Types Of Nanofluids Research Articles

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.

Thermal performance investigation of transient natural convective nanofluid flow in a square cavity with inclined periodic magnetic field

The goal of this paper is to analyze the thermal exhibition of transient free convective nanofluid flow in a square cavity with inclined periodic magnetic field using one-component thermally equilibrium homogeneous model. Distinct thermal settings (constant, parabolic, and sinusoidal) for the left heated wall are deliberated when the right wall of the cavity is cold and the horizontal walls are insulated. For numerical simulations, eight types of nanofluids consisting Cu, Co, Zn, and Al2O3 nanoparticles along with H2O and kerosene as base fluids have been employed. During numerical computation, the impacts of different factors (Hartmann number, Rayleigh number, nanoparticles volume fraction, period, and inclination angle) on the fluid flow and heat transfer are examined. The numerical results show that cobalt-kerosene nanofluid distributes the maximum heat transfer rate compared to other 7 types of nanofluids. The results also indicate that sinusoidal thermal scenery at the left heated wall delivers the uppermost average Nusselt number compared to the other types of thermal approaches. The optimum thermal performance is achieved at magnetic field's inclination angle δ=π3 and period number λ = 1 for the case of sinusoidal scenery.

Radiative flow of temperature-dependent viscosity power-law nanofluids over a truncated cone saturated heat generating, porous media: Impacts of Arrhenius energy

In this paper, the coupled flow of the pseudo-plastic, dilatant/Newtonian nanofluids along truncated cones is treated using a set of non-similar solutions. The dynamic viscosity is assuming to be a variable and depending on flow region temperature. The non-Darcy model where the quadratic drag is significant is applied to formulate this situation and the medium's permeability is varied according to the modified Ostwald-de-Waele power law model. Both of the Arrhenius activation energy and non-linear radiation flux impacts are assumed. The converted system is treated using the effective finite differences analyses with Blottner scheme. The major outcomes disclosed that the temperature and nanoparticles distributions are higher in case of the pseudo-plastic nanofluids while the dilatant nanofluids types gives the higher rates of the heat and mass transfer. The Darcy flow case causes higher values of the Nusselt number comparing to the non-Darcy case. Further, presence of the activation energy supports the convective situation and enhances the Nusselt and Sherwood coefficient.

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.

A Review on the Nanofluids-PCMs Integrated Solutions for Solar Thermal Heat Transfer Enhancement Purposes

The current review offers a critical survey on published studies concerning the simultaneous use of PCMs and nanofluids for solar thermal energy storage and conversion processes. Also, the main thermophysical properties of PCMs and nanofluids are discussed in detail. On one hand, the properties of these types of nanofluids are analyzed, as well as those of the general types of nanofluids, like the thermal conductivity and latent heat capacity. On the other hand, there are specific characteristics of PCMs like, for instance, the phase-change duration and the phase-change temperature. Moreover, the main improvement techniques in order for PCMs and nanofluids to be used in solar thermal applications are described in detail, including the inclusion of highly thermal conductive nanoparticles and other nanostructures in nano-enhanced PCMs and PCMs with extended surfaces, among others. Regarding those improvement techniques, it was found that, for instance, nanofluids can enhance the thermal conductivity of the base fluids by up to 100%. In addition, it was also reported that the simultaneous use of PCMs and nanofluids enhances the overall, thermal, and electrical efficiencies of solar thermal energy storage systems and photovoltaic-nano-enhanced PCM systems. Finally, the main limitations and guidelines are summarized for future research in the technological and research fields of nanofluids and PCMs.

