Bioconvection Due to Gyrotactic Microorganisms in Couple Stress Hybrid Nanofluid Laminar Mixed Convection Incompressible Flow with Magnetic Nanoparticles and Chemical Reaction as Carrier for Targeted Drug Delivery through Porous Stretching Sheet

In this paper, the steady electrically conducting hybrid nanofluid (CuO-Cu/blood) laminar-mixed convection incompressible flow at the stagnation-point with viscous and gyrotactic microorganisms is considered. Additionally, hybrid nanofluid flow over a horizontal porous stretching sheet along with an induced magnetic field and external magnetic field effects that can be used in biomedical fields, such as in drug delivery and the flow dynamics of the microcirculatory system. This investigation can also deliver a perfect view about the mass and heat transfer behavior of blood flow in a circulatory system and various hyperthermia treatments such as the treatment of cancer. The simple partial differential equations (PDEs) are converted into a series of dimensional ordinary differential equations (ODEs), which are determined using appropriate similarities variables (HAM). The influence of the suction or injection parameter, mixed convection, Prandtl number, buoyancy ratio parameter, permeability parameter, magnetic parameter, reciprocal magnetic prandtl number, bioconvection Rayleigh number, coupled stress parameter, thermophoretic parameter, Schmidt number, inertial parameter, heat source parameter, and Brownian motion parameter on the concentration, motile microorganisms, velocity, and temperature is outlined, and we study the physical importance of the present problem graphically.     

A multi-domain spectral method for non-Darcian mixed convection flow in a power-law fluid with viscous dissipation

The purpose of this study is to investigate non-Darcian mixed convection flow, heat and mass transfer in a non-Newtonian power-law fluid over a flat plate embedded in porous medium with suction and viscous dissipation and also is to demonstrate the application and utility of a recently developed multi-domain bivariate spectral quasi-linearisation method (MD-BSQLM) in finding the solutions of highly nonlinear differential equations. The flow is subject to, among other source terms, internal heat generation, thermal radiation and partial velocity slip. The coupled system of nonlinear partial differential equations are solved using a MD-BSQLM to find the fluid properties, the skin friction, as well as the heat and mass coefficients. We have presented selected results that give the significance of some system parameters on the fluid properties. This MD-BSQLM has not been used before in the literature to find the nature of the solutions of power-law fluids. Indeed, validation of this numerical method for general fluid flows, heat and mass transfer problems has not yet been done. This study presents the first opportunity to evaluate the accuracy and robustness of the MD-BSQLM in finding solutions of non-Newtonian fluids.     

Variable chemical species and thermo-diffusion Darcy–Forchheimer squeezed flow of Jeffrey nanofluid in horizontal channel with viscous dissipation effects

This research communicates the applications of thermos-diffusion effect associated to the squeezing flow of Jeffrey nanofluid due to horizontal channel. The problem presents the applications of inertial effects by following the Darcy–Forchheimer flow. Moreover, the effects of viscous dissipation and activation energy phenomenon has been discussed. The dimensionless attention of problem is retained. The shooting technique is implemented to present the numerical computations. The numerical validation of results is reported. The essential assessment of physical flow parameters is studied. The numerical outcomes are presented for heat and mass transfer phenomenon. It is observed that presence of inertial forces control to velocity flow in the regime. The enhancing contribution of thermal and concentration rate is noted for inertial constant.     

Diffusion of liquid hydrogen in time-dependent MHD mixed convective flow

An innovative study on liquid hydrogen diffusion in time-dependent mixed convection flow is carried out in the presence of magnetic field effects. In fact, this is the first approach to analyze such flow problems, and also this is the first research paper to study the non-uniform heat sink/source and nonlinear chemical reaction in the presence of liquid hydrogen diffusion. Initially, the governing equations are reduced to dimensionless form by using non-similar transformations and are linearized by applying quasilinearization technique. Then, the finite difference approximation is utilized to discretize the resulting equations. The mixed convection is analyzed along with exponentially stretching surface through various graphs on profiles as well as gradients. The results display that the non-uniform heat source parameter increases the fluid velocity as well as temperature, and the magnetic parameter reduces the friction at the wall. Specifically, the skin friction coefficient decreases about 40% in the presence of magnetic field. The mass transfer rate increases for high-order chemical reaction and for destructive chemical reaction rate. The mass transfer rate is found to be high for the diffusion of liquid nitrogen than that for the diffusion of liquid hydrogen. In fact, the mass transfer rate increases about 22% for the diffusion of liquid nitrogen. This study can assist the design engineers who are working in pertain to the diffusion of liquid gases in mixed convection regimes. Also, the obtained data in the present study can be more useful for future investigations about time-dependent mixed convection nanofluid flow problems.

