Different Types Of Nanofluids Research Articles

Numerical simulation on thermohydraulic performance of different types of nanofluids in a corrugated-triangular channel

Nanofluids have garnered significant interest as a potential solution to address overheating challenges across diverse industries. Researchers are actively exploring different types of nanofluids to mitigate these issues. In this study, a numerical analysis was conducted using ANSYS software to examine the fluid flow and heat transfer characteristics of nanofluids (ranging from 0 to 4 volume fractions) in a corrugated wavy channel within the turbulent range. Various nanoparticles, including Al2O3, CuO, SiO2, and ZnO, were employed and dispersed in different base fluids such as ethylene glycol, glycerin, and water. The particle size of the nanoparticles ranged from 20 to 70 nm. The results revealed that SiO2/water-based nanofluids provide better heat transfer than all the water-based nanofluids. The maximum average Nusselt number and pressure drop of 200 and 115 Pa, respectively, were observed for SiO2 nanofluid (volume fraction of 0.04) with a particle size of 20 nm. Highlights Al2O3, CuO, SiO2 and ZnO considered in this work. Corrugated plates with three different corrugated angles of 20° to 60° are tested. Eexperiments are performed for different heat flux in turbulent range. Maximum heat transfer obtained for SiO2/water nanofluid.

Numerical Investigation of Nanofluid as a Coolant in a Prismatic Battery for Thermal Management Systems

Abstract This study delves into the realm of numerical investigation of the heat transfer performance of nanofluids as coolants for prismatic batteries. Nanofluids are being employed in battery cooling systems to enhance overall thermal management and ensure the safe operation of batteries, particularly in situations involving high heat generation. In this study, different types of nanofluids were used along with a base fluid of ethylene glycol–water (EG–water 50%). The energy equations consider the effects of viscous dissipation and heat generation. The model generates a set of nonlinear partial differential equations, which can be transformed into ordinary differential equations (ODEs) using appropriate similarity variables. These ODEs are then solved numerically by employing the Runge–Kutta–Fehlberg method along with the shooting method to obtain solutions. The simulations in both 2D and 3D showcase the results for various parameters pertaining to thermal and velocity fields, heat transfer rate, and drag force. The findings reveal that heat generation leads to a staggering increase in temperature of 78.22%. However, using aluminum nanoparticles (NPs) as opposed to copper nanoparticles quickly reduced the battery’s maximum temperature by 9.31%. The exceptional heat generation strengths of CuO–EG and Al2O3–EG nanofluids also resulted in a significant increase in their heat transfer rates of around 40.42% and 42.13%, respectively. Additionally, the aluminum NPs exhibited a more rapid heat transfer rate of 4.06% when compared to the copper nanoparticles. This research contributes to the development of improved cooling strategies for prismatic battery applications, ultimately paving the way for enhanced battery performance, an extended lifespan, and improved safety in a wide range of industries and electric vehicles.

ANALYTICAL EXAMINATION OF NANO-FLUID-ASSISTED COOLING RATE ENHANCEMENT IN A CAR RADIATOR

In recent years, nanofluids have been extensively utilized to improve heat transmission in various mediums. The use of nanofluids can enhance the thermal efficiency of thermosyphons. This study focuses on analyzing the thermal efficiency of automobile radiators by utilizing three different types of nanofluids. In this study, we conducted a thermal performance analysis of a car radiator by examining the effects of three different types of nanoparticles mixed with water: CuO-water, ZnO-water, and MgO-water nanofluids. The thermal performance of these three nanofluids was compared and analyzed. The experimental setup included a radiator with a hydraulic diameter of 0.0191 m and a total length of the radiator channel of 10.5354 m. The analyses are conducted at different volume fractions, ranging from 0.5% to 3%, and a constant inlet velocity of 0.24 m/s is maintained. The findings demonstrated a substantial enhancement in thermal efficiency when employing CuO-water nanofluid as a coolant for vehicle engine cooling in the radiator. Conversely, ZnO-water and MgO-water nanofluids exhibited very limited improvements in comparison to pure water. The thermal conductivity of CuO-water nanofluid is greater than that of pure water. The CuO-water nanofluid yields the most significant enhancements in terms of the mass flow rate and heat transfer coefficient, as revealed by this investigation. Hence, it is advisable to utilize CuO-water nanofluid in automobile radiators to achieve optimal heat transfer efficiency in comparison to the base fluid.

