Influence Of Reactions Research Articles

Influence of chemical reaction on transient natural convective flow in an infinite vertical cylinder packed with porous material

A study of mass and heat transport on fully developed laminar and transient free convective flow in a vertical cylinder containing a porous substance inside it. The Laplace Transform Method (LTM) is used to solve the governing equations with suitable boundary conditions. A compact form solution represented by using Bessel and modified Bessel functions. The numerical results were thoroughly scrutinized using graphs and tables to illustrate the effects of newly discovered fluid characteristics, including time, Grashof, mass Grashof, Schmidt, Prandtl, Darcy numbers, viscosity ratio on the concentration and the velocity profiles. The velocity and concentration profiles progressively increase with varying time values until reaching a steady state. Furthermore, it is found that the velocity profiles are decreased by the Prandtl, Schmidt number, and viscosity ratio. In contrast, the Darcy, Grashof, and mass Grashof numbers exhibit an opposite effect. The rate of mass transport, skin friction, and mass flux are presented in tables. The major finding of the current research is that the viscosity ratio parameter decelerates the skin friction and mass flux. This study has potential applications in innovative fields such as solar energy systems, chemical engineering processes, etc.

Application of Fibonacci wavelet in the analysis of unsteady MHD Williamson nanofluid flow over a permeable stretching sheet via porous medium

This research investigates the unsteady flow behavior of a magnetohydrodynamic Williamson nanofluid (WNF) over a permeable stretching sheet within a porous medium. It considers the influence of chemical reactions, Joule heating, heat generation/absorption, thermal radiation, and viscous and porous dissipation. The study on magnetohydrodynamic WNF over a permeable stretching sheet within a porous medium has gained much significance due to its numerous industrial and engineering applications. The study employs the Fibonacci wavelet series collocation method (FWSCM) for analysis. An appropriate similarity transformation transforms the governing partial differential equations (PDEs) into nonlinear coupled ordinary differential equations (ODEs). These ODEs are solved using FWSCM. The accuracy of the FWSCM is validated with some previous studies, the Mathematica NDSolve command, and the Haar wavelet collocation method (HWCM). The graphs and tables are used to discuss the physical parameter’s impact. The findings of this study reveal that the Nusselt number increases by 45.32 % with the Weissenberg number and 31.25 % with the unsteadiness parameter. In comparison, it decreases by 45.01 % with the heat generation/absorption parameter, 4.89 % with the porosity parameter, and 1.95 % with the chemical reaction parameter.

Effects of chemical action of polishing medium on the material removal of SiC

The chemical action mechanism in the chemical mechanical polishing of SiC substrate remains elusive, which has great limitations on the selection of polishing solution and polishing parameters. In this paper, the cutting process of unreacted SiC (U–SiC) and the SiC reacted with H2O (R-SiC-H2O) and H2O2 (R-SiC-H2O2) was studied with an individual diamond abrasive particle by molecular dynamics simulation. The influence of chemical reaction and cutting speed on the material removal of SiC was explored by focusing on the removal rate, surface quality, machining temperature and machining stress. The simulation results showed that the number of removed atoms increased, and the surface roughness and subsurface damage depth decreased for SiC at the same cutting speed after the chemical action. Although the number of removal atoms increased with the increase of cutting speed, the surface roughness and subsurface damage depth increased at the same time. The effects of the polishing medium on the material removal process for SiC can be attributed to the decrease of surface hardness and Si–C bonding energy after the reaction of the polishing medium and SiC. The results provide a guidance for the selection of chemical mechanical polishing systems and machining parameters.

Key Factors of Quality Formation in Wuyi Black Tea during Processing Timing.

