Effect Of Nanoparticles Addition Research Articles

Effect of nanoparticle additives on the refrigerant and lubricant mixtures heat transfer coefficient during in-tube single-phase heating and two-phase flow boiling

Lubricant in heat exchangers acts as a contaminant and it affects the heat transfer and pressure losses. Nanolubricants, that is, nanoparticles dispersed in lubricant oils, have shown potential to augment heat transfer rates in refrigerant direct-expansion evaporators. However, the mechanisms of such heat transfer enhancements are still unclear. Experiments were conducted to study the saturated two-phase flow boiling heat transfer phenomena of refrigerant R410A with two nanolubricants in a 9.5 mm I.D. smooth copper tube. The nanolubricants had non-spherical ZnO nanoparticles and spherical γ-Al2O3 nanoparticles dispersed in Polyolester (POE) lubricant. Al2O3 nanolubricant shared similar thermal conductivity in the wet state as that of ZnO nanolubricant. However, Al2O3 nanolubricant had about 15% higher heat transfer coefficient that ZnO nanolubricant. The heat transfer coefficients of R410A-nanolubricant mixtures degraded by about 20% with respect to that of the R410A, but improved at higher vapor qualities. The experiments showed that long-term flow boiling testing of R410A and nanolubricant mixtures resulted in a continuous gradual increase of the heat transfer coefficient. In smooth copper tubes, nanoparticle deposition on the tube inner wall, which was experimentally observed, and the near wall interactions of nanoparticles promoted additional nucleate boiling and led to such increase.

Effect of Nano Particle Addition on the Performance and Emission Characteristics of a Compression Ignition Engine

Inorganic nanotubes are attracting the attention of many scientists and investigators, due to their outstanding application potential in different fields. Researches have been performed in the field of internal combustion engines by adding nanoparticles into the diesel fuel and in biodiesel and blends and their effect on overall performance were studied. It is understood that doping of nanoparticles tend to decrease the emission levels from the engines. Owing to that idea, this project is directed to investigate the effect of doping nanoparticle over the performance and emission characteristics of a compression ignition engine. Nanotubes are mixed with diesel fuel as a fuel additive at different compositions that are 25 ppm, 50 ppm, 100 ppm to find the variation in performance and emission characteristics and results indicate that nanoparticle doped fuel shall be used as an alternate fuel without any modifications to engine structure.

Compatibility of container materials for Concentrated Solar Power with a solar salt and alumina based nanofluid: A study under dynamic conditions

Thermal energy storage (TES) is an efficient solution for improving the dispatchability of Concentrated Solar Power (CSP) plants. A system, consisting of two tanks with Solar Salt (NaNO3 60% wt. and KNO3 40% wt.) is commonly used. However, the investment cost of this technology is very high, due to the huge amount of salts required (thousands of tons). A pronounced interest is evident for improving the thermophysical properties of molten salts by adding small amounts of nanoparticles in order to reduce the mass of molten salts at CSP. At the moment, the effect of nanoparticle addition on corrosion of container materials is poorly explored. In particular, there are no works regarding the dynamic effect of nanoparticles on the corrosivity of molten salts. In this work we present first ever dynamic corrosion tests for Solar salt doped with alumina nanoparticles (1% wt.). Carbon Steel A516 and SS347, used in double-tank system, were tested. Corrosion rates were 94.8 μm yr−1 and negligible respectively (1000 h, 385 °C). Detailed examination of construction materials revealed incorporation of nanoparticles into the corrosion layer and considerably lower corrosion rate as compared to the previously reported work on the nanoparticles-free Solar salt.

The Effect of Nanoparticles Addition on the Properties of Polymer Weighted Drilling Fluid

The experimental studies of polymer drilling fluid s weighted with B-5 and B-6 barite with the addition of silicon oxide nanoparticles wt. 2% are presented. The concentration of barite particles in muds ranged from 10 to 40 wt. %. The size of microparticles was 70 μm. The size of nanoparticles was 5 nm. The effect of nanoparticles addition on rheological and tribological parameters of polymer drilling fluids weighted with barite depending on the concentration of microparticles was established.