Performance enhancement of flat-plate and parabolic trough solar collector using nanofluid for water heating application

Flat plate solar collector (FPSC) and parabolic trough solar collector (PTSC) are widely used for residential solar water heating (SWH) applications. This work studied two different solar collector systems. Nanofluid and its influence on the residential solar water heating (SWH) systems were investigated. The two SWH systems were designed, installed, tested, and compared at varying mass flow rates (mf) of 0.47, 1.05, and 1.75 kg min−1 in ambient environmental conditions. The comparative study was conducted according to thermal efficiency (ηth), useful energy gain (QU), stored energy (QS), outlet hot water temperature (To), and difference temperature (ΔT) between the cold inlet and hot outlet water from the collectors. The analysis of outcomes showed that the PTSC was more efficient than FPSC. The FPSC and PTSC systems performance were investigated using two different types of nanofluids. Carbon nanotubes in water and ethylene glycol were utilized. A remarkable improvement in the average thermal efficiency 64.1 % and 80.6 % of FPSC and PTSC systems using ethylene glycol nanofluid were obtained respectively. The total reduction in CO2 emissions was 31.26 kg/day and 39.28 kg/day for the FPSCs and PTSCs, respectively in the presence of ethylene glycol nanofluid. A significant saving in CO2 release is owing to the renewable clean energy of solar collectors.

Effect of Magnetic Field on the Instability of Jeffrey Nanofluid (CuO + Blood and Cu + Blood) Filled in Hele-Shaw Cell with Rotation

There are so many works present in the literature with Hele-Shaw cell, Jeffrey nanofluid, magnetic field, and rotation individually, but here we carried out the combined study of these and it is important because there are so many applications of these in engineering, it may be used in energy absorption in the solar panel, because of Hele-Shaw cell is approximately similar to the solar panel. The main goal of the article is to analyse the instability of Jeffrey nanofluid filled in Hele-Shaw cell in the presence of the magnetic field and rotation. During the investigation, we obtained that the rotation parameter directly affects the behaviour of the Hele-Shaw number and magnetic Chandrasekhar number. Here we also analyze the behaviour of two different types of nanofluids (CuO + Blood and Cu + Blood) on the onset of convection and found that the onset of convection gets delayed in (Cu + Blood). Heat/mass transfer in the system has been analyzed by Mathematica NDSolve and Runge-Kutta-Fehlberg method (RKF-45) and found that the rate of heat/mass transfer is exactly the same by both methods. The Taylor number directly affects the behaviour of heat transfer and also found that the onset of convection gets advanced in Jeffrey fluid.

Determination of optimum parameters using different nano fluids in heat pipe heat exchangers with response surface method

In this study, optimum parameters affecting the thermal efficiency of heat pipes were determined experimentally with response surface method using different types of nanofluids in heat exchangers. Experimental design was carried out at three levels for four parameters affecting thermal efficiency. Experiments were made for Al2O3, TiO2 and SiO2 at 0.2-0.4-0.6% concentrations. Nanofluid suspensions were formed using isopropyl alcohol as the base fluid. The inlet temperatures in the evaporator region were determined as 30-60-90 °C, and the Reynolds numbers in the condenser region were determined as 7200, 14400 and 21600. The thermal efficiencies of the heat pipes were calculated as a result of the experiments carried out in accordance with the experimental design created with the response surface method. The accuracy of the model was tested with analysis of variance (ANOVA) and optimum parameters were obtained as nanoparticle SiO2, concentration 0.32%, evaporator inlet temperature 90 °C and Reynolds number 21600 in the condenser.

