Search

This study investigated fluid flow and forced convective heat transfer in rectangular microchannels with square barriers, as illustrated in Fig. 1. In the first situation, three obstacles were positioned along the microchannel's top wall. In the second scenario, obstacles were positioned along the microchannel's bottom wall. In the final example, three square obstacles are placed symmetrically on either side of the microchannel wall. With the help of the Finite Element Method (FEM), we investigate the physicochemical behavior of the microchannel. The development of computer code within COMSOL multiphysics made it possible to simulate heat transport and fluid flow. The results include the implications of the rarefaction effect on fluid flow and heat transmission and decisions regarding the location of barriers and the shape of obstacles in squares. In addition, with the lowest value in skin friction and a lower Nusselt number, the third example, which has barriers on both sides, provides a valuable method for reducing the fluid temperature at the exit of the microchannel. This is because it has barriers on both sides. In the section under "Results and Discussion," we provide an in-depth analysis of the numerical data derived from the microchannel. • Objective: This study aims to numerically investigate forced convective heat transfer in a rectangular channel featuring multiple square obstacles. The simulation employs the FEM to model fluid flow and temperature distribution. • Geometry and complexity: The channel geometry incorporates square obstacles, introducing geometric complexity. The FEM is chosen for its capability to handle intricate geometries accurately. [ABSTRACT FROM AUTHOR]

This novel study unfolds the heat and mass transfer investigation of Williamson nanofluid (WNF) through a porous medium past a stretching plate, along with considering heat generation/absorption. Nanoparticles hold significant significance in thermal engineering, industrial operations, and biomedical advancements, contributing to enhanced heat transfer, cooling mechanisms, thermal extrusion processes, and applications in cancer treatment, particularly in addressing brain tumors. The coupled ordinary differential equations (ODEs) are gained from governing partial differential equations (PDEs) by applying sufficient transformations. Then the ODEs of a nonlinear nature, along with boundary conditions, are solved through bvp4c, a built-in MATLAB program. A good agreement has been found in comparing the present study with already published papers. Numerical values for skin friction, mass transfer, and heat transfer are shown through a table against involved physical parameters, especially for both injection (S < 0) and suction (S > 0) cases, by varying the values of unsteadiness parameter A and Weissenberg number W e . The effects of the physical parameters on velocity, temperature, and mass profile are graphically depicted and illustrated minutely. It is noted that both the magnetic and Williamson parameters cause the thickness of the boundary layer to be reduced. It can be deduced from these findings that the rate of heat transfer over the surface of the plate decreases as the unsteadiness parameter increases. Furthermore, it is observed that an increase in the parameters of thermophoresis and Brownian motion leads to a higher temperature of the nanofluid. [ABSTRACT FROM AUTHOR]

This study employs a two-dimensional and incompressible flow of Herschel–Bulkley visco-plastic materials in order to investigate the hydrodynamic forces that are acting on a barrier that is located close to the inlet of a channel. As the benchmark configuration, the flow domain that has been selected is a channel that still contains the impediment. The two important parameters of the Herschel–Bulkley Model (HBM) are the yield stress τ y and power law index n. Obtaining special situations within the HBM, such as Newtonian, power-law, and Bingham fluids, can be accomplished by assigning certain values to these parameters at the appropriate times. Utilizing a numerical strategy grounded in the Finite Element Method (FEM), we tackle the nonlinearity of the governing equations as well as the viscosity models. As a result of this nonlinearity, FEM becomes an essential tool. The generation of a refined hybrid mesh is done in order to guarantee accuracy in the computations. The stable finite element pair ( ℙ 2 ∕ ℙ 1 ) has been selected for discretization purposes. The discretized nonlinear system is linearized with Newton's method and subsequently, a direct linear solver PARDISO has been employed in the inner iterations. The pressure, velocity, and viscosity profiles are plotted for various values of n and Bingham number (Bn). In addition, the velocity behavior is observed along the y-direction in a channel through line graphs. Code validation is done as a special case Bn = 0 and a good agreement is found with the results available in the literature. Finally, a correlation analysis has been performed for the drag coefficient C d and lift coefficient C l . [ABSTRACT FROM AUTHOR]

