As a model for hazardous material pumps, this paper examines the magnetohydrodynamic chemically reacting thermo-solutal peristaltic transport of a non-Newtonian couple stress fluid through a microchannel containing a porous medium. The effects of thermal radiative heat transfer, Joule heating, Soret thermodiffusion, viscous dissipation, and heat generation/absorption are also included. The microchannel walls have convection boundary conditions, and sinusoidal peristaltic waves are considered. The conservation equations for mass, momentum, energy, and concentration are simplified via lubrication approximations. The moving boundary value problem is rendered dimensionless and solved analytically. Numerical evaluations of the axial velocity, temperature, and concentration are conducted in MATLAB. The Bejan number is enhanced with a couple stress (non-Newtonian) parameter, mean flow rate, and Brinkman number. Temperatures are boosted with Hartmann (magnetic) number and Brinkman number but suppressed with the couple stress parameter. The entropy generation parameter is reduced with an increment in couple stress parameter and radiation parameter; whereas it is boosted with the Brinkman number. Pressure gradient is enhanced with an increment in the Hartmann (magnetic) number but depleted with the Darcy number and couple stress parameter. Concentration is strongly reduced in the core zone of the channel with an increment in Soret number, Brinkman number, Hartmann number, mass Biot number, and Schmidt number, but increased with a chemical reaction parameter. Nusselt number magnitudes are elevated with the thermal Biot number, Brinkman number, couple stress parameter, and magnetic parameter but are reduced with an increasing radiation parameter. A substantial modification in bolus size is induced with increasing Hartmann number, Darcy number, and couple stress parameter.
Single basin spillways are critical hydraulic structures that are designed to mitigate structural damage by reducing high-velocity fluid flow, yet their performance with non-Newtonian fluids remains under explored. This study aims to computationally analyze the flow behavior of a cross power law non-Newtonian fluid in a single basin spillway using the finite volume method (FVM) implemented in open-source field operation and manipulation (OpenFOAM). The mathematical model is programmed in C++, which is simulated under various operating conditions, focusing on velocity and pressure distributions. Results reveal high velocity and pressure near the basin, with the basin effectively reducing flow speed, thus enhancing structural safety. Graphical representations of velocity and pressure profiles highlight flow patterns and hydraulic performance. A mesh independent test and comparison with existing literature are provided for confirmation of the results computed. The findings of the proposed model provide insights into optimizing single basin spillway designs for efficient water management and improved durability in civil engineering applications.
This study investigates the coupled effects of Soret and Dufour on double-diffusive convection within an anisotropic porous layer saturated by a non-Newtonian fluid governed by the power-law model (Oswald-de Waele). The horizontal walls are subjected to constant heat and mass fluxes, while the vertical boundaries are adiabatic and impermeable. The system is formulated by combining the generalized Darcy law with the Boussinesq approximation and subsequently reduced to a single nonlinear equation through the parallel flow assumption. Numerical resolution was carried out using a Newton iterative scheme implemented in MATLAB. The results reveal that increasing the Soret and Dufour effects lowers the critical Rayleigh number, thereby promoting the earlier onset of convection. The centerline velocity of the fluid decreases slightly with the intensification of these effects, as well as with variations in the Lewis and permeability numbers, with a maximum reduction of 1.86% observed for Du = 1 at Le = 2. In contrast, the Soret effect remains below 0.5% for Ra = 100. Permeability proved to be a key factor, since low values constrain convective motion, whereas higher values facilitate internal circulation and enhance both heat and mass transfer. An increase in the Lewis number shifts the dynamics in favor of solutal diffusion. Heat and mass transfer rates attain a quasi-steady behavior for Ra >= 200 or Le >= 0.5, indicating saturation regimes dominated by diffusion. These findings highlight the stabilizing influence of thermodiffusive effects on convection and demonstrate how hydrodynamic and diffusive parameters interact to modulate coupled heat and mass transport. The conclusions of this study may serve to guide the optimization of coupled transfer processes in practical applications such as thermal energy storage, industrial processes, and geophysical or biological flows involving non-Newtonian fluids.
