2nd international Conference on Numerical Heat Transfer and Fluid Flow

The paper deals with the flow of two immiscible couple stress fluids in a channel filled with porous medium in the presence of a transverse magnetic field. The flow in the channel is assumed to be governed by Stokes's couple stress fluid theory. At the fluid-fluid interface, we assume that the velocities, vorticities, shear stresses and couple stresses are continuous. The resulting equations are solved analytically by using slip conditions at the boundaries and interface conditions at the fluid-fluid interface. The fluid velocity components in both the regions are obtained in closed form. The effects of couple stress parameters, slip parameter, Hartmann number, porosity parameter on velocity components are investigated. In the absence of slip, the limiting cases are obtained and discussed briefly.
Keywords: immiscible couple stress fluids, porous medium, Hartmann number, slip

The present article analyses the significance of melting heat transfer in presence of Hall current on the laminar slip flow over an exponentially stretching surface in an electrically conducting incompressible viscous fluid. The numerical solutions to the governing equations are evaluated using a local similarity and non-similarity approach along with successive linearisation procedure and Chebyshev collocation method. The influence of pertinent parameters on the velocity, temperature, concentration, heat and mass transfer rates is analyzed. Tabular values for the skin-friction for the physical parameters are displayed. It is seen that increasing the value of melting parameter temperature and concentration reducing while, both the velocities increases. Moreover, a comparative analysis is conducted between the results obtained and known results in the literature for the specific values of the physical parameters, and are found to be in excellent agreement.
Keywords: Heat and Mass transfer, Hall Current, Melting Condition.

An analysis is conducted for laminar micropolar nanofluid flow in anuprightconduit filled with a porous medium. The permeability of the porous substrate is presumed to be varying across the width of the channel while a heat source/sink is also pondered. The governing equations are solved using the homotopy analysis method. Graphs are presented for the effects of permeability parameter and micropolar parameter on velocity, microrotation and temperature for both heat source and heat sink. It was perceived that increasing the permeability intensified the fluid flow velocity while the microrotation decreased for the same. The velocity, microrotation and temperature of the fluid was all observed to be lower for heat sink than for heat source.
Keywords: Micropolar, Nanofluid, Variable Permeability, Heat Source/Sink

To design a highly efficient hermetic reciprocating compressor for HVAC applications, understanding of thermal behavior of compressor is necessary. The compact structure and airtight assembly of compressor components make the system complex. The major inadequacy linked with the compressor is overheating, that is, a rise in refrigerant temperature before entering the compression chamber. To avoid overheating, understanding of thermal interactions inside the different components of a compressor is necessary. This paper presents a short review of methods of heat transfer analysis and various techniques used by researchers worldwide to study the thermal behavior of the compressor. The objective of this paper is to put forth currently used techniques of heat transfer analysis. A brief description of the method, its methodology, and work in literature based on that method is presented. The pros, cons, and application areas of each technique are also discussed in brief. Each method has its application area and differs from other methods in accuracy and complexity.
Keywords: Hermetic Compressor, Reciprocating compressor, Heat transfer, Thermal analysis, Review.

This paper examines the magneto hydrodynamic flow of an electrically conducting micropolar fluid flow between parallel porous disks with constant uniform suction through the surface of the disks. The fluid is subjected to an external transverse magnetic field. The governing equations of the fluid flow are linearized using quasilinearization method and further, solved by the Chebyshev spectral collocation method. The numerical data for velocity, microrotation and temperature fields are used to evaluate entropy generation and Bejan number. It has been found that the entropy generation decreases with increase in Hartman number. Heat transfer irreversibility dominates at the lower and upper disks whereas fluid friction irreversibility dominates at the center of the parallel disks are observed from all Bejan number profiles.
Keywords: Parallel disks, Micropolar fluid, Magnetic field, Entropy, Bejan number

Simulation of natural convection in a Cu-water filled porous cavity with the magnetic field effects are studied numerically. The cavity is heated at bottom wall while the vertical boundary walls are kept at lower temperature and top wall of the cavity is adiabatic. The two-dimensional governing equation in a cartesian coordinate is represented by continuity, momentum and energy equation which is transformed into the vorticity and stream function. The finite difference technique is used to solve the equations. The flow in a cavity is represented as streamlines and isotherms for the different values of parameters Ra, Da and Ha at volume fraction 𝜙=0.1. The heat transfer rate is altered by increase in Ra at different Da and Ha. The flow patterns and heat transfer range inside the cavity is more affected by magnetic field at Da = 100. The results obtained is compared with the one available in the literature for validation and further cases are discussed using plots.
Keywords: Nanofluid, porous, magnetic, cavity