In this paper, we analyze how Eyring fluid film behavior on a vertically upward moving slippery flat plate can help predictive models in engineering, notably in coating and lubrication operations. This paper deals with the stagnant points and uniform film analysis of Eyring fluid film flow on a vertically upward moving slippery flat plate. The formulated ordinary differential equation is solved for exact analytic solution. Exact analytic expressions for velocity, flow rate, average velocity, shear stress components, and stagnant points are derived. A highly nonlinear algebraic equation is derived for film thickness. Equation is solved by Newton's method using Maple code. The thickness of film widens with increasing relaxation time, constant plate velocity, and fluid density, while it decreases with increasing fluid viscosity and constant slip parameter. The analysis delineates that the positions of stagnant points tend to relocate closer the slippery plate as the Stokes number, Deborah number, and constant slip parameter increase. A high Deborah number enhances drainage, causing stagnant points to relocate closer to the slippery plate and the development of a stable elastic layer adjacent to the plate. For stagnant points and fluid film thickness, a comparison between the Eyring fluid and existing studies (EPTT, LPTT, UCM, and Newtonian fluid) is also provided. The validity of this paper with the existing studies is also presented by reducing Eyring fluid model to Newtonian model. The results of this research are significant for a wide range of biofluid applications, including agrochemical uses, paint and surface coating flow behavior, thin films on the cornea and lungs, and chemical and nuclear reactor design. [ABSTRACT FROM AUTHOR]

This paper conducts an extensive comparative analysis of numerical methods employed in modeling blood flow through arteries with Magnetohydrodynamics (MHD) and hybrid nanofluids. The study investigates the effectiveness and precision of distinct numerical approaches: Akbari Ganji's Method (AGM), Fourth-Order Runge–Kutta (RK4), Finite Volume Method (FVM), and the Finite Element Method (FEM). These methods are essential for comprehending the intricate fluid dynamics that arise in the presence of magnetic fields and hybrid nanofluids a phenomenon relevant in numerous medical applications. Blood flow is subjected to a homogeneous magnetic field in a radial direction while the magneto-hemodynamics effect is taken into account. A variety of medical, physiological, and surgical procedures, as well as the regulation of blood pressure, heat distribution, wound healing, diagnostic imaging, and drug discovery, depend on blood flow through arteries to carry out vital functions such as oxygen and nutrition delivery, organ maintenance, and wound healing. Our findings highlight that while each method has strengths, their applicability varies based on the problem's characteristics and computational resource constraints. This analysis aids researchers and practitioners in selecting the most suitable method for their modeling requirements, advancing numerical techniques for complex fluid dynamics involving MHD and hybrid nanofluids. [ABSTRACT FROM AUTHOR]

In this paper, inscribed non-Newtonian Williamson fluid relaxation and contraction phenomena due to the effect of magnetohydrodynamics (MHD) is taken into account. This issue is modeled, and precise solutions are handled using a low Reynolds number and long wavelength approximation. Graphical depiction of the consequences of various parameters on temperature and velocity are provided. It becomes clear that the temperature reactions to increases in Biot numbers are decreased. Considering a cylindrical coordinate system, the impact of various physical parameters on the temperature distribution, velocity, the pressure gradient, and frictional force are secured from the flow for non-Newtonian Williamson fluid exposed from MATLAB. Additionally, it has been discovered that the velocity profile at the tube's center increases for shear-thinning a fluid and decreases for thickening a fluid. Furthermore, the peristaltic walls show the opposite behavior. [ABSTRACT FROM AUTHOR]