     

Numerical analysis of mixed convection heat transfer and laminar flow in a rectangular inclined micro-channel totally filled with Water/Al2O3 Nano fluid

A numerical analysis was carried out of mixed convection heat transfer for a laminar flow in a rectangular inclined microchannel totally filled with a water/Al2O3 nanofluid. The governing conservation equations are translated into a dimensionless form using the thermal single relaxation time and they modify the lattice Boltzmann method with double distribution functions. The viscous dissipation effects are adapted to the energy equation. The effects of nanoparticle volume fractions ? (0?≤???≤?0.04) and inclination angles γ (0°?≤?γ?≤?60°) on the flow of the nanofluid and the heat transfer are investigated. The obtained results are presented in terms of streamlines, isotherms, slip velocity, wall temperature and Nusselt number. The results show that the higher values of the volume fraction of Al2O3 and the large values of inclination angles improve the heat transfer rate.

     

Numerical study of nonlinear mixed convection inside stagnation-point flow over surface-reactive cylinder embedded in porous media

Nonlinear mixed convection of heat and mass in a stagnation-point flow of an impinging jet over a solid cylinder embedded in a porous medium is investigated by applying a similarity technique. The problem involves a heterogenous chemical reaction on the surface of the cylinder and nonlinear heat generation in the porous solid. The conducted analysis considers combined heat and mass transfer through inclusions of Soret and Dufour effects and predicts the velocity, temperature and concentration fields as well as the average Nusselt and Sherwood number. It is found that intensification of the nonlinear convection results in development of higher axial velocities over the cylinder and reduces the thickness of thermal and concentration boundary layers. Hence, consideration of nonlinear convection can lead to prediction of higher Nusselt and Sherwood numbers. Further, the investigation reveals that the porous system deviates from local thermal equilibrium at higher Reynolds numbers and mixed convection parameter.

     

Effects of radiation on mixed convection stagnation-point flow of MHD third-grade nanofluid over a vertical stretching sheet

This paper considers the problem of the two-dimensional mixed convection stagnation-point flow of a magnetohydrodynamic non-Newtonian nanofluid bounded by a vertical stretching sheet. Convective surface boundary and zero surface nanoparticle mass flux conditions are employed. The effects of buoyancy, radiation, Brownian motion, thermophoresis, and viscous dissipation are taken into account. The stretching velocity is assumed to vary linearly with the distance from the stagnation point. The fluid is electrically conducted with uniform magnetic field, and the work done due to deformation is taken into consideration. The three-coupled partial differential boundary layer equations are reduced to ordinary differential equations by using proper similarity transformations. Analytical solution by homotopy analysis method is obtained. Effects of different physical parameters on the dynamics of the problem are analyzed and discussed.

     

Microvascular blood flow with heat transfer in a wavy channel having electroosmotic effects

The present paper addresses microvascular blood flow with heat and mass transfer in complex wavy microchannel modulated by electroosmosis. Investigation is carried out with joule heating and chemical reaction effects. Further, viscous dissipation is also considered. Using Debye–Huckel, lubrication theory, and long wavelength approximations, analytical solutions of dimensionless boundary value problems are obtained. The impacts of different parameters are examined for temperature and concentration profile. Furthermore, nature of pressure rise is also investigated to analyze the pumping characteristics. Important results of flow phenomena are explored by means of graphs.     

The convective heat transfer analysis of the casson nanofluid jet flow under the influence of the movement of gyrotactic microorganisms

Jet flows provide an effective mode of energy transfer or mass transfer in industrial applications. When compared to traditional cooling through convection, jet flows have high heat and mass transfer coefficients. Further, the devices equipped with jet flow provides efficient use of fluid and also offers enhanced heat and mass transfer rates. Hence in this study, the jet flow of Casson nanofluid containing gyrotactic microorganisms that stabilises the nanoparticle suspension is discussed. To control the fluid from outside external magnetic field is imposed. The model with these characteristics are useful in the appliances like coolants in automobiles, nuclear reactors, micro-manufacturing, metallurgical process etc. Such a model is created by employing PDE, which are then transformed into a system of ODE. The DTM is employed to obtain the solution to system of equations, and the results are interpreted using graphs. It is perceived that the velocity of the nanofluid flow is decreased because of the increased yield stress created by the greater values of the Casson parameter. As a result, the temperature profile is found to be increasing. Meanwhile, it is observed that for increased value of chemical reaction parameter diminishes the nanoparticle concentration. The motile density is found to decrease for increase in the Peclet number and the bioconvection Schmidt number. Further, the thermophoresis improves the temperature and concentration profile of the nanofluid.     

