Hydrodynamic Fluid Flow Research Articles

Hydrothermal analysis of time‐fractional magneto hydrodynamic viscous fluid flow on a plate

Hydrothermal analysis of time‐fractional magneto hydrodynamic viscous fluid flow on a plate

AIRCRAFT HYDRAULIC DRIVE ENERGY LOSSES AND OPERATION DELAY ASSOCIATED WITH THE PIPELINE AND FITTING CONNECTIONS

Theoretical research on hydraulic processes occurring in aircraft hydraulic drives is presented in the studies. Installation of angular fitting connections in aircraft pipeline systems influences hydrodynamic processes and fluid flow characteristics analysed in the research. The provided analysis is based on a validated numerical model utilizing Navier–Stokes equations and the k-epsilon turbulence model. Fluid flow inside the aircraft hydraulic drive pipeline system was investigated with flow rates up to 100 l/min. A mesh independence study was conducted for numerical simulation of the fluid flow. The obtained results include fluid pressure drops, energy losses, and operational delays associated with fluid flow vortex formations at 45° and 90° angular fitting connections. Additionally, compared results from standard methods of calculation for angular fitting connections, including the equivalent length and equivalent length same shape methods.

MHD Fluid Flow Bounded by Two Parallel Vertical Plates in A Porous Media with Heat Transfer

We are investigating Magneto hydrodynamic fluid flow between two parallel vertical plates in a porous media with heat transfer. We will nondimensionalize the governing equations and then transform the resulting equations using the central difference approximation method. We will simulate the resulting equations using MATLAB to establish the effect of non dimensionalized parameters on the fluid velocity and temperature. We will graphically present the effect of the Darcy, Hartmann, Prandtl, and Reynolds numbers on the velocity and temperature profile. We have made the following conclusions from this study. The fluid velocity is inversely proportional to Darcy’s and Hartmann’s numbers. Fluid velocity increases as the Reynolds number is increased. Fluid temperature declines with a rise in the Prandtl number when the distance between the plates is greater than one and increases the fluid temperature when the distance between plates is less than one. Fluid temperature increases as Hartmann and Darcy numbers are increased. No velocity and temperature profile effect exists on varying Prandtl and Reynolds numbers. The findings have practical applications in industrial processes such as cooling systems.

Radiation Absorption and Diffusion Thermo Effects on Unsteady MHD Kuvshinski Fluid Flow Past an Inclined Porous Plate in the Presence of Thermal Radiation and Chemical Reaction

The aim of the present paper is to investigate investigated the Radiation absorption and diffusion thermo on unsteady magneto hydrodynamic Kuvshinski fluid flow past an infinite vertical permeable moving plate in Presence of thermal radiation, heat absorption and homogenous chemical reaction, subjected to variable suction. The plate is assumed to be embedded in a uniform porous medium and Moves with a constant velocity in the flow direction in the presence of a transverse magnetic Field. The equations governing the flow are transformed into a system of nonlinear ordinary differential equations by using perturbation technique. Graphical results for the velocity distribution, temperature distribution and concentration distribution based on the numerical solutions are presented and discussed. Also discuss the effects of various parameters on the skin-friction coefficient and the rate of heat transfer in the form of Nusselt number and rate of mass transfer in the form of Sherwood number at the surface. Velocity and temperature distribution is observed to increase with an increase in Radiation absorption and Dufour parameter, whereas diminishes with enhances of Magnetic field, heat absorption coefficient, radiation parameter and chemical reaction parameter in respective velocity, temperature and concentration distributions.

Analysis of the Hydrodynamics Behavior Inside a Stirred Reactor for Lead Recycling

This work focuses on an analysis of hydrodynamics to improve the efficiency in a batch reactor for lead recycling. The study is based on computational fluid dynamics (CFD) methods, which are used to solve Navier–Stokes and Fick’s equations (continuity and momentum equations for understanding hydrodynamics and concentration for understanding distribution). The reactor analyzed is a tank with a dual geometry with a cylindrical body and a hemisphere for the bottom. This reactor is symmetrical vertically, and a shaft with four blades is used as an impeller for providing motion to the resident fluid. The initial resident fluid is static, and a tracer is defined in a volume inside to measure mixing efficiency, as is conducted in laboratory and industrial practices. Then, an evaluation of the mixing is performed by studying the tracer concentration curves at different evolution times. In order to understand the fluid flow hydrodynamics behavior with the purpose of identifying zones with rich and poor tracer concentrations, the tracer’s concentration was measured at monitoring points placed all around in a defined control plane of the tank. Moreover, this study is repeated independently to evaluate different injection points to determine the best one. Finally, it is proved that the selection of an appropriate injection point can reduce working times for mixing, which is an economically attractive motivation to provide proposals for improving industrial practices.