Medicinal plants have played an important role in treating different diseases. Melia azedarach is a plant with significant medical and biological applications. This research aimed to explore the possible bioactivity of various biological compounds. The gas chromatography-mass spectrometry (GC-MS) analysis of Melia azedarach identified 25 compounds, among which 1-ethyl-3-methyl-2-nitrosobenzene and 2-ethyl-1,3-dimethyl-5-(nitromethyl)benzene were the main phytochemicals present in the crude extract of Melia azedarach. Mycobacterium tuberculosis is a zoonotic pathogen that causes tuberculosis (TB). The hypothetical protein OHO21363.1 of Mycobacterium tuberculosis is characterized using an in silico approach for exploring immunogenicity and virulence. After the homology prediction and characterization, this protein was predicted to be a PEE family protein with virulence and immune response functions. This virulent protein lies in the extracellular region of the cell according to subcellular localization and gene ontology. Due to its virulence factor and disease privilege against the host immune response, it can be used as a potential receptor for drug designing. After the GC-MS analysis, the 28 phytochemicals were retrieved and analyzed. Pharmacophore characterization of 1-ethyl-3-methyl-2-nitrosobenzene and 2-ethyl-1,3-dimethyl-5-(nitromethyl)benzene was performed to get the initial information on phytochemical bonding properties. Chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) predicted that out of 28 drugs, only 2 could cross the PGP+ through the blood–brain barrier and gastrointestinal tract without violating Lipinski's rule of 5. Both 1-ethyl-3-methyl-2-nitrosobenzene and 2-ethyl-1,3-dimethyl-5-(nitromethyl) benzene were predicted to have the best docking score against the protein, with –4.9 KJ/Mol and –5.0 KJ/Mol, respectively. Molecular dynamics simulation showed favorable results and provided useful information about the behavior and interactions of the molecules in the dock complex. Immune simulation confirms no immune response on the protein, proving it to be a virulent protein. The phytoconstituents present in Melia azedarach have the potential for multiple pharmacological applications. These findings can be used to design the potential drug candidates against TB. These ligands may be good candidates to fight against the resistant strain of TB compared to the drugs available in the market in the future. More research must be conducted to identify the bioactive compounds that may be used to treat different ailments. The research investigates the bioactivity of compounds found in Melia azedarach, identifying key phytochemicals through GC-MS analysis. Using in silico methods, a virulent protein from Mycobacterium tuberculosis is characterized, suggesting its potential as a drug target due to its role in immune evasion. Pharmacophore characterization and ADMET prediction highlight two compounds from Melia azedarach as promising candidates for drug development against tuberculosis, with molecular docking and simulation supporting their efficacy. [ABSTRACT FROM AUTHOR]

This research highlights the physical significance of nanoparticle in magnetohydrodynamics (MHD) stagnation point flow (SPF) over a stretchable surface with porosity effect and boundary slip phenomenon. The nanoliquid and its advanced thermal activity are shown extra auspicious results when the flow is considered over a permeable (porous) medium. In addition, the nanoparticles of radius size play an important role in the thermal performance of nanofluid. In this work, copper is accounted as a nanoparticle and water as a base fluid. Nanomanufacturing, surface engineering, coatings, nanofabrication and tribology are some of the important and special mechanical characteristics of nanoparticles [D. Guo, G. Xie and J. Luo, J. Phys. D, Appl. Phys.  47, 013001 (2014)]. The flow is electrically conducted in the presence of applied magnetic field. Mixed convection, Joule heating and viscous dissipation effects are accounted in the mathematical modeling. Appropriate similarity variables are used to convert the couple governing system of PDEs into ordinary ones and results are computed through bvp4c via shooting concept. From the obtained results, it is divulged that the velocity field increases against higher estimations of unsteady parameter, while it declines versus larger magnetic parameter and radius of nanoparticles. The engineering interest like skin friction and Nusselt number is mathematically calculated and results are computed in a tabular form, and their obtained outcomes show that the magnitude of skin friction rises against unsteadiness parameter and radius of nanoparticles. This study is an extended work of [Verma et al.Chem. Eng. J. Adv.12, 100366 (2022)] with some extra flow assumptions like MHD, SPF, Joule heating, heat generation/absorption and viscous dissipation. Obtained results are compared with [Grubka and Bobba J. Heat Transf.  107, 248 (1985)], Verma et al. [Chem. Eng. J. Adv.  12, 100366 (2022)] and [Elbashbeshy and Emam Therm. Sci.15,  477 (2011)] found 100% accuracy with them. The most important result of the conducted study is that the skin friction coefficient immensely augments subject to larger estimations of radius of nanoparticles when permeability of porosity is less. [ABSTRACT FROM AUTHOR]

