Axial Fluid Velocity Research Articles

Electro-Osmotic Mechanism of Ellis Fluid With Joule Heating, Viscous Dissipation, and Magnetic Field Effects in a Pumping Microtube.

The dynamics of electro-osmotically generated flow of biological viscoelastic fluid in a cylindrical geometry are investigated in this paper. This flux is the result of walls contracting and relaxing sinusoidally in a magnetic environment. The blood's viscoelasticity and shear-thinning viscosity are the primary causes of its non-Newtonian characteristics. Hence, the rheology of the fluid (blood) is accurately captured with the Ellis fluid model. Both Joule heating and viscous dissipation are accounted for during thermal analysis. The electric potential induced in the electric double layer (EDL) is obtained by applying the Debye-Huckel linearization to the nonlinear Poisson-Boltzmann equation. Mathematical modelling is incorporated in cylindrical coordinates in wave frame of reference. Assuming a long wavelength and creeping flow characterized by a low Reynolds number, the Ellis fluid model's governing equations are simplified. The resulting differential equations are evaluated numerically via the built-in tool NDSolve of the Mathematica. Graphical representations are utilized to visually and comprehensively assess the thermal characteristics, flow features, heat transfer coefficient, and skin friction coefficient. Various factors are taken into consideration, including the impact of Ellis fluid parameters, electric double layer, magnetic field, Brinkman number, and Ohmic dissipation. Ellis fluid's axial velocity boosts with a rise of the electro-osmotic parameter and power-law index while decreasing with an increase in the Hartmann number and material fluid parameter. The fluid temperature is directly proportional to EDL parameter and parameters of Ohmic and viscous dissipation. The presence of both electric and magnetic fields may aid in the management and control of Ellis fluid (blood) mobility at different temperatures, which is helpful in controlling bleeding during surgeries. The current model may be used in clinical scenarios involving the gastrointestinal system and capillaries, electrohydrodynamic therapy, delivery of drugs in pharmacological, and biomedical devices. This research creates a theoretical model that can predict the effects of different parameters on the characteristics of fluid flows that are like blood.

Mathematical modeling of electroosmotically driven peristaltic propulsion due to transverse deflections of two periodically deformable curved tubes of unequal wavelengths

The present study aims to investigate the viscid fluid propulsion due to the electroosmosis and transverse deflections of the sinusoidally deformable tubes of unequal wavelengths in the presence of electro-kinetic forces. This situation is estimated from the physical model of physiological fluid flow through a tubular structure in which an artificial flexible tube is being inserted. In this model, both peristaltically deforming tubes are taken in a curved configuration. The flow-governing momentum equations are simplified by the approximation of the long wavelength as compared to the outer tube's radius, whereas the Debye–Hückel approximation is used to simplify the equations that govern the electric potential distribution. Here, the authors have used the DSolve command in the scientific computing software MATHEMATICA 14 to obtain the expressions for electric potential and axial velocity of viscid fluid. In this work, the authors have analyzed the impact of various controlling parameters, such as the electro-physical parameters, curvature parameter, radius ratio, wavelength ratio, and amplitude ratios, on the various flow quantities graphically during the transport of viscid fluid through a curved endoscope. Here, contour plots are also drawn to visualize the streamlines and to observe the impacts of the control parameters on fluid trapping. During the analysis of the results, a noteworthy outcome extracted from the present model is that an increment in electro-physical parameters, such as Helmholtz–Smoluchowski velocity and the Debye–Hückel parameter, are responsible for enhancement in the shear stress at the inner tube's wall and the axial velocity under the influence of electro-kinetic forces. This is because of the electric double layer (EDL) thickness, which gets reduced on strengthening the Debye–Hückel parameter. This reduced EDL thickness is responsible for the enhancement in the axial velocity of the transporting viscid fluid. The present model also suggests that the axial velocity of viscid fluid can be reduced by enhancing the ratio of wavelengths of waves that travel down the walls of the outer curved tube and the inner curved tube. The above-mentioned results can play a significant role in developing and advancing the endoscopes that will be useful in many biomedical processes, such as gastroscopy, colonoscopy, and laparoscopy.