Thermal impacts of electromagnetic trihybrid nanofluid flow through a porous expanding sheet with chemical amalgamation: Entropy analysis

The challenge arises from the inadequacy of conventional fluids to facilitate effective heating and cooling processes in industries. Trihybrid nanofluids, consisting of a combination of three distinct types of nanoparticles suspended in base fluids, emerge as the upcoming generation of heat transfer mediums. This innovative category of fluids can be attributed to their broad potential applications in a multitude of nanotechnology and heat transfer devices. The aim of the present study is to analyse the generation of entropy resulting from the changes in temperature-dependent viscosity in the motion of an electromagnetic trihybrid nanofluid over a porous stretched surface. This investigation considers the impact of radiation, heat sources, and chemical reactions. The nonlinear partial differential equations that govern the system are converted into ordinary differential equations using a similarity substitution. The resulting ODEs are subsequently resolved by means of the shooting mechanism in conjunction with the Runge-Kutta-Fehlberg methodology. The findings of the study have been elucidated via the execution of a comparative analysis involving three types of nanofluids. The velocity of the nanofluids decreased by 13.12% and 15.8% due to changes in viscosity and porousness, while it exhibited a 13.12% increase in trihybrid nanofluids with enhanced convection.The velocity demonstrates an inverse relationship with electric and magnetic fields, leading to a 2% variation in nanoparticle behavior. However, the temperature increases by 8.24% in trihybrid nanofluids subjected to the same fields. The Eckert number, radiation, and heat source parameters enhance the temperature in trihybrid nanofluids by 8.12%. The electric and magnetic field intensities result in a reduction of entropy production in nanofluids by 4.92%, while the Bejan number experiences a 14.48% increase in trihybrid nanofluids under the same fields. Moreover, Eckert number, heat generation, and electric and magnetic fields lead to accelerated heat transfers. The findings suggest that trihybrid nanofluids transfer heat 9.24% faster than regular or hybrid nanofluids.

Complex dielectric response and EDL characteristics of different types of ionic liquid iron oxide nanofluids (ionanofluids)

Ionic liquid based magnetic nanofuids (ILMFs), an important subclass of ‘IoNanofuids’, have promising prospectus in numerous technological fields. Herein, we have investigated on the dielectric response and ac conductance behaviour of 1 wt% iron oxide-based ILMFs synthesized using pyridinium-based ILs viz., 1-Butyl-4-methylpyridinium tetrafuoroborate (A), 1-Butyl-4-methylpyridinium chloride (B), 1-Butyl-4-methylpyridinium bromide (C) and 1-Butylpyridinium bromide (D), and having variable stability. The dielectric permittivity exhibited a strong correlation with temperature and frequency, especially at low frequency ranges. Havriliak-Negami (H-N) function was plotted for all the four ILMFs which demonstrated a complex dielectric behaviour. The complex dielectric responses (in the range between 10−1–107 Hz) of these ILMFs at various frequencies and temperatures showed two relaxation processes following either Debye or non-Debye nature. The ILMF synthesized in B and D were the stablest. In B, two relaxation processes at 104 Hz and 6 × 102 Hz were observed (at 373.15 K), the temperature dependence being much stronger for the second process. Cole-Cole processes are observable in both relaxations. α parameters varied in the range 0.8 – 1.0 and 0.62 – 0.9 for first and second relaxation process respectively and β parameter equal to 1 at all temperature range for both relaxation processes. In ILMF synthesized using D, Debye relaxation with two relaxation processes were observed closer at 9.1 × 103 Hz and 1.1 × 103 Hz. All the α and β parameters were 1 or 0.99 indicating same relaxation time for all molecules. With D having higher anion-cation interaction energy, Debye process could be observed. The alternating current (AC) conductance of these ILMFs tends to increase with increase in temperature as well as frequency of applied field till 105 Hz after which it decreases.

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.

Effect of nanomaterials functionality on the acidic crude oil: Wettability and oil recovery studies