The study on the effect of hydrodynamic flow on the photocatalytic performance of photocatalytic reactors.

The scalability of photocatalytic reactor is the major challenge due to the inability of the light penetration when the laboratory scale reactors are ascended. It is well known that the characteristic length of photocatalytic reactor is one of the influential parameters determining the efficiency of light penetration and also affects the hydrodynamic fluid flow behaviour inside the reactor. This study visualizes hydrodynamic flow behaviour of three differently configured photocatalytic reactors through numerical simulation of the fluid mass transport inside the reactors. The three photocatalytic reactors are (1) concentric cylindrical glass tube micro-reactor (CGTR), (2) UV-LED strip photocatalytic reactor (STR) and (3) classical annular reactor (CAR) from our previous work. The simulations of flow behaviour confirmed that CGTR exhibited plug flow regime, STR exhibited arbitrary flow (in-between continuously stirred tank reactor and plug flow reactor) and CAR behaved like continuously stirred tank reactor. Also, interpretations of numerical modelling were validated through plotting experimental residence time distribution curve. Furthermore, the comparison of performance parameters revealed that the highest modified space time yield (STYmodified) 225s-1and highest modified photocatalytic space time yield (PSTYmodified) 9.375s-1/kW/m3 was obtained for plug flow reactor when compared to continuously stirred tank reactor (CAR) and arbitrary flow reactor (STR). The study confirms that decrease in characteristic length of photocatalytic reactor onsets plug flow regime, which has highest photocatalytic performance efficiency.

Computational modelling for decarbonised drying of agricultural products: Sustainable processes, energy efficiency, and quality improvement

Drying agricultural products consumes massive amounts of energy. The rapid depletion of non-renewable energy sources, along with rising environmental concerns, are opening up new opportunities for developing sustainable drying systems and reducing its carbon footprint. Drying modelling is a powerful tool for understanding the mechanism and predicting fluid flow hydrodynamics and heat and mass transfer during the drying process. The current review outlines the state-of-the-art of various modelling techniques for drying technologies, explores the unresolved bottlenecks in technology development, and provides new avenues for more innovative and sustainable drying technologies. First, the drying mechanism and novel drying technologies are explained. Then, various modelling methods are summarised. Finally, new insights into quality and energy modelling using CFD are discussed. Based on the research achievements, future challenges of CFD modelling and their contribution to improving the drying process in terms of high quality and low energy consumption and decarbonisation are addressed. • A comprehensive understanding of the drying mechanism is indispensable in CFD modelling. • Energy and environmental concerns create new avenues for developing sustainable drying. • CFD is conducive to heat and mass transfer prediction and drying parameter optimisation. • Modelling the drying process should be geared towards integrating energy and quality aspects.

CFD Simulation of a Hybrid Solar/Electric Reactor for Hydrogen and Carbon Production from Methane Cracking