The paper deals with analytical study of an incompressible micropolar fluid flow through a channel bounded below by a porous bed in the presence of an inclined magnetic field. The flow in the channel is assumed to be governed by the micropolar fluid equations and that in the porous region by Darcy's law. The governing equations are analytically solved and the expressions for velocity and microrotation are derived in closed forms. The effects of the Hartmann number, inclination angle, micropolar parameter, and porosity parameters on velocity and microrotation are studied. The results are analyzed and depicted through graphs.
Keywords: Hartmann number, inclination angle, micropolar fluid, porous bed

Exploration of the coupled action of Arrhenius function, viscous heating, radiative thermal energy and dual stratifications on the mixedconvection flow of a Maxwell based nano fluid over a linearly stretched surface with effecting a magnetic force andconsidering the impact ofDarcy–Forchheimer and porous medium is the focus of this investigation. The transport equations of the problem are deduced to a set of nonlinear conjugated equations with the aid of suitable scaling analysis. Application of the BVC45 method to these equations conceded the computational solution. Maxwell variabledwindled down the flow. Activation energy as wellas parameter pertaining to temperature difference augmented concentration.
Keywords: Activation energy, Dual stratifications, nonNewtonian based nanofluid, Viscous heating.

A multiphase Volume of Fluid (VOF) model along with phase-change was developed to simulate evaporation and condensation of water droplets impacting upon a dry heated surface in the film evaporation regime. Simultaneous calculation of heat and mass transfer for the phase change during evaporation/condensation was modeled by coupling them through a mass flux model based on latent heat of vaporization of water and the pressure jump across the liquid interface (modified Schrage's model). To incorporate this coupling in the VOF model a User Defined Function in ANSYS FLUENT ® was written to analyze the growth of the vapor layer during evaporation...........
Keywords: Droplet Evaporation, Volume of Fluid (VOF), Phase Change Model.

Micromixers are most essential components of μTAS (micro Total Analysis System) for carrying biochemical and biomedical analyses. Serpentine type passive micromixers are one of the simplest and effective mixing devices employed in various applications. They incur low cost of manufacturing, easier fabrication and integration. Among serpentine micromixers (curved, zig-zag and square wave), it is reported that square-wave type micromixer showed better mixing characteristics. In our previous study, it is found that square wave micromixer with convergent and divergent horizontal sections (sqw-cd) performed significantly better mixing. However, this design of micromixer (sqw-cd) is associated with considerably higher pressure drops. In the present study a novel design of serpentine trapezoidal micromixer has been proposed.........
Keywords: Mixing quality, Passive micromixer, Square-wave mixer, Trapezoidal mixer

The MHD stagnation point flow and heat transfer over a linearly shrinking sheet has been considered in this article. The Navier-Stokes equations are transformed into a coupled set of non-linear ODEs using similarity variables, and then solved numerically. We have found that there exist two solution branches up to a particular value of the shrinking rate, treated as critical value. It is noticed that increasing in magnetic parameter (Hartmann number), increase the absolute value of the critical point. The effects of Hartmann number and shrinking parameter show opposite character in the velocity and thermal profiles for both the solution branches. To understand the flow phenomena, it's essential to determine the stable solution. Thus, we have carried a linear temporal stability analysis of these two solution branches to embed the physically stable solution.
Keywords: Stagnation point flow, Dual solutions, Shooting technique, Stability analysis, Shrinking sheet.

The bioconvection in an annular region between concentric cylinders filled with couple stress fluid containing microorganisms is considered. The outer cylinder is assumed to be rotating while the inner cylinder is stationary. The governing equations are linearized using successive linearization method and then solved using Chebyshev collocation method. The influence of couple-stress parameter, bioconvection Peclet-number, Prandtl number, Lewis number and chemical reaction parameter on motile microorganism distribution are analyzed graphically. Also, the density number of motile microorganism is examined for various governing parameters along with slip parameter of concentration and motile microorganism.
Keywords: Bioconvection, Couplestress fluid, density number of motile microorganism.