The size of nanoparticles influences the viscosity and thermal conductivity of a nanofluid flow. In this exploration, the impacts of the dynamic viscosity and thermal conductivity of the Corcione model on the magneto-hydrodynamics (MHD) Cu-water nanofluid flow over an exponentially stretched surface are examined. It is pertinent to mention that the whole scenario is done at 300 K and the freezing temperatures of 273.15 K with a particle size of 25 nm. The Navier slip and convective boundary conditions are assumed at the surface. A homogeneous single-phase model is adopted to formulate the problem. Nonlinear, coupled momentum, and energy balance nondimensionalized ordinary differential equations (ODEs) are constructed with suitable transformations. To solve these ODEs numerically, a renowned bvp4c technique of MATLAB software is employed. The effects of the arising parameters are represented graphically and numerically and are depicted in tables and graphs. It is witnessed that the velocity of the copper-water nanofluid declined with larger estimations of the volume fraction of nanoparticles, although the temperature distribution showed the reverse tendency. Moreover, at the surface for higher values of the slip parameter, the velocity profile reduces and the temperature of the fluid augments for higher values of the Biot number. The validation of the model is also executed by comparing it with the published result in the limiting case. An outstanding correlation is attained. [ABSTRACT FROM AUTHOR]

There are various implementations of common fluids in industrial and chemical processes. With the cooperation of the nanoparticles, the lower thermal properties of such fluids can be augmented. By using a new kind of nanofluid namely hybrid nanofluid, the heat transfer rate of such fluids can be boosted more quickly. The main intention of this research is on entropy analysis in the stagnant point flow of a hybrid nanofluid. The mixed convection nonlinear thermal radiative flow on a stretchable vertical sheet is examined under the influences of the induced magnetic field and chemical reactions. The impacts of Joule heating, partial slips and viscous dissipation are also involved. After the execution of the appropriate similarity transformations, the constituting equations of the flow problem emerge as the nonlinear dimensionless setup of ordinary differential equations. An amplification is examined in the velocity field, entropy generation, and induced magnetic field relative to the mixed convection parameter. With the improved Brinkman number, an augmentation is developed in the entropy of the system. Moreover, both the heat transfer rate and the surface drag force exhibit an accelerating behavior relative to the mixed convection parameter. [ABSTRACT FROM AUTHOR]

This study aims to analyze the two-dimensional incompressible, steady MHD-mixed convective nanofluid flow with homogenous–heterogeneous (hh) reaction and Cattaneo–Christov heat flux (CCHF) past a rotating cone. The uniqueness of the presented model is the consideration of the surface-catalyzed reaction while considering the hh reactions on the surface of the cone in the existence of a permeable medium. Owing to this supposition, the rate of reaction is provoked in the least possible time. Moreover, irreversibility analysis is also performed for the suggested mathematical model in the wake of the second law of thermodynamics. The impacts of slip conditions and heat sink/source are also assessed here. The numerical model of these governing equations is solved using the MATLAB bvp4c package that addresses the system of ODES extracted from the governing PDEs. Graphs are used to evaluate the important consequences of the main arising parameters versus the concerned fields. The results revealed that in the presence of a high magnetic field, the temperature is enhanced. Moreover, the Entropy generation is boosted for magnetic and diffusion parameters. The results presented for this model are also corroborated by associating them with the published study. [ABSTRACT FROM AUTHOR]

In this exploration, temperature-dependent Yamada–Ota and Xue hybrid nanoliquid models are investigated over a curved stretchable surface embedded in an absorbent media. Hybrid nanofluids are formed by the combination of single and multi-walled carbon nanotubes (CNTs) as nanoparticles with engine oil as base fluid. The goal of this study is to interpret how the modified Fourier law combined with temperature-dependent thermal conductivity, Newtonian heating and variable heat source/sink enhances thermal performance. A mathematical formulation of the problem is illustrated in the curvilinear coordinates. Highly nonlinear dimensionless ODEs are solved numerically by engaging the bvp4c approach. The impression of the key parameters is illustrated graphically. Drag force coefficient and Nusselt number are highlighted through tables. It is comprehended that the fluid velocity decays on augmenting the velocity slip parameter while elevates on amplifying the curvature parameter. Furthermore, an enhancement in the temperature field is noted for the conjugate parameter. A significant correlation with the existing outcomes is perceived when a comparison with the existing literature is made. [ABSTRACT FROM AUTHOR]