Energy, exergy, environment and techno-economic analysis of parabolic trough collector: A comprehensive review

Inexhaustible energy sources are the focus of the energy industry for meeting the increased need for energy and reducing carbon emissions. Among various alternatives, harnessing solar energy has become a promising choice around the world. Parabolic trough collectors (PTCs) are an effective way to transform radiant energy into thermal energy, as well as electricity. However, these collectors can be improved by refining their design and tweaking the parameters related to thermal behavior. This may be done either by enhancing the surface area or improving the heat transfer coefficient of the heat carrying medium. These kinds of improvements could be achieved by making the use of nanofluids and by using inserts or fins within the collector tube. The current study provides an extensive review of PTCs from the points of view of their design, along with their thermal characteristics. Different types of nanofluids as the working liquid are investigated and discussed to achieve better PTC performance. Inserts within the collector tube and various design approaches, including fins, twisted tubes, U-shaped tubes, coiled wire inserts, and porous twisted tape inserts, are reviewed and discussed in detail. Finally, based on this review, challenges of PTC applications are described and future research recommendations are proposed.

Experimental investigation of a solar evacuated tube collector embedded with a heat pipe using different nanofluids and controlled mechanical exciting pulsations

Numerous studies have been conducted to enhance the thermal performance of evacuated tube solar thermal collectors using various techniques, such as different working fluids, concentrators, and modifications to the absorber design. This work presents a parametric study to improve the thermal performance of a solar-evacuated tube collector embedded with a heat pipe (SETCHP) by utilizing different types of nanofluids and controlled mechanical excitation. The experiment involved six identical SETCHPs operating under the same conditions, with one setup filled with pure acetone as a reference. The second and third setups were filled with (0.5% vol Al2O3)/based acetone and (0.5% vol CuO)/based acetone, respectively. The remaining three setups were modified by imposing controlled mechanical excitation with different frequencies (27–82 Hz) to investigate the effect of vibration on thermal performance. The results demonstrated that the optimal enhancement was achieved with mechanical vibration pulses at 82 Hz, improving efficiency by 91% and 86% with Al2O3/based acetone and CuO/based acetone, respectively. The enhancement percentage of effective heat transfer coefficient (EHTC) and convective heat transfer coefficient (CHTC) varied with solar intensity and vibration, with improvements ranging from 5 to 82% and 3–53%, 26–160% and 5–60%, and 6.5–140% and 6.5–54% for pure acetone, Al2O3, and CuO (0.5% vol) acetone-based nanofluids, respectively.

Numerical investigation on cooling cylindrical lithium-ion-battery by using different types of nanofluids in an innovative cooling system

Temperature is known to greatly affect the efficiency, security, and cycle life of lithium-ion battery (LiB) cells. LiB cells are delicate to changes in temperature by using a variety of nanofluids. This study uses a novel cooling system with a Re between 15 × 103 and 30 × 103 to lower the cells' temperature. Al2O3, CuO, SiO2, and ZnO with nanoparticles concentrations of 5% and nanoparticle diameters of 20 nm dispersed in a base liquid (water) are used to produce the effects. The findings demonstrate that as the Re rises, so does the Nusselt number. An innovative cooling system is designed and numerically tested to show how different kinds of nanofluids affect the increment in heat transmission and distribution of temperature in LiB cells. The temperature of LiB cells drops by flowing the water between the 52 batteries inside the cooling pack. For each spacing value, the Reynolds numbers are increased, which results in an increase in the average Nusselt numbers. According to the computational fluids dynamics results, the Nusselt number rises with increasing spacing. The results show that Re of 18000, 22000, 25000, 27500, and >30000 are needed for SiO2 nanofluids, Al2O3 nanofluids, ZnO nanofluids, CuO nanofluids, and pure water, respectively, to get battery pack temperature of <40 °C (the typical operating conditions). Higher Re values improve the heat transfer slightly with the expense of pumping power; therefore, Re of 18000 with SiO2 nanofluids is preferred. The utilization of nanofluids also shows that SiO2 exhibits the best thermal cooling for battery packs among all investigated nanofluids. Al2O3 nanofluid is also an excellent option, followed by ZnO nanofluid. For example, the temperature reduction of the hottest battery cell reaches >47, 44, 43, 42, and 42 °C for SiO2 nanofluids, Al2O3 nanofluids, ZnO nanofluids, CuO nanofluids, and pure water, respectively.

