Double Diffusion Research Articles

Thermosolutal and hydromagnetic performance of radiative hybrid nanofluid in a wavy porous enclosure with a plus-shaped baffle

The objective of this article is to explore the thermosolutal transmission rates with hydromagnetic Fe3O4-H2O nanofluid and Fe3O4-Cu-H2O hybrid nanofluid flow in a partially heated wavy porous enclosure with a plus-shaped baffle. A portion of length b on the bottom border is heated and soluted uniformly, while the rest portions of the bottom wall are assumed as adiabatic. The side curved borders are considered as cold and low concentration, while the adiabatic condition is imposed in the upper flat border. A plus-shaped cold baffle is located at the geometric center of the chamber. The porous cabinet is filled with a radiative Fe3O4-H2O nanofluid and Fe3O4-Cu-H2O hybrid nanofluid. The streamfunction (ψ)- vorticity (ζ) form incorporating the energy and species transport equations of coupled Navier-Stokes governing equations are solved by an efficient compact scheme. We have validated our in-house computational code with reliable published numerical and experimental works. This work explores the impacts of various well-defined parameters such as Rayleigh number (104≤Ra≤106), Hartmann number (0≤Ha≤40), Darcy number (10−4≤Da≤10−2), buoyancy ratio (N=1), Lewis number (1≤Le≤20), radiation parameter (1≤Rd≤10), heater size (0.2≤b≤0.8), volumetric heat source/sink coefficient (−10≤Q≤10) and solid volume fraction (0.0≤ϕhnp≤0.04) of the hybrid nanofluid. We have found that for the change in the radiation parameter (Rd) from 1 to 10, energy transfer is improved by 150.67% for Fe3O4-Cu-H2O hybrid nanofluid and 149.80% for Fe3O4-H2O nanofluid whereas solutal transfer is diminished by 4.76% and 4.83%, respectively. Our result revealed that Fe3O4-Cu-H2O hybrid nanofluid is more useful than Fe3O4-H2O nanofluid in the case of double diffusion.

Evaluation of the Effects of Edible Coatings of Ocimum sanctum and Aloe vera on Jaggery Shelf Life

Background: In western Uttar Pradesh, jaggery is a widespread cottage enterprise based on agriculture, and farmers are forced to sell their product at a lesser price when it is still fresh. Therefore, it was thought to be desirable to create better storage techniques in order to extend its shelf life. Aloe vera, and Ocimum sanctum, often known as "Tulsi," are frequently utilised as antimicrobial food additives because they offer a host of other health advantages in addition to their well-known antibacterial qualities. Because the edible coatings made of these herbs provide a semi-permeable barrier to gases and water vapours, they may prolong the shelf life of jaggery by preventing degradation. Objective: The goal of the current study was to assess the ability of edible coatings of common Indian herbs, such as tulsi and Aloe vera,, to extend the shelf life of jaggery while maintaining attributes that are equal to those of fresh jaggery, in accordance with the guidelines set forth by the Food Safety and Standards Authority of India (FSSAI). Methodology: The physicochemical characteristics, antioxidant activity, total viable count, and antibacterial activity of tulsi-Aloe vera, coated (TAC), Ocimum sanctum, and Aloe vera, (AC) jaggery were assessed and compared with non-coated control. The physicochemical properties were ascertained using standard methodology for measurement of reducing sugars, proteins, phenols, saponins, tannin, alkaloids, and flavonoids. The antimicrobial activity was ascertained by means of the agar double diffusion method. According to established protocol, antioxidant activity was assessed using the DPPH radical scavenging assay and the reducing power assay. Results: According to the research, there is no discernible microbiological deterioration and the edible coatings containing tulsi and Aloe vera, extend the shelf life of jaggery during storage. When compared to uncoated jaggery, coatings were efficient at preventing the growth of both Gramme positive and Gramme negative microorganisms. Over the course of six months, the herb-infused coatings also retained their phenolic, flavonoid, and tannin contents, which improved their anti-oxidant efficacy when compared to the untreated control group.

