Optimization and sensitivity analysis of heat transfer rate of tri-hybrid nanofluid of stagnation point flow

The aim of this investigation is to explore the flow phenomena in two distinct hybrid nanofluids (with micropolar fluid as the base fluid) undergoing hydromagnetic pulsation between two vertical walls, accompanied by entropy generation. This study also explores the unique heat transfer characteristics of F e 3 O 4 − Ti O 2 and A l 2 O 3 − MgO hybrid nanofluids, with the effects of Ohmic heating, thermal radiation, and viscous dissipation. The goal of using hybrid nanofluids is to improve the performance of biological systems such as nano-drug delivery in arteries, magnetic bio-separation, artificial kidneys, pressure surges, magnetofection agents, biomedical engineering, cancer treatments, and brain tumor treatment. The governing partial differential equations are transformed into a system of ordinary differential equations, which are then solved numerically by a shooting technique with a fourth-order Runge-Kutta method using a bvp4c MATLAB solver. Graphical explanations are provided for the flow variables such as the velocity, the microrotation, the temperature, the entropy generation, and the Bejan number. The heat transfer rate is an increasing function of the thermal radiation parameter; when the thermal radiation parameter increases from 1 to 3 the increases in the heat transfer rates in micropolar fluid (the base fluid), first hybrid nanofluid ( F e 3 O 4 − Ti O 2 ), and second hybrid nanofluid ( A l 2 O 3 − MgO ) are respectively 55%, 51%, and 43.86%. However, while the heat transfer rate (the Nusselt number) is a diminishing function of the Hartmann number. Further, the outcomes reveal that the hybrid nanofluids with emerging physical effects are helpful to treat cancer patients, recovering the damaged tissues and cells in arteries, and various medical-related procedures.

In current work, the unsteady stagnation point’s flow on a special third-grade fuzzy hybrid ( A l 2 O 3 + Cu/SA ) nanofluid (HNF) through a permeable convective shrinking/stretching sheet has been scrutinized. In addition, the adverse consequences of heat source, viscous dissipation, nonlinear thermal radiation, and fuzzy nanoparticle volume fraction are likewise taken into consideration. Non-linear coupled partial differential equations (PDEs) get transformed into ordinary differential equations (ODEs) using an effective similarity transformation. After that, the ODEs are numerically solved using the bvp4c algorithm. Regarding validation, the present results align with earlier published research. The effects of heat distribution, flow rate, Nusselt number, and skin friction coefficient on hybrid nanofluid dynamics are explored using graphical and tabular forms. The nanoparticle volume fraction is considered a triangular fuzzy number (TFN) [0, 5%, 10%]. With the use of TFNs, ODEs are transformed into fuzzy differential equations (FDEs). The TFNs are controlled using a widely used ζ - cut technique and ζ - cut ∈ [ 0 , 1 ] , which requires minimal computational effort to examine their dynamical performance. Also, the comparison of A l 2 O 3 /SA, Cu/SA and A l 2 O 3 + Cu/SA through the fuzzy membership functions (MFs). The fuzzy MFs show that the hybrid nanofluid ( A l 2 O 3 + Cu/SA ) in terms of rate of heat transfer is better than both Cu/SA and A l 2 O 3 /SA nanofluids.