The Impact of Heat Transfer and a Magnetic Field on Peristaltic Transport with Slipping through an Asymmetrically Inclined Channel

This theoretical investigation explores the intricate interplay of slip, heat transfer, and magneto-hydrodynamics (MHD) on peristaltic flow within an asymmetrically inclined channel. The channel walls exhibit sinusoidal undulations to simulate flexibility. The governing equations for continuity, momentum, and energy are utilized to mathematically represent the flow dynamics. Employing the perturbation method, these nonlinear equations are systematically solved, yielding analytical expressions for key parameters such as stream function, temperature distribution, and pressure gradient. This study meticulously examines the influence of various physical parameters on flow characteristics, presenting comprehensive visualizations of flow streamlines, fluid axial velocity profiles, and pressure gradient distributions. Noteworthy findings include the observation that the axial velocity of the fluid increases by 55% when the slip parameter is increased from 0 to 0.1, indicative of enhanced fluid transport. Furthermore, the analysis reveals that the pressure gradient amplifies by 80% with increased magnetic field strength from 0.5 to 4, underscoring the significant role of MHD effects on overall flow behavior. In essence, this investigation elucidates the complex dynamics of peristaltic flow in an asymmetrically inclined channel under the combined influence of slip, heat transfer, and magnetohydrodynamics. It sheds light on fundamental mechanisms that govern fluid dynamics in complex geometries and under diverse physical conditions.

Optimizing Reverse Osmosis Feed Spacer Design for Enhanced Dimethylphenol Removal from Wastewater: A Study of Hydrodynamics and Performance Indicators

Due to its high pollutant rejection and low energy usage, the spiral wound module of reverse osmosis (RO) process is the most commonly used technology utilised in wastewater treatment. For a spiral wound module, the presence of a feed spacer is important as a key solution to mitigate the concentration polarisation phenomenon, due to disorderly fluid flow, and to improve the mass transfer coefficient. Undoubtedly, improvements in the spiral wound module design, mainly in the symmetrical shape of the feed spacer, can have a significant impact on the cost and probable use of these modules. Despite the wide interest in appraising the impact of feed spacer geometry and orientation on the performance of a spiral wound module for RO process-based water desalination, the hydrodynamics of feed spacers (pressure drop and mass transfer coefficient) and the associated influences of feed spacer design (the height of the feed spacer, the angle of the filaments, and the porosity) on the removal of pollutants from wastewater have not yet been addressed. The current investigation aims to fill this gap by studying the hydrodynamics and design parameters of the selected parallelogram feed spacer type ultrafiltration (UF−3) for the removal of dimethylphenol from wastewater. Using model-based simulation, the impacts of UF−3 feed spacer design parameters, including the height, angle between the filaments (orientation), and porosity on the pressure drop, friction factor, axial flow fluid velocity, mass transfer coefficient, water flux, dimethylphenol rejection, recovery rate, and specific energy consumption are detailed in this study. The study intends to demonstrate the optimum design features of UF−3 feed spacer that should be considered to assure the highest elimination of dimethylphenol from wastewater in addition to the lowest specific energy consumption.

Numerical investigation of gas-liquid flow hydrodynamics in three-dimensional bottom-blown reactor via LES-VOF coupled model

In this study, a coupled interface-resolved volume of fluid model and large eddy simulation is employed to explore bubble dynamics in a three-dimensional bottom-blown reactor. After the model validation, the bubble plume area, motion characteristics, and force analysis are analyzed. Three distinct stages of bubble rising are quantitatively identified: disengaging nozzle stage, accelerated ascent stage, and stable upward stage. Specifically, an increase in reactor height reduces both the bubble rising velocity and interphase surface tension impact. Moreover, the influence of inlet size on bubble volume frequency distribution surpasses that of gas injection velocity. The gas penetration depth remains relatively unchanged amidst variations in boundary conditions, while the liquid type profoundly influences it. Axial fluid velocity, dynamic pressure, Reynolds number, and turbulent viscosity peak at the reactor center. Liquid back-mixing is found near the bottom blowing wall region, coupled with an enhanced distribution of turbulent viscosity.