The Performance of SiO2 Nanofluid-based Split-frequency PV/T Energy

The efficiency of both solar photovoltaic and thermal power generation is relatively low, with the maximum panel temperature of conventional PV/T modules reaching 68.4 °C at noon, and the average electrical efficiency is only 12.98%. In this paper, the energy performance of a PV/T module based on SiO2 nanofluid was studied. Firstly, three different types of nanofluids, SiO2 nanofluid with a mass fraction of 0.3%, mass fraction of 0.5%, and mass fraction of 0.7%, were prepared and tested for their solar spectrum transmittance, and the results manifested that only the SiO2 nanofluid with 0.5% mass fraction exhibited strong absorption characteristics in the band after 400–1150 nm. Three liquid film thicknesses of 5 mm, 10 mm, and 15 mm, and three nanofluid mass fractions of 0.3%, 0.5%, and 0.7% were selected for the calculation of the spectral transmittance and the experiments on the thermal efficiency of the whole PV/T module. After conducting twenty-minute experimental tests on the power generation efficiency, thermal efficiency, and panel temperature of the flat panel, the results turned out the maximum efficiency reached 52.19%, which was found at a liquid film thickness of 10 mm and a nanofluid mass fraction of 0.7%, with a lower temperature of 40 °C, and an average of 10 °C lower than conventional PV panels.

A Study of a Thermally-Vigorous Rayleigh-Bénard Convection in a Hybrid Nanofluid Using Non-Classical Boundary Condition

A linear stability analysis of a thermally-vigorous Rayleigh-Bénard convection in a mono and a hybrid nanofluid is carried out using the single-phase model. We make use of non-classical boundary condition on velocity (rough boundary condition) and temperature (third-type boundary condition) instead of a specific boundary condition (free-free isothermal, rigid-rigid isothermal, etc.) which is traditionally considered. The thermophysical properties are calculated using phenomenological laws and mixture theory. A unique and novel combination of a single-term Galerkin technique and the Maclaurin series expansion is used to solve the boundary-eigen-value problem obtained in the problem. The critical value of the wave number and the Rayleigh number that are calculated using the procedure are quite accurate up to 5 and 3 decimal places respectively. A comparative study on the instability in two types of nanofluids is carried out so as to infer which type of nanofluid suits best for thermally vigorous systems. This paper aims to provide a theoretical basis to ease the selection process pertaining to the making of a choice from different types of nanofluids. To validate the study sixteen limiting cases have been obtained. To visualize the flow behavior physically, streamlines have been plotted.

A molecular dynamics study of thermal conductivity and viscosity in colloidal suspensions: From well-dispersed nanoparticles to nanoparticle aggregates

This study investigates the microscopic transport behavior of nanofluids addressing some debatable points including the anomalous thermal conductivity (κ), against the predictions of classical effective medium theories. International Nanofluid Property Benchmark Exercise (INPBE) [J. Buongiorno et al., J. Appl. Phys. 106 (2009) 094312] has shown that no such anomaly found in well-dispersed nanofluids after conducting experiments for range of different types of nanofluids. However, a number of molecular dynamics based studies reported otherwise making inconsistent conclusion with INPBE. In this work, it is argued that the over predicted κ values reported in previous computational studies can be attributed to the ill-defined partial enthalpy formulation of the Green-Kubo method for multicomponent systems. Present study begins by addressing this issue via non-equilibrium molecular dynamics and shows that the results are in agreement with the conclusions of INPBE. Further, it is shown that the contribution of potential micro-mechanisms such as micro-convection due to Brownian motion, and the solid-like liquid layering are either absent or suppressed by the interface thermal resistance. The observed decreasing trend of viscosity enhancement to thermal conductivity enhancement ratio (Cη/Cκ) with increasing particle size indicates the improved heat transfer performance in nanofluids with larger nanoparticles. The effect of nanoparticle aggregation, the proposed originative mechanism of anomalous κ, is evaluated arranging nanoparticles as chain-like structures. A 67% improvement in κ is achieved with negligible viscosity variation. This rapidly reduces Cη/Cκ indicating better heat transfer performance with the presence of conductive paths due to the aggregation or in general extended nanostructures.