PurposeThe purpose of this study is to provide that porous media and viscous dissipation are crucial considerations when working with hybrid nanofluids in various applications.Recent years have witnessed significant progress in optimizing these fluids for enhanced heat transfer within porous (Darcy–Forchheimer) structures, offering promising solutions for various industries seeking improved thermalmanagement and energy efficiency.Design/methodology/approachThe first step is to transform the original partial differential equations into a system of first-order ordinary differential equations (ODEs). The fourth-order Runge–Kutta method is chosen for its accuracy in solving ODEs. The present study investigates the free convective boundary layer flow of hybrid nanofluids over a moving thin inclined needle with the slip flow brought about by inclined Lorentz force and Darcy–Forchheimer porous matrix, viscous dissipation.FindingsIt is found that slip conditions (velocity and Thermal) exist for a range of the natural convection boundary layer flow. In the hybrid nanofluid flow, which consists of Al2O3 and Fe3O4 are nanoparticles, H2O − C2H6O2 (50:50) are considered as the base fluid. The consequence of the governing parameter on the momentum and temperature profile distribution is graphically depicted. The range of the variables is 1 ≤ M ≤ 4, 1 ≤ d ≤ 2.5, 1 ≤ δ ≤ 4, 1 ≤ Fr ≤ 7, 1 ≤ Kr ≤ 7 and 0.5≤λ ≤ 3.5. The Nusselt number and skin friction factors are used to calculate the numerical values of various parameters, which are displayed in Table 4. These analyses elucidate that upsurges in the value of the Fr noticeably diminish the momentum and temperature. It is investigated to see if the contemporary results are in outstanding promise with the outcomes reported in earlier works.Practical implicationsThe results can be very helpful to improve the energy efficiency of thermal systems.Social implicationsThe hybrid nanofluids in heat transfer have the potential to improve the energy efficiency and performance of a wide range of systems.Originality/valueThis study proposes that in the combined effects of hybrid nanofluid properties, the inclined Lorentz force, the Darcy–Forchheimer model for porous media and viscous dissipation on the boundary layer flow of a conducting fluid over a moving thin inclined needle. Assessing the potential practical applications of the hybrid nanofluids in inclined needles, this could involve areas such as biomedical engineering, drug delivery systems or microfluidic devices. In future should explore the benefits and limitations of using hybrid nanofluids in these applications.

This study investigates the flow and heat transfer of mono and hybrid nanofluids owing to a stretching cylinder in a porous medium under the influence of a magnetic field and convective boundary condition. The hybrid nanofluid is made up of copper (Cu) and silver (Ag) nanoparticles dispersed in a water-ethylene glycol mixture at a mass ratio of 50:50. The binary mixture of water and ethylene glycol is intermixed with spherical-shaped nanoparticles (copper) to create a mono nanofluid. The study considers the effects of generalized Fourier’s law and heat generation/absorption. The novelty of the study lies in considering the comparison of hybrid and mono nanofluid flows heat transfer efficiency with assumed effects and convective condition at the boundary of the cylinder. A system of ordinary differential equations (ODEs) controlling the flow and heat transport are derived using similarity transformations and are solved numerically using the bvp4c program of MATLAB software. The work explores the ways in which different parameters, such as the shape of the nanoparticles and their volume percentage, affect the pertinent profiles and are depicted in the form of graphical illustrations and numerically tabulated values. The results demonstrate that, in comparison to mono nanofluids, hybrid nanofluids including spherical and blade nanoparticles have a higher heat transfer rate and reduced surface drag when the particle volume fraction is increased in a water-ethylene glycol combination. Furthermore, there is a 0.83% increase in the heat transfer rate for hybrid nanofluids in comparison to mono nanofluids. This is because compared to mono nanofluids, hybrid nanofluids have lower viscosity and better heat conductivity. The results obtained in this study are vetted by making a comparison with published works and an excellent agreement between the values is seen. The study may find use in solar thermal systems, electronic cooling, heat exchangers, and other areas.

