFs; 9) characterization and stability of PO-based NFs; 10) analysis of electrical, physical, and chemical properties; and 11) current status of PO-based insulating liquid in Malaysia. This article highlights PO’s development, trends, and status and its NF as a liquid insulating alternative in transformers. The properties and performance of the liquid are also reported in this article. The promising results, shortcomings, and imbalances between PO and other types of natural ester oils are discussed, and suggestions are made for future work worth exploring.

Synthesis of ZrO2 Based Nanofluids for Cooling and Insulation of Transformers

Nanofluids have recently emerged as an important new technology for heat transfer in various engineering applications. In this work, zirconia (ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) nanoparticles were synthesized using a microwave-assisted sol-gel method for the preparation of nanofluids through a two-step synthesis process. The electrical, thermal, and rheological properties of the nanofluids produced were studied as a function of the ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> concentration (g/L). These fluids showed potential as an alternative to the traditionally available ester-based transformer oil. The effect of the ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanoparticle additions on the nanofluid was evaluated by the measurements of thermal conductivity, breakdown voltage (BDV), and viscosity. The results show an improvement in cooling, insulation, and BDV due to ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , which is explained in terms of a nanoparticle-assisted charge capture mechanism. The optimal performance of the nanofluid was obtained for a concentration of 0.2 g/L of ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanoparticles in the transformer oil.

A critical analysis on the energy and exergy performance of photovoltaic/thermal (PV/T) system: The role of nanofluids stability and synthesizing method

The main aim of this paper is to realize for the first time the effect of nanofluid preparation method on the performance of photovoltaic/thermal (PV/T) system in a comparative experimental study. Silver nanofluid via one-step and two-step method at different concentrations of 1%, 3%, and 5% were prepared. The stability of nanofluid at all concentrations was measured via zeta-sizer before and after experiments and the results showed the stability of nanofluid in one-step prepared is significantly higher than two-step. It was elucidated that the energy and exergy of the PV/T for one-step nanofluid substantially improved compare to the two-step preparation method. Moreover, it was found that by increasing nanofluid from 1 to 3% and 3 to 5% in one-step method all efficiencies were linearly increased but for two-step prepared nanofluid the maximum rate of enhancement was obtained from 1 to 3%. It was observed that when system operated with two-step prepared nanofluid, performance of the system for 3% at turbulent-flow regime is higher than 5% at laminar-flow regime which directly related to the stability of nanofluid. Based on our results it can be concluded that nanofluid preparation method and its stability also play crucial roles on the performance of PVTs.

Influence of nano-additives on engine behaviour using diesel-biodiesel blend

Biodiesel, a potential liquid alternative fuel, offers an excellent property such as extend the longevity and clean burning fuel and reduces the greenhouse gas emissions since the trees planed for feedstock of biodiesel absorbs. It also helps to reduce dependency on fossil fuel and helps to economy. Biodiesel offers numerous advantages over conventional diesel, but it has some issues such as its high viscosity, poor cold flow properties, higher nitric oxide (NOx) emissions and poor oxidation stability. Although there are many methods in order to overcome this drawback, addition of nanoparticles in biodiesel has emerged as one of the potential solutions. The nanoparticles improve the thermochemical properties of the fuel. Some studies have been carried out on nano-sized particles in diesel–biodiesel fuel emulsions. The current paper discusses about the effect of nano particles on engines performance and emission parameters and engine life. The paper also discusses about the effect of different size and dosage of nano particles on diesel engine behaviour. The preparation of nanofluid, several characterization methods and enhancing the stability of biodiesel via various techniques are also presented in this paper.