Industrial heat exchangers, such as pre-coolers, require compact designs capable of delivering high thermal performance with minimal pressure loss. However, achieving this balance is challenging, especially when incorporating porous structures like metal foams that enhance heat transfer but introduce additional flow resistance. This study addresses the need for an optimized design by numerically and probabilistically analyzing forced convection in aluminum metal foam-coated tube banks under varying operating conditions. Using commercial computational fluid dynamics tools, the effects of metal foam thicknesses (0.75, 2, and 3.25 mm), porosities (0.90-0.95), and free-stream velocities (5-25 m/s) were evaluated on key performance indicators, i.e., Nusselt number, pressure drop, and outlet temperature. The Darcy-Forchheimer-Brinkman model and local thermal equilibrium energy model were used to capture flow and heat transfer within the porous domain. A Monte Carlo simulation framework, integrated with Sobol sensitivity analysis, quantified the influence of design parameters on thermal-hydraulic performance. Quantitatively, the metal foam-C configuration (2-mm thickness, 95% porosity) enhanced heat transfer by 30% with only a 15% increase in pressure drop compared to a bare tube, offering the best overall performance. Thicker foams (metal foam-A and metal foam-B, 3.25 mm) improved Nusselt number sensitivity by up to 50% but also increased pressure drop sensitivity by 35%- 40%, demonstrating the trade-off between enhancement and resistance. Foam thickness and porosity were identified as dominant factors influencing performance variability. The novelty of this study lies in its probabilistic sensitivity framework for heat exchanger optimization, a departure from conventional deterministic studies. The integration of Monte Carlo and Sobol analysis enables a robust, uncertainty-aware approach to metal foam selection and thermal design. These insights contribute to the development of energy-efficient heat exchangers optimized for performance and reliability under real-world variability.
The impact of non-Newtonian fluid on a rotating rough sphere over irregular boundaries is analyzed in the present study. This model analyzed the effects of the Casson parameter (beta), buoyancy mixed convective parameter (lambda), Brownian motion parameter (N-b), Lewis number (Le), and irregular boundary parameter beta(1) on primary and secondary velocity profiles, temperature, concentration, and skin friction profiles in an innovative manner. The set of modeled governing equations is dimensional in nature. In order to nondimensionalize the governing equations, certain nonsimilar transformations are applied. After being linearized using the quasilinearization approach, the converted dimensionless equations are numerically solved using the finite difference method and iterative Varga's algorithm. The graphical representation of numerical results exhibits the increased primary skin friction coefficient and velocity profiles for increasing values of beta, and a reverse trend is observed for secondary skin friction coefficient, temperature, and concentration profiles. In particular, the effect of non-Newtonian fluid diminishes the species concentration boundary layer and enhances the skin friction values. The thermal diffusivity to mass diffusivity enhances the skin friction profiles and concentration profiles. The variation of primary and secondary skin friction coefficient for varying values of various nondimensional parameters are also mentioned in this paper.
This study investigates the unsteady thin film fluid dynamics and heat transfer features of nanofluid comprising Al2O3 nanoparticles dispersed in a base fluid along a stretching sheet enclosed within a porous medium. The model incorporates effects of radiation, Ohmic heating, electromagnetohydrodynamic (EMHD), and viscous dissipation. The impact of different nanoparticle shapes is also analyzed. The governing partial differential equations are transitioned into ordinary differential equations by means of similarity transformations and computed using coupled fourth-order Runge-Kutta integration and shooting process. The variations in velocity and temperature trends are presented visually for key factors by executing the code in MATLAB. Skin friction and thermal flow rate on the surface are also tabulated. The results indicate velocity deceleration with increasing magnetic field and porosity parameters. The electric field enhances the temperature, but the velocity slip reduces it. Platelet-shaped nanoparticles prove most effective in augmenting heat transfer compared to other shapes. The findings have practical implications for thermal management systems, enhanced oil recovery, and magnetohydrodynamic (MHD) fluid transport. The current solutions compare well with literature reports. The study offers key perspectives on the transport behavior of nanofluids within porous substrate, with relevance to practical applications.