Investigation on multiphase flow of multi-size cuttings particles and non-Newtonian drilling fluids in oil and gas horizontal well drilling using kinetic theory of granular flow

Effective cuttings transport has long been a challenge in oil and gas horizontal drilling, and inadequate wellbore cleaning can result in severe drilling accidents including stuck pipe. The transportation of multi-size cuttings by non-Newtonian drilling fluids in the horizontal wellbore with a rotating drill pipe was systematically investigated using the kinetic theory of granular flow. Collisions between particles and their two-way coupling with drilling fluid turbulence were modeled. Flow regime of multi-size cuttings has been predicted, and effects of particle size composition characteristics were studied. The spatial inhomogeneity of the non-Newtonian fluid viscosity and the sedimentation of particles result in a complex stratified flow regime for multi-size cuttings transport. Cuttings concentration and drilling fluid axial velocity distributions both show swaying phenomena with drill pipe rotation. Moreover, the secondary flow regions appear with negative tangential velocities. The cuttings transport ratio (CTR = 0.846) is the best in the case of cuttings with different particle sizes injected in a uniform concentration. While in the case where the concentration of injected multi-size cuttings is negatively correlated with particle size, the cuttings velocity fluctuations caused by collisions and frictions are the most severe, and the borehole cleaning is the worst (CTR = 0.803).

Structural parameter design of welded plate heat exchanger based on multi-objective optimization algorithm

A numerical investigation was conducted to explore the heat transfer and flow characteristics of welded plate heat exchanger with chevron sinusoidal corrugated plates and to find the optimal parameter design in this paper. For better thermo-hydraulic performance, the effects of chevron angle (β = 30°,45°,60°), the height of the corrugations (H = 3,5,7,9) and the pitch of corrugations (P = 15,20,30,45,60) were studied with inlet velocity ranged from 0.1 m/s to 0.5 m/s. Moreover, artificial neural networks (ANNs) and multi-objective genetic algorithm (MOGA) were employed to obtain optimization solutions of the structural parameters. With the analysis of flow form inside the flow channel, it was proposed that the chevron sinusoidal corrugated plates were helpful to transform the axial velocity of fluid to radial velocity, forming turbulence and secondary flow in the narrow region. The numerical results showed that the comprehensive performance of the plate with β = 45° was better than the other two, while P = 30 mm and H = 9 mm also performed well in this paper. Besides, an optimal parameters set was obtained with P = 15.132 mm, H = 3.005 mm, β = 45.495° when the velocity of inlet was set as 0.1 m/s, the maximum JF could reach 0.034 as the results of multi-objective optimization.

Optimization of thermohydraulic performance of tube heat exchanger with L twisted tape

A numerical investigation was conducted to explore the heat transfer optimization effect of circular tube heat exchanger with L-shaped twisted tape insert and to find the optimal parameter design in this paper. For better thermohydraulic performance, the effects of twist pitch (P), inner diameter (D), tape width (W) and number of tape (N) were studied with Reynolds number ranged from 1875 to 3750. Moreover, response surface method (RSM) was employed to indicate the relationship between the Nusselt number (Nu) and these parameters. With the analysis of flow structure inside the tube, it was conducted that the twisted tape insert was helpful to transform the axial velocity of fluid to radial velocity, forming vortex in the L region. The numerical results showed that the Nu and friction factor (f) of the tube fitted with L-shaped twisted tape insert gained an 199% to 208% increase and 674% to 696% when compared with that of smooth tube respectively. Besides, an optimal parameters set was obtained with P = 65.59 mm, W = 0.95 mm, D = 8.80 mm, in which the Nu and f were increased by 204% and 704% respectively as the results of response surface method.