Flow of magnetohydrodynamic blood-based hybrid nanofluids with double diffusion in the presence of Riga plate for heat optimization and drug applications

In a recent study, researchers investigated the flow behavior of Casson Hybrid nanofluids (HNFs) combination of single and multi-walled carbon nanotubes (SWCNTs), (MWCNTs) on a Riga plate for drug delivery applications. The study found that the Casson HNFs exhibited non-Newtonian behavior on the Riga plate, with the presence of nanoparticles causing an increase in viscosity and shear-thinning behavior. This rheological behavior is favorable for drug delivery applications as it improves the stability and dispersion of drug particles in the fluid. The similarity equations of the flow problem are easily tackled with the homotopy analysis method (HAM) built on fundamental homotopy mapping. In high-speed flows, Riga actuators are expected to achieve the requirements, since HNF is enhanced by modified Hartmann numbers. As the Eckert number, heat generation/absorption parameter, and thermal relaxation time parameter decrease the temperature, thermal transport increases. Furthermore, with the increments in paramount parameters, the skin friction coefficient and heat transfer rate are remarkably meliorated under higher modified Hartmann number. Furthermore, the study also found that the Casson Hybrid nanofluids showed enhanced heat transfer properties on the Riga plate, which is beneficial for localized drug delivery applications that require precise temperature control.

Cattano Christov double diffusion model for third grade nanofluid flow over a stretching Riga plate with entropy generation analysis

The current investigation delves into the convective heat and mass transfer characteristics of third-grade radiative nanofluid flow within a porous medium over a Riga plate configuration. The Riga plate structure incorporates magnets and electrodes strategically arranged on a plate surface. To enhance the accuracy of energy and concentration expressions within the third-grade fluid flow, the Cattano Christov Double Diffusion model is employed. Entropy generation analysis is conducted by applying the second law of thermodynamics, and Darcy's model is employed to characterize the behavior of a porous medium. Appropriate similarity transformations have been used to convert the partial differential equations monitoring the fluid flow model into dimensionless ordinary differential equations. The Galerkin weighted residual method is employed to resolve these equations numerically. The findings contain detailed explanations of how relevant factors affect the temperature field, concentration field, velocity field, entropy generation, and Bejan number, in addition to graphic representations of the results. The findings indicate that the medium's porosity and Brinkman number promote entropy generation. The Bejan number and entropy production is affected by the thermal radiation parameter, which first rises and then declines after a certain distance.

Entropy Analysis for Three-Dimensional Stretched Flow of Viscous Fluid Engaging Radiation Effect and Double Diffusion Phenomenon

Entropy Analysis for Three-Dimensional Stretched Flow of Viscous Fluid Engaging Radiation Effect and Double Diffusion Phenomenon

Effects of double diffusion and induced magnetic field on convective flow of a Casson nanofluid over a stretching surface

Magnetohydrodynamic (MHD) flows have several applications in a wide area of engineering such as industrialized processes, including generating MHD electrical power, processing of magnetic materials, etc. The present examination focuses on incorporating the induced magnetic field (IMF) and multiple slips on the convective MHD Casson nanofluid flow over an elongating sheet with Brownian motion and thermophoresis effects. Heat source/sink, non-linear radiation, and suction/injection impacts are added to strengthen the study. The governing equations are framed with the above assumptions and converted from PDE to ODE using a suitable transformation. The MATLAB solver “bvp5c” is engaged to solve the governing equations and the results are depicted through graphs and tables. Moreover, a good agreement is found while comparing these results with pre-existing results. It is established that an increase in the Casson fluid parameter diminishes the fluid's velocity. Also, the induced magnetic field plays a vital role in decreasing the speed of the fluid. Further, with an increase in the double-diffusive parameters, the temperature rises. As the chemical process and Schmidt number parameter elevate, the concentration drops. The convective parameter and the velocity slip parameter both enhance skin friction. The Nusselt number rises when the Prandtl number gets larger. This investigation makes major contributions to reactor safety devices, crystal growth in liquids, chemical-catalyzed reactors, geophysics, solar technology, etc.

