Narrow Results

Understanding and optimizing heat transfer processes in complex fluid systems is the driving force behind studying the magnetohydrodynamic (MHD) flow of ${\mathrm{\text{Al}}}_2{\mathrm{\text{O}}}_3$–$\mathrm{\text{Cu}}∕{\mathrm{\text{H}}}_2\mathrm{\text{O}}$ nanofluid across a radiative moving wedge, taking into account the impacts of viscous dissipation and Joule heating. Nanofluids, such as ${\mathrm{\text{Al}}}_2{\mathrm{\text{O}}}_3$–$\mathrm{\text{Cu}}∕{\mathrm{\text{H}}}_2\mathrm{\text{O}}$, increase heat transmission and thermal efficiency. However, the complicated challenges caused by fluid characteristics and radiative heating need a thorough investigation. This study examines MHD hybrid nanofluid heat transfer via a permeable wedge using joule heating, mass suction, viscous dissipation, variable viscosity, thermal radiation, variable thermal conductivity, and variable Prandtl number. We use similarity transformation to solve the ordinary differential equations that follow from the governing partial differential equations. We then check the results for correctness and dependability. To ensure the reliability and validity of the outcomes, source parameters are crucial to the validation process. The consequence of changing these parameters on the heat transmission properties of the MHD hybrid nanofluid is studied for both the scenario without and with thermal radiation by methodically analyzing the percentage increase or reduction. The validation process also includes a comparison of the computed values, such as the heat transfer rate and skin friction factor, with established theoretical predictions. This examination guarantees that the numerical solution, executed using the bvp4c technique in MATLAB, corresponds to the anticipated physical behavior of the system being studied. In addition, the findings exist using both graphical and tabular forms, which allows for a clear and succinct illustration of how different physical limitations affect flow characteristics.

This study explores the potential of hybrid nanofluids (HNFs) in enhancing the efficiency of thermal management systems, particularly in medical engineering applications where precise temperature control is critical. Motivated by the need for innovative and sustainable cooling solutions, this research examines the infusion of carbon nanostructures (CNS) into HNFs to improve thermal exchange performance. The study applies the non-Newtonian Maxwellian model and the Cattaneo–Christov thermal flow framework to simulate their behavior in specialized curved channels analogous to heat exchangers in medical devices such as imaging equipment or cryogenic systems. Hypothetical trials and computerized simulations evaluate the heat transfer rate and flow dynamics of nanotube-infused HNFs. Key factors, including heat radiation, fluid resistance, sliding velocity, and permeable substances, are assessed to determine efficiency improvements. By utilizing similarity transformation to simplify the governing partial differential equations (PDEs) and employing the finite element method (FEM) alongside Akbari–Ganji’s method (AGM) for precise solutions, the study highlights the potential of multi-layered carbon nanotube–single-layered carbon nanotube with engine oil mixed nanofluids to significantly enhance heat transfer. The findings demonstrate a 1.65% improvement in thermal performance, suggesting promising implications for advanced thermal management systems in medical devices and healthcare technologies.

Inspired by the flimmer hairs found on the flagella of certain species of choanoflagellates, we show in this paper that nanoscale flagella hair on slender flagellum surfaces can drive flow with nanoscale motion. Using molecular dynamics, we provide numerical proof that the nanoscale hairs, moving in a biased periodic motion, can attain high water flow rates in excess of 1200 $\mu$m${}^3\cdot$ s${}^{-1}$. This flow rate is on par with the experimentally measured flow rates of natural sponges, which are known to be capable of exceptionally high pumping efficiency. This paper highlights the potential of using collective motion of nanohairs to pump fluid and suggests a range of parameters of the force function that can achieve significant flow.

Interferometric lithography offers a facile, inexpensive, large-area fabrication capability for the formation of large areas of nanoscale periodic features. A self-aligned frequency doubling process to a 22-nm half-pitch is demonstrated. Many investigations of nanoscale phenomena require large-area samples, both for scientific investigations and certainly for ultimate large-scale applications. The utility of interferometric lithography is demonstrated to applications in nanophotonics and nanofluidics. For nanophotonics, metamaterial fabrication, negative index metamaterials and plasmonic applications are discussed. Two approaches to the fabrication of nanofluidic structures: etching and oxidation of silicon substrates, and colloidal deposition of silica nanoparticles to form porous walls and roofs followed by calcination to remove the photoresist and sinter the particles. These later structures have evident biomimetic functionality.

We present a convergence study for a hybrid Lattice Boltzmann-Molecular Dynamics model for the simulation of dense liquids. Time and length scales are decoupled by using an iterative Schwarz domain decomposition algorithm. The velocity field from the atomistic domain is introduced as forcing terms to the Lattice Boltzmann model of the continuum while the mean field of the continuum imposes mean field conditions for the atomistic domain. In the present paper we investigate the effect of varying the size of the atomistic subdomain in simulations of two dimensional flows of liquid argon past carbon nanotubes and assess the efficiency of the method.

The structure and transport of neutral and charged fluids under nanoscopic confinement are derived from the kinetic and microscopic perspective. As compared to lumped parameter approaches, the strategy is to resolve the collision between particles for hard-core forces and to use a mean field treatment for soft- and long-ranged forces. The numerical strategy adapts the Lattice Boltzmann (LB) scheme to handle interatomic and electrostatic interactions.

Large-scale molecular dynamics (MD) simulations of freely decaying turbulence in three-dimensional space are reported. Fluid components are defined from the microscopic states by eliminating thermal components from the coarse-grained fields. The energy spectrum of the fluid components is observed to scale reasonably well according to Kolmogorov scaling determined from the energy dissipation rate and the viscosity of the fluid, even though the Kolmogorov length is of the order of the molecular scale.