Chemical enhanced oil recovery often involves the injection of chemicals, such as surfactants, polymers, nanoparticles, and macromolecules. These chemicals are to alter the rock-oil-water interactions and mobilize the oil towards the production well. However, they often pose considerable challenges in the harsh environment of the oil-wet reservoirs, such as chemical instability, and high retention/adsorption of chemicals in the near-wellbore. Herein, we investigated the effect of functionalized silica nanofluids on improving oil recovery in the carbonate reservoir as a function of the oil acidity. To do so, we synthesized two types of silica nanofluids functionalized with sulfonate and carboxylate groups. We used two crude oils with different total acid numbers (TAN) of 0.4 and 5.7 mg/KOH. All experiments were ran at 100 °C and salinity of 67–240 kppm to simulate the harsh reservoir conditions of the Saudi Arabia. Spontaneous imbibition oil recovery studies were conducted to assess their effects on oil recovery. Contact angle and interfacial tension were performed at different conditions to examine the oil recovery mechanism. Further, in order to corroborate the previous research and comprehend the principles underlying the oil recovery, we also examined the electrokinetic zeta potential in parallel. Also, to better understand how oil and nanofluid functional groups interact, we conducted a surface complexation model study. In addition, molecular simulation (density functional theory and molecular dynamics) are employed to gain atomistic insights on the implicated molecular interactions between nanosilica particles with calcite surface in seawater brine. DFT simulations predicted that both functionalized nanosilica can form thermodynamically stable complexes with a dry and hydrated calcite surface. Further, MD simulations reveal that a good amount of both functionalized nanosilica are interacting with calcite surface in the diffuse electric double layer of the calcite-brine interface. However, the carboxylated functionalized nanosilica particles interact with rock stronger than sulfonated ones. Further, the carboxylated nanosilica could form stable complexes with naphthenic acids mediated by calcium ions, which supports the synergy effect observed experimentally. The results shed light on much more complex mechanisms behind the oil recovery rather than the common peripheral understanding. This work provides a good insight into the applicability of nanofluids for enhanced oil recovery for further research and field trials.

A numerical investigation of cross‐diffusion on magnetohydrodynamic Cu‐Al2O3/H2O hybrid nanofluid flow over a stretching sheet with chemical reaction

AbstractHybrid nanofluids (HNFs) are a promising type of nanofluid (NF) that combines two different nanoparticles to enhance their thermal and mechanical properties. They have gained significant attention in various engineering and scientific applications. This research focuses on studying the temperature‐dependent viscosity of a magnetohydrodynamic copper‐alumina‐water‐based HNF with thermal radiation, diffusions, and chemical reaction on a stretching sheet embedded in a porous medium. To achieve this, we transform the partial differential equations (PDEs) governing the system into a system of nonlinear ordinary differential equations (ODEs) using systematic similarity transformations. The resulting ODEs are solved using the shooting mechanism in combination with the Runge–Kutta–Fehlberg methodology. The results for the impact of the nanoparticle reactions on thermal, concentration, and velocity profiles, surface drag force, as well as mass and heat transfer rates are presented through graphs and tables. The key findings of this study demonstrate that the HNF accelerates velocity by 6.62%, but the magnetic field weakens it by 9.26%. Chemical reaction and Schmidt number affect nanoparticle concentration inversely. Radiation and heat source parameters increase the temperature by 14.89%, but the Prandtl number decreases it by 2.2%. Moreover, the Cu‐Al2O3/H2O HNF exhibits better thermal efficiency by 17.75% compared with the copper‐water NF. This research holds potential for applications in heat transduction, energy production, biomedical research, the manufacturing sector, aerospace technology, and more.

Pool Boiling Heat Transfer Characteristics of SiO2 and BN Nanoparticles Dispersed Mono and Hybrid Nanofluids.