The current work analyzes the impact of thermal radiation on the nonlinearslip flow of an unsteady magnetohydrodynamic Casson hybrid nanofluid over a heated surface embedded in the Darcy-Forchheimer porous medium. The hybrid nanofluid flows in the presence of a varying magnetic field and heat generation. The viscous dissipation, Brownian motion, and thermophoretic force are taken into consideration. The surface is extendable, permeable, and variably thickened. The hybrid nanofluid includes copper, titanium dioxide nanoparticles, and water as the base fluid. The driving PDEs are turned into nondimensional ODEs using a similarity transformation. The ODEs are solved computationally by the finite difference method, incorporating Newton's linearization process. The effects of the involved factors on heat transport and solute fluxes are presented in plots and tabular forms for skin friction, heat transfer rate, and mass transfer rate. A comparison with earlier published studies is exhibited, and an excellent agreement is obtained. The computational results indicate that the slip velocity and Forchheimer factor enhance the Nusselt number and reduce the Sherwood number. The higher values of slip velocity parameters, the nanoparticle volume fractions, and thermal radiation enhance the friction force. On the other hand, the increment of the Forchheimer factor, Casson parameter, Schmidt number, and porosity parameter cause an increase in drag force. It is observed that as the TiO2 nanoparticles volume fraction increases (0 to 5%) at fixed Cu nanoparticles volume fraction, the Nusselt number increases by 19.14%, whereas both the skin friction and Sherwood number decrease by 0.4% and 11.99%, respectively. The findings of the current study may have significant applications in engineering and biotechnology systems such as cancer therapy, dialysis, blood transfusion, and treatment.
Accurate quantification of diffusion coefficients in porous media is critical for environmental engineering, geotechnical engineering, and petrochemical industries, particularly in applications involving contaminant transport, groundwater remediation, and energy storage systems. Traditional quasi-steady state (QSS) diffusion setups, while widely utilized, often suffer from significant errors due to premature assessments and suboptimal configurations. These errors, previously unquantified, can substantially impact the reliability of transport predictions in porous media applications. This study optimizes the QSS setup through a systematic investigation of measurement errors, particularly during the critical early phases of diffusion tests. A finite element model, specifically designed for QSS diffusion tests, systematically investigates errors associated with nonlinear concentration gradients, enabling precise determination of steady-state onset. Our findings reveal significant deviations in diffusion coefficients during initial stages (t < 255 hr, error > 33%), attributed to inadequate diffusion flux relative to the imposed concentration gradient. These errors systematically decrease to below 5% at 605 hr, coinciding with the establishment of linear concentration profiles. Statistical validation demonstrates exceptional consistency across multiple timescales (mean absolute percentage error 3.8-4.1%, n = 4, Cr = 0.4-0.5%), with mass flux consistency validated to within 3.2 x 10(-6) mmol m(-2) s(-1). Establishing a linear concentration gradient stabilizes diffusion coefficients (CoV < 2.1%), highlighting the necessity for methodological precision. The model accurately predicts the timeframe for achieving reliable steady-state conditions (R-2 = 0.992), reducing unnecessary extended test durations while maintaining measurement accuracy. This research provides a comprehensive framework for optimizing diffusion test setups, enhancing accuracy and efficiency in measuring diffusion phenomena in porous media. The insights are crucial for improving diffusion metrics reliability in environmental engineering and energy sectors, with direct applications in contaminant transport prediction, subsurface characterization, and energy storage system design. By identifying and quantifying errors in premature QSS assessments, this study advances precise diffusion measurement, significantly contributing to both scientific understanding and practical applications in porous media transport phenomena.