Systematic preparation and physical property characterization of a novel stable BiOIO3 nanofluids

Nanofluids due to their good thermal conductivity and stability, have been proposed as a way to surpass the performance of currently available heat transfer fluids in the near future. In this work?we focuses on the preparation of nanofluids with excellent stability and thermal conductivity, which a new type of stable BiOIO3 (one type of infrared nonlinear optical crystal) nanofluids is successfully prepared by using the two-step method. After the initial physical characterization of BiOIO3 particles, five different dispersants are used to disperse the BiOIO3 nanoparticles, and the best performing nanofluids with a zeta potential value of 144.45 and an average particle size of 22.90nm could be prepared with PVP dispersant. Furthermore, the addition of PVP dispersant in UV-Visible experiments smooth the light absorption curve of the nanofluids, reach a peak of 1.1 at around 350 nm. In the most important thermal conductivity test, the value of thermal conductivity of BiOIO3 nanofluid becomes larger with increasing concentration at 50?C, reaching a maximum value of 1.52 at 0.134vol%, which increases by 0.72 over the same volume concentration of TiO2, indicating the importance of the laminar structure. In view of the excellent properties, new laminar structured nanofluids with light-absorbing properties are expected to receive more attention and exploration in the future

Application of iron oxide nanoparticles in oil recovery – A critical review of the properties, formulation, recent advances and prospects

Iron oxide nanoparticles (IONPs) are of particular interest in multiple fields and in enhanced oil recovery (EOR) due to their unique advantages and characteristics. Albeit several laboratory research articles on IONPs in EOR are available, a critical review is still elusive in literature. Herein, critical information on the properties, formulation and application of IONPs in oil recovery is depicted. The basic physical, structural and physicochemical properties of IONPs were introduced. Thereafter, the preparation of iron oxide nanofluids (IONFs) was discussed. Likewise, potential application of IONPs, in petroleum industry was elucidated. Subsequently, effectiveness of IONPs in EOR was compared with other nanoparticles and the efficacy of surface coatings were reviewed. Finally, the main challenges hindering the applications of IONPs in oil field reservoir were identified and solutions proffered. Experimental results from the literature indicate that the effectiveness of IONPs in reservoir applications is directly related to their surface coatings. The coatings are used to enhance stability and transportation, minimise rock adsorption, and target specific oil recovery mechanisms, resulting in incremental oil recovery. Hence, surface treatment is a necessity for reservoir condition applications. • The bottom-up approach offers superior control and flexibility. • Growth process determines the final size, particle distribution and shape of the IONPs. • Salinity has the most devastating effect on the transport, retention and oil recovery system of IONFs. • IONPs are very economical, ecologically benign and has potentials for oil field applications.

Comparative analysis of CuO-based spiral flow photovoltaic sheet and tube thermal system

The current work investigates experimental characteristics of the PVT system integrated with CuO-water spiral flow heat exchanger and compared with non-cooled PV module. The work describes detailed procedure of nanoparticles preparation, SEM characterizations, and heat extraction characteristics of nanofluid in PVT application. The heat exchanger was pasted at the back of polycrystalline PV module to form PVT system to examine cooling ability, power generation, thermal-electrical yield and overall efficiency at a different volume concentration of CuO nanoparticles at steady mass-flow rate of 0.08 kg/s. From the experiments, it was concluded that the CuO-water nanofluids assisted to lessen surface temperature of PV module by extracting heat that enhanced electrical efficiency by an average of 3.53%. It was also seen that electrical and thermal performance was improved at higher volume concentration and overall efficiency of 30.77% and 36.59% were obtained at 0.01% and 0.03% of volume concentration.

Preparation and performance evaluation of an active nanofluid for enhanced oil recovery in ultra-low permeability reservoirs

The presence of nano-pore throats results in oil recovery of less than 15% in ultra-low permeability reservoirs. In this work, a new type of nanofluid was developed using chemically modified ultra-small silicon dots (SiDots) dispersed in water for enhanced oil recovery (EOR) of ultra-low permeability reservoirs. First, the ultra-small SiDots were synthesized by the hydrothermal method. Then, active SiDots were obtained by grafting sodium p-aminobenzene sulfonate onto the surface of the SiDots at room temperature with glutaraldehyde as a crosslinking agent. The active SiDot nanoparticles spontaneously dispersed in water; thus, the active SiDot nanofluid could be prepared without an external force. The active SiDot nanofluid exhibited high interfacial activity, reducing the interfacial tension and increasing the expansion modulus of the oil–water interfacial film. In addition, the active SiDot nanofluid showed excellent temperature (110 °C) and salinity resistance (12 × 104 mg/L). The result of imbibition experiments showed that the maximum recovery rate of the active SiDot nanofluid was 38%. The recovery rate of the active SiDot nanofluid was>15% higher than that of brine water and 5% higher than that of surfactants. The active SiDot nanofluids exhibited excellent application potential for EOR in ultra-low permeability reservoirs.