The propagation of strong cylindrical shock wave in a rotating axisymmetric non‐ideal gas with radiation heat flux

In this manuscript, we studied a quasi‐linear hyperbolic system of partial differential equations which describes the one‐dimensional adiabatic unsteady flow behind a strong cylindrical shock wave propagating in a rotating non‐ideal gas, which has a varying azimuthal fluid velocity together with a varying axial fluid velocity, with radiation heat flux, and similarity solutions are obtained by using the Lie group‐theoretic method. The basic idea of this method is that it changes the system of PDEs representing the one‐dimensional flow through the similarity variable to the system of ODEs. The flow profiles are drawn behind the shock followed by a brief discussion on the behavior of the solutions via graphs. The effects of variation in non‐ideal parameter, adiabatic index of the gas, Alfven–Mach number and ambient azimuthal velocity exponent on the flow variables are described. All numerical calculations have been performed using the “Mathematica” software.

Rotation, electromagnetic field, and variable thermal conductivity effects on free convection flow past an eternity vertical porous plate

AbstractThe present research may facilitate the reduction of the number of conversion steps required to include the low output voltages in an electrokinetic biomass process. Variable thermal conductivity and electroosmosis flow have already established great potential in the thermo‐elastic models of various manufacturing industries and have been widely used in energy technologies. As a result, the current framework investigates the characteristics of natural convection flow with the influence of variable thermal conductivity and electroosmosis over an eternity vertical porous plate. Coriolis forces and Hall current effects are considered in the momentum equations, and also thermal radiation and variable thermal conductivity are taken as energy equations. A linear chemical reaction parameter is used in the concentration equation. The equation of Poisson–Boltzmann is exploited to depict the electric potential characteristics within the accelerated plate medium. The pdepe command in Matlab software is used to figure out the numerical solutions to equations about momentum, energy, and concentration. The expressions of fluid transverse velocity, fluid axial velocity, fluid temperature, and concentration profiles are presented as numerical results and also derived vital relevant stream parameters diagrammatically, whereas the numerical values of primary skin friction, secondary skin friction, and Nusselt number are presented in tabular form for various values of pertinent flow parameters. The temperature rises as the strength of the thermal conductivity variable parameter increases. Also, as the values of the Taylor number and the thermal conductivity variable parameter go up, the primary velocity goes down. Similarly, secondary velocity increases in the opposite direction as the Taylor number and thermal conductivity variable parameter increase.

Numerical simulations on the settling dynamics of an ellipsoidal particle in a viscoelastic fluid

The settling dynamics of a rigid ellipsoid in an unbounded viscoelastic fluid under inertialess conditions is studied through direct numerical simulations. The governing equations are solved by the finite element method with an Arbitrary Lagrangian–Eulerian formulation to handle the particle motion. The viscoelastic fluid is modeled through the Giesekus constitutive equation. Simulations are carried out up to a value of Deborah number of 5. The settling of prolate and oblate spheroidal particles is first addressed. The sedimentation, lift, and angular velocities are computed as a function of the orientation angle and for aspect ratios from 1/8 to 8. Regardless of the particle shape, initial orientation, and Deborah number, the particle rotates to align its longest axis along the force direction. A high extensional stress region behind the particle is observed at high aspect ratios due to the large curvature of the tip, leading to a fast decay of the axial fluid velocity downstream and to the appearance of a negative wake. Similarly, a triaxial ellipsoid reaches a final orientation with major axis parallel to the falling direction. The particle shape affects the orientational dynamics, both in terms of the orbits followed by the orientation vectors and the time needed to reach the equilibrium orientation, and the steady-state settling velocity. The fastest sedimentation rate is observed for a prolate spheroid with aspect ratio of about 2 whereas the slowest one for a high aspect ratio oblate spheroid. Triaxial ellipsoids settle with rates in between these two limiting behaviors.