This study reports an experimental investigation of pool boiling (PB) heat transfer performance of hybrid (two types of particles) and mono (single-particle) nanofluids consisting of Boron nitride (BN) and Silicon dioxide (SiO2) nanoparticles (NPs). While hybrid nanofluids (HNFs) were prepared in a total particle concentration of 0.05 vol.% with four different percentages of these two types of NPs (are 0.01/0.04, 0.02/ 0.03, 0.03/0.02, and 0.04/0.01 (BN vol.%/SiO2 vol.%)), two mono nanofluids (MNFs) of BN and SiO2 nanoparticles were prepared at the same total concentration of 0.05 vol.% for each NP type. Both nanofluids (NFs) were prepared in the base fluid (BF), which is the mixture of 15 vol.% of ethylene glycol (EG) and 85 vol.% of distilled water (DW). Then, the boiling heat transfer performance of these MNFs and HNFs was assessed by experimentation in a pool boiling test rig. The obtained results demonstrated good improvements in critical heat flux (CHF) and burnout heat flux (BHF) of both types of NFs. The CHF increased by up to 80% for BN-based MNF and up to 69% for HNF at 0.04 vol.% BN, which is the maximum percentage of BN into HNF, while the lowest improvement in CHF was 48% for the SiO2-based MNF compared to the BF. Similarly, the BHF was found to increase with the increasing in the loading of BN nanoparticles and a maximum enhancement of BHF of 103% for BN-based MNF was observed. These HNFs and MNFs exhibited significantly improved pool boiling heat transfer performance compared to this BF, and it became lower by increasing the percentage of SiO2 NPs in the HNFs.

Hydrothermal behavior of different hybrid nanofluids in a dimpled tube heat exchanger

The thermal and fluid flow performance of three types of hybrid nanofluid (HNF) inside a dimpled tube was investigated. The water with a dual mixture of Cu particles combined with CuO, TiO2, and Al2O3 nanoparticles (NPs) is used as heat transfer fluid (HTF). The fluid flow and heat transfer were studied numerically using the two-phase mixture and sensitivity analysis was made to reveal the effect of the Reynolds number (Re) and solid volume fraction (ϕ) of HNF on the Nusselt number (Nu), friction factor and overall thermal performance factor. The results demonstrated that under the investigated Re number of 30,000 to 50,000 and ϕ = 0.5% to 1.5%, the highest heat transfer improvement is for Cu-CuO/water HNF and the lowest is for Cu-TiO2/water; also, the improving effect of ϕ increase is more considerable at lower Re numbers. Between different HNFs, the quotient of f/f0 is the highest in the case of Al2O3Cu/water HNF. The highest value of thermal performance factor is dedicated to HNF of CuOCu/water followed by Al2O3-Cu/water and Cu-TiO2/water which average 1.065, 1.055, and 1.039, respectively; also, this factor for Al2O3Cu/water has the lowest sensitivity to ϕ change and for Cu-TiO2/water has the lowest sensitivity to change of Re number.

Evaluation of tool wear during turning of Ti6Al4V alloy applying MQL technique with Cu nanoparticles diversified in terms of size

In case of hard-to-cut materials, as titanium alloy Ti6Al4V, eco-friendly cooling methods or their modifications are still being developed. Therefore, various types of nanofluids are applied in the cutting process to reduce friction in the cutting zone and thus heat accumulation in the tool corner. This paper presents an analysis of the selected tool wear indicators, as well as the wear mechanisms, after turning with various cooling/lubricating techniques, including: MQL with the addition of copper nanoparticles (CuNPs), dry machining and the MQL technique without nanoparticles. Four sizes of CuNPs were applied: 22 nm, 35 nm, 65 nm and 80 nm. Analysis of SEM images and maps of elemental distributions on the cutting edge working surfaces allowed to determine that the smallest sizes of copper nanoparticles introduced in the cutting fluid result in reduced tool flank wear, as well as the reduced width and depth of the crater wear on the rake face. With the smallest size of copper nanoparticles, a “ball bearing” and tribofilm formation effects were obtained, which prevented intense adhesive and abrasive wear. Turning, applying MQL + CuNPS 22 nm method resulted in a decrease of selected tool wear rates from 25.7% to 55% compared to effects reached during dry machining, and from 11.7% to 39.2% compared to effects of MQL turning without addition of nanoparticles to the cutting fluid.