Effect of Nanoparticles Addition on the Microstructure and Properties of Lead-Free Solders: A Review

With the development of microelectronic packaging and increasingly specific service environment of solder joints, much stricter requirements have been placed on the properties of lead-free solders. On account of small size effect and high surface energy, nanoparticles have been widely used to improve the microstructure and properties of lead-free solders. Therefore, the composite solders bearing nanoparticles have recently attracted wide attention. This article reviewed the recent research on SnAgCu, SnBi, and SnZn composite solder alloys and introduced the effect of nanoparticles on their microstructure, mechanical properties, wettability, and reliability. The mechanism of nanoparticles strengthening was analyzed and summarized. In addition, the shortcomings and future development trends of nanoparticle-reinforced lead-free solders were discussed, which is expected to provide some theoretical reference for the application of these composite solder in 3D IC package.

Effect of different nanoparticles on microstructure, wetting and joint strength of Al–12Si–20Cu braze filler

The effect of nanoparticle additives (La2O3, SiC, and ZrO2) on microstructure and brazing characteristics of Al–12Si–20Cu alloy produced by induction melting was studied. The morphology and composition of the samples was studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analysis. The melting point of the fillers was determined by differential thermal analysis (DTA). Filler wettability was studied in terms of spread ratio (SR) on Al 3003 substrate. The joint strength was assessed by tensile shear study in brazed lap-joints of Al 3003 sheets. The results demonstrated that addition of La2O3 in Al–12Si–20Cu showed best wetting (79.6%) and melting (531.2 °C), while the addition of SiC alloy showed moderate tensile shear strength (79.1 MPa) and lowest wettability (76.34%) among Al–12Si–20Cu–La2O3 and Al–12Si–20Cu–ZrO2 and Al–12Si–20Cu–La2O3 SiC composites. The addition of ZrO2 in Al–12Si–20Cu alloy showed moderate wetting (78.2%) and lowest tensile strength (78.3 MPa) compared to Al–12Si–20Cu–La2O3 and Al–12Si–20Cu–SiC. The mechanism behind the microstructural modification of Al–12Si–20Cu alloy in the presence of nanoparticle additives has also been discussed.

Heat treatment effect on the microstructure and corrosion behavior of Al-6061 alloy with influence of α-nanoalumina reinforcement in 3.5% NaCl solution

Al-6061 alloy based nanocomposites were synthesized using sol-gel prepared nanoparticles of α-alumina in their varying weight percentages (0, 0.5, 1.5, and 2.5 wt%) via powder metallurgy route. The synthesized nanocomposites were sintered and heat treated under solutionized and T6 conditions. Afterwards, electrochemical corrosion tests were performed in 3.5% NaCl solution to see the effect of nanoparticle addition on the corrosion behavior of the composites. Heat treatment results indicate that solutionized composites exhibit better corrosion resistance as compared to the composites treated under sintered condition. Heat treatment under T6 condition showed poorest corrosion resistance. Nanocomposite reinforced with 0.5 wt% of nanoparticles showed excellent corrosion resistance than that of 1.5 wt% of nanoalumina incorporated composite. After 2.5 wt% incorporation of nanoparticles, the corrosion rate of the composite becomes very high even more than that of the base alloy. Increase of nanoparticle concentration was found to increase their agglomeration at the grain boundary region that increases porosity in the composite. This ultimately increases the corrosion reaction because of the enhanced chemical reactivity. The microstructural examination of the synthesized nanocomposites were found in good agreement with the corrosion rate determined from electrochemical tests.

Utilisation of sebacic acid and nanohydroxyapatite in polyurethane nanocomposite coating

The present research is focused on two-pack polyurethane (PU) coatings formulated from a polyester polyol based on renewable sebacic acid in combination with poly(ethylene glycol)-400. The purpose behind incorporating the sebacic acid was to increase the chain length. The polyester polyol was prepared by melt condensation in the presence of tosylic acid as a catalyst and characterised (acid value, Fourier transform infrared spectroscopy, gel permeation chromatography, proton (1H) nuclear magnetic resonance etc.). The prepared polyester polyol was converted to PU coatings by reacting with diphenylmethane diisocyanate. Simultaneously, to improve the physical properties of the aforesaid PU coatings, hydroxyapatite nanoparticles, which were synthesised from waste eggshells of hens’ eggs, were added in amounts of 1, 3 and 5%. The effect of nanoparticle addition on the properties of the final PU coatings such as gloss, adhesion and flexibility was studied. The dispersion of nanoparticles was observed by scanning electron microscopy, while the thermal behaviour was studied by thermogravimetric analysis and differential scanning calorimetry techniques.