Methane pyrolysis is a transitional technology for environmentally benign hydrogen production with zero greenhouse gas emissions, especially when concentrated solar energy is the heating source for supplying high-temperature process heat. This study is focused on solar methane pyrolysis as an attractive decarbonization process to produce both hydrogen gas and solid carbon with zero CO2 emissions. Direct normal irradiance (DNI) variations arising from inherent solar resource variability (clouds, fog, day-night cycle, etc.) generally hinder continuity and stability of the solar process. Therefore, a novel hybrid solar/electric reactor was designed at PROMES-CNRS laboratory to cope with DNI variations. Such a design features electric heating when the DNI is low and can potentially boost the thermochemical performance of the process when coupled solar/electric heating is applied thanks to an enlarged heated zone. Computational fluid dynamics (CFD) simulations through ANSYS Fluent were performed to investigate the performance of this reactor under different operating conditions. More particularly, the influence of various process parameters including temperature, gas residence time, methane dilution, and hybridization on the methane conversion was assessed. The model combined fluid flow hydrodynamics and heat and mass transfer coupled with gas-phase pyrolysis reactions. Increasing the heating temperature was found to boost methane conversion (91% at 1473 K against ~100% at 1573 K for a coupled solar-electric heating). The increase of inlet gas flow rate Q0 lowered methane conversion since it affected the gas space-time (91% at Q0 = 0.42 NL/min vs. 67% at Q0 = 0.84 NL/min). A coupled heating also resulted in significantly better performance than with only electric heating, because it broadened the hot zone (91% vs. 75% methane conversion for coupled heating and only electric heating, respectively). The model was further validated with experimental results of methane pyrolysis. This study demonstrates the potential of the hybrid reactor for solar-driven methane pyrolysis as a promising route toward clean hydrogen and carbon production and further highlights the role of key parameters to improve the process performance.

Assessment of novel solvent system for CO2 capture applications

Based on the faster absorption kinetics of primary or secondary amines and the lower regenerating potential of tertiary amines, mixed amine solvents are being examined as a viable choice for CO2 capture. The critical parameters in the CO2 absorption process are the solubility of the solvent and the reaction kinetics of amine with CO2. Hence, the current work seeks to address these critical parameters by investigating the diffusivity and intermolecular interaction intensity of amines. In this regard, various secondary and tertiary amines (2EAE-TMPAD, 2EAE-DEAB, 2EAE-1DMA2P, 2MAE-2DMAE, 2EAE-2DMAE, and DMCA-MCA) are suggested as a mixed solvent. Molecular dynamic simulation is employed in the Material Studio program. The diffusivity and intermolecular interaction intensity results are interpreted by mean square displacement and radial distribution function analysis, respectively. The findings of current research demonstrate that 2EAE-TMPAD has the highest diffusion rate as compared to other blends. The order of diffusion rate in the blended amines system is 2EAE-TMPAD > 2EAE-DEAB > 2EAE-1DMA2P > 2MAE-2DMAE > 2EAE-2DMAE. The screening of the DMCA-MCA blended system shows that 10 %DMCA-20 %MCA has higher interaction strength than that of other concentrations. Furthermore, the diffusion coefficient of the DMCA-MCA blend is 0.61E-9 m2/s at 313 K, which agrees well with the experimental studies. The findings described in this paper are useful for evaluating the optimal hydrodynamics of fluid flow inside the absorption column and designing the column height, considering kinetics and mass transfer data.

A study of hydrodynamic viscous fluid flow parameters change regularities in case of a conical diffuser

Studies of patterns of changes in hydrodynamic parameters of the viscous incompressible fluid in a conical diffuser were conducted. The specificity of the viscous liquid flow in a conical diffuser is that the kinetic energy of the flow, depending on the opening angle, is converted into pressure energy. Depending on Reynolds numbers and diffuser opening angles, the velocity vector field is stationary. With an increase in the Reynolds number, the symmetry of the flow relative to the axis of the diffuser is broken. A general solution to the approximate Navier-Stokes equations is given, based on the diffuser opening angle and the Reynolds number. A method for integrating the boundary value problem has been developed, and the patterns of velocity changes across the diffuser length at a parabolic distribution of velocities in the inlet section are obtained. By integrating partial differential equations that match all boundary conditions, the solution to the boundary value problem can be found. Graphs of changes in radial and axial velocities along the length and with a fixed value of the opening angle are shown; the flow pattern and the transition of a single-mode flow to multimode regimes are obtained. For a fixed opening angle and Reynolds number, the conditions for flow separation from a fixed wall are derived, where the flow velocity changes the sign. A mixing process is observed in the multi-mode region, which is accompanied by numerous pulsation phenomena and an unstable diffuser operation, where the resulting solutions are inappropriate. Based on the results of the studies obtained, it is possible to correctly design a conical diffuser, namely, under the condition of non-separated flow, to choose the opening angle and its length.