Effect of Baffle Board on Aerodynamic and Stealth Performance of Double S-Duct Caret Intake

Intake is not only the main air supply component of an aircraft, but also one of the forward radar scattering sources. The aerodynamic and stealth performance of intake is critical to the serviceability of advanced fighter aircrafts. The effects of baffle boards with different configurations on the performance of the caret intake with a double S-duct diffuser are presented in this article. The multi-level fast multipole method (MLFMM) and the SST k-ω turbulence model were respectively used to calculate the surface current and the flow field. It was found that the average RCS value of intake can be effectively reduced by installing the baffle board with vertical orientation in the front diffuser, with the DC60 value and the loss of outlet total pressure both increased slightly. The boundary layer separation and the RCS characteristics of intake were closely related to the configuration of the corrugated baffle board. Compared with the traditional curved board, by installing the corrugated board with optimized corrugation number and shape, the stealth performance of intake can be further improved, and the loss of aerodynamic performance can be also reduced.

ANTIBIOTIC RESISTANCE OF ESBL-PRODUCING E. COLI AND OTHER GRAM-NEGATIVE BACTERIA ISOLATED FROM STREET-VENDED FOODS IN BANGLADESH

The prevalence and impact of antibiotic-resistant pathogens transmitted through food, particularly street-vended foods, is becoming a major public health concern. Although a significant proportion of the urban population in developing countries consumes street-vended foods, the role of these foods in spreading antibiotic resistance has been rarely investigated. In this study, 50 bacterial isolates were obtained from 25 samples representing five categories of street-vended foods: Phuchka, Chatpati, Sausage, Bun, and Salad. The IMVIC test revealed a notably high occurrence of Escherichia coli (n=32) within the collected samples. Three representative isolates were selected for molecular identification using DNA sequencing of 16S rDNA. They were identified as Klebsiella oxytoca, Burkholderia fungorum, and Serratia nematodiphila. The antibiotic susceptibility of the identified isolates (n=35) was investigated using twelve antibiotics following the Kirby-Bauer disk diffusion method. Around 65.63% of the E. coli isolates (n=21) exhibited multidrug resistance. Double Disc Synergy Test (DDST) and Phenotypic Confirmatory Disk Diffusion Test (PCDDT) confirmed ESBL production of Eight multidrug-resistant E. coli isolates (38.09%). The multiple antibiotic resistance (MAR) index showed that 22 E. coli isolates had MAR above 0.2, with resistance mostly against oxacillin, ampicillin, and cefuroxime. The Klebsiella oxytoca isolate showed multidrug resistance viz., ampicillin, oxacillin, cefuroxime, and kanamycin. The Burkholderia fungorum isolate showed no distinct inhibition zone against ampicillin and chloramphenicol. Additionally, the Serratia nematodiphila isolate showed no distinct inhibition zone against three antibiotics, including ampicillin, oxacillin, and cefuroxime. These findings might contribute to the knowledge of emerging antibiotic-resistant foodborne pathogens and raise concerns about the safety of street-vended foods in Bangladesh.

Double diffusive mixed convective flow over a wedge and cone in the presence of Brownian diffusion and thermophoresis parameter

