Mixed convection of a nanofluid past an inclined wavy surface in the presence of gyrotactic microorganisms

The mixed convection of a nanofluid flow past an inclined wavy surface in the existence of gyrotactic microbes is considered. To convert the wavy surface to a plane surface, a transformation of coordinates is applied. The governing equations that are nonlinear and the accompanying boundary conditions are converted into a dimensionless form using pseudo-similarity variables. Using a local linearization process, the system of nonlinear partial differential equations is linearized. The resulting system is solved using the Bivariate Chebyshev pseudo-spectral collocation method. The influence of different physical and geometrical factors on the parameters of engineering importance of the flow is analyzed and illustrated graphically. It is observed that the skin friction, the density of motile microorganisms, and nanoparticle mass transfer rate are increasing with an increase in the bioconvection Peclet and Schmidt numbers whereas these quantities are decreasing with an increase in Rayleigh number. The local Nusselt number, nanoparticle Sherwood number, and density number of microbes increases with an increase in the Brownian motion and thermophoresis parameter. These physical quantities are increasing when the surface changes from horizontal to vertical.     

Analysis of the impact of physical parameters on a water-based Al2O3 nanofluid using the KKL model

A nanofluid is treated as a smart fluid that is useful for heat transfer enhancement, which is paramount in several industrial applications, transportation, biomedical as well as electronics. This is due to the enhanced thermophysical properties, such as Brownian motion and thermal conductivity of the suspended nanoparticles in the base fluid. The present investigation explores an electrically conducting flow of a water-based nanofluid past a thin film placed horizontally. In particular, the Al₂O₃ nanoparticle is merged into the water for the preparation of the nanofluid. For the enhancement in heat transfer properties, the Brownian thermal conductivity based on the Koo-Kleinstreuer-Li model is introduced. The Adomian decomposition method, a semi-analytical technique, is employed to handle the system of ordinary differential equations. The originality of the current investigation is the statistical analysis of the various characterizing parameters governing the flow phenomena. The influences of these physical parameters on the flow phenomena are displayed in graphs and tables. The major findings of the outcomes are listed as follows: an increase in particle diameter decreases the Brownian conductivity, whereas fluid temperature enhances it significantly. Also, the increase in volume concentration leads to a decrease in the fluid temperature, resulting in faster cooling processes for the production of materials in industries.     

Statistical analysis on three-dimensional MHD convective Carreau nanofluid flow due to bilateral nonlinear stretching sheet with heat source and zero mass flux condition

This study focuses on analyzing the response of a magnetohydrodynamic convective Carreau nanofluid flow over a bilateral nonlinear stretching sheet in the presence of a heat source and zero mass flux condition. The problem has been solved numerically using the MATLAB built-in function bvp5c. The findings of velocity, temperature, and concentration profiles based on the various parameters are illustrated using graphs. The impact of various parameters on the heat transfer rate is scrutinized using statistical techniques, like, correlation coefficient, probable error, and regression. The effect of various parameters on skin friction coefficients is studied via tables and slope of linear regression. It is observed that the statistical results coincide with the numerical results. It is also noticed that the stretching ratio parameter increases the Y-directional velocity profile. Accuracy of the numerical procedure has been validated through a restrictive comparison of the present work with previous published results and is found to be in good agreement.     

The three-dimensional bioconvective flow of Sisko nanofluid under Robin's conditions

The proposed model investigates three-dimensional bioconvective Sisko nanofluid flow under Robin's conditions. The Sisko nanofluid has versatile implications in drilling fluids, cement slurries, waterborne coatings, and so on. Furthermore, the inclusion of gyrotactic microorganisms prevents the deposition and agglomeration of the nanoparticles in the base fluid. Buongiorno's model is included to explore the behavior of Brownian motion and thermophoretic factors. The energy and mass transmissions along with the gyrotactic microorganism density are illustrated by the partial differential expression system with Robin's conditions. These are further reframed into an ordinary differential equation system with the aid of similarity transformation. The developing model is tackled by using the MAPLE inbuilt package BVP. The nanofluid acts as a good cooling agent for higher values of the thermophoresis parameter. Furthermore, the pseudoplastic nanofluid performs better than the dilatant nanofluid. The developed model is very useful in energy production and engineering products.     