The paper’s primary goal is to investigate mass and heat transfer processes in reactive nanofluid particles. Within Buongiorno’s model, three chemical reactions are discussed. The main subject is on the nanoparticle fractions at the boundary. The characteristics of $Nt$ and $Nb$ with regard to the nanoparticle fraction have been found to be passively rather than actively controlled at the boundary. To put it another way, these qualities naturally develop and are controlled by the circumstances at the boundary or interface where the nanoparticles interact with the surrounding medium. They are not the result of active manipulation or outside forces. The system of partial differential equations was converted into ordinary differential equations using similarity transformations. To solve the system of ODEs, they combined the shooting method with a numerical technique known as RK-Fehlberg. The study examines various physical parameters and their effects using graphs. The paper also contains a table showing how different parameters affect the regional Nusselt and Sherwood numbers. This enables a deeper comprehension of the impact that these variables have on the heat and mass transfer within the reactive nanofluid particles. Core findings: Examining three chemical reactions involving nanofluids has led to the study’s key discoveries. Additionally, it looks into how specific physical variables may affect the Nusselt and Sherwood numbers.

This study investigates analytically the stability analysis of a nonlinear convective boundary layer (BL) flow of the nanofluids GO-EG and GO-W on a shrinking surface in the presence of a magnetic field and viscous dissipation. We provide a second-order nonlinear ordinary differential equation (NODE) for temperature distribution (TD) and a third-order NODE for velocity profile (VP) coupling based on the thermophysical characteristics of the base fluid and nanofluid as well as similarity transformations (STs) in the fundamental governing equations of momentum and energy. The analytical method HAM is used to answer the equations that have been gathered. In many different industries, such as manufacturing, automotive, microelectronics, and defense, cooling of various types of equipment and devices has very important challenges. To fulfill the demands of the engineering and industrial industries, it is hoped that this issue would significantly improve the heat transformation ratio.

In this article we review recent developments in molecular transport and fluidics in carbon nanotube (CNT)-based nanochannels. Atomic molecular dynamics simulations and theoretical studies based on Fokker–Planck diffusion equation on the transport of large and long polymer molecules in CNTs are the focus of the article. Fast translocation and diffusion processes of large molecules in CNTs are reviewed and discussed, considering the effects of interfacial interactions and molecular conformations and structures at interface. The transport features for multiple molecules diffusing through CNTs are also discussed.

A model for gas transport through nanochannels is presented. Molecular simulations of Argon (modeled as a Lennard–Jones fluid) flowing over a carbon surface were performed to develop a correlation for molecular wall slip based on temperature and angle of collision. The correlation is used to modify the oscillatory model of diffusion. Molecular transport is argued to be in one of two domains: near wall localized diffusion at low and moderate temperatures, and delocalized diffusion at high temperatures. The molecular diffusivity is found to exceed that predicted by Knudsen diffusion at high temperatures, and diffusive oscillatory models at all temperatures. Molecular simulations compare favorably with the presented model.

Nature has generated sophisticated and very efficient molecular motors, employed for nanoscale transport at the intracellular level. As a complementary tool to nanofluidics, these motors have been envisioned for nanotechnological devices. In order to pave the way for such applications, a thorough understanding of the mechanisms governing these motors is needed. Because of the complexity of their in vivo functions, this understanding is best acquired in vitro, where functional parameters can independently be controlled. I will report on work in my group that studies and harnesses the transport properties of molecular motors on functionalized structures of reduced dimensionality such as carbon nanotubes,¹ lithographically designed electrodes,² microwires,³ loops⁴ and swarms.⁵ In addition, I will show results that demonstrate the potential of this work for biomedical advances.⁶

In recent times, nanoparticle-embedded flows are becoming household fluid in emerging medical interventions associated with thermal therapy. The place of thermal analysis is critical to underscore the potential of bio-nanofluidics and to perform a biothermal mechanical analysis of its performance during remediation strategies. This paper presents a thermal expedition of a hybrid nanofluid embedded in blood flow under a transient regime on the strength of a robust numerical scheme. The effect of heterogeneous–homogeneous chemical reaction on a magnetic field mediated hyperthermia over a porous substrate is mathematically expatiated in this report. Under Boussinesq approximation, the thermal model was formulated for the problem while homotopy analysis was employed to capture chemical dynamics and thermal transport in hybrid blood-based nanoliquid. Elaborate analysis of the prevailing physicochemical attributes of the flow under magnetic field imposition is sufficiently discussed within the framework of biological systems. These observations reported in this study could find application in the field of bio-nanotechnology in thermal-based therapy procedures in a realistic clinical scenario.

One-dimensional flows of a simple liquid through nanochannels are studied by numerical solution of Enskog-Vlasov kinetic equation which provides and approximate but accurate description of a fluid whose molecules interact through Sutherland potential. The accuracy of the results is assessed by comparisons with molecular dynamics simulations. The deviation from hydrodynamic behavior is studied as a function of relevant flow parameters. Finally, it is shown that the model allows a natural extension capable of describing fluid-wall interaction by the same formalism.

Interferometric lithography offers a facile, inexpensive, large-area fabrication capability for the formation of large areas of nanoscale periodic features. A self-aligned frequency doubling process to a 22-nm half-pitch is demonstrated. Many investigations of nanoscale phenomena require large-area samples, both for scientific investigations and certainly for ultimate large-scale applications. The utility of interferometric lithography is demonstrated to applications in nanophotonics and nanofluidics. For nanophotonics, metamaterial fabrication, negative index metamaterials and plasmonic applications are discussed. Two approaches to the fabrication of nanofluidic structures: etching and oxidation of silicon substrates, and colloidal deposition of silica nanoparticles to form porous walls and roofs followed by calcination to remove the photoresist and sinter the particles. These later structures have evident biomimetic functionality.