In this paper, we consider the inclined magnetic field, Hallcurrent and convective boundary on laminar incompressiblenatural convection flow through a porous channel withslip conditions. The governing equations determined theflow regime is transformed into a system of ordinary differentialequations by utilizing suitable similarity transformations.Spectral Quasilinearization Method (SQLM) has beenapplying to solve the dimensionless governing equations;those were received by using similarity transformations fromthe system of governing partial differential equations withboundary conditions. The influence of emerging parameterson fluid flow velocities and temperature are presented graphically.
Keywords: Inclined magnetic field, Hall current, Convective boundary, Porous medium, SQLM

The Newtonian fluid flow due to free convection over an isothermal cone with dispersions of thermal and solutal transport situated in a non-Darcy porous medium, is considered in this paper. Numerical solution of the non-dimensional representation of governing equations are provided using the shooting method in conjunction with the Runge-Kutta technique of 4th order and also provided the comparison table to show the accuracy of present investigation. The variation of physical quantities is discussed in non-Darcian porous medium for dispersion parameters in a wide range of their values in both aiding buoyancy and opposing buoyancy cases.
Keywords: Double Dispersion, Newtonian Fluid, Vertical Cone, Non-Darcy Porous Medium.

The proposed work in this manuscript reflects the influence of double dispersion in the presence of Soret and Dufour effects due to natural convection flow over a vertical cone saturated porous medium. The nondimensionalization performed through similarity variables and the attained similarity equations are solved numerically via the Chebyshev spectral quasi-linearization method. The impression of governing parameters on the flow characteristics is accounted through figures and tables. Moreover, the heat and mass transfer rates also reflected with variations of the governing parameters. The exactness of present computations also verified through a comparison of prior published results and found to be in great consent.
Keywords: Double dispersion effect, Natural convection, Soret and Dufour effects, Chebyshev spectral quasi-linearization method.

Taylor slug flow through microchannel has attracted many researchers because of its capability of improving thermal performance of a system. The Global Nusselt number for Taylor flow is always higher than that of simple primary fluid flow through same microchannel. This enhanced Nusselt number can be further enhanced by droplet manipulation techniques which is the aim of present study. In present novel study, analysis of Taylor flow through rectangular microchannel with obstruction in path has been carried out using ANSYS FLUENT 15.0. The Nusselt number for simple primary fluid flow and Taylor flow with and without obstruction through same microchannel is compared...........
Keywords: Taylor slug flow, Obstruction,Heat transfer, microchannel

This article presents the significance of thermal radiation and Soret effect on laminar, incompressible natural convective fluid flow through a porous channel with Navier slip. The governing partial differential equations, defining the flow regime, are transformed into a system of ordinary differential equations by employing suitable transformations. Spectral Quasilinearization Method (SQLM) is applied to solve the dimensionless governing equations. The influence of emerging parameters on fluid flow velocity, temperature, and concentration are shown graphically.
Keywords: Natural Convection, Soreteffect, Radiation effect, Navier slip, SQLM.

The consequence of varying pressure drop on a Herschel-Bulkleyfluid through porous tube has been explored. The governing equations of the model areanalytically solved under long wavelength and small Reynolds number approximations.Results areobtainedfor the parameters: Darcy number, slip parameter, yield stress, axial radius on the pressure difference. Theobservationsdisclose that the building up of the porous thickening of the wall enhances the pressure. Also, rise in Darcy numbersreduces the pressure rise.
Keywords:Peristalsis, Porous tube, Pressure drop, Slipparameter

This paper studies the boundary layer flow and heat transfer in an incompressible viscous electrically conducting nanofluid containing ferroparticles or non-magnetic nanoparticles external to a stretching cylinder in the presence of magnetic induction. We consider water as a base fluid embedded with the two types of nanoparticles namely magnetic (Manganese Franklinite (Mn-ZnFe2O4), Ferric Oxide (Fe3O4)) and non-magnetic (Silicon Dioxide (SiO2), Nimonic 80a). The governing non-linear partial differential equations and associated wall and free stream boundary conditions are reduced to a set of non-linear ordinary differential equations with appropriate boundary conditions using similarity transformation. The resulting equations are solved numerically using an efficient, stable, spectral relaxation method (SRM).........
Keywords: Electromagnetic induction;metallic nanoparticles; coating boundary layers;stretching cylinder; spectral relaxation method (SRM).