Heat Transfer and Fluids Properties of Nanofluids

As it is popular research field, extensive research has been performed in various areas of nanofluids, and most of the studies have demonstrated significant enhancements in their thermophysical properties and thermal transport performance compared to those of conventional thermal fluids. However, there have been unanimous conclusions regarding such enhancements and their underlying mechanisms. Nanofluids' potential and thermal applications mainly depend on their convective and boiling heat transfer performances, which are also not unbiased in the literature. On top of this, a major challenge with nanofluids is obtaining sustainable stability and persistent properties over a long duration. All these issues are very crucial for nanofluids' development and applications, and a lot of research in these areas has been conducted in recent years. Thus, this Special Issue, featuring a dozen of high-quality research and reviews on different types of nanofluids and their important topics related to thermophysical and electrical properties as well as convective and boiling heat transfer characteristics, is of great significance for the progress and real-world applications of this new class of fluids.

Numerical modelling of different types of nanofluids used to enhance the thermal performance of automotive radiator

Numerical modelling of different types of nanofluids used to enhance the thermal performance of automotive radiator

Three-dimensional numerical investigation of hybrid nanofluids in chain microchannel under electrohydrodynamic actuator

Energy efficiency enhancement methods have received considerable attention within the industry and scientific community, owing to the rising concern of global energy sustainability. The present article attempts to scrutinize the effects of electrohydrodynamics and nanofluids on the rate of heat transfer and fluid flow in the 3-D chain microchannels. Improved heat exchangers (e.g., chain microchannel) would have a key role in increasing of the performance of such systems since they provide efficient thermal management needed for more robust computational power. To date, analysis of electrohydrodynamics and nanofluids in the chain microchannel was not comprehensively discussed. Here, steady-state, laminar, and three-dimensional chain microchannel are numerically modeled based on a control volume method in Fluent. Results show that by increasing the volume fraction of nanoparticles, the viscosity of the nanofluid increases leading to an increase in pressure drops. Moreover, Nusselt at Re = 125, 250, 500 and 1000 for hybrid nanofluid () is 1.206, 1.541, 2.075 and 2.707, respectively which, in turn, depicts surging by 22.94%, 24.17%, 24.70% and 24.707% in comparison to water, respectively. In addition, at low Reynolds number (0.416 the lower Reynolds results in decreasing of percentage of pressure drop. Meanwhile, imposing electrohydrodynamic (V = 30 KV) at Re= 125, 250, 500 and 1000 leads to increasing by 23%, 22%, 20% and 18% of Nusselt number in comparison to absence of electric field, respectively. It means that the considered effect of the increasing the Nusselt number at lower Reynolds number is more effective. Moreover, heat transfer rises with augmentation of supplied voltage and Reynolds number. Highlights Using active (electrohydrodynamics and hybrid nanofluid) and passive (3-D chain microchannel) methods to enhance heat transfer rate. Adding two additional equations (including and V) in Fluent With Using UDS (User Defined Scalar). Writing UDM to achieve E () as well as UDF to solve source terms (E and Considering the charge convection term () in the electric current density ( owing to used fluids (water and nanofluids) in this article, whilst it is negligible for air. Investigation of effects of different types of nanofluid and their concentration as well as impacts of adding electrode and its voltages. Imposing electrohydrodynamic (V = 30 KV) at Re= 125, 250, 500 and 1000 leads to increasing by 23%, 22%, 20% and 18% of Nusselt number in comparison to absence of electric field, respectively.