Electrical magneto hydrodynamic Jeffrey fluid flow with thermal radiation through stretched cylinder

The current study investigates the effects of electrical and magnetic fields on the stagnation point in Jeffrey fluid flow along a stretched cylinder with thermal radiation and chemical reaction. The Cattaneo-Christov model with double stratification and thermal relaxation was used. Heat and mass transfer are investigated. Governing partial differential equations are converted to ordinary differential equations using similarity transformation. FEM technique is used to calculate the numerical solution of a set of nonlinear coupled equations with coding implementation in MATLAB. The numerical outcomes of current work are more significant when they are correlated with previous work. The interest in computational attempts at the formation of boundary layers for concentration distribution, fluid velocity, and temperature increases as significant parameters are varied. The main outcomes of this study are that increasing electrical effects is to decreases fluid velocity while increasing magnetic parameters is to decreases the flow velocity. Another effect is that an increase in thermal radiation and heat transfer raises the temperature of the fluid. Furthermore, the fluid concentration is reduced due to the increased level of a chemical reaction.

Impact of thermal energy on MHD Casson fluid through a Forchheimer porous medium with inclined non-linear surface: A soft computing approach

In this work, the influence of thermal energy in term of heat source, thermal radiation and chemical reaction on magneto hydrodynamic Casson fluid flow model (MHD-CFM) over a nonlinear slanted extending surface with slip velocity in a Forchheimer permeable medium is numerically studied using the Levenberg Marquardt methodology with backpropagated learning mechanism. It is valuable to evaluate the flow of Cason fluids based on materials (such as drilling muds, clay coatings, various suspensions and certain lubricating oils, polymeric melts, and a wide range of colloids) in the occurrence of heat transfer. Using efficient data, PDEs of (MHD-CFM) were converted to ordinary differential equations. These obtained non-linear ODEs are then rectified using the computational power of the Lobatto IIIA approach to obtain a dataset of Levenberg Marquardt algorithm based trained neural networks (LMA-TNN) for six scenarios of this presented model, which were graphically represented using nftool to obtain regression, efficiency, fit curve, error bars, and trained state analysis. The velocity, temperature, and concentration profiles were computed, and the findings were presented. Additionally, the skin friction coefficient, Nusselt number, & local Sherwood number are explored. The graphs show that when values of radiation parameter and the Forchheimer porous media parameter increase, the temperature of the plate drops. In the existence of a chemical process and a high Schmidt number, the concentration drops. The accuracy achieved in terms of relative error demonstrates the validity and significance of the solution process.

Coupled CFD-DEM modeling to predict how EPS affects bacterial biofilm deformation, recovery and detachment under flow conditions.

The deformation and detachment of bacterial biofilm are related to the structural and mechanical properties of the biofilm itself. Extracellular polymeric substances (EPS) play an important role on keeping the mechanical stability of biofilms. The understanding of biofilm mechanics and detachment can help to reveal biofilm survival mechanisms under fluid shear and provide insight about what flows might be needed to remove biofilm in a cleaning cycle or for a ship to remove biofilms. However, how the EPS may affect biofilm mechanics and its deformation in flow conditions remains elusive. To address this, a coupled computational fluid dynamic– discrete element method (CFD‐DEM) model was developed. The mechanisms of biofilm detachment, such as erosion and sloughing have been revealed by imposing hydrodynamic fluid flow at different velocities and loading rates. The model, which also allows adjustment of the proportion of different functional groups of microorganisms in the biofilm, enables the study of the contribution of EPS toward biofilm resistance to fluid shear stress. Furthermore, the stress–strain curves during biofilm deformation have been captured by loading and unloading fluid shear stress to study the viscoelastic properties of the biofilm. Our predicted emergent viscoelastic properties of biofilms were consistent with relevant experimental measurements.

DNA Coil Dynamics and Hydrodynamic Gating of Pressure-Biased Nanopores.

Nanopores are ideally suited for the analysis of long DNA fragments including chromosomal DNA and synthetic DNA with applications in genome sequencing and DNA data storage, respectively. Hydrodynamic fluid flow has been shown to slow down DNA transit time within the pore, however other influences of hydrodynamic forces have yet to be explored. In this report, a broad analysis of pressure-biased nanopores and the impact of hydrodynamics on DNA transit time, capture rate, current blockade depth, and DNA folding are conducted. Using a 10nm pore, it is shown that hydrodynamic flow inhibits the early stages of linearization of DNA and produces predominately folded events which are initiated by folded DNA (2-strands) entering the pore. Furthermore, utilizing larger pores (30nm) leads to unique DNA gating behavior in which DNA events can be switched on and off with the application of pressure. A computational model, based on combining electrophoretic drift velocities with fluid velocities, accurately predicts the pore size required to observe DNA gating. Hydrodynamic fluid flow generated by a pressure bias, or potentially more generally by other mechanisms like electroosmotic flow, is shown to have significant effects on DNA sensing and can be useful for DNA sensing technologies.