The present study investigates the flow patterns and turbulence characteristics in a baffled reactor stirred by six-bladed Rushton Turbine (RT) placed at 1/3rd and 1/9th height of the tank above its bottom surface using the Computational Fluid Dynamics (CFD) approach. The well-known double loop to single loop flow pattern transition and the associated reduction in the power number were accurately predicted using the steady state Multiple Reference Frame (MRF) impeller modelling scheme along with the standard 𝑘−𝜀 turbulence model closure. The substantial reduction in the characteristics of trailing vortices (size, strength and coherency) with the decrease in the impeller clearance leads to the formation of weaker wake region behind the blades. The weak entrainment of the wake reduces the pressure drag and torque associated with the rotating impeller which in turn decreases the impeller power number.
Keywords: Stirred tank reactor, Turbulent Flow, Impeller clearance, Flow pattern transition

Numerical simulations are performed for scramjet combustor with different fuel scheme using Fluent tool Ansys 17.2. For fuel injection spilt part is done at the inlet wall of the combustor. This research work shows the internal flow behaviour of fuel with air for scramjet combustor. Temperature, pressure and velocity profile shows the turbulence mixing effects at various sections of cross-stream flow. Two dimensional Reynolds- Averaged Navier-Stokes equation and k-ε model has been considered for modelling chemical reacting flows for hydrogen-air and methane-air fuel. The finite rate/eddy dissipation chemistry turbulence model is considered for combustion modelling.
Keywords: CFD, combustion, scramjet, injection and efficiency

In this article, a topological existence and uniqueness proof is given for a non-linear boundary value problem arising due to the steady, laminar stagnation point flow of an incompressible viscous fluid near a rough surface. The no-slip boundary conditions are replaced by the partial slip boundary conditions, owing to the surface roughness. Further, numerical results are also given to validate the qualitative analysis of the solution.
Keywords: Stagnation point flow, Existence-Uniqueness, Shooting argument

In the Present paper, numerical simulations have been carried out on two-phase fluid flow and heat transfer in plain and wavy circular microchannels of diameter 100microns and length of 30D. Microchannel is divided into two sections of cold and hot sections. Two immiscible fluids water and mineral oil are considered as primary and secondary fluids. In the plain circular microchannel, droplet shape is constant when it the flow is fully developed, whereas in wavy channels because of uneven surface, the droplet shape is continuously changes. This will increase the pressure drop in the wavy microchannel. The droplet shape, pressure distribution along axis and channel wall have been also discussed for plain and wavy........
Keywords: Two-phase flow, wavy channel, pressure drop and heat transfer

Joule heating effect on a chemically reacting nanofluid in vertical channel has been investigated in this paper. By using HAM, the non dimensionalized governing equations are solved. Effect of chemical reaction, magnetic parameter and Joule heating on entropy generation, Bejan number, nanoparticle volume fraction, temperature and velocity are investigated and represented geometrically.
Keywords: Chemical reaction, Entropy generation, HAM, Joule heating, Nanofluid

In this paper, the possible solutions for the thermophoretic deposition of particles on a fully developed flow of an electrically conducting fluid saturated porous medium between a vertical channel in the presence of Soret effect, are investigated analyticallyand numerically using shooting method along with 4th Runge-Kutta method. In order to explore the effects of various physical parameters, we also tried to find all possible analytical solutions wherever exist. Finally, the effects of various physical parameters on flow fields are discussed in order to analyze the usefulness of the problem undertaken
Keywords:Thermophoretic Transport; Convective Flow; Vertical Channel; Electrically Conducting Fluid; Porous Medium; Soreteffect.

In this investigation we are concentrating on Finite state element method is worn toward analyses the arithmetical explanation for magneto hydrodynamic border layers. It is a mathematical study in which viscous incompressible electrical conductible magnetic fields have been examined through heat & mass move techniques. In this the plate is assumed as constant in velocity and getting the way of fluid flow through stream speed as considered to go after the exponentially raising preamble surface. The graphical representations of numerical results are shown as velocity, Temperature (TEMP) and the concentration of boundary layers. This work mainly connected with skin rubbing coefficient Nusslet as well as Sherwood records.
Keywords: Heat & Mass transfer; Free Convection; MHD; Limited Element Technique

The purpose of this paper, the thermal radiation on an unsteady incompressible laminar MHD mixed convective flow of couple stress fluid through a uniformly expanding or contracting porous pipe which time-dependent rate in presence chemical reaction is to examine. The constitutive relation which governing the flow, energy, concentration and with associate boundary conditions are transformed in to nonlinear coupled system of ordinary differential equations by using similar variables. HAM based Mathematica sofware package BVPh2.0 has been employed to obtain the solution. The influence of different emerging non-dimensional important parameters on velocities, temperature and concentration profiles analyzed and exhibited in the form of graphs. The temperature of the fluid is increased by increasing of inverse Darcy parameter whereas the velocity is decreased. The temperature and concentration are increased with chemical reaction parameter.
Keywords: MHD, couple stress fluid, porous pipe, BVPh 2.0, mixed convection, thermal radiation.