Thermophysical and tribological properties of nanolubricants: A review

Recent studies in heat transfer evident that the nanofluid shows better heat transfer results as compared to base fluid. This influences the research community for the dispersion of nanoparticles in lubricants to enhance its thermophysical and tribological properties and these suspensions are termed as Nanolubricants. This review focuses on the effect of nanoparticle additives on thermophysical and tribological properties of base lubricant. Initial section briefly summarizes the variation in thermophysical properties namely viscosity, thermal conductivity, density and specific heat of nanolubricants. In later section, the coefficient of friction and anti-wear properties of nanolubricants are summarized. This review along with the replenishment of current knowledge, also discusses the fundamental mechanisms that evolve with the dispersion of nanoparticles.

A Study on Polyurethane Hybrid Nanocomposite Foams Reinforced with Multiwalled Carbon Nanotubes and Silica Nanoparticles

ABSTRACTMultifunctional polyurethane foams reinforced with multiwalled carbon nanotubes and silica nanoparticles enhanced specific properties. We studied the effects of nanoparticle addition into polyurethane on mechanical properties and thermal stability by means of tensile, Charpy impact, hardness tests, and thermogravimetric analysis. Nanoparticles added to polyurethane are multiwalled carbon nanotubes, two types of silica nanoparticles, and multiwalled carbon nanotube/spherical silica as hybrid filler. Hybrid polyurethane/spherical silica/multiwalled carbon nanotube nanocomposite with the constant overall content of 0.75 wt% showed higher tensile strength, hardness, and thermal stability than either of nanoparticles at this content, which approves a synergistic effect between multiwalled carbon nanotubes and silica nanoparticles.

Frequency-Selective Surface to Determine Permittivity of Industrial Oil and Effect of Nanoparticle Addition in X-Band

A frequency-selective surface (FSS) structure is proposed for characterization of the permittivity of industrial oil using a transmission/reflection (TR) measurement scheme␣in the X-band. Moreover, a parameter study is presented to distinguish the dielectric constant and loss characteristics of test materials. To model the loss empirically, we used CuO nanoparticles artificially mixed with an industrial oil. In this study, the resonant frequency of the FSS is the basic parameter used to determine the material characteristics, including resonance properties such as the magnitude of transmission (S 21), bandwidth, and frequency shift. The results reveal that the proposed FSS structure and setup can act well as a sensor for characterization of the dielectric properties of industrial oil.

Tribological Performance of Green Lubricant Enhanced by Sulfidation IF-MoS₂.

Biopolymers reinforced with nanoparticle (NP) additives are widely used in tribological applications. In this study, the effect of NP additives on the tribological properties of a green lubricant hydroxypropyl methylcellulose (HPMC) composite was investigated. The IF-MoS2 NPs were prepared using the newly developed gas phase sulfidation method to form a multilayered, polyhedral structure. The number of layers and crystallinity of IF-MoS2 increased with sulfidation time and temperature. The dispersity of NPs in the HPMC was investigated using Raman and EDS mapping and showed great uniformity. The use of NPs with HPMC enhanced the tribological performance of the composites as expected. The analysis of the worn surface shows that the friction behavior of the HPMC composite with added NPs is very sensitive to the NP structure. The wear mechanisms vary with NP structure and depend on their lubricating behaviors.

Double-stage sintering behavior of a nickel nanoparticle dispersed micro powder

Powder metallurgy (PM) has undergone innovations through powder advances and novel process development. Another option for advancement of PM technology is exploitation of the extreme bimodality of nano/micro powder mixtures. The present study describes bimodal powder preparation involving dispersion of nickel nanoparticles onto the surface of a micro powder to facilitate the compaction ability and sinterability of the Ni micro powder. The bimodal powder is designed by synthesizing Ni nanoparticles by reactive RF thermal plasma from a Ni(OH)2 micro powder, selecting a spiky-shaped Ni micro powder as the supporting powder, and then filling the pockets on the surface of the micro powder with the nanoparticles. Simple 3-D turbulent mixing successfully produces spheroidized and smoothened micro-granules consisting of well-dispersed nanoparticles on the surface of the micro powder. Nanoparticle compaction is usually difficult, but the compaction behavior of the micro-granules is similar to that of the micro powder. The effect of nanoparticle addition on sinterability, investigated by dilatometry, includes double-stage sintering behavior of the micro-granule powder, whereas the spiky-shaped micro powder shows a typical monotonous sintering behavior. Consequently, the first shrinkage at low temperature arises from the enhanced sinterability of the nanoparticles, while the second shrinkage shows similar behavior to the micro powder. Within the scope of this study, the micro-granules show a higher relative density than the micro powder.