Flotation as a separation technology for recovering pulp fines and sustainable nanocellulose production

• Fines from refined pulp were separated and enriched by froth flotation. • Flotation was controlled by pulp suspension rheology and fluid flow hydrodynamics. • Fines separation was quantified by fines enrichment ratio and fines recovery. • Fines recovery and fines enrichment ratio balance enables process optimisation. • Quality of fines and fines sheets was comparable to nanocellulose. Nanocellulose has great potential in the pulp and paper industry, but current nanocellulose production methods require high energy. One way to achieve energy efficient production of nanocellulose is to develop a large-scale process of separating small fibers (fines) from large fibers. In this study, a laboratory mill was used to produce moderately refined (30.8% fines) and highly refined (81.8% fines) Bleached Eucalyptus Kraft (BEK) pulp. Refined samples were subjected to flotation separation, and separation efficiency was quantified by fines recovery and fines enrichment ratio. At high pH (11.9), with a surfactant concentration of 0.15 mM, the surface tension of the air–water interface was 44 mN/m and the Sauter mean diameter of the bubbles in the froth was 0.948 mm. These conditions provide the required froth stability and low bubble size to achieve selective separation of fines. Maximum recoveries of 80.4% and 43.0% were achieved at pH 11.9 and 1.0 wt% for moderately refined and highly refined pulp, respectively. Maximum enrichment ratios of 4.33 and 4.37 were observed for moderately refined and heavily refined pulp at pH 11.9 and 1.5 wt%, respectively. The aspect ratio of float fibers increased by 14% and 18% for moderately and highly refined BEK, respectively. Flotation was shown to be controlled by the viscosity and surface charge of the pulp suspension. Viscosity and zeta potential values were maximised at pH 11.9 and 1.0–1.5 wt% pulp solids, promoting agglomeration of long fibers and enhanced fines separation. Experimental results were found to be statistically significant via ANOVA. Fines were shown to have analogous properties to commercial nanocellulose. This study demonstrates that size-selective fiber flotation is governed by pulp suspension rheology and fluid flow hydrodynamics, and that flotation represents a promising technology for fines separation and production of a sustainable nanocellulose substitute.

Design and Fluid Dynamics Features of a Low-Flow High-Head Pump with Barske-Type Impeller

The article presents the results of research devoted to the design and numerical calculation of a low-flow high-head centrifugal pump with Barske-type impeller using computer simulation methods. The main features of fluid flow hydrodynamics, as well as the influence of a number of design geometry on the energy and cavitation characteristics of the pump, are found. The focus is on the analysis of the influence of the end gap between the impeller blades and the casing, as well as the cavitation qualities of the pump. The issue of cavitation qualities of a pump with different geometry of the pump inlet area investigated. In addition, a comparison of different outlet types and the selection of the best option provided. Analysis of the importance of installing the ribs in the suction line, taking into account the vortex structure of the flow in the impeller, was carried out. In addition, the results of changes in energy characteristics when pumping a working fluid with high kinematic viscosity are given.