Effect of Coriolis and buoyancy forces on three-dimensional flow of chemically reactive tangent hyperbolic fluid subject to variable viscosity

Thermophoresis effect has wide range of applications in electro-static precipitators and in biology for calculating single biological macro molecules, such as genomic-length DNA and HIV virus in the micro channels. Current study deal with effects of Coriolis and buoyancy forces on the three-dimensional boundary layer flow of tangent hyperbolic fluid with thermo-migration and haphazard motion of nano-sized particles. Arrhenius kind of chemical reaction is taken along an exponentially stretchable surface. The main focus of current exploration is to execute shear thinning nano-liquid flow past an exponentially rotating stretchable surface under the influence of variable viscosity, mixed convection and activation energy. We are motivated to explore the features of three-dimensional shear thinning model combined under the features of mixed convention, variable viscosity, and activation energy. The mathematical model is designed to generate PDEs and converted them into ODEs by employing fractious transformation. The numerical outcomes are exhibited via graphs by employing Bvp4c numerical technique whereas the values of skin friction coefficient are calculated by monopolizing shooting method. Characteristics of the parameters appearing in modeling like the viscosity parameter, power-law index, local Weissenberg number, mix convection parameter, rotation parameter, Prandtl number and chemical reaction parameter are comprehensively analyzed through graphical behavior. The impact of governing parameters on skin friction, heat and mass transfer rates is illustrated through tables. The detail analysis anticipates that the elevation in Weissenberg number and porosity caused decline in velocity. Further, the temperature behaves doppositely analogous to development Prandtl besides the thermophoresis parameter.     

Modeling of thermal processes in high pressure liquid chromatography: I. Low pressure onset of thermal heterogeneity

Heat due to viscous friction is generated in chromatographic columns. When these columns are operated at high flow rates, under a high inlet pressure, this heat causes the formation of significant axial and radial temperature gradients. Consequently, these columns become heterogeneous and several physico-chemical parameters, including the retention factors and the parameters of the mass transfer kinetics of analytes are no longer constant along and across the columns. A robust modeling of the distributions of the physico-chemical parameters allows the analysis of the impact of the heat generated on column performance. We developed a new model of the coupled heat and mass transfers in chromatographic columns, calculated the axial and radial temperature distributions in a column, and derived the distributions of the viscosity and the density of the mobile phase, hence of the axial and radial mobile phase velocities. The coupling of the mass and the heat balances in chromatographic columns was used to model the migration of a compound band under linear conditions. This process yielded the elution band profiles of analytes, hence the column efficiency under two different sets of experimental conditions: (1) the column is operated under natural convection conditions; (2) the column is dipped in a stream of thermostated fluid. The calculated results show that the column efficiency is remarkably lower in the second than in the first case. The inconvenience of maintaining constant the temperature of the column wall (case 2) is that retention factors and mobile phase velocities vary much more significantly across the column than if the column is kept under natural convection conditions (case 1).     

Stability conditions of an electrified miscible viscous fluid sheet

The Kelvin-Helmholtz problem of viscous fluids under the influence of a normal periodic electric field in the absence of surface charges is studied. The system is composed of a streaming dielectric fluid sheet of finite thickness embedded between two different streaming finite dielectric fluids. The interfaces permit mass and heat transfer. Because of the complexity of the considered system, a mathematical simplification is adopted. The weak viscous effects are taken into account so that their contributions are incorporated into the boundary conditions. Therefore, the equations of motion are solved in the absence of viscous effects. The boundary value problem leads to two simultaneous Mathieu equations of damped terms having complex coefficients. The symmetric and antisymmetric deformations reduced the coupled Mathieu equations to a single Mathieu equation. The classical stability criterion is found to be substantially modified due to the effect of mass and heat transfer. The analytical results are numerically confirmed. It is found that the sheet thickness and mass and heat transfer parameters have a dual influence on the stability criteria. It is also found that the field frequency has a stabilizing influence especially at small values of the wave number. In contrast to the case of a pure inviscid fluid, it is found that the uniform normal electric field plays a dual role in the stability criteria. This role depends on the choice of the numerical values of the physical parameters of the system under consideration.     

Numerical simulations for radiated bioconvection flow of nanoparticles with viscous dissipation and exponential heat source

A nonlinear radiative bioconvection flow of nanofluid due to impulsively porous space is investigated. The applications of externa heat source with exponential relations, viscous dissipation and magnetic force are considered for fully developed stretched flow. The microorganisms are uniformly decomposed with the nanofluids. The thermal analysis is observed with interaction of slip phenomenon and convective boundary constraints. The dimensionless system of governing model is obtained with new imposed variables. The numerical computations are performed by using the shooting method. The confirmation of numerical data is achieved with already reported studies. Thermal observations govern to the flow system in view of parameters are suggested. It is observed that declining change in velocity is subject to the stretching parameter and permeability of porous space. The implementation of slip and convective boundary constraints effectively enhanced the transportation phenomenon. Based on interaction of nonlinear thermal radiated phenomenon and porous medium, different applications of problem are claimed in solar systems, extrusion processes, manufacturing systems, soil sciences, petroleum engineering, chemical processes etc.     