As the most consumed tea in the world, all kinds of black tea are developed from Wuyi black tea. In this study, quality components, regulatory gene expression, and key enzyme activity during the processing were analyzed to illustrate the taste formation of WBT. Withering mainly affected the content of amino acids, while catechins and tea pigments were most influenced by rolling and the pre-metaphase of fermentation. Notably, regulatory gene expression was significantly down-regulated after withering except for polyphenoloxidase1, polyphenoloxidase2, leucoanthocyanidin dioxygenase, chalcone isomerase, and flavonoid 3', 5'-hydroxylase. Co-expression of flavonoid pathway genes confirmed similar expression patterns of these genes in the same metabolic pathway. Interestingly, rolling and fermentation anaphase had a great effect on polyphenol oxidase, and fermentation pre-metaphase had the greatest effect on cellulase. Since gene regulation mainly occurs before picking, the influence of chemical reaction was greater during processing. It was speculated that polyphenol oxidase and cellulase, which promoted the transformation of quality components, were the key factors in the quality formation of WBT. The above results provide theoretical basis for the processing of WBT and the reference for producing high-quality black tea.

Exploring the numerical simulation of Maxwell nanofluid flow over a stretching sheet with the influence of chemical reactions and thermal radiation

The significance of the study lies in illuminating the consequences of thermophoresis and Brownian motion on heat and mass transfer, offering valuable insights crucial for practical applications. The purpose of this study is to look into how Casson–Williamson and Maxwell nanofluids flow over a stretching sheet in order to understand how heat and mass move in that situation. The mathematical structure comprises a set of partial differential equations (PDEs) converted into ordinary differential equations (ODEs) through a similarity transformation. Subsequently, the well-established MATLAB BVP4C method, integral to the finite difference approach, is applied to solve these ODEs. For the assurance of the method’s reliability and precision, the acquired outcomes are cross-referenced with existing literature, which is a crucial step in validation. The numerical results are depicted visually and in tables, specifically highlighting the impulse of different influencing elements on the Nusselt number, friction factor, and Sherwood number. Notably, an enhancement within the Brownian motion parameter (Nb) and the thermophoresis parameter (Nt) is found to correspond to higher local Nusselt numbers, indicating an enhancement in heat transfer. Conversely, elevated quantities of the Brownian motion parameter (Nb) result in a reduction in local Sherwood numbers. Physically, a higher Brownian motion parameter causes significant nanofluid particle displacement, enhancing their kinetic energy and intensifying heat generation in the boundary layer. The magnetic parameter (M) influences speed profile decline caused by the Lorentz force, which hinders fluid motion.

Theoretical and experimental investigation on material removal mechanism in dual-rotation polishing of fused silica glass

Fused silica glass is utilized extensively in various optical components owing to its excellent optical properties, but its high hardness and brittleness make it difficult to process with high surface accuracy and low subsurface damage. To solve this problem, a series of experiments is carried out to explore the mechanism of material removal during dual-rotation polishing of fused quartz glass. A predictive model is proposed to predict the material removal rate and the microtopography of polished surface. This model considers fundamental physics of the dual-rotation polishing process, for instance, the surface micro-topography and the pressure distribution of the polishing pad, the brittle–ductile material removal mechanism, the planetary motion during the polishing, and the influence of chemical reactions. The reliability and accuracy of the model are quantitatively evaluated through practical experiments. It is turned out that the simulated results reasonably agree with the experimental data. In addition, simulation experiments show that a Gaussian removal function with a strong central peak can be obtained when the eccentricity is 0.9 and the rotating speed ratio is between −10 and −1. This indicates that the theoretical model can be successfully applied to the prediction and optimization of polishing processes.

Insights of rising bubble dynamics of air‐blown biomass gasification in bubbling fluidized bed gasifier