The present study aims to offer new numerical solutions and optimisation strategies for the fluid flow and heat transfer behaviour at a stagnation point through a nonlinear sheet that is expanding or contracting in water-based hybrid nanofluids. Most hybrid nanofluids typically use metallic nanoparticles. However, we deliver a new approach by combining single- and multi-walled carbon nanotubes (SWCNTs-MWCNTs). The flow is presumptively steady, laminar, and surrounded by a constant temperature of the ambient and body walls. By using similarity variables, a model of partial differential equations (PDEs) with the magnetohydrodynamics (MHD) effect on the momentum equation is converted into a model of non-dimensional ordinary differential equations (ODEs). Then, the dimensionless first-order ODEs are solved numerically using the MATLAB R2022b bvp4C program. In order to explore the range of computational solutions and physical quantities, several dimensionless variables are manipulated, including the magnetic parameter, the stretching/shrinking parameter, and the volume fraction parameters of hybrid and mono carbon nanotubes. To enhance the originality and effectiveness of this study for practical applications, we optimise the heat transfer coefficient via the response surface methodology (RSM). We apply a face-centred central composite design (CCF) and perform the CCF using Minitab. All of our findings are presented and illustrated in tabular and graphic form. We have made notable contributions in the disciplines of mathematical analysis and fluid dynamics. From our observations, we find that multiple solutions appear when the magnetic parameter is less than 1. We also detect double solutions in the shrinking region. Furthermore, the increase in the magnetic parameter and SWCNTs-MWCNTs volume fraction parameter increases both the skin friction coefficient and the local Nusselt number. To compare the performance of hybrid nanofluids and mono nanofluids, we note that hybrid nanofluids work better than single nanofluids both in skin friction and heat transfer coefficients.

This study used an experimental setup consisting of a flat tube with a louvered finned crossflow configuration to examine the effects of utilizing a ZnO-TiO2-water hybrid nanofluid on heat transfer rate, heat transfer coefficient, Nusselt number, and pressure drop. The studies were carried out under laminar flow conditions (200 < Re < 800), at four different temperatures (50, 60, 70, 80 °C), four different volume concentrations of nanoparticles (0.025, 0.05, 0.1, 0.2%), and three different volume flow rates (4, 6, 8 LPM). The findings were compared with pure water (0%). The results indicate that using hybrid nanofluid improves the heat transfer performance and increases pressure loss in comparison with pure water. When comparing hybrid nanofluid to pure water, the largest increases in heat transfer rate, heat transfer coefficient, Nusselt number, and pressure drop were 87.8%, 21.7%, 26.4%, and 10%, respectively. In addition, it was found that, up to a specific value (0.05%), increasing the nanoparticle volume concentration enhanced the heat transfer rate, heat transfer coefficient and Nusselt number, but which began to decrease on increasing the concentration past this value. Therefore, it was concluded that nanoparticle volume concentrations greater than 0.05% negatively affect heat transfer under the current operating conditions. The maximum heat transfer rate, heat transfer coefficient, and Nusselt number were obtained under the conditions of an 8 LPM volume flow rate, 80 °C inlet temperature, and 0.05% volume concentration.

Hybrid nanofluids are significant in biomedical, industrial, transportation, as well as several engineering applications due to their high thermal conductivity and mass transfer enhancement nature in contrast to regular fluids and nanofluids. Taking this into consideration, the present problem explores the flow of hybrid nanofluid (Ag − TiO 2/H 2 O) over a stretching cylinder subject to Newtonian heat and mass conditions. The novel aspect of the current work is to analyze the heat and mass transfer characteristics of MHD hybrid nanofluid flow on Darcy-Forchheimer porous medium in addition to activation energy, nonlinear thermal radiation, heat generation/absorption, viscous and Joulian dissipation. Further, Silver (Ag) and Titanium oxide (TiO 2) are the constituent nanoparticles of the water-based hybrid nanofluid owing to their stable chemical features and extensive industrial manufacturing. By introducing suitable similarity transformations, the governing partial differential equations (PDEs) of the developed model are reduced to ordinary differential equations (ODEs), and then the numerical solution is procured with shooting technique by using MATLAB solver bvp4c. The influence of the pertinent parameters is depicted graphically and described elaborately. The analysis indicates that velocity exhibits a declining trend against the permeability and Forchheimer parameters, while the temperature profiles show opposite behavior. The radiation and conjugate heat parameters (R, γ 1) upgrade the heat transfer rate, while the curvature and conjugate mass parameters (α c , γ 2) amplify the mass transfer rate. The maximum heat transfer rate of Ag − TiO 2/H 2 O hybrid nanofluid is 2.3344 attained for γ 1 = 0.6. The investigation demonstrates larger heat and mass transfer rates for Ag − TiO 2/H 2 O hybrid nanofluid than Ag − H 2 O nanofluid. The outcomes of the present investigation have practical applications in conjugate heat transfer over fins, development of vaccines, effluent treatment plants, solar cells, heat exchangers, and many more. An excellent agreement is achieved on comparing our numerical results with the published results in the literature.