Effect of Nanoparticle Additives on Partitioning of Cephalexin in Aqueous Two-Phase Systems Containing Poly(ethylene glycol) and Organic Salts

In this work, the ability of four nanoparticles including Al2O3, TiO2, graphene, and graphene oxide (GO) as additives for extraction of cephalexin in aqueous two-phase systems composed of polyethylene glycol (PEG) and three sodium-based organic salts was investigated. For this purpose, phase diagrams and the liquid–liquid equilibrium (LLE) data for the {PEG 6000 + sodium citrate, sodium tartrate, sodium succinate + H2O} and partition coefficient for cephalexin were determined. The addition of 0.001 wt % graphene oxide increased the partition coefficient by 9% for the {PEG + sodium citrate + water} system, while other nanoparticles had no effect or decreased the partition coefficient. To investigate the effect of GO concentration on the partition coefficient, various concentrations ranging from 0.005 to 0.04 wt % was examined. It is observed that at a GO concentration equal to 0.01 wt %, the maximum partition coefficient improvement is achievable to be 59%. The highest partition coefficient 5.74 was obtained for the system {PEG6000 19 wt %, sodium citrate 10 wt %, and GO 0.01 wt %}. It can be concluded that a trace amount of nanoparticles can change the partition coefficient either by increasing or decreasing. It seems that the concentration of nanoparticle also has a significant effect on the partition coefficient.

Preliminary analysis of the possibility of preparing PVB/IF-WS2 composites. Effect of nanoparticles addition on thermal and rheological behavior of PVB

A possibility of using inorganic fullerene-like tungsten disulfide, IF-WS2, nanoparticles as a filler in poly (vinyl butyral), PVB, for improving its thermal and rheological properties is examined. PVB is a thermoplastic polymer with excellent properties, widely used: in ballistic protection, for protection of safety glass, in metal primers and coatings, temporary binders. Two different molecular weights of PVB were previously examined in this research: Mowital B60H and B75H. Both grades of PVB were dissolved in different solvents: ethanol and 2-propanol. Thin films were prepared by solvent casting technique. The glass transition temperature (Tg) of the tested samples was determined using differential scanning calorimetry (DSC), at three different heating rates (5°C/min, 10°C/min and 20°C/min). After choosing a solvent and PVB grade, IF-WS2 nanoparticles were added to PVB solutions and dispersed by ultrasonic irradiation. Compatibility, i.e. interaction of IF-WS2 with the dissolved PVB was examined by microcalorimetry method. The nanoparticles dispersion and deagglomeration in matrix of PVB was analyzed by scanning electron microscope (SEM). The effect of IF-WS2 on rheological properties of the chosen samples has been examined using Dynamic Mechanical Thermal Analysis (DMTA), observing storage modulus, loss modulus and the loss factor as functions of temperature for the tested composites.

Numerical study on skin friction reduction of nanofluid flows in a Taylor–Couette system

In this study, the effects of nanoparticle addition in a vertical Taylor–Couette system are studied. The model is made up of two concentric vertical cylinders. The inner cylinder is rotating and the outer one is stationary. The base fluid is 5W-30 oil and the nanoparticles are made up of diamond, WS2 and MoS2. Single phase flow is assumed. The parameters considered are the nanoparticle concentration and the flow Reynolds number. The results showed that adding nanoparticles to the base fluid in laminar flow regime affect skin friction lightly. However, the skin friction decreased in turbulent flow regime appreciably. The maximum decrease is about 13.8% with WS2-oil nanofluid and the minimum amount accounts by using diamond nanoparticles.