MHD Williamson nanofluid across a permeable medium past an extended sheet with constant and irregular thickness

The main resource of this paper is to establish over fluid flows sheet using mathematical modeling for constant and variable thickness by including magnetic fields, electric fields, porous medium, heat propagation/immersion, and radiative heat relocation. The Implicit Finite Difference Method (IFDM) is applied to simplify using similarity conversions to implicate partial differential equations to convert into ordinary differential equations. IFDM has been implemented in MATLAB to tabulate numerical observations of the local parameters. Nusselt and Sherwood numbers are analyzed and measured for different parameters in different constant and variable thickness conditions of fluid properties. The influence of various parameters is explained through temperature, velocity, concentration, and nanoparticle volume fraction graphical representations. The coefficient of the skin friction for irregular fluid properties is shown to have a greater influence than that compared for constant fluid properties. Nevertheless, there is a reverse case in the local Nusselt number that is lower for the fluctuating fluid properties than with constant fluid properties. The results showed high-exactness computational outcomes are attained from the IFDM.     

Experimental research on titanium dioxide nanofluid in vacuum flash evaporation

This study is purposed to conduct experimental investigation into the characteristics of vacuum flash evaporation with nanofluid under adsorption conditions, with the effects of nanoparticle concentration, surfactant concentration, and nanofluid stability taken into consideration. By measuring absorbency, solute concentration, and sedimentation graph, a new nanofluid with excellent dispersion was developed for the vacuum ice-making system. It has been demonstrated that the low concentration of additive is conductive to not only the maintenance of vacuum but also the generation of binary ice. For nanofluid, there are two distinct freezing stages in the process of vacuum flash evaporation. The supercooling stage of nanofluid is delayed with the increase of surfactant concentration, whereas the TiO₂ nanofluid applied to the vacuum ice-making system under adsorption shows stability. Moreover, it is indicated that, for the vacuum ice-making system with TiO₂ nanofluid, the pH level is around 8.5, the surfactant is sodium dodecyl benzene sulfonate-span 60 (SDBS-SPAN), the ratio of SDBS to SPAN is about 10:7, the concentration of TiO₂ nanoparticle is around 0.20 wt%, and the ratio of TiO₂ nanoparticle to SDBS-SPAN is about 10:5. Compared with pure water, undercooling is reduced by 77.92%; the ice packing factor and thermal conductivity are increased by 40.61% and 67.27%, respectively. The results of test and analysis can be applied to conduct further research on vacuum flash evaporation.     

Significance of heat source/sink on the radiative flow of Cross nanofluid across an exponentially stretching surface towards a stagnation point with chemical reaction

A numerical review on magnetohydrodynamics radiative motion of Cross nanofluid across an exponentially stretchable surface near stagnation point with varying heat source/sink is addressed. Brownian movement and thermophoretic impacts are assumed. The governing equations for this study are first altered as a system of ordinary differential equations by similarity transformation. With an aid of the Runge–Kutta 4th order mechanism together with the shooting procedure, the impacts of several pertinent parameters including chemical reaction on regular profiles (velocity, temperature, and concentration) are explicated. The consequences of the same parameters on surface drag force, transfer rates of heat, and mass are visualized in tables. From the analysis, it was noticed that the magnetic field parameter enhances the temperature and decreases the velocity of the Cross nanofluid. Also, fluid temperature is an increasing function with thermal radiation and nonuniform heat source/sink. The rate of heat transfer is increased with thermophoresis and diminished with Brownian motion. Sherwood's number is diminished with Brownian motion but it was boosted up with thermophoresis. The present results are compared with published results and those are in agreement.