Hybrid nanofluids (HNFs) are a new breed of nanofluids that possess numerous tempting applications encompassing microfluidics, transportation, defense, medical, etc. The objective of this novel exploration is to inspect the behavior of Hamilton–Crosser (H-C) and Yamada–Ota (Y-O) HNF flow models past a stretching cylinder. The H-C model is also used to gauge which particle shape (blade, platelet, cylinder, brick) is more effective in the improvement of the heat transfer rate. The envisioned flow is influenced by the Hall current, Cattaneo–Christov (C-C) heat flux and variable thermal conductivity (TC). The uniqueness of the projected model is the notion of a heterogeneous reaction sprouting on the surface of the cylinder in the presence of an absorbent medium. Owing to this supposition, the chemical reaction occurs in the least possible time. The proposed model's novelty lies in the consideration of the surface catalyzed reaction in the HNF flow models past a stretching cylinder amalgamated with the unique impacts of the Hall current, C-C heat flux and variable TC. The thermal performance of the two renowned models H-C and Y-O is also evaluated. The MATLAB software bvp4c technique is used for numerical outcomes of this coupled system. The analysis depicts that the performance of the Y-O HNF flow model is far above the H-C HNF flow model. It is also inferred from the results that blade-shaped nanoparticles possess higher TC than the other nanoparticles. The heat transfer rate for blade-shaped nanoparticles is stronger than the other nanoparticles. The fluid concentration reduces for higher surface-catalyzed reaction parameter. The corroboration of the proposed model is also given in this study. The comparative results disclosed that in the case of the magnetic parameter M , the minimum error percentage is 0.015% for M = 0. 5 , and permeability parameter λ , the least error percentage is 0.037% for λ = 1. 0. [ABSTRACT FROM AUTHOR]

This paper studies a chemical reactive Maxwell nanofluid flow in porous media with generalized Fourier and Fick laws in the presence of temperature-dependent thermal conductivity and robin conditions past a spinning cone. The characteristics of the fluid flow are examined using the Buongiorno nanofluid model. The equations that regulate the flow are highly nonlinear and are simplified using similarity transformations. Numerical solution is obtained by employing the bvp4c technique. The characteristics of various parameters on tangential and azimuthal velocities, heat, and mass transfers are depicted graphically. An opposing behavior on the tangential and azimuthal velocity fields is depicted in elevating the Deborah number. The solutal field upsurges on increasing the order of the reaction. The mass flux strengthens by augmenting the Schmidt number and solutal relaxation time. The validation of the proposed model in the limiting case is also given. [ABSTRACT FROM AUTHOR]

The role of non-Newtonian fluids can't be denied owing to their immense industrial and engineering applications. Taking this point in mind, the motivation of the current investigation is to examine the influence of a magnetic dipole on two-dimensional nonelectrical conducting Oldroyd-B fluid flow in the existence of thermophoretic particle deposition along a linearly stretching surface. The exponential space-based thermal source and the temperature-dependent heat source/sink are incorporated into the thermal equation. The fluid concentration is strengthened with binary activation energy and Arrhenius chemical reaction. The set of ordinary differential equations that are attained after applying the similarity transformations is resolved numerically by the bvp4c approach of MATLAB software. The impact of diverse parameters on velocity, temperature, and concentration are graphically examined. The quantities of physical importance are also computed and analyzed numerically. The results revealed that fluid velocity and temperature have opposing trends for the ferromagnetic interaction parameter. It is also witnessed that the fluid concentration arguments for the chemical reaction parameter. The validation of the model in the limiting case is also given. [ABSTRACT FROM AUTHOR]

Honeycomb-shaped, hierarchical porous structure is fabricated using the breath figure method. Different solvents are used to fabricate porous membranes with five different concentrations using spin coating. The diameter of the pores is controlled by the polymer concentration as well as different solvents. Using methanol as an additive solvent a homogeneous porous film is achieved. Furthermore, the effect of different solvents on the titania nanoparticles on the breath figure porous structure shows how titania particles are confined in the polymer matrix. So, using methanol as an additional solvent would be far more practical for synthesizing homogeneous films with different pore sizes than the standard procedure for fabricating the breath figure structure. [ABSTRACT FROM AUTHOR]