Structure and arrangement optimization of non-diagenetic gas hydrate jet crushing nozzles based on CFD simulation

To optimize the optimal nozzle structure and multiple nozzle arrangement for hydrate jet crushing and to promote the development of solid fluidization extraction technology for shallow unconformity hydrate in China’s oceans, the submerged jet flow field of six commonly used nozzle structures in the downhole in-situ jet crushing process was analyzed on the basis of the solid fluidization extraction process in double-layer pipes, and the effect of the jet hole arrangement on the overflow performance of hydrate slurry in the outer annulus of double-layer pipes was also investigated. It was demonstrated that tapered straight nozzles were preferably selected as the nozzle type for hydrate solid fluidization mining process based on jet core stage length, jet energy dissipation rate, and jet fluid axial velocity. In the meantime, the optimum arrangement of the nozzles was preferred on the basis of the annular pressure drop and the flow resistance coefficient, with the number of single circle not higher than 3 and the axial spacing of the nozzles not lower than 50 mm. This study can provide a theoretical basis for nozzle selection and tool design for the solid fluidization jet crushing process of marine unconformable hydrates.

Dean flow velocity of shear-thickening SiO2 nanofluids in curved microchannels

We report the effects of a curvilinear microchannel width, height, and radius of curvature, as well as the kinematic viscosity and axial velocity of shear-thickening nanofluids, on the average Dean velocity (VDe) of the secondary flow in the microchannel. Manipulation of inertial and Dean drag forces in curvilinear microchannels has enabled high-throughput and high-resolution size-based separation of microparticles and cells in various biomedical applications. VDe plays a deterministic role in the estimation of the Dean drag force and the design of these microfluidic devices. Despite the previous numerical and experimental studies on VDe of Newtonian and shear-thinning viscoelastic fluids, VDe of shear-thickening metallic nanofluids, such as SiO2 nanoparticles in water, in curved microchannels is still unknown. Such shear-thickening fluids are being used in thermal microsystem applications and are on the verge of entering the field of inertial microfluidics for particle and cell sorting. Our investigations have shown that VDe of shear-thickening SiO2–water nanofluids scales directly with the channel width and the fluid axial velocity, while being inversely proportional with the SiO2 concentration and the channel radius of curvature. Our non-dimensional analysis has led to the development of an empirical correlation that relates VDe-based Reynolds number of the nanofluid to the Dean number and the normalized kinematic viscosity of the nanofluid. It provides a significant accuracy in estimating VDe of shear-thickening fluids, compared to application of Newtonian or shear-thinning equations in the literature, which could be useful toward future design of particle and cell sorting and washing microdevices.

Propagation of cylindrical shock waves in rotational axisymmetric dusty gas with magnetic field: Isothermal flow

In this article, the effect of the dust particles is studied on the propagation of a cylindrical shock wave in rotational axisymmetric ideal gas under isothermal flow conditions with the magnetic field. Here, magnetic pressure, azimuthal fluid velocity, and axial fluid velocity are supposed to vary according to a power law in the undisturbed medium. With the help of Sakurai's technique, we obtain approximate solutions analytically by expanding the flow parameters in the form of a power series in ϕ=(CV)2. The power series method is used to derive the zeroth and the first-order approximations. The solutions for the zeroth-order approximation are constructed in analytical form. Distributions of the hydrodynamical quantities are analyzed graphically behind the shock front. Also, the effects of shock Cowling number (co), mass fraction of the solid particles in the mixture (kp), adiabatic exponent (γ), and rotational parameter (L) on the flow variables are discussed. It is investigated that the density and pressure near the line of symmetry in the case of isothermal flow become zero, and hence a vacuum is formed at the axis of symmetry when the flow is isothermal. The present work may be used to verify the correctness of the solution obtained by self-similarity and numerical methods. Furthermore, the results obtained in the present work are found to be in good agreement with those obtained from the study by Nath and Singh [Can. J. 98, 1077 (2020)].

