Numerical simulation of combined mixing and separating flow in channel filled with porous media

Various flow bifurcations are investigated for two dimensional combined mixing and separating geometry. These consist of two reversed channel flows interacting through a gap in the common separating wall filled with porous media of Newtonian fluids and other with unidirectional fluid flows. The Steady solutions are obtained through an unsteady finite element approach that employs a Taylor-Galerkin/pressure-correction scheme. The influence of increasing inertia on flow rates are all studied. Close agreement is attained with numerical data in the porous channels for Newtonian fluids.Peer reviewedSubmitted Versio

Numerical Modelling of Mixing and Separating of Fluid Flows through Porous Media

In present finite element study, the dynamics of incompressible isothermal flows of Newtonian and two generalised non–Newtonian models through complex mixing–separating planar channel and circular pipe filled with and without porous media, including Darcy’s term in momentum equation, is presented. Whilst, in literature this problem is solved only for planar channel flows of Newtonian and viscoelastic fluids. The primary aim of this study is to examine the laminar flow behaviour of Newtonian and inelastic non–Newtonian fluids, and investigate the robustness of the numerical algorithm. The rheological properties of non–Newtonian fluids are defined utilising a range of constitutive equations, for inelastic non–Newtonian fluids non–linear viscous models, such as Power Law and Bird–Carreau models are used to capture the shear thinning behaviour of fluids. To simulate such complex flows, steady–state solutions are sought employing time–dependent finite element algorithm. Temporal derivatives are discretised using second order Taylor series expansion, while, spatial discretisation is achieved through Galerkin approximation in combination to deal with incompressibility a pressure–correction scheme adopted. In order to achieve the algorithm of semi-implicit form Darcy’s–Brinkman equation is utilized for the conversion in Darcy’s terms and diffusion, while Crank–Nicolson approach is adopted for stability and acceleration. Simple and complex flows for various complex flow bifurcations of the combined mixing–separating geometries, for both two–dimensional planar channel in Cartesian coordinates, as well as axisymmetric circular tube in cylindrical polar coordinates system are investigated. These geometries consist of a two-inverted channel and pipe flows connected through a gap in common partitions, initially filled with non-porous materials and later with homogeneous porous materials. Computational domain is having variety it has been investigated with many configurations. These computational domains have been appeared in industrial applications of combined mixing and separating of fluid flows both for porous and non-porous materials. Fully developed velocity profile is applied on both inlets of the domain by imposing analytical solutions found during current study for porous materials. Numerical study has been conducted by varying flow rates and flow direction due to a variety in the domain. The influence of varying flow rates and flow directions are analysed on flow structure. Also the impact of increasing inertia, permeability and power law index on flow behaviour and pressure difference are investigated. From predicted solution of present numerical study, for Newtonian fluids a close agreement is realised between numerical solutions and experimental data. During simulations, it has been noticed that enhancing fluid inertia (flow rates), and permeability has visible effects on the flow domains. When the Reynolds number value increases the size and power of the vortex for recirculation increases. Under varying flow rates an early activity of vortex development was observed. During change in flow directions reversed flow showed more inertial effects as compared with unidirectional flows. Less significant influence of inertia has been observed in domains filled with porous media as compared with non-porous. The power law model has more effects on inertia and pressure as compared with Bird Carreau model. Change in the value of permeability gave significant impact on pressure difference. Numerical simulations for the domain and fluids flow investigated in this study are encountered in the real life of mixing and separating applications in the industry. Especially this purely quantitative numerical investigation of flows through porous medium will open more avenues for future researchers and scientists

Heat transfer augmentation through engine oil-based hybrid nanofluid inside a trapezoid cavity