The present article examines the double diffusion mixed convective nanofluid flow over a wedge and cone in which slip effects as Brownian motion and the thermophoretic parameter are considered. Mixed convective flow over wedges and cones is applied in different technical fields such as fiber technology, nuclear cooling systems, surface treatment, spray deposition techniques, and polymer production. Double diffusion is increasingly significant in scientific fields like astronomy, geosciences, oceanography, and chemical processes. Mixed convection occurs in several applications such as electric devices, solar panels, nuclear power plants, heat exchangers, radiators, and atmospheric boundary layer fluxes. The governing equations of the study are highly coupled nonlinear partial differential equations with surface constraints. The process of similarity transformation used to converts partial differential equations into nondimensional ordinary differential equations, which can be resolved using the MATLAB Bvp5c function. The graphical representation and detailed analysis of variations in velocity, temperature, and concentration distributions of nanofluids are presented. As the mixed convection parameter increases, the fluid’s velocity rises, with a more pronounced effect observed in the cone compared to the wedge. As the Brownian diffusion parameter grows, the fluid temperature increases, and velocity is more pronounced in the wedge scenario compared to the cone. Moreover, an increase in the thermophoresis parameter results in an elevation in the fluid’s temperature. Additionally, the wedge has a higher concentration of fluid and nanoparticles compared to the wedge. Fluid concentration falls with increasing Schmidt number, but fluid nanoparticle concentration decreases with increasing Lewis number.

Diffusive-convection staircases in the polar oceans: the interplay between double diffusion and turbulence

Numerical simulations have been conducted to examine the structure of diffusive-convection staircases in the presence of vortical-mode-induced turbulent forcing. By modulating the input power $P$ and the background density ratio $R_\rho$ , we have identified three distinct types of staircase structures in these simulations: namely staircases maintained in the system driven by double-diffusion, by turbulence or by a combination of both double-diffusion and turbulence. While we showed that staircases maintained in the double-diffusion-dominated system are accurately characterised by the existing model originally proposed by Linden & Shirtcliffe (J. Fluid Mech., vol. 87, no. 3, 1978, pp. 417–432), we introduced new physical models to describe the staircase structures maintained in the turbulence-dominated system and the system driven by both turbulence and double-diffusion. Our integrated model reveals that turbulence fundamentally governs the entire life cycle of the diffusive-convection staircases, encompassing their formation, maintenance and eventual disruption in the Arctic Ocean's thermohaline staircases. While our previous work of Ma & Peltier (J. Fluid Mech., vol. 931, 2022b) demonstrated that turbulence could initiate the formation of Arctic staircases, these staircases are sustained by both turbulence and double-diffusion acting together after formation has occurred. Strong turbulence may disrupt staircase structures; however, the presence of weak turbulence could lead to unstable stratification within mixed layers of the staircases, as well as enhancing vertical heat and salt fluxes. Turbulence can even sustain a stable staircase structure factor when $R_\rho$ is relatively large, following a similar mechanism to the density staircases observed in laboratory experiments. Consequently, previous parameterisations (e.g. Kelley, J. Geophys. Res.: Oceans, vol. 95, no. C3, 1990, pp. 3365–3371) on the vertical heat flux across the diffusive-convection staircases may provide a significant underestimation of the heat transport by ignoring the influences of turbulence.

Ground effect of an inverted double element wing diffuser on a sedan car

The diffuser is a critical component in sports cars, enhancing aerodynamics by increasing downforce and reducing drag. Previous studies have focused on its dependence on diffuser incidence, height, and base pressure. The design of the car, particularly the rear end shape and the rear wing's presence, affect base pressure and the diffuser's performance. Previous studies have investigated the effects of diffuser geometry on aerodynamic performance, but the current study is the first to examine the relationship between the diffuser and the rear tires. It also provides specific and quantitative results on the impact of different diffuser design parameters on drag and downforce. The relationship between the rear tires and the double-element inverted wing diffuser using computational fluid dynamics (CFD) was investigated. This is an essential problem because the diffuser is a critical component of sports cars, and its design can significantly impact aerodynamic performance. CFD was used to simulate the flow of air around the car model. The CFD model was based on the Nissan Sunny (Versa) type Almera design, and the diffuser main element and flap wing angles were set at 4 and 15.5°, respectively. The flap gap, overlap distance, and wing ride height above the ground were varied to achieve an optimal aerodynamic design. The study found that the wing's ride height significantly influences the flow through the diffuser. The diffuser significantly impacts base pressure and downforce production. Increasing the ride height decreases base pressure, leading to an increase in downforce until a specific point near the car body, where downforce further increases. The study concluded that the best double-element diffuser design was selected based on lift-to-drag results and the allowable dimensions of the car, wing ride height, element gap, and overlap distances. Ultimately, the best diffuser wing design features a ride height of 154 mm, a gap distance of 10 mm, and an overlap of 5 mm. This design reduces drag by approximately 2.7 % and remarkably increases downforce ten times compared to the baseline car model.