Multi-objective optimization of a photovoltaic thermal system with different water based nanofluids using Taguchi approach

In this study, the effect of different nanofluids on the electrical and thermal efficiencies of photovoltaic thermal (PVT) systems was investigated experimentally and the variables affecting the efficiency were optimized by the Taguchi method. Experiments were carried out under laboratory conditions on the PVT system presently developed. In this study, a novel partitioned cooler block in the form of a rectangular prism was designed and used. Thus, the contact between the cooler block and the back surface of the PV panel and the associated PVT efficiency were increased. The following physical characteristics have been identified as the independent variables for the experiments carried out: SiO2/Water, Al2O3/Water and CuO/Water as different types of nanofluid, 0.1, 0.2 and 0.3 as volumetric concentration, 0.55, 1.1 and 1.65 lpm as volumetric flow rate and 300, 600 and 900 W/m2 as irradiance level. The reliability of the measurements made during the experiments was ascertained through the uncertainty analysis performed. The maximum electrical efficiencies of the PVT system for SiO2/Water, Al2O3/Water, and CuO/Water nanofluids were found to be 20.69 %, 21.18 %, and 20.77 %, and the maximum thermal efficiencies to be 57.06 %, 63.01 %, and 66.49 %, respectively. As the optimization method for determining the most optimum combination of variables, Taguchi analysis has been employed. As a result of this analysis, it has been shown that the most effective variables on the electrical efficiency of the PVT system are the irradiance, flow rate, volumetric concentration, and nanofluid type, respectively. On the other hand, regarding the thermal efficiency of the PVT system, the most effective variables are the irradiance, flow rate, nanofluid type, and volumetric concentration, respectively.

The role of nanofluids and fins in a heat exchanger on waste energy recovery from a diesel engine: An experimental and numerical study

A 3.7 kW diesel engine and a shell-and-tube heat exchanger were used in this study to decrease the temperature of exhaust gases and reduce the effects of greenhouse gases, respectively. The innovations utilized in this paper include the use of four novel non-linear arrangements of fins on the heat exchanger body, two different types of nanofluids (Ag, Fe3O4) in single and hybrid forms, and using the nanoparticles shape factor. The embedded simulation in the ANSYS-FLUENT commercial software was evaluated under the K-epsilon (κ−ɛ) turbulence modeling. The study results showed that the exhaust gases’ temperature drops by an average of 7.0% by increasing the curvature of the fins, while this value was obtained as 5.80% by enhancing the height of the fins from 8 mm to 24 mm. Examining the effect of the shape of the used nanoparticles revealed that changing the shape factor from Spherical to Lamina led to the increase of heat transfer rate by 4.33%. Also, at a constant shape factor, increasing the number of fins caused a 47.12% growth in the heat transfer rate. Therefore, one can say that the arrangement and number of fins have a larger influence on increasing the heat transfer rate than the nanoparticles shape factor. Moreover, increasing the concentration of nanofluids from 1% to 5% led to a 0.67% drop in the temperature of the exhaust gases. According to the research results, we can recognize the parameters of the number, shape, and arrangement of the fins, the type of nanofluid, and the nanoparticles shape factor as factors effective in reducing the temperature of exhaust gases from a diesel engine.

Effect of CuO‐, SiO2‐, and Al2O3‐based nanofluids on automotive cooling systems from laminar to turbulent flow regime—A CFD study