General reaction-diffusion equation comprises of the prey-taxis phenomenon. Prey-taxis express the active movement of predator species in the direction of prey due to high concentration of prey or some sort of cue. We propose a reaction-diffusion-advection equation for plankton interaction. Analytically we discuss the local stability of system dynamics. Our numerical investigation reveals that increasing active movement of the predator shows chaotic behaviour of the system. Prey ability of better defense reduces the predator density.
Keywords: Phytoplankton-Zooplankton, Monod-Haldane functional response, Prey-taxis, Spatio-temporal pattern

To study the various separation process of mixed liquids. The production of bioethanolhasgainedattentionrecently..........
Keywords: Ethanol water separation, Distillation, Heat transfer, Surfactant

The effect of variable viscosity, thermal conductivity, thermophoresis on convective heat transfer flow past a wavy surface with heat sources and thermal radiation is considered, the non-linear, coupled equations have been solved by employing Runge-Kutta shooting method. We find that an increase in radiation parameter (Rd), thermal conductivity parameter ( ), thermophoretic parameter () and amplitude parameter (a) reduces the velocity, enhances the temperature and concentration. Also skin friction, Nusselt and Sherwood numbers reduces with increasing amplitude (a) of wavy surface.
Keywords:Thermophoresis, Heat source, Magnetic field, Variable viscosity, Thermal conductivity, amplitude of wavy surface.

When outdoor coil of heat pump is subjected to low ambient temperature and high relative humidity, surface temperature of outdoor coil falls below dew point temperature and freezing temperature then frost starts accumulating on the outdoor coil surface. This accumulated frost reduces the heat transfer between coil and surrounding hence degrades system performance, so this frost needs to be removed to avoid this. Currently many methods are available for defrosting and lot of literature is available for each method. In this work detailed literature survey for various methods is carried out. Drawbacks of each method and modification to be done is also discussed here and finally most suitable method of defrosting for air source water heat pump is suggested.
Keywords: Defrosting, Heat pump, Hot gas bypass defrosting, reverse cycle defrosting

In this article, natural convection of AL2O3-water nanofluid in an open cavity under the presence of sinusoidal heating is investigated numerically. The cavity is placed horizontal and right end is open to cold nanofluid and left vertical wall is heated keeping top and bottom as adiabatic. From the open end of the cavity cold AL2O3-water nanofluid is injected. The flow inside the cavity is due to density variation caused by temperature difference (buoyancy force).The non-dimensional governing equations are solved by finite difference method. The main parameters involving the investigation are Rayleigh number(104≤𝑅𝑎≤105), nanoparticles volume friction(0.0 ≤𝜙≤0.04) and phase shift of the heating temperature 0≤𝛾≤𝜋 . It is observed that sinusoidal heating changed direction of heat flow (environment to cavity and cavity to environment), phase change changes the position of heat transfer direction. The presence of nanoparticles under sinusoidal heating enhances heat propagation and as Ra increases, heat propagation decreases.
Keywords: partially open cavity, Sinusoidal heating, Nanofluid, Natural convection

The protrusions known as tubercle, on the leading edge of a humpback whale flipper help in the maneuverability of the whale despite its huge size. This work is computational study of stall characteristics and the flow pattern on a tubercledNACA 0021 airfoil and its comparison with a baseline airfoil at a low Reynolds number of 100 000. SST 𝑘−𝜔 turbulence model based on unsteady RANS scheme is used to model the flow over airfoils at variosangles of attack. Lift and drag study concludes that airfoil with tubercles delays stall compared to baseline airfoil and has softer stall. Tubercled airfoil maintain high lift coefficients even at high angle of attack. From the flow pattern it is also seen that tubercled airfoil created a number of counter rotating vortices in the plane vertical to airfoil unlike the baseline airfoil. The relative strength of vortices on the suction and pressure surfaces of airfoil depends on the symmetricity of flow.
Keywords: Tubercle, vortices, stall delay