Squeezing motion of radiative magnetized ternary hybrid nanofluid containing graphene-graphene oxide-silver nanocomposite in water base fluid placed between two parallel plates

The present article explores flow of ternary hybrid nanofluid (THN) between two parallel plates in which upper one is in squeezing motion. The study of squeezing flow has its importance in industrial applications, like the flow between pistons and nozzles in the engine of vehicles. THN (graphene-graphene oxide-silver/water) is used to improve the efficiency of heat carrier fluid by the synergetic effects of nanoparticles. Magnetic field and thermal radiation effects are also included in the problem. Governing mathematical form of the problem is constructed by using a modified Buongiorno nanofluid model. Dimensionless system of ODEs reduced from PDEs through transformations and further simplified towards the solution with the numerical approach ‘bvp4c’, a MATLAB based solver. The reliability of the outcomes is confirmed by matching them with the previously published works. The findings reveal that the nanofluid velocity reduces with squeezing and magnetic parameters in the mid-section between the plates and its temperature can be controlled by the amount of nanoparticles dispersed into it, Prandtl number and the radiation effect. Overshoot in the concentration is attained for higher temperature gradient forces. Also, local Nusselt and local Sherwood numbers show contrasting trends for the upper and lower plates with the types of nanofluid (ternary/binary/unary), Prandtl number and radiation effect, but remain stationary with compression and magnetic effect. That means better transfer characteristics are found for ternary nanofluid, radiation and magnetic effects for the lower plate, but drag also intensifies; so suitable choices are considered for practical purposes. By the comparative analysis, it can be concluded that the performance of ternary hybrid nanofluid is relatively more efficient than binary and unary for heat transfer applications.

Heat Exchangers Using Multi Types of Nanofluids: A Review

A heat exchanger, which may be found in cooling systems, refineries, power plants, and other facilities, is one of the frequently utilized devices in the application heat transfer process. Water, mineral oil, and ethylene glycol—which has poor heat transfer characteristics—were the typical fluids utilized in heat exchangers. Hence, nanofluid was employed to enhance the fluid's ability to transport heat in heat exchangers. The issue of enhancing heat transmission in heat exchangers with nanofluid was researched experimentally, theoretically, and experimentally. Some of the research done in this area is as follows.

Enhancing photovoltaic panel efficiency using a combination of Zinc Oxide and Titanium Oxide water-based nanofluids

The efficiency of a photovoltaic (PV) panel decreases as its temperature increases, which is caused by an increase in solar irradiation. To maintain high electricity efficiency, it is necessary to keep the PV's operating temperature low. Therefore, a cooling system is needed to decrease the temperature of PV panels, especially when solar irradiation is high. Hybrid nanoparticles have attracted considerable interest in the field of PV cooling because of their distinctive characteristics and potential uses. They have the ability to significantly improve the performance and efficiency of solar panels. By offering advantages such as effective heat dissipation, improved heat transfer, favorable optical properties, increased stability, and cost-effectiveness, hybrid nanoparticles play a critical role in enhancing PV cooling. Leveraging these unique attributes, hybrid nanoparticles hold the potential to elevate the efficiency, reliability, and overall performance of photovoltaic systems. This study involved a three-stage process. The initial two stages focused on identifying the optimal concentration of Zinc oxide water-based nanofluid and Titanium oxide water-based nanofluid. The third stage sought to determine the ideal combination of these two nanofluids. Throughout each stage, five identical PV modules were utilized and placed adjacent to one another. During the experiment, one PV module was used as a base, while the other four were coated on their backside with a specific concentration of the corresponding nanofluid type. During the study, K-type thermocouples were employed to measure the hourly averaged backside temperature of each module. These thermocouples were attached to the backside of the modules to obtain accurate readings. Additionally, a GL 220 midi logger was utilized to record the voltage, current, and power of each PV throughout the duration of the experiment. Based on the findings of the study, it was found that in general, the performance of each PV was improved upon the coating process, with the best PV panel performance obtained when using a mixture of 0.4% TiO2 and 0.2% ZnO concentration by increasing the output power by 22.81% and increasing the efficiency by 29.47%.