Heat Generation/Absorption in MHD Double Diffusive Mixed Convection of Different Nanofluids in a Trapezoidal Enclosure

Numerical simulation of MHD double-diffusive mixed convection flow of different nanofluids in a trapezoidal enclosure is performed with an internal heat generation/absorption source inside the enclosure. The nondimensional momentum, heat and mass equations are solved numerically by using the finite difference method. The present study focused mainly on the increment of the rate of heat and mass transfer using internal heat generation or absorption sources inside a lid-driven trapezoidal cavity. Considering numerous governing parameters (Q = −5 to 5, Ha = 0 to 30, Ri = 0.01 to 100) the flow velosity, temperature and concentration profiles are calculated for various nanofluids. Graphs and numerical tables are utilized to examine how different physical entities affect the distribution of flow, temperature and concentration. It is noted that enhancing values of Ha reduces the mass and heat transfer rate. It is observed that heat generation/absorption significantly affect the heat transfer rate as internal heat generation source increases heat transmission rather than mass transfer. The involvement of heat generation/absorption source significantly affects the heat transfer rate. By considering Al2O3-water nanofluid, the solid volume percentage has an accelerating effect on the Nusselt and Sherwood numbers as compared to the other nanofluids in the study.

Synergetic optimisation of mechanical and electrical properties of aramid composite insulation paper by modulation of fibrid morphology

AbstractThe fibrids in aramid insulation paper exhibit good adhesion ability. However, the effects of fibrids morphology on the mechanical and electrical properties of aramid insulation paper remains poorly understood. Aramid fibrids with different morphological structures were prepared by modifying the preparation process, and then they were used to fabricate aramid composite insulation paper under the same condition. The results showed that increasing the shear rate and aramid solution concentration affected the magnitude of the shear force and double diffusion process, thus affecting the average length, specific surface area, and crystallinity of the fibrids. When the rotor frequency is 25–30 Hz and the solution concentration is 15%, the fibrid has a large specific surface area while ensuring high crystallinity, which is beneficial to the improvement of breakdown strength. When the average length of fibrids is 0.8–1.4 mm, the fine content is 1.3%–2.3%, specific surface area is 57.5–62 m2 g−1, and crystallinity is 18.5%–27%, the aramid composite insulation paper has the optimal mechanical and electrical properties. Combined with the micromorphology test results, the influence mechanism of fibrids properties on the mechanical properties, dielectric properties, and AC and DC breakdown strength of aramid composite insulation paper was obtained. The result is of great theoretical significance and practical value for the preparation and application of high‐performance aramid composite insulation paper.

Double Diffusive Convection with Cross-Diffusion Effects in Hybrid Nanoliquids in an Inclined Slot

This novel study examines the effects of cross-diffusion, and nanoparticles on a hybrid nanoliquid undergoing double-diffusive convection in an inclined slot. The hybrid nanoliquid considered is unique and it contains a mixture of base liquid to which nanoparticles are suspended. The thermophysical properties of the hybrid nanoliquid are calculated using phenomenological laws and mixture theory. The results are compared with the case of mono nanoliquid and hybrid nanoliquid with one base liquid and two nanoparticles. In order to study the convective system, the shooting method along with Runge-Kutta 4th order method is employed, and the results are illustrated graphically. It is noticed that the solutal Rayleigh number, Soret parameter and inclination of the plates delay the onset of convection, while the Dufour parameter, diffusivity ratio, and the addition of nanoparticles advance the onset of the convection.