What dominates heat transfer performance of hybrid nanofluid in single pass shell and tube heat exchanger?

This research examines the rheological and thermal properties of a Williamson hybrid (Al2O3 and Cu/EO) nanofluid flow across Riga wedge under influence of heat source, velocity slip, stagnation point, and thermal effect. This study combines fuzzy logic and an artificial neural network approach to model dynamic behavior of the hybrid nanofluid that involves complicated interactions and predicts its performance under different conditions. Triangular fuzzy number (TFN) is used to analyze the importance of fuzzy volume fractions of nanomaterials. TFN is used to compare the thermal properties of nanofluids including Cu/EO, Al2O3/EO, and hybrid nanofluid (Al2O3 and Cu/EO), using triangular fuzzy number the concentration of nanoparticles swaying the thermophysical properties are considered as uncertain parameters. The ANN framework integrates two optimization techniques: LMS (Levenberg‐Marquardt scheme) used for quick training and BRS (Bayesian regularization scheme) used for improved generalization, is implemented to investigate the physical properties and initial data. Results indicate that the hybrid nanofluid improves heat transfer efficiency compared to conventional fluids, making it a promising candidate for advanced thermal management systems. Best validation performance of LMS and BRS for skin friction and Nusselt number is 3.5665e‐07 and 4.0682e‐10 at epoch 272 and 63, respectively. Potential applications include cooling technologies, heat exchangers, electronic device cooling, and industrial thermal regulation. These findings provide a robust foundation for optimizing nanofluid formulations in energy‐efficient engineering applications.

This article investigates Maxwell hybrid nanofluids (Cu-Al2O3/water and CuO-Ag/water) at a stagnation point over an extended sheet. The issue is motivated by its potential importance in enhancing thermal efficiency in modern heat transfer applications, crucial in optimizing manufacturing processes and energy conservation technology. Therefore, the present study investigates a non-Newtonian Maxwell nanoliquid across a mixed convection boundary layer (BL) and heat broadcast past a shrinking/stretching surface containing hybrid nanoparticles. In the current work, two different kinds of hybrid nanofluids are involved: Cu-Al2O3/water and CuO-Ag/water. Copper particles (Cu) and Copper oxide particles (CuO) are mixed into an Al2O3/water and Ag/water nanofluid to study these two types. The flow is acted upon the impact of a uniform magnetic field(MF) and a stagnation point. The issue arises from their enhanced thermal conductivity and heat transfer capabilities, which are crucial for enhancing energy efficiency in advanced cooling systems and engineering applications involving stagnation point flows. By utilizing suitable transformations, the partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs). The prototype undergoes computational analysis utilizing the fourth-order Runge-Kutta (RK-4) method in conjunction with the shooting technique. The outcomes of the current work have applicable importance concerning the stagnation point flow, like cooling of nuclear reactors, cooling of microelectronic procedures by supporters, wire drawing, polymer extrusion, and many engineering hydrodynamic applications. The influences of the picked factors on the temperature, velocity, heat transmission rate, and skin friction factor are theoretically and numerically investigated. It is found that the existence of different hybrid nanoparticles with the influences of other parameters plays a significant role in both the velocity and temperature distributions. Additionally, the stagnation point creates a separation limit in the liquid flow that reverses the magnetic field influence between these flow regions.