AbstractUnderstanding the complex dynamics and spatial distribution of rising bubbles in fluidized bed gasifiers is crucial for designing, optimizing, and scaling up of the reactor. However, existing studies on bubble dynamics mainly focused on cold flow investigations, failing to capture the behavior of bubbles under the influence of chemical reactions and intricate coupling of heat transfer. Therefore, a reactive Lagrangian model is established to explore intricate bubble behaviors during biomass air gasification. The model is well validated with experiment, and the impact of operating parameters including bed temperature and equivalence ratio (ER) on the bubble behaviors is studied. The growth, coalescence, break, and eruption of rising bubbles are studied. A lower ER is recommended for better gasification performance. With an increase in the ER from 0.12 to 0.3, both the lower heating value and combustible gas concentration experienced a decrease of approximately 38.5% and 38.3%, respectively. The lateral feeding of biomass leads to asymmetrical distribution of bed temperature and bubble properties. Near the biomass inlet, a larger bubble aspect ratio is observed, possibly attributed to the hindrance in the lateral bubble growth due to the lateral biomass feeding. The bubble coordinate number is introduced to characterize the degree of bubble distribution density in a specific region. It is found that increasing the operating temperature results in a reduction in the density and an increase in the volume of bubbles at the bottom, resulting in a denser distribution of bubbles in this region. Although this concentrated bubble distribution may impact local heat and mass transfer, the differences in bubble distribution under temperature dominance gradually decrease along the reactor height. The impact of the operating conditions on the thermal properties and spatial distribution of bubbles obtained in this work can provide valuable guidance for practical gasification operations.

Computational analysis of magnetized Casson liquid stretching flow adjacent to a porous medium with Joule heating, stratification, multiple slip and chemical reaction aspects

This article aims to investigate the characteristics of thermo-solutal magnetohydrodynamic (MHD) non-Newtonian smart coating boundary layer flow of a stretching substrate adjacent to a porous medium, considering the influence of chemical reactions and thermal radiation subject to a transverse static magnetic field. A non-Darcy drag force model is deployed to capture both Darcy bulk drag and inertial Forchheimer (quadratic) drag effects. A diffusion flux model is deployed for radiative heat transfer. The Casson viscoplastic model has been utilized to simulate rheological characteristics. Due to polymeric slip effects, three slip phenomena are included at the wall (hydrodynamic, thermal and concentration) in the formulation. Furthermore, viscous dissipation and Ohmic heating (Joule dissipation) are also included. Robust scaling similarity variables are deployed to transform the governing partial differential equations into ordinary differential equations. Subsequently, the emerging dimensionless coupled nonlinear boundary value problem is solved utilizing the Bvp4c method in MATLAB version 2022. This numerical approach allows for a logical parametric examination of all key control parameters on the transport phenomena, enabling a comprehensive understanding of the system behavior. Validation with previous studies is included. Detailed graphical and tabular computations are included for velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number, for the influence of Darcian parameter, Forchheimer inertial parameter, mixed convection, velocity (momentum) slip, magnetic number, Casson parameter, nonlinear thermal convection parameter, nonlinear concentration convection parameter, radiation parameter, thermal stratification parameter, Prandtl number, heat source/sink parameter, Eckert number, thermal slip parameter, Schmidt number, chemical reaction, solutal stratification parameter and solutal slip parameter. Detailed interpretation of the physics associated with these multiple effects is included. The simulations provide further insight into the transport characteristics of electromagnetic viscoplastic coating material manufacturing.

Effect of Chemical Reaction and Variable Thermal Conductivity in MHD Williamson Nanofluid Flow with Gyrotactic Microorganisms

The primary objective of this study deals with numerical analysis of gyrotactic microorganisms in Williamson nanofluids under the influence of chemical reaction and variable thermal conductivity along with porous medium. Using the similarity transformations, the non-linear PDEs are transformed into ODEs. RK-Fehlberg with a shooting strategy utilised to address ODEs with the influence of MATLAB software. Effect of Permeability, Prandtl number, magnetic field, Williamson parameter, Schmidt number, Peclet number, the profiles of velocity, temperature, concentration, and motile microbe density are explored in detail, and the potential results are displayed in graphs. The density number, Nusselt number, skin friction coefficient, and Sherwood number displayed in tables.