A computational simulation for peristaltic flow of thermally radiative sisko nanofluid with viscous dissipation, double diffusion convection and induced magnetic field

The main objective of this framework is to formulate a model and carry out simulations on the thermally radiative biological fluid of Sisko nanofluid in the non-uniform channel under the combined effects of induced magnetic field and double diffusion convection. Additionally, the effect of viscous dissipation is also considered. The formulation and simplification of the governing equations for a non-Newtonian fluid with nanoparticles and double diffusion convection is done under the assumption of a long wavelength and low Reynolds number. The numerical solution of the proposed problem is calculated by utilizing built in commands in Matlab and Mathematica software’s. The equation solving is done in Mathematica using the integrated program NDSolve. The framework provides expressions for temperature, nanoparticle fraction, velocity, pressure rise, stream functions, pressure gradient, magnetic force function, and concentration. The impact of relevant parameters on various physical quantities is then analyzed through graphical representations, considering both non-Newtonian and viscous fluid behavior. The present analysis suggests that an increase in heat radiation may cause a drop in the temperature distribution strengthening the cooling effects. It is also found that as Brinkman number rise, buoyancy-driven flows have a greater impact on fluid motion. The concentration of nanoparticles may fluctuate and maybe decrease in specific locations in accordance with the dispersion and advection phenomena. Furthermore, this finding has important ramifications for the field of biomechanics too. Examples include comprehending chyme movements in the digestive system and the prospective use in operations to regulate blood flow by adjusting the magnetic field’s strength.

Investigating double-diffusive natural convection in a sloped dual-layered homogenous porous-fluid square cavity

This article investigates natural convection with double-diffusive properties numerically in a vertical bi-layered square enclosure. The cavity has two parts: one part is an isotropic and homogeneous porous along the wall, and an adjacent part is an aqueous fluid. Adiabatic, impermeable horizontal walls and constant and uniform temperatures and concentrations on other walls are maintained. To solve the governing equations, the finite element method (FEM) employed and predicted results shows the impact of typical elements of convection on double diffusion, namely the porosity thickness, cavity rotation angle, and thermal conductivity ratio. Different Darcy and Rayleigh numbers effects on heat transfer conditions were investigated, and the Nusselt number in the border of two layers was obtained. The expected results, presented as temperature field (isothermal lines) and velocity behavior in X and Y directions, show the different effects of the aforementioned parameters on double diffusion convective heat transfer. Also results show that with the increase in the thickness of the porous layer, the Nusselt number decreases, but at a thickness higher than 0.8, we will see an increase in the Nusselt number. Increasing the thermal conductivity ratio in values less than one leads to a decrease in the average Nusselt number, and by increasing that parameter from 1 to 10, the Nusselt values increase. A higher rotational angle of the cavity reduces the thermosolutal convective heat transfer, and increasing the Rayleigh and Darcy numbers, increases Nusselt. These results confirm that the findings obtained from the Finite Element Method (FEM), which is the main idea of this research, are in good agreement with previous studies that have been done with other numerical methods.

Investigation of thermal radiations impacts with double diffusive convection for Prandtl nanofluid with slip in an asymmetric ciliated channel

Thermal radiations are extensively utilized in the medical sciences, and the investigation of thermal radiation combined with double diffusive phenomena is the burning research area because of its enormous applications in treatment of various diseases. Cilia play significant part in many physiological processes of animal and humans. A novel mathematical prodigy for Prandtl nanofluid with thermal radiations and double diffusion convection by implementing slip at boundaries is presented for cilia induce flow in an asymmetric microchannel. Mathematical scheme for the physiological flow is developed and then pertinent equations are designed exploiting low Reynolds number and long wavelength simplifications. Solution for the physiological nanofluid is gathered by emphasizing on the novel BVP4C technique in MATLAB and resulting outcomes are elaborated with aid of graphical illustrations. Pros and cons of various physical flow parameters like thermal slip parameters, Prandtl fluid parameters, Grashof parameter, Prandtl parameter , Brownian motion parameter, thermal radiation parameter, Brinkmann number, Soret parameter are examined on the velocity, magnetic force function, temperature profile, concentration and nanoparticles volume fraction. It is reported that slip parameter really effects the nanofluid transport within the ciliated microchannel, it reduces the fluid flow, diffusion phenomena of the nanoparticles in the ciliated microchannel surges when radiation parameter is strengthened. The reported investigation will be instrumental in heat radiation effect for regulation of blood circulation to cure the cancer tissues in multiple drug delivery systems and will pave the way for the designs of certain diagnostic and pharmacological devices.