There has been significant interest in exploring a stagnation point flow due to its numerous potential uses in engineering applications such as cooling of nuclear reactors. Hence, this study proposed a numerical analysis on the unsteady magnetohydrodynamic (MHD) mixed convection at three-dimensional stagnation point flow in Al2O3–Cu/H2O hybrid nanofluid over a permeable sheet. The ordinary differential equations are accomplished by simplifying the governing partial differential equations through suitable similarity transformation. The numerical computation is established by the MATLAB system software using the bvp4c technique. The bvp4c procedure is excellent in providing more than one solution once sufficient predictions are visible. The influence of certain functioning parameters is inspected, and notable results exposed that the rate of heat transfer is exaggerated along with the skin friction coefficient while the suction/injection and magnetic parameters are intensified. The results also signified that the rise in the volume fraction of the nanoparticle and the decline of the unsteadiness parameter demonstrates a downward attribution towards the heat transfer performance and skin friction coefficient. Conclusively, the observations are confirmed to have multiple solutions, which eventually contribute to an investigation of the analysis of the solution stability, thereby justifying the viability of the first solution.

Dual solutions for mixed convective stagnation-point flow of an aqueous silica–alumina hybrid nanofluid

This study utilizes the two-phase mixture model to conduct a numeric study of Al2O3/Water and Al2O3-Cu/Water (hybrid) nanofluid's hydrodynamic and thermal behavior in a laminar confined impinging slot jet in 50 ≤ Re ≤ 300 and nanoparticles volume fractions (NVF) ranging from 0 - 2%. This study considers various aspect ratios (H/W), including 2, 4, and 6, to investiate the confining effects. This paper gives a comparative analysis of nanofluids and hybrid nanofluids in terms of the parameters concerning the flow: Reynolds and local Nusselt number (Nux), average Nusselt number (Nuavg), flow lines' contour, and temperature distribution under similar geometric conditions and Reynolds number. In comparison with nanofluids, the hybrid nanofluids have higher local Nusselt number on the entire target surface, this advantage of hybrid nanofluid attribute to higher thermal conductivity of them. The average Nusselt numbers of nanofluids and hybrid nanofluids plotted at different Refor various aspect ratios(H/W=2,4), and the effect of aspect ratio and momentum are explained. Furthermore, pumping power of both fluid analysed for all nanoparticles volume fraction (0 - 2%) at different Reynolds number. The result shows that pumping power of hybrid nanofluid is higher than base fluid and nanofluid, because the dynamic viscosity of hybrid nanofluid is higher than base fluid (water) and nanofluid. Besides; the study identified some correlations in the hybrid nanofluids regarding the stagnation point and the average Nusselt numbers. Presumably, these correlations are valid under certain conditions: 50≤ Re ≤ 300, 2 ≤ H/W≤ 6, and volume fracture (0 - 2%).

This paper presents the numerical study of thermal performance factor of Al2O3-Cu/water hybrid nanofluid in circular and non-circular ducts (square and rectangular). Turbulent regime is studied with the Reynolds number ranges from 10000 to 100000. The heat transfer performance and flow behaviour of hybrid nanofluid are investigated, considering the nanofluid volume concentration between 0.1 and 2%. The thermal performance factor of hybrid nanofluid is evaluated in terms of performance evaluation criteria (PEC). This present numerical results are successfully validated with the data from the literature. The results indicate that the heat transfer coefficient and Nusselt number of Al2O3-Cu/water hybrid nanofluid are higher than those of Al2O3/water nanofluid and pure water. However, this heat transfer enhancement is achieved at the expense of an increased pressure drop. The heat transfer coefficient of 2% hybrid nanofluid is approximately 58.6% larger than the value of pure water at the Reynolds number of 10000. For the same concentration and Reynolds number, the pressure drop of hybrid nanofluid is 4.79 times higher than the pressure drop of water. The heat transfer performance is the best in the circular pipe compared to the non-circular ducts, but its pressure drop increment is also the largest. The hybrid nanofluid helps to improve the problem of low heat transfer characteristic in the non-circular ducts. In overall, the hybrid nanofluid flow in circular and non-circular ducts are reported to possess better thermal performance factor than that of water. The maximum attainable PEC is obtained by 2% hybrid nanofluid in the square duct at the Reynolds Number of 60000. This study can help to determine which geometry is efficient for the heat transfer application of hybrid nanofluid.

MHD slip effects on (50:50) hybrid nanofluid flow over a moving thin inclined needle with consequences of non-linear thermal radiation, viscous dissipation, and inclined Lorentz force