A finite difference explicit-implicit scheme for fractal heat and mass transportation of Williamson nanofluid flow in quantum calculus

This study introduces a novel and versatile fractal finite difference scheme designed to address unsteady flow challenges in quantum calculus over flat and oscillatory sheets. Motivated by the need to advance our understanding of nanofluid dynamics, particularly in heat and mass transportation, this research aims to bridge existing gaps and contribute to improving computational methodologies. Our approach involves a two-stage scheme incorporating explicit and implicit methods, focusing on q-derivatives for spatial terms within the mathematical model. The system encompasses the Navier-Stokes equation, energy equation, and concentration equation, offering a comprehensive framework for analyzing mixed convective Williamson nanofluid flow under the influence of chemical reactions. The convergence condition for the time-dependent partial differential equations system, particularly the scalar convection-diffusion equation, is presented. Stability requirements for our proposed fractal scheme are also delineated. Notably, our study explores the implications of the Weisenberg parameter on the velocity profile, revealing a decline that underscores its influence on nanofluid behavior. Our fractal finite difference scheme demonstrates a substantially faster convergence rate than the fractal Crank-Nicolson scheme. This outcome emphasizes the computational efficiency and efficacy of our proposed technique. In a broader context, our work contributes to the field by leveraging fractal geometry and quantum calculus to enhance our understanding of nanofluid dynamics. These tools present exciting opportunities for groundbreaking applications and technological advancements across various industries. As we delve into these research areas, our work sets the stage for exploration, providing a framework with great potential for transformative progress in nanofluid dynamics.

Influence of chemical reaction on electro-osmotic flow of nanofluid through convergent multi-sinusoidal passages

AimIn the present study, the influences of chemical reactions on heat transfer and the peristaltic pumping of nanofluid in a convergent channel are analyzed. This mathematical analysis is looked at under the postulates of greater wavelength and smaller Reynold's number. Research methodologyThe governing equations are initially transformed from fixed to a wave frame by using linear transformations. Furthermore, these transformed equations are non-dimensioned with the help of similarity variables. Due to the complex form of non-dimensional flow equations, numerical solutions for velocity profile, stream function, temperature profile, and nanoparticle concentration are obtained with the help of Mathematica 11.0 software. These numerical solutions are described via graphs in Mathematica software. These numerical solutions are plotted for numerous rheological parameters. The transportation of nanofluid is based upon multi-sinusoidal natures (cosine wave, sine wave, triangular wave, square wave, sawtooth wave) of peristaltic waves. OutcomesIt is found that with an increasing heat source parameter, the channel flow is decelerated due to the magnitudes of velocity profile and stream function are reduced. While sharp enhancements are noticed in both temperature and nanoparticle concentration by increasing the heat source parameter under chemical reaction effects. The high temperature is obtained with larger chemical reactions. The contrast among viscous and non-viscous fluids is also addressed. A significant enhancement is observed in both velocity profile and stream function by increasing the electroosmotic parameter. Significances and applicationsThe study is relevant to nano-cooling systems, drug delivery systems, and microfluidic pumps where laminar flows in convergent domains arise. This model is significant for the thermal enhancement of mechanical and chemical rheological processes.

Numerical calculation of unsteady MHD nanofluid flow across two fluctuating discs with chemical reaction and zero mass flux

AbstractThe fluid flow across spinning discs has several applications in different fields of engineering such as flywheels, gas turbine engines, brakes, and gears. The significance of heat source, Hall current, and magnetic field on the nanofluid flow between two spinning disks is studied in the present analysis. The upper disk spins as well as rotates, which generates the 3D flow. The evaluation and modeling of the mass density, flow motion, and energy transfer are performed using a system of partial differential equations (PDEs). The computational technique parametric continuation method (PCM) is employed to solve the modeled equations. The outcomes are relatively compared to the published literature for validity purposes. It has been noticed that during the downward motion of the upper disc, the effect of the magnetic field declines, while the influence of the hall current improves the velocity field. The temperature field rises with the ascending motion of the upper disk, whereas it shrinks with the downhill oscillation. Moreover, the mass diffusion ratio develops with the impact of hall current, while lessens with the influence of chemical reaction.

