Bioconvective Reiner–Rivlin nanofluid flow over a rotating disk with Cattaneo–Christov flow heat flux and entropy generation analysis

The non-Newtonian fluids possess captivating heat transfer applications in comparison to the Newtonian fluids. Here, a new type of non-Newtonian fluid named Reiner–Rivlin nanofluid flow over a rough rotating disk with Cattaneo–Christov (C–C) heat flux is studied in a permeable media. The stability of the nanoparticles is augmented by adding the gyrotactic microorganisms in the nanofluid. The concept of the envisaged model is improved by considering the influences of Arrhenius activation energy, chemical reaction, slip, and convective conditions at the boundary of the surface. The entropy generation is evaluated by employing the second law of thermodynamics. The succor of the Shooting scheme combined with the bvp4c MATLAB software is adapted for the solution of extremely nonlinear system of equations. The noteworthy impacts of the evolving parameters versus engaged fields are inspected through graphical illustrations. The outcomes show that for a strong material parameter of Reiner–Rivlin, temperature, and concentration profiles are enhanced. The behavior of Skin friction coefficients, local Nusselt number, Sherwood number, and local density number of motile microorganisms against the different estimates of emerging parameters are represented in tabular form. The authenticity of the intended model is tested by comparing the presented results in limiting form to an already published paper. A proper correlation between the two results is attained.

Multiple slips impact in the MHD hybrid nanofluid flow with Cattaneo–Christov heat flux and autocatalytic chemical reaction

The present study deliberates the nanofluid flow containing multi and single-walled carbon nanotubes submerged into Ethylene glycol in a Darcy–Forchheimer permeable media over a stretching cylinder with multiple slips. The innovation of the envisaged mathematical model is enriched by considering the impacts of non-uniform source/sink and modified Fourier law in the energy equation and autocatalytic chemical reaction in the concentration equation. Entropy optimization analysis of the mathematical model is also performed in the present problem. Pertinent transformations procedure is implemented for the conversion of the non-linear system to the ordinary differential equations. The succor of the Shooting technique combined with the bvp4c MATLAB software is utilized for the solution of a highly nonlinear system of equations. The impacts of the leading parameters versus engaged fields are inspected through graphical sketches. The outcomes show that a strong magnetic field strengthens the temperature profile and decays the velocity profile. Also, the fluid velocity is lessened for growing estimates of the parameter of slip. Additionally, it is detected that entropy number augmented for higher thermal relaxation parameter and Reynolds number. To substantiate the existing mathematical model, a comparison table is also added. An excellent correlation is achieved here.

Open Porous Composite Monoliths for Biomedical Applications via Photocrosslinking of Low Internal Phase Nano-Emulsion Templates

Highly cross-linked polyethylene glycol monoliths (HCPEG) with interconnected micro and nanoporosity are produced via photo-crosslinking of low internal phase emulsions (LIPE). Unlike previous works, this approach allows the pre-processing functionalization of both polymer matrix and porosity by loading both phases of the emulsion template with several active fillers, such as enzymes, semiconductive polymers, and metallic nanostructures. Importantly, both polymer matrix and porosity of the resulting composite HCPEG monoliths show neither serious cross-contamination nor morphological alterations. All in all, this material behaves like a network of nano/micro flasks embedded into a permeable media. Mechanical and dielectric properties of these composites HCPEG monoliths can be tuned by varying the content of fillers. Since these composite materials are produced by photo-crosslinking of LIPEs, they can be easily and rapidly processed into complex shapes like microneedles arrays through replica molding without detrimental modifications of the porous morphology. In principle, the proposed strategy allows us to fabricate medical devices. As proof of concept, we embedded glucose oxidase enzyme in the nanoporosity and the resulting composite porous material retained the catalytic activity towards the oxidation of glucose.

Nonlinear radiative Maxwell nanofluid flow in a Darcy–Forchheimer permeable media over a stretching cylinder with chemical reaction and bioconvection