Удосконалення процесу обробки тіл обертання електричною дугою

In modern mechanical engineering, electrical discharge machining (EDM) methods are widely used for machining bodies of rotation from difficult-to-machine materials. Those methods ensure sparing cutting and make it possible to machine any electrically conductive material irrespective of its physical and chemical properties, in particular hardness. There is a known method for dimensional machining of bodies of rotation with electric arc using a wire electrode tool that is pulled along in the machining area thus "compensating" for that tool's EDM wear and tear. The machining accuracy is therefore significantly heightened. However, when implementing this method, an effect of splashing the working fluid outside the working area of the machine and a pronounced luminous effect from the burning of the electric arc in the machining area are observed. That worsens the working conditions. In addition, when pulling the wire electrode tool along the convex surface of the electrode holder, the sliding friction arises, which eventually leads to mechanical destruction of the contact point. As a result, a deep kerf is formed on the electrode holder. When the depth of the kerf reaches the diameter of the wire electrode tool, the destruction of the electrode holder by the electric arc begins. Consequently, the durability of the electrode holder in the known method is unsatisfactory. A method of dimensional machining of bodies of rotation with electric arc using a wire electrode tool with the immersion of the machining area in the working fluid has been proposed, which makes it possible to improve the working conditions of the operator by eliminating the effect of fluid splashing and removing the luminous effect of arc burning in the machining area. In addition, it has been proposed to make the electrode holder in the form of a roller that rotates with a guide groove for the wire electrode tool, while the nozzle for creating the transverse hydrodynamic fluid flow has been proposed to be mounted in a separate fixed housing that is adjacent to the electrode holder. This technical solution replaces the sliding friction with the rolling one thus enhancing the durability of the electrode holder. Mathematical models of the process characteristics of the DMA-process (dimensional machining with electric arc) for bodies of rotation using a wire electrode tool with the immersion of the machining area in the working fluid have been obtained that make it possible to control the machining productivity, the specific machining productivity, the specific electric power consumption, and the roughness of the surface machined.

Buoyancy driven mixed convection flow of magnetized Maxell fluid with homogeneous-heterogeneous reactions with convective boundary conditions

This investigation explored the significances of heterogeneous and homogeneous reactions on magneto hydrodynamic Maxell fluid flow induced by radially stretching disks under influence of buoyancy driven force. The steady state system is examined for the specific case in which the coefficient of diffusion of the reactants and auto catalytic agent are identical. The mathematical formulation for present flow problem is developed by using flow assumptions. The analytical solution for formulated flow problem is determined analytically by using homotopy analysis method (HAM) by using MATHEMATICA software. It is noticed that presence of Deborah number and thermal Biot number enhances the temperature profile. The homogeneous and heterogeneous parameter and Deborah number decays the concentration profile effectively. Further, an improved concentration distribution is noted for Archimedes number.

Experimental Investigation of Fluid Flow Hydrodynamics in Porous Medium Pipeline

Porous medium square pipelines with pellet packed bed and cylindrical packed bed are employed to experimentally study the flow characteristics of water. Differences of flow characteristics between the pellet packed bed and cylindrical packed bed, as well as the circular pipe and the square pipe, are discussed by measuring the pipeline pressure drop under different flow rate, and the relationship between the pipe resistance coefficient and flow is analyzed. The results show that the pressure drop per unit length in the square pipe increases with the increase of flow rate and increases with the decrease of pellet diameter. The structure of large diameter pellet packed bed is more advantageous to form a relatively stable flow.

Computational modeling of media flow through perfusion-based bioreactors for bone tissue engineering.

Bioreactor system has been used in bone tissue engineering in order to simulate dynamic nature of bone tissue environments. Perfusion bioreactors have been reported as the most efficient types of shear-loading bioreactor. Also, combination of forces, such as rotation plus perfusion, has been reported to enhance cell growth and osteogenic differentiation. Mathematical modeling using sophisticated infrastructure processes could be helpful and streamline the development of functional grafts by estimating and defining an effective range of bioreactor settings for better augmentation of tissue engineering. This study is aimed to conduct computational modeling for newly designed bioreactors in order to alleviate the time and material consuming for evaluating bioreactor parameters and effect of fluid flow hydrodynamics (various amounts of shear stress) on osteogenesis. Also, biological assessments were performed in order to validate similar parameters under implementing the perfusion or rotating and perfusion fluid motions in bioreactors' prototype. Finite element method was used to investigate the effect of hydrodynamic of fluid flow inside the bioreactors. The equations used in the simulation to calculate the velocity values and consequently the shear stress values include Navier-Stokes and Brinkman equations. It has been shown that rotational fluid motion in rotating and perfusion bioreactor produces more velocity and shear stress compared with perfusion bioreactor. Moreover, implementing the perfusion together with rotational force in rotating and perfusion bioreactors has been shown to have more cell proliferation and higher activity of alkaline phosphatase enzyme as well as formation of extra cellular matrix sheet, as an indicator of bone-like tissue formation.