Exergetic performance evaluation of solar air heater having V-down perforated baffles on the absorber plate

Baffles serve as heat transfer augmentation features in solar air heaters; however, they increase pressure drop in flow channels. Perforated baffles are relatively good heat transfer augmentation features with superior performance over conventional smooth duct solar air heater and as a result find application in some solar air heaters. The exergy method is employed to in determining the roughness parameters, as second law-based exergy analysis is suitable for design of roughened solar air heaters. The exergetic efficiency of V down perforated baffled roughened duct solar air heater is studied analytically, and the results obtained compared with conventional system. Results indicate that high efficiency with optimum V down perforated baffle improves the heat absorption and dissipation potential of a solar air heater. Design plots are prepared to predict the optimum roughness parameter as a function of temperature rise parameter.     

Chemical reaction and Soret effect on an unsteady MHD heat and mass transfer fluid flow along an infinite vertical plate with radiation and heat absorption

In the current investigation, it is anticipated to examine the influence of heat absorption and radiation on an unsteady transient MHD heat and mass transfer natural convective flow of an optically thin non-Grey Newtonian fluid through an abruptly started infinite vertical porous plate with ramped wall temperature and plate velocity in the presence of Soret and chemical reaction of the first order is solved precisely. Using the similarity variables, the governed PDE's are converted into dimensionless governing equations and they are solved numerically by employing the finite element technique. Numerical calculations and graphs are used to illustrate the important features of the solution on fluid flow velocity, heat, and mass transfer characteristics under different quantities of parametric circumstances entering into the problem. Moreover, we computed the physical variables such as the coefficient of drag force, rate of heat, and mass transfer. The findings indicate that when the thermal radiation parameter increases, the thermal boundary layer becomes thinner. To establish the veracity of our present results, we compared them to previously published research and found substantial concordance.     

Steady hydromagnetic flow of a non-Newtonian power law fluid due to a rotating porous disk with heat transfer

The steady magnetohydrodynamic (MHD) flow of an incompressible viscous non-Newtonian power law fluid above an infinite rotating porous disk with heat transfer is studied. A uniform magnetic field is applied perpendicularly to the plane of the disk and a uniform injection or suction is applied through the surface of the disk. Numerical solutions of the nonlinear differential equations which govern the hydromagnetic and heat transfer are obtained. The effects of characteristics of the non-Newtonian fluid, the magnetic field parameter and the suction or injection velocity on the velocity and temperature distributions are considered.     

Investigation of double-diffusive mixed convection effect on the particles dissolution in the shear flow using coupled SPM–LBM

Journal of Thermal Analysis and Calorimetry - In the present study, double-diffusive mixed convection related to the heat and mass transfer of the solid particles dissolution in a shear flow was...     

Pulsating flow in a channel filled with a porous medium under local thermal non-equilibrium condition: an exact solution

Journal of Thermal Analysis and Calorimetry - The present work investigates analytically the problem of forced convection heat transfer of a pulsating flow, in a channel filled with a porous medium...     

Modeling of ammonothermal growth processes of GaN crystal in large-size pressure systems

Gallium nitride (GaN) is a wide-bandgap semiconductor material with a wide array of applications in optoelectronics and electronics. Modeling of the fluid flow and thermal fields is discussed, and simulations of velocity and volumetric-flow-rate profiles in different pressure systems are shown. The nutrient is considered as a porous media bed, and the flow is simulated using the Darcy?CBrinkman?CForchheimer model. The resulting governing equations are solved using the finite-volume method. We analyzed the heat and mass transfer behaviors in autoclaves with diameters of 2.22, 4.44, and 10 cm. The effects of baffle design on flow pattern, and heat and mass transfer in different autoclaves are analyzed. For the research-grade autoclave with diameter of 2.22 cm, the constraint for the GaN growth is found to be the growth kinetics and the total area of seed surfaces in the case of baffle opening of 10%. For large-size pressure systems, the concentration profiles change dramatically due to stronger convection at higher Grashof numbers. The volumetric flow rates of the solvent across the baffles are calculated. Since ammonothermal growth experiments are expensive and time consuming, modeling becomes an effective tool for research and optimization of ammonothermal growth processes.