A comprehensive review on the impact of nanofluid in solar photovoltaic/thermal system

Solar energy is a major renewable energy resource used in power production, heating processes, and other applications such as domestic and industrial utilization. It is an abundant form of green energy. Different techniques have been made for energy conversion and one among them is solar photovoltaic/thermal (PV/T) system. Unfortunately, the greatest cause of concern is the rise in temperature of solar PV cells, which will have a negative effect on electrical performance. Thereby, eliminating excess heat on PV cells with heat transfer fluids to lower the temperature of the cells can improve electrical efficiency. A nanofluid is a promising heat transfer fluid to effectively enhance the system efficacy compared with conventional fluids. As the nanoparticle size is very small, the surface area of the nanoparticle is large so it enhances the heat transfer rate. Thereby, recently it has taken on a new dimension for research studies to enhance its thermal behavior for engineering application. This review paper discusses about the importance of nanofluid in solar PV/T system and advantages of employing nanofluid in PV/T system which has high thermo-physical properties. Nanoparticle and nanofluid preparation methods were presented. The thermo-physical properties like thermal conductivity, viscosity, density, and specific heat capacity were also discussed.

A comparative study on the tribological behavior of mono&proportional hybrid nanofluids for sustainable turning of AISI 420 hardened steel with cermet tools

The current study examines the influence of various mono and proportional hybrid nanofluids prepared with multi-walled carbon nanotube (MWCNT), alumina (Al2O3) and molybdenum disulphide (MoS2) on the performance of cermet tools in turning of AISI 420 hardened steel. First, mono-nanofluids were prepared using each nanoparticle separately (i.e., Al2O3, MWCNT and MoS2). Afterward, hybrid nanofluids were prepared at three different nanoparticle mixture ratios i.e., particle A:particle B of 1:1 (50 vol% + 50 vol%), particle A:particle B of 1:2 (33.34 vol% + 66.66 vol%), particle A:particle B of 2:1 (66.66 vol% + 33.34 vol%) in a constant volume concentration of 0.6%. Prepared nanofluids (nine different hybrid nanofluids and three different mono nanofluids) were cooperated with the MQL system and their effects on the machinability characteristics such as surface roughness, surface topography, temperature, tool flank wear, and wear mechanisms were investigated. The results were compared with dry and base-fluid MQL assisted cutting results. The surface roughness was decreased by 41.54%, 37.38% and 30.62% through Al2O3:MoS2 (2:1), Al2O3:MoS2 (1:2) and Al2O3:MoS2 (1:1) hybrid nanofluids compared to base fluid, respectively. It was found that different ratios of one more than nanoparticles have a significant effect on the synergistic effect. Based on the all experimental results, it can be concluded that it is necessary to optimize the nanoparticle ratios used in the preparation of hybrid nanofluids.

Investigation on performance of bio synthesized copper nano fluid in helical coil and shell type heat exchanger

Tulsi leaf extracts has been used to produce biosynthesized copper nanoparticles. This biosynthesized nanoparticle is used for the preparation of nanofluid. The performance of nanofluid in a helical coil heat exchanger was studied for heat transfer rate and analyzed using standard correlation at the laboratory of NIT, Raichur. The fluid inlet temperature of the coil was 60 °C and temperatures of fluid inside a shell of 32 °C were maintained. A dean number in the range of 1000 – 10,000 was set on the shell side. The inlet fluid flow was constant at the coil. Thermal analysis has been carried out considering flow rate, overall heat transfer coefficient, and inlet and outlet temperature. When compared to the base fluid, using bio-synthesized Nanoparticles improved the heat transfer coefficient.