Effect of ageing time on the tensile behavior of Sn–3.5 wt% Ag–0.5 wt% Cu (SAC355) solder alloy with and without adding ZnO nanoparticles

In this work, lead-free composite solder was produced by mixing ZnO-nano-sized particles with Sn–3.5% Ag–0.5% Cu solder. The effects of nano-particle addition on the melting behavior, microstructure and tensile properties of the as-solidified composite solder are systematically investigated. In comparison with solder without the addition of ZnO nanoparticles metallographic observations revealed that the grain size of β-Sn, the intermetallic compounds (IMCs) average grain size and distance decreased significantly in the composite solder matrix. This was possibly ascribed to the strong absorption effect and high surface free energy of ZnO nanoparticles. Our results show that 0.5wt% addition of ZnO nanoparticles led to an improvement in microstructure, proof stress (ơy0.2), ultimate tensile stress (ơUTS) and fracture stress (ơf) compared with non-composite solder. Differential scanning calorimetry (DSC) revealed that the melting temperature of SAC355 composite solder is slightly higher by about 1.1K than that of the conventional SAC355 solder. The observed increase of mechanical properties was rendered to refined IMCs, acting as a strengthening phase in the solder matrix. Ageing the specimens of both solders for different aging times at all different testing temperatures, resulted in the decrease of tensile properties investigated. This was attributed to ripening of IMC particles leading to decrease of their pinning action of dislocation movements which was emphasized by SEM examinations. This interpretation is in consistence with the theoretical prediction from dispersion strengthening theory.

The effect of nanoparticle additives on lubrication performance in deep drawing process: Evaluation of forming load, friction coefficient and surface quality

The success of a sheet metal forming process is strongly dependent on the performance of provided lubricant at the tool/blank interface. Recent studies have revealed that the tribological properties of lubricating oils can be improved by adding small volume fraction of nanoparticle additives. Nevertheless, the efficiency of Nano-lubricants in actual sheet metal forming processes has not been evaluated so far. In this study, the tribological behavior of Al2O3 nanoparticles dispersed in CM202A press drawing oil was investigated in deep drawing process. Experimental tests were conducted for different concentrations of nanoparticles. The comparison between the formed cups under various lubrication regimes were conducted in terms of surface quality and maximum deformation load. Also, the friction coefficient at die/blank interface was determined inversely by finite element analysis. The results indicated that the friction reduction capability of base oil is enhanced by adding the Al2O3 nanoparticles, which consequently reduces the required forming load. In addition, a noticeable improvement in the surface quality of the formed cups is acquired.

Effect of Nanoparticle Additives on Journal Bearing Lubricated with Non-Newtonian Carreau Fluid

This research work presents the influence of Al2O3 nanoparticle additives on the performance characteristics of a journal bearing. Non-Newtonian fluid based on Carreau viscosity model was represented for SAE10W50 oil blended with Al2O3 nanoparticles in this work. Reynolds equation and energy equation have been formulated and solved numerically using finite difference method and multigrid multilevel techniques with boundary conditions. The static characteristics of the journal bearing under isothermal and adiabatic conditions were examined. The results show that the addition of Al2O3 nanoparticles improve load-carrying capacity of the journal but almost no change on film temperature due to good thermal property of Al2O3 nanoparticles.

Effect of Silica and Tin Oxide Nanoparticles on Properties of Nanofibrous Electrospun Separators

Innovative separators able to improve the performance and safety of Li-ion batteries are under investigation to meet the growing demand for large-size and high energy density electrochemical cells. In this work, highly porous nanofibrous Poly(vinylidene fluoride) (PVdF) separators loaded with oxide nanoparticles were produced by electrospinning. Silicon oxide and tin oxide nanoparticles were added to PVdF and membranes were characterized by SEM-EDS and TGA. The effect of nanoparticle addition on electrolyte uptake, mechanical properties and conductivity was investigated and such properties were compared to those of a commercial separator (Celgard 2400). Results showed that a small amount of additive can significantly improve the properties of PVdF electrospun membranes and that the different nanoparticles investigated in this work have different effect on membrane performances. In particular, the addition of SiO2 increases the rate of electrolyte uptake and the toughness of the electrospun membrane, while the addition of SnO2 decreases the rate of electrolyte uptake and increases the stiffness of the electrospun membrane. When loaded with nanoparticles, PVdF membranes maintain their insulating character also at high temperature. Preliminary electrochemical results on half-cell vs Li with LiFePO4 and electrospun separators showed good cycling performance, highlighting interesting features of this technology.