AbstractIn recent studies, much attention has been given to nanofluids suggesting that adding nanoparticles in base fluids offers a higher heat transfer rate compared with conventional fluids. This study is based on the numerical investigation of different types of nanofluids, consisting of CuO (50 nm), SiO2 (40 nm), and Al2O3 (15 nm) nanoparticles at different volume concentrations. Several simulations were performed from low to high Reynolds numbers, corresponding to laminar and turbulent flow regimes using ANSYS‐Fluent CFD solver. Results suggest that under a laminar flow regime with the same Reynolds number of 2000, CuO‐based nanofluids perform better as compared with SiO2 and Al2O3‐based nanofluids with Nusselt number (Nu) having percentage increase of 90% and 60% comparing with SiO2‐ and Al2O3‐based nanofluids, respectively. However, at higher Reynolds numbers when the flow is turbulent, Al2O3‐based nanofluids demonstrate better performance having a percentage increase in Nusselt numbers equal to 40% and 23% as compared with CuO and SiO2‐based nanofluids respectively under the same Reynolds number of 15,000. This implies that turbulence has a significant effect on heat transfer rate, and is not only related to thermal conductivity. This study will help in designing more compact cooling systems for engines and the internal environment of motor vehicles.

Numerical investigation of nanofluids comprising different metal oxide nanoparticles for cooling concentration photovoltaic thermal CPVT

The impact of utilizing Nanofluids with different metal oxide nanoparticles on heat transfer enhancement and fluid flow for concentration photovoltaic thermal the CPVT collector with Fresnel lens is demonstrated using CFD simulation. With the rising temperature, the electrical efficiency and output power of Multi-Junction Solar Cells drop. Four different types of nanofluids and water are utilized as cooling fluids to disperse heat from Multi-Junction Solar Cells by moving the fluid within the mini-channel beneath the PV Solar Cells. In the current analysis, the Reynolds numbers range from 2000 to 18000. For all forms of cooling fluids, the average Nusselt numbers are augmented by rising Reynolds numbers. The CFD results demonstrated that the Nusselt number of all nanofluid cooling fluids is greater than that of water. When compared to water in a CPVT collector, water-SiO2 nanofluid provides the maximum heat transfer improvement of 12.5%. The silicon dioxide nanoparticles have high thermal conductivity, with the water-SiO2 nanofluid exhibiting the greatest heat transfer increase, followed by water-Al2O3, water-ZnO, water-CuO, and water. The average top surface temperature of the mini-channel for the CPVT collector is reduced by 7% when water-SiO2 nanofluid is used as a cooling fluid and by 3.4% when water is used. The usage of water-SiO2 nanofluid has a significant impact on the heat dissipation with high heat transfer enhancement from Multi-Junction Solar Cells in CPVT collector, leading to an increase in electrical efficiency.

Quantitative investigation of nanofluid imbibition in tight oil reservoirs based on NMR technique

Nanofluids have been effective chemical additives for enhanced oil recovery (EOR) in tight oil reservoirs due to their special properties. However, oil imbibition recoveries vary for different nanofluids. The oil/water distribution in rocks during imbibition using various nanofluids was less discussed in previous studies. In this study, we systematically examined the imbibition efficiencies of various nanofluids at 60 °C. Furthermore, the migration of nanofluids and oil distribution in the rock pores were monitored using nuclear magnetic resonance (NMR). The nanofluids were prepared by dispersing silica nanoparticles and five different types of surfactants (i.e., anionic-nonionic, anionic, nonionic, amphoteric and cationic surfactants in deionized (DI) water. Subsequently, interfacial tension (IFT) and contact angle measurements were conducted to reveal the underlying EOR mechanisms of various nanofluids. The experimental results showed that the EOR potential of the different types of nanofluids was in the order anionic-nonionic > anionic > nonionic > amphoteric > cationic > brine. Anionic-nonionic (sodium lauryl ether sulfate (SLES)) and anionic (sodium dodecyl sulfonate (SDS)) nanofluids exhibited excellent capability of wettability alteration, and increased oil recovery by 27.96% and 23.08%, respectively, compared to brine. The NMR results also showed that mesopores (0.1–1 μm) were the dominant developed pores in the rocks, and contributed the most to imbibition efficiency. In addition, the imbibition of nanofluids initially took place in mesopores and micropores before moving into macropores. This study provides fundamental information on the selection of nanofluids for EOR in tight oil reservoirs. The study also improved the understanding of oil/water distribution during the imbibition of the proposed nanofluids.