A review on recent development of nanofluid utilization in shell & tube heat exchanger for saving of energy

The principal goal of this paper is to provide a generic review of the utilization of nanofluid in shell & tube heat exchangers for energy-saving. Shell & tube heat exchanger is used in many industries like the aviation industry, renewable energy, heating and cooling of electronic equipment, oil and gas industries, automotive industries, thermal power plant, etc because of its smaller area and high heat transfer rate. The utilization of nanofluid in such equipment increases heat transfer rate very rapidly due to better thermophysical properties as compared to other fluids. In this research article, first, a brief introduction of shell & tube heat exchanger is provided after that nanofluid, properties of nanofluid and preparation of nanofluid are presented and then utilization of different nanofluid in shell & tube heat exchanger has been examined. This paper also provides the comparative results of utilization of different nanofluids in shell & tube heat exchangers. Finally, it is found that nanofluids enhance the heat transfer rate, reduces the size of the heat exchanger, and ultimately saving energy.

Preparation, Properties, Stability and Applications of Nanofluids: A Review

Preparation, Properties, Stability and Applications of Nanofluids: A Review

Determination of heat transport mechanism using nanoparticle property and interfacial nanolayer in a nanofluidic system

Elucidation of heat transport mechanism is the key for the preparation and application of nanofluids with high thermal conductivity. However, the effect of microscopic parameters on nanoparticle property, especially thermal conductivity of nanofluids has limited studied. To establish the relationship between nanolayer structure characteristics and thermal conductivity, Al2O3, CuO, and Cu nanoparticles were dispersed in deionized water (W). The thermal conductivity of nanofluids was measured at various temperatures (293–333 K) and volume fractions (0.5–2.0 vol%). The thermal conductivity of nanofluids decreased in the following order: CuO/W > Al2O3/W > Cu/W nanofluids. Nanoparticles with a high thermal conductivity do not always exhibit a high thermal conductivity of nanofluids. Then, number density (N), nanolayer structure, and its thickness (δ) were obtained from a molecular dynamics simulation. The simulation results show that two obvious interfacial nanolayers exist around the central nanoparticle; however, the interfacial potential of the first layer is much higher than that of the second layer. Therefore, the morphology of the first layer mainly determines the thermal conductivity in a nanofluidic system. However, the trend of number density differs from that of thermal conductivity. Moreover, the thickness of interfacial nanolayer is similar for different nanofluids. Thus, only the number density or thickness of nanolayer is not a determined parameter to evaluate the thermal conductivity. A new parameter, N/δ (ratio of number density and thickness), is described to quantitatively evaluate the relationship between nanolayer structure and thermal conductivity. The high value of N/δ indicates that denser and more ordered liquid molecules arrange around the nanoparticles, creating a higher heat transfer channel than other regions and thus exhibiting a higher thermal conductivity of nanofluids.

Data-driven analysis of molten-salt nanofluids for specific heat enhancement using unsupervised machine learning methodologies

High specific heat molten-salt is essential for sensible heat thermal energy storage. Current scientific researches focus on Molten-salt nanofluid as a potential solution. However, the causality between system parameters introduced in nanofluid preparation and specific heat enhancement is not clearly understood. Since difficulties are associated with identifying the explicit relations due to complex molecular interactions between molten-salt and nanoparticles, we inquired whether there is a common pattern/clusters in the nanofluid samples reported in earlier studies. The data-driven correlations among samples are explored by employing unsupervised machine learning methods: Hierarchical cluster analysis (HCA) and Principal component analysis (PCA). Three principal components, capturing 81.3% variation of the entire dataset, revealed that the descending order of contribution of the system parameters in the specific heat enhancement percent is concentration, temperature, density ratio, and nanoparticle size. The multivariate clusters emerging from HCA showed the interdependency of density ratio on the temperature, which significantly affects nanofluid's stability at higher concentration, causing a decrease in specific heat enhanced percent. Furthermore, the variation in nanoparticle size was found to have a negligible effect on specific heat enhancement.