Entropy minimized MHD microrotations of Cross nanomaterials with cubic autocatalytic chemical reaction

AbstractThe Cross viscosity model is a generalized non‐Newtonian nanofluid model that has widespread engineering and industrial applications like in the synthesis of polymeric solutions, polymeric latex spheres, animal blood, biological fluids, and polyacrylamides. To analyze the micromotion of such nanofluids, a micropolar flow model is introduced. Entropy generation (EG) minimization is important in thermal fluid systems undergoing heat transportation to achieve improved thermohydraulic execution. Homogeneous and heterogeneous reactions involve complex interactions involving the production and consumption of reactant species. Nonlinear thermal radiation plays a vital role in thermal systems undergoing a drastic change in the temperature gradient. The main focus of this study is the investigation of MHD microrotation in Cross nanofluids subject to nonlinear thermal radiation and autocatalytic chemical reactions. The findings from this study show that amplifying the Weissenberg number and power‐law index leads to augmentation in axial and transverse fluid velocity components and emaciation in microrotations. Strengthening the magnetic field yields enfeeblement of fluid velocities. In addition, increasing the micropolar parameter leads to the growth of flow velocity, microrotation, and fluid temperature. An increase in Brinkman number contributes to the thicker thermal boundary layer. EG number grows with a rise in Reynolds number.

Convective heat transfer in magnetized flow of nanofluids between two rotating parallel disks

Abstract Inspired by several implementations (metal mining, turbine disc, spinning disk, mechanical engineering and drawing of plastic film) of nanoliquid flow between rotating disks, we have reported a theoretical analysis on magnetohydrodynamic flow of kerosene base liquid containing three different nanoparticles namely manganese-zinc ferrite, cobalt ferrite and nickel-zinc ferrite between two parallel rotating-disks. Thermal radiation and convection thermal-conditions are considered. Furthermore, the significant properties of induced magnetic field are accounted to control the flow and thermal transport phenomenon. Furthermore, the temperature distribution is improved by employing Cattaneo-Christov heat flux. This communication is critical in the engineering sector due to different implementations including power technology, cooling reactors, fuel cells etc. The system of nonlinear higher order dimensionless equations is found by applying appropriate similarities-transformations. The exact solution of such strong nonlinear equations is not possible therefore we construct the numerical solution by employing bvp4c (shooting approach) in the MATLAB. Physical trends of velocities, pressure and thermal fields are discussed in detail. The outcomes indicate that stretching parameter of lower disk causes improvement in axial and radial fluid velocity. Fluid radial velocity near the lower disk is improved for growing Reynolds number. Moreover, the thermal field is enhanced for growing thermal Biot parameter at lower disk.

Electro-osmatic flow of Jeffrey fluid in an asymmetric micro-channel under the effect of Magnetic field

In this article, we have investigated the peristaltic transport of electro-osmotic flow of Jeffrey fluid in an asymmetric channel, in which the walls are modulated by the peristaltic array of patches. In the presence of Electrical Debye Layer (EDL), the Poisson Boltzmann equation for the electrical potential within the micro channel is considered. To evaluate the electrical potential, Debye-Huckel linearization is employed the governing equations are modeled and reduce by small Reynolds number and long wavelength approximation and solved the exact solution. The axial fluid velocity, temperature, pressure gradient, pressure rise and stream functions are discussed with the effects of pertinent parameters (Hartmann number, Phase angle, relaxation time parameter) through the graphs.