Heat and mass transfer analysis of a Maxwell-power-law fluid in a laminar planar jet flow with Cattaneo–Christov double diffusion theory

This paper focuses on the heat and mass transfer characteristics of a steady laminar planar jet flow of a Maxwell-power-law (MPL) fluid. MPL is a renowned fluid model with shear thinning and viscoelastic characteristics that can accurately exhibit the rheological features of polymer liquids. In the envisioned study, the MPL constitutive equation is introduced based on an experiment utilizing the Xanthan gum solution. The heat and mass equations are supported by the Cattaneo–Christov double diffusion (CCDD) concept with unique characteristics of thermal conductivity, mass diffusion, and chemical reaction. Thermal conductivity and mass diffusion coefficient are considered to be velocity gradient-dependent. The problem is addressed numerically by the bvp4c method in Matlab after applying the similarity transformations to the governing equations. The impacts of related parameters on velocity, temperature, and concentration are analyzed. Results show that an upsurge in the power-law index hinders momentum, energy, and mass transmission. An interesting phenomenon is that the variation in relaxation time can hinder or promote the heat and mass transfer of a Maxwell-power-law fluid jet before or after the intersection point, respectively. The study can provide a theoretical reference for engineering applications of jets.

Oxidation resistance of Mo/Cr bilayer coating on Zr alloy in a 1200 °C steam environment

The Cr-coated Zr alloys demonstrate excellent resistance to high-temperature steam oxidation. However, the rapid diffusion pathways for oxygen formed by the inter-diffusion between the coating and alloy at high temperatures significantly affect the steam oxidation resistance of the coated alloys. To address this issue, we developed a Mo/Cr bilayer coating on Zr alloy by a combination of dc-MS and HiPIMS surface treatments. The coating exhibits outstanding steam oxidation resistance at high temperatures, resulting in a mass gain approximately 86.6% and 44.1% lower than that of the bare Zr alloy and Cr coating, respectively, after 30 min of steam oxidation at 1200 °C. This is mainly because, during the oxidation process, the Mo interface layer undergoes a transformation into a thin and high-quality double diffusion layer structure, effectively avoiding high-temperature inter-diffusion between the Cr coating and Zr alloy, thereby inhibiting the formation of oxygen diffusion pathways.

Double diffusion of rotated z‐shaped and sloshing fins in a nanofluid‐porous cavity

AbstractThis work examines the double diffusion of rotated Z‐shaped and sloshing fins inside a nanofluid‐porous cavity. The novelty of this research lies in its utilization of the ISPH method to handle the complex fluid‐structure interactions occurring at double diffusion within the nanofluid‐porous cavity. Two thermal/solutal conditions of the rotated Z shaped entitled C1 (), and C2 () are conducted in this work. The ISPH method solves the nonlinear systems of the fluid‐structure interactions during thermosolutal convection. The impacts of the inclined magnetic field and Soret–Dufour numbers are discussed. The Z shaped rotates circularly around its center and the four fins are sloshing on the boundaries. Natural convection is dominant because the rotation speed is slow, and the buoyancy force is strong. The obtained simulations revealed the changes in the isotherms, isoconcentration, and the nanofluid velocity under the variations of boundary conditions in Z shaped. It is seen that C1 always supports higher velocity, temperature, and concentration as well as mean Nusselt number ‐Sherwood number compared to C2. The Soret number plays a good role in the improvement of double diffusion and nanofluid velocity compared to the Dufour number which has fewer contributions.