Heat transfer occurs as a result of density differences caused by temperature changes. It has several industrial applications. To improve performance, one must investigate the heat transfer behaviour of the working fluid. Hence, the purpose of this work is to report a heat transfer analysis of a partially heated trapezoid cavity filled with a hybrid nanofluid. The temperature conditions of the cavity are such that the bottom boundary is partially heated, inclined side boundaries are kept at a lower temperature, and the upper boundary is kept adiabatic. A trapezoidal shape heated obstacle is considered in the cavity’s centre. The heat transfer and flow take place inside the cavity due to density variation. The mechanism is regulated by mass, momentum, and energy conservation, as well as related boundary constraints. The solutions are determined by the use of a numerical technique known as the Finite Element Method after the governing equations are transformed into non-dimensional form, which brings up physical parameters affecting the heat transfer and flow. The initial study is performed for three types of nanofluids with silver and magnesium oxide nanoparticles inside water 2, kerosene , and engine oil . The study revealed that the engine oil-based hybrid nanofluid produced an increased heat transfer rate. Simulation is performed using engine-based hybrid nanofluid with the range of physical parameters, such as Rayleigh number (105≤≤107), Hartmann number (0≤≤100) and nanoparticles volume fraction (0≤≤0.2). It is found that the heat transfer rate is enhanced by increasing the fraction of nanoparticles in the base fluid. Moreover, imposition of magnetic field has reverse impact on the fluid movement

Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe

Numerical scheme to simulate combined mixing and separating Newtonian fluid flow in a channel

The paper presents a semi-implicit time-stepping Taylor-Galerkin pressure correction primitive variable finite element algorithm to simulate fluid flow for two dimensional planar combined mixing and separating geometry. Two cases; one with reversed channel flows interacting through a gap in the common separating walls filled with Newtonian fluids in both arms of the channels and other with unidirectional flows were modeled in order to examine the performance of the scheme. Steady solutions were obtained using unsteady finite element scheme. The influence of increasing inertia on variation in flow directions and varying flow rate configurations in both channel arms are studied in detail. The scheme is found to be fast, robust and stable for varying Reynolds numberPeer reviewe

A FEM Study for Non-Newtonian Behaviour of Blood in Plaque Deposited Capillaries: Analysis of Blood Flow Structure

Inelastic behaviour of blood is predicted by employing Power law and Carreau model along partially blocked capillaries. Numerical results for stream function have been computed for predicting the reattachment length and intensity in the capillaries at various levels of obstacle and inertia. The predicted results obtained by employing FEM (Finite Element Method) under semi-implicit Taylor-Galerkin/ pressure-correction scheme. The numerical results have been quantified in terms of reattachment length and intensity, which illustrates that their formation takes place in the downstream of a capillary segment and augment in length as increases inertia or obstacle level. The obtained results are match able with analytical results. This study is accommodating for developing devices related to heart diseases in futur

Cubic Iterated Methods of Numerical Differential Method for Solving Non-Linear Physical Functions

In this research two iterated methods have been developed for solving non-linear equations, which arises in applied sciences and engineering. The proposed iterated methods are converged cubically, and it is derived from modified euler method and improved euler method with steffensen method. The cubic iterated methods of numerical differential method are work on physical application functions and compared with variant newton iterated method. The numerical outcome of proposed cubic iterated methods of numerical differential method is examined with C++/MATLAB. From the numerical results, it can be observed that the cubic iterated methods of numerical differential method are good for accuracy point of view, iteration perception and function evaluation as the assessment of variant newton iterated method for solving non-linear physical functions

To Investigate Obstacle Configuration Effect on Vortex Driven Combustion Instability

Combustion instability inside a chamber may lead to catastrophic failure. It is due to inappropriate combustion or flow physics. Flow-driven instability is mostly governed by surface, corner, or obstacle vortex shedding. Inhibitorsare placed inside a solid fuel combustion chamber to control the burning of the solid fuel grain. They burn slowly as compared to solid fuel and create protrusions inside the combustion chamber. These protrusions work as flow obstacles. An obstacle vortex is shed from the inhibitor and produces pressure oscillations. The effects of inhibitor position on pressure oscillation inside a solid fuel combustion chamber is investigated in the present study. Large eddies must be resolved to compute vortex-driven flow. Therefore, the Detached Eddy Simulation is applied to cylindrical combustion chambers having inhibitor and nozzle. Five different configurations are simulated. All parameters of different configurations are similar except inhibitor position. The inhibitor is moved upstream and downstream from the reference position to examine its effect on pressure oscillations. Pressure time histories at eight distinct places of the combustion chamber are recorded. Fast Fourier Transform (FFT) has been utilized to get pressure oscillation frequency and amplitude. It is interesting to reveal that the maximum amplitude of pressure oscillation occurs when the inhibitor to stagnation point distanceis close to the combustion chamber diameter. It is up to 70% higher as compare to reference inhibitor position results. Computed results are also compared with available experimental data for validation purpose