A self-similar solution for unsteady adiabatic and isothermal flows behind the shock wave in a non-ideal gas using Lie group analysis method with azimuthal or axial magnetic field in rotating medium

The similarity solutions using Lie group analysis for shock wave propagation in a rotational axisymmetric non-ideal gas with azimuthal or axial magnetic field in the case of isothermal and adiabatic flows are obtained. All possible cases of similarity solutions are discussed using the Lie group analysis for the isothermal and adiabatic flows. The arbitrary constants involved in the generators of local Lie groups bring various possible cases of solutions with exponential law and power law shock paths. Similarity solution for isothermal and adiabatic flows with power law shock path is discussed in detail. The density of ambient medium is taken to be constant. The axial and azimuthal fluid velocities and magnetic field in the ambient medium are assumed to be varying according to power law. The effect on shock wave strength and that on the flow variables due to variation of the Alfven Mach number, adiabatic index of the gas, non-idealness parameter, rotational parameter and initial magnetic field variation exponent are investigated. It is found that these parameters have decaying effects on shock wave. The obtained results in the case of isothermal and adiabatic flows are also compared with each other.

Approximate Analytical Solution for Ionizing Cylindrical Magnetogasdynamic Shock Wave in Rotational Axisymmetric Self-Gravitating Perfect Gas: Isothermal Flow

The propagation of ionizing cylindrical magnetogasdynamic shock wave in rotational axisymmetric self-gravitating perfect gas under isothermal flow condition is investigated. Mathematical model for the considered problem using system of PDEs is presented. The density, magnetic pressure, azimuthal fluid velocity and axial fluid velocity are assumed to be varying according to power law with distance from the axis of symmetry in the undisturbed medium. The flow variables are expanded in power series and using that the zeroth and first order approximations are discussed. Solutions for zeroth order approximation are constructed in approximate analytical form. The effect of flow parameters namely: gravitational parameter $$G_{0}$$ , shock Cowling number $$C_{0}$$ , rotational parameter L and ambient density variation index q are studied on the flow variables and total energy of disturbance. Distribution of gasdynamical quantities are discussed. Radial fluid velocity and mass tends to zero near the axis of symmetry in general; but magnetic pressure, axial fluid velocity, non-dimensional components of vorticity vector $$l_{\theta }^{(0)}$$ and $$l_{z}^{(0)}$$ tend to positive infinity near the axis of symmetry. Azimuthal fluid velocity decreases as we move inwards from the shock to the axis of symmetry. Density and pressure vanish near the axis of symmetry thus forming a vacuum there. $$J_{0}$$ decreases with increase in value of ambient density variation index q or gravitational parameter $$G_{0}$$ ; whereas it increases with increase in value of rotational parameter L or shock Cowling number $$C_{0}$$ .

Erosion-Corrosion of AISI 302 Stainless Steel Sudden Expansion Pipes in High Salt Wastewater: Effect of Fluid Flow on Different Positions of a Sudden Expansion Pipe

Erosion-corrosion (E-C) is common in chemical industries. Sudden expansion pipes (SEP) are one of the flow components which may experience severe erosion rates. Computational fluid dynamic modeling (CFD) and flow-through experiments were used to study E-C for a SEP of AISI 302 stainless steel. A typical geometry for SEP was investigated: 20 mm diameter inlet pipe, 40 mm diameter outlet pipe, with an inlet flow rate of 0.1 m/s, and 10 wt% concentration of SiO2. CFD simulation results showed that turbulence energy and wall shear were highest at 5 mm and fluid axial velocity was lowest at 5 mm from the inlet/outlet SEP connection point. E-C test results showed that the most severe E-C occurred between 5 mm and 7 mm downstream of the SEP. At deeper lengths into SEP, the corrosion rate decreased and remained constant. The results indicated that increasing wall shear and turbulence energy increased the mechanical effects of particles on SEP and hence increased the E-C rates of the reattachment point. This work provides a means of understanding E-C behavior and predicting erosion damage of SEP.