Studies accentuating nanomaterials suspensions and flow traits in the view of their applications are the focus of the present study. Especially, the usage of such materials in biomedical rheological models has achieved great importance. The nanofluids’ role is essential in the cooling of small electronic gizmos like microchips and akin devices. Having such exciting and practical applications of nanofluids our goal is to scrutinize the Maxwell MHD nanofluid flow over an extended cylinder with nonlinear thermal radiation amalgamated with chemical reaction in a Darcy–Forchheimer spongy media. The presence of gyrotactic microorganisms is engaged to stabilize the nanoparticles in the fluid. The partial slip condition is considered at the boundary of the stretching cylinder. The Buongiorno nanofluid model is betrothed with impacts of the Brownian motion and thermophoresis. The analysis of entropy generation is also added to the problem. The highly nonlinear system is tackled numerically is addressed by the bvp4c built-in function of the MATLAB procedure. The outcomes of the prominent parameters versus embroiled profiles are portrayed and conversed deeming their physical significance. It is perceived that fluid temperature is augmented for large estimates of the radiation and Darcy parameters. Moreover, it is noticed that the magnetic and wall roughness parameters lower the fluid velocity. To corroborate the presented results, a comparison of the current study with a previously published paper is also executed. An outstanding correlation in this regard is attained.

Simulation of Flow Through Variable Permeability Darcy-Brinkman Layers

In this paper, coupled parallel flow in a triple layer channel is studied numerically. The channel consists of a clear fluid sandwiched between two Darcy-Brinkman permeable layers of variable porousness. A single binary equation is presented, in which the penetrability within transition porous layers, is portrayed by a nth degree objective capacity. However, because of the absence of explanatory arrangement of the issue, direct numerical simulations are performed in order to give a novel knowledge into the fluid dynamics inside permeable media of variable porousness. These simulations are carried out through utilizing a modified steady state finite volume solver from the open source programming bundle OpenFOAM. After check and approval of the solver and mathematical technique, parametric investigation is acted in which the Darcy number, intensity of the penetrability degree, transition layer thickness, channel depth, fluid viscosity, and pressure gradient vary. The findings of the current study show that velocity increases when: First, the Darcy number, the degree, or the channel depth increases. Second, when the transition layer thickness decreases. Also, strain rate is almost independent of both Darcy number and degree, and nearly doubles when either the thickness of transition layer halves or the channel depth doubles. In addition, velocity and strain rate are found to scale with viscosity and pressure gradient.

Upshot of heterogeneous catalysis in a nanofluid flow over a rotating disk with slip effects and Entropy optimization analysis

The present study examines homogeneous (HOM)–heterogeneous (HET) reaction in magnetohydrodynamic flow through a porous media on the surface of a rotating disk. Preceding investigations mainly concentrated on the catalysis for the rotating disk; we modeled the impact of HET catalysis in a permeable media over a rotating disk with slip condition at the boundary. The HOM reaction is followed by isothermal cubic autocatalysis, however, the HET reactions occur on the surface governed by first-order kinetics. Additionally, entropy minimization analysis is also conducted for the envisioned mathematical model. The similarity transformations are employed to convert the envisaged model into a non-dimensional form. The system of the modeled problem with ordinary differential equations is analyzed numerically by using MATLAB built-in bvp4c function. The behavior of the emerging parameters versus the thermal, concentration, and velocity distributions are depicted graphically with requisite discussion abiding the thumb rules. It is learned that the rate of the surface catalyzed reaction is strengthened if the interfacial area of the permeable media is enhanced. Thus, a spongy medium can significantly curtail the reaction time. It is also noticed that the amplitude of velocity and thermal profile is maximum for the smallest value of the velocity slip parameter. Heat transfer rate declines for thermophoresis and the Brownian motion parameter with respect to the thermal slip parameter. The cogency of the developed model is also validated by making a comparison of the existing results with a published article under some constraints. Excellent harmony between the two results is noted.

Feasibility of repurposing existing and abandoned hydrocarbon wells in the form of a geothermal well-triplet system

There are various types of extraction and utilization possibilities of geothermal energy, of which a large group is energy recovery. The development of this sector is slow mainly due to its high initial investment demand and the long planning phase. The overall goal of the present research is cutting the cost of the drilling phase as the most expensive part of the establishment by repurposing unused and abandoned hydrocarbon wells. The article assesses the feasibility of a geothermal well-triplet system chosen to be the most promising technique amongst several utilization possibilities depending on the characteristics of both the geological media and the method itself. From the 14 examined abandoned wells three were found to be suitable based on their current condition and distance from each other. The mentioned technique requires an adequately porous and permeable media which was not provided by the initial depth of the wells, thus the considerable option left was to overdrill the existing wells till they reach the target geology, the known fractured karstic aquifer below. The current study summarizes the final results of a long going research, from the geographical-, lithological surveys till the potential heat-transport modeling. This article supports the final aspirations of a further going research project as an integral part of it carried out by the University of Miskolc.