Influence of Chemical Reactions in a Boundary Layer on the Overall Heat-and-Mass Transfer Coefficient

Influence of Chemical Reactions in a Boundary Layer on the Overall Heat-and-Mass Transfer Coefficient

Influence of Chemical reaction and heat generation/absorption on Unsteady magneto Casson Nanofluid flow past a non-linear stretching Riga plate with radiation

The use of Casson fluid is of considerable importance in the manufacturing of pharmaceutical products, including the incorporation of china clay and biological fluids such as synovial liquids. Therefore, the primary objective of this work is to examine the characteristics of the Casson fluid flow. The Casson fluid is a non-Newtonian model often used to analyze the unsteady magnetohydrodynamic (MHD) heat and mass transfer in nanofluid flow scenarios across a non-linearly stretched Riga plate. The heat and mass transfer equations include the analysis of radiation and chemical reactions, respectively. Furthermore, the process of heat transmission is intensified by the existence of an external heat source or heat sink. By applying appropriate similarity transformations, the partial differential equations (PDEs) are converted into a set of nonlinear ordinary differential equations (ODEs). These ODEs are then solved numerically by utilizing the Runge-Kutta-Fehlberg-45 method, with the help of a shooting strategy. The validity of the study is determined by a comparative analysis of the present results in relation to prior research. The main objective of this research is to assess the influence of relevant flow parameters on the fluid flow, temperature, and concentration gradients, which will be visually represented and reported in tabular form. The augmentation of the Casson fluid coefficient (β) hinders the advancement of both velocity and temperature. The augmentation of the thermophoresis parameter (Nt) and magnetic factor (M) results in an elevation of θ(η) and a reduction in the curves depicting the volume fraction of nanoparticles. This study establishes a significant connection between many biological and engineering applications, particularly in the analysis of blood samples and the administration of drugs via blood circulation.

Significance of gyrotactic microorganisms on the MHD tangent hyperbolic nanofluid flow across an elastic slender surface: Numerical analysis

Abstract In the current study, we numerically analyze the significance of motile microbes on the magnetohydrodynamic steady convective streams of tangent hyperbolic (TH) nanofluid flow across an elastic nonlinearly stretching surface of an irregular thickness. The consequences of an external magnetic field, thermal radiation, and thermal conductivity are also examined on the TH nanofluid. The governing system of equations (nonlinear set of partial differential equations) is transfigured into a system of ordinary differential equations (ODEs) by using the similarity variable conversions. Furthermore, the reduced form of nonlinear ODEs is numerically computed through the parametric continuation method (PCM) using MATLAB software. The relative evaluation is carried out to authenticate the numerical outcomes. It has been observed that the energy field accelerates with the Rayleigh number, Weissenberg number, and Brownian motion. The mass propagation ratio improves with the effect of activation energy and decreases with the influence of chemical reactions. Furthermore, the motile microbes’ profile declined with the outcome of the Peclet and Lewis numbers. The skin friction increases up to 7.3% with various magnetic values ranging from 0.5 to 1.5. However, the energy transfer rate declines to 5.92%. The thermal radiation boosts the energy propagation rate and flow velocity by up to 11.23 and 8.17%, respectively.

Chemically reactive MHD fluid flow along with thermophoresis and Brownian effects

In the current manuscript, the aim of the study is to analyze the Eyring-Powell nanofluid flow under the influence of chemical reaction and radiation effects in a slender cylinder in the presence of a non-linear heat source/sink. The flow of Eyring-Powell nanofluid through a slender cylinder along with chemical reaction and MHD effect is not studied yet. Which is the novelty of current research work. Flow analysis is taken near the stagnation point. MHD effect is considered for controlling turbulence. Rosseland model is applied for the estimation of heat flux. The governing system of PDE’S is converted into highly nonlinear ODE’S by utilizing suitable similarity transformations along with the boundary conditions. The resulting coupled systems of nonlinear ordinary differential equations (ODE), accompanied by boundary conditions, are solved using the powerful bvp4c method in MATLAB software. The physical significance of evolved parameters is investigated by graphs and tables. Nusselt number and skin friction are analyzed for several parameters. It is observed that the increase in the MHD effect rises the velocity but lessens the temperature profile and the concentration of the fluid declines when the chemical reaction parameter is incremented. The specific application of the study is that the Eyring-Powell is used in a variety of industrial applications, including lubrication, plastics processing, and oil drilling.