Natural Convection Cooling of a Heat Source Placed at the Bottom of a Square Cavity Filled with Water-Based Nanofluid

The present work deals with the cooling process of a heat source, placed in the center of the bottom wall of a square cavity. A numerical resolution using finite volume method was carried out. The cavity is filled with a water-based Nanofluid, where four different types have been assumed. The vertical and top walls are under low temperature TC. Two thermal conditions were assumed at the source (q-imposed or T-imposed), while the remaining parts of the same wall are isolated. The effects of Rayleigh number (Ranf), source length (SL), volume concentration of nanoparticles (Φ) and their types were analyzed. The case of pure water (Φ = 0%), studied first, served as a reference case. The results obtained for this case, showed the increase of disturbances in the dynamic and thermal fields, in addition to the average rate of heat transfer (Nu) when Ra increases and SL decreases. SL = 1.0 case showed exception. These effects are more important for the T-imposed case than the other. Subsequently, the Al2O3-Water Nanofluid is considered with 0 <Φ≤ 10%. An increase in circulation intensity with improvement of local (Nu) and average (Nu) heat exchange rates have been recorded when Φ increases, although mentioning that its effect is significantly stronger for the q-imposed case. In the last part of the work, three other types of Nanofluids were assumed, where the obtained results showed the main improving effect of higher thermal conductivity on the heat transfer intensity. An important result which can be summed up in the great rapprochement of the heat exchange intensities for strong Ranf and Φ for SL close to 1.0, for the two heating types. In other words, the condition on the source loses its importance for such considerations.

Stagnation Bioconvection Flow of Titanium and Aluminium Alloy Nanofluid Containing Gyrotactic Microorganisms over an Exponentially Vertical Sheet

The pivotal aim of this research is to address a natural stagnation bioconvection flow of a hybrid nanofluid containing gyrotactic microorganisms over an exponentially stretching and shrinking vertical sheet. The mathematical formulation of simplified Navier-Stokes equations is made in the presence of a few parameters such as Prandtl number, concentration to thermal buoyancy ratio, microorganism to thermal buoyancy ratio, Lewis number, bioconvection Peclet number, bioconvection Lewis number, microorganisms concentration difference and buoyancy parameter. The two types of nanofluid containing titanium alloy (Ti6Al4V) and aluminium alloy (AA7075) immersed in water are considered for the investigation. In the analysis, the governing partial differential equations (PDEs) are transformed into a set of ordinary differential equations (ODEs) by a similarity transformation. The resulting equations are rewritten in MATLAB software through the Bvp4c method to obtain the solutions. The effects of hybrid nanofluid of titanium alloy (Ti6Al4V) and aluminium alloy (AA7075), microorganisms’ concentration difference parameter, and bioconvection Lewis Number are observed in this mathematical model in the presence of stretching and shrinking sheets. The numerical values are obtained for the skin friction coefficient, local Nusselt number, local Sherwood number, and local density of motile microorganisms for the reporting purpose. In addition, the profiles of the velocity, temperature, concentration, and microorganism are visualized as the main findings of this article.

Eminence of ferrite particle shapes in stratified nanofluids concerning the melting phenomenon: Lie group and spectral analysis

The current study is being done to determine how the shape factors of NiZnFe2O4 (nickel zinc ferrite) nanosolid particles affect the free convective flow of engine oil (C8H18) based stratified nanofluid over a melting stretchable surface, which play a part in establishing flow patterns and thermal features. NiZn ferrite nanoparticles of needle, platelet, and brick shapes are used to assess the impact of shape factors in the presence of melting phenomena, heat generation/absorption, and viscous dissipation. Optimal solutions are obtained by the spectral local linearization method via Lie group analysis, with an emphasis on residual errors. According to the evaluation, this type of nanofluid is found to have a lower friction factor, entropy, and Bejan number when compared to conventional fluids. In the presence of viscous dissipation, brick-shaped particles are found to have a higher heat transport rate, whereas needle-shaped particles minimize entropy by 58.66%. Suspended ferrite nanoparticles with a melting effect reduce the entropy up to 62.4% and stratified nanofluid with a brick shape has a higher heat transfer rate as compared to ordinary nanofluid. It is also observed that heat absorption produces less heat transport compared to heat generation. This research is found to be useful in many sectors, such as tumor treatments, electromagnetic interfaces (EMI), microwave applications, bone plate surgeries, and aerodynamic extrusion processes.