Hybrid nanofluids (HNF) are the advanced form of nanofluids used for improved heat transfer purposes. Taking this point in mind, the objective of the presented endeavor is to examine the Yamada–Ota HNF flow model comprising (gold–silver/engine oil) over a stretched cylindrical surface and a sheet (as a limiting case) in a permeable medium. The novelty of this research is the consideration of the surface-catalyzed reaction along with the homogeneous–heterogeneous reactions to accelerate the chemical reactions in the shortest possible time. The heat transport phenomenon is strengthened with the support of Joule heating, heat absorption/generation, and the convective heat boundary condition at the surface of the cylinder. The obtained ordinary differential equations are reduced from the partial differential equations using boundary layer theory and are numerically computed using the Keller box method. It is witnessed that for varied estimates of the magnetic parameter, the thermal profile enhances while the velocity field reduces. It is also noted that the fluid concentration is reduced when the surface-catalyzed parameter is enhanced. The validation of the envisioned model in a limiting case is also added to this investigation. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to scrutinize the axisymmetric flow of second-grade nanofluid with variable viscosity near a stagnation point under the influence of the Cattaneo–Christov double diffusion model. A Riga plate is assumed to be the source of the three-dimensional flow. The consequences of the anisotropic slip conditions and the Buongiorno model are included in the formulation of the constituting equations of the fluid flow. The highly nonlinear ordinary differential equations are developed with the executions of the relevant similarity transformations on the problem's governing equations. For the asymptotic analysis, the appropriate expansions are implemented on the nonlinear system of ordinary differential equations. The bvp4c technique of the MATLAB package is implemented on the nonlinear ordinary equations for the numerical solutions. In order to explore the impact of the parameter slip factor on the pattern of velocities, temperature, and concentration profiles, several graphs are plotted. From this study, we conclude that the normalized velocities boost up with the amplification in the slip factor parameter but the temperature profile exhibits a declining behavior. The concentration field exhibits the accelerating behavior relative to the slip parameter. [ABSTRACT FROM AUTHOR]

The current paper focused on an unsteady bio-convective Maxwell nanofluid flow subject to convective boundary conditions through an exponentially stretching curved surface. The transportation of heat and mass are observed with thermophoresis and Brownian effect along with chemical reaction. The mathematical flow model is converted into a system of nonlinear system of ODEs via suitable transformation. The numerical solution of a nonlinear system of equations is established with the help of bvp4c MATLAB technique. It is deeply studied that in the curved surface, the pressure is never ignored. The graphical representation of several parameters along the temperature, concentration, microorganism density and velocity distribution is presented. It is examined that the greater estimation of curvature parameter boosts the temperature of fluid and concentration of nanoparticles, although a reverse trend is seen for the velocity profile. Further, it is examined from the numerical values that the heat and mass transfer rate reduce consequently with the enlargement of the curvature parameter. [ABSTRACT FROM AUTHOR]

Among an extensive range of materials, biocarbon has acquired considerable interest because of its superiority of wide absorption bandwidth, strong absorption, accessibility, cost-effective and eco-friendly. Here, the inherited morphology of the biocarbon has been utilized to tune the performance of the microwave absorber. Biocarbon (wheat straw & peanut shells) and industrial waste (MnFe2O4) have been used to fabricate microwave absorption composites. Biocarbon wastes with two different morphologies, sheetlike and distorted, have been used to prepare the composites. Composite with sheetlike morphology attained the minimum reflection loss (RLmini) of − 19 dB but, on the other hand, composite with distorted morphology achieved RLmini of − 43 dB, as well as, it is the effective absorption bandwidth (EAB) covers the whole X-band. Our findings reveal that microwave absorption performance of the absorbers strongly relies on the anisotropic morphology of the biocarbon. It is expected that composites with anisotropic morphology of the biocarbon may be utilized to modify microwave absorption performance for practical applications. [ABSTRACT FROM AUTHOR]