Influence of chemical reaction and thermal convective condition on the heat and mass transport in boundary layer flow over a magneto-radiated wedge with cross diffusion

The analysis of Boundary Layer Flows (BLFs) is of huge significance due to its large-scale applications most likely in aerodynamics, manufacturing of vehicles front faces and many other advanced research areas. Therefore, this study is organized by exercising significant important engineering parameters like surface convection, radiative flux, MHD and thermal and mass diffusion. The developed model embedded the concrete effects of velocity slip, diffusion convection, thermal radiations, magnetic field, chemical reaction and thermo-mass gradients. Later, the numerical treatment is made via RK scheme and the model efficaciously is tackled with desired accuracy. Then the results are decorated over the region (wedge and sheet) and deeply examined. It is observed that slippery surface of wedge and sheet [Formula: see text] enlarges the fluid movement rapidly. The directed magnetic field ([Formula: see text] controlled the fluid motion which can be beneficial from industrial view point. Further, temperature and concentration distributions upsurge by strengthening convective heat ([Formula: see text] and diffusion convection processes. Moreover, skin friction and Nusselt number improved against the parameters under consideration.

Evaluations on numerical simulations of ozone dry deposition over the Yangtze River Delta1

Regional simulation of ozone dry deposition is an important tool for understanding ozone pollution threats and quantifying the ozone impact on terrestrial ecosystems. In this study, we evaluate ozone dry deposition in the Yangtze River Delta (YRD) region using two different dry deposition schemes. The WRF-Chem model, Wesely dry deposition scheme, and revised Surfatm dry deposition scheme were used to simulate the ozone dry deposition process in the YRD region, and results are compared with the observation over a winter wheat field. The results show that the simulated ozone concentrations (cO3) of the two dry deposition schemes were good and lower than the measurements. The simulated ozone dry deposition velocity (Vd) in the Surfatm dry deposition scheme was more close to the measurements. The mean value of cO3 and Vd in the YRD region ranged from 30 to 50 nL L−1 and from 0.2 to 0.5 cm s−1 in the daytime, respectively. To improve the simulation results of the ozone dry deposition process, the simulation errors due to different land use types, the parameters revisions as well as meteorological factors on dry deposition resistance functions, and the influence of chemical reactions must all be considered.

Influence of chemical reaction and variable mass diffusivity on non-Newtonian fluid flow due to a rough stretching sheet with magnetic field and Cattaneo-Christov fluxes

A non-Newtonian Williamson fluid flow due to a stretching sheet with radiation, magnetic field, and viscous dissipation effects is described using variable conductivity and variable diffusivity. The Cattaneo-Christov model is used to correctly compute the physical properties of a heat and mass flux model. Both the chemical reaction phenomenon and the slip velocity have an impact on the heat and mass mechanism. The physical problem is represented mathematically as a nonlinear coupled differential system. After that, the shooting method is used to solve the mathematical model numerically. To gain a better understanding of the behavior of governing emergent factors on dimensionless velocity, concentration, and temperature profiles, physical interpretations are created and discussed utilizing graphical and tabular representations. The results show that the Sherwood number and the Nusselt number are both decreased by the magnetic, viscosity, and slip velocity parameters. Also, according to the findings it has been observed that the concentration outlines enhances for the magnetic number, the viscosity parameter, and the slip velocity parameter, but they dwindle for expanding reaction rate values. Finally, after confirmation of our numerical results, the theoretical results show good agreement with previously published work.

Effective simulations of interacting active droplets

Droplets form a cornerstone of the spatiotemporal organization of biomolecules in cells. These droplets are controlled using physical processes like chemical reactions and imposed gradients, which are costly to simulate using traditional approaches, like solving the Cahn–Hilliard equation. To overcome this challenge, we here present an alternative, efficient method. The main idea is to focus on the relevant degrees of freedom, like droplet positions and sizes. We derive dynamical equations for these quantities using approximate analytical solutions obtained from a sharp interface limit and linearized equations in the bulk phases. We verify our method against fully-resolved simulations and show that it can describe interacting droplets under the influence of chemical reactions and external gradients using only a fraction of the computational costs of traditional methods. Our method can be extended to include other processes in the future and will thus serve as a relevant platform for understanding the dynamics of droplets in cells.