Presence Of Reaction Research Articles

Irreversibility of mixed convection peristalsis flow of nanofluid under the influence of heat mass flux with slip and thermal radiation

This analysis communicates the thermophoretic and Brownian motion aspects in magneto-peristalsis with variable viscosity characteristics of viscous material. The magnetic and porosity characteristics of Darcy and Darcy–Forchheimer are considered. Mixed convection is taken in momentum equation via thermal and concentration coefficients. Viscosity is engaged as a variable function of temperature. Moreover, thermal radiation, viscous dissipation and Joule heating aspects are taken into heat equation. Mass equation is discussed in the presence of chemical reaction. Boundary constraints for velocity are taken as the second-order convective condition for heat, and heat mass flux effects are also present. Irreversibility phenomenon is discussed via entropy and Bejan number. Flow modeling is simplified through large wavelength and low Reynolds number assumptions. The dimensionless simplified system of coupled equations is solved numerically. Numerical solution of the system is acquired via built-in shooting procedure. It is noticed that velocity depicts the opposite behavior at center and channel boundary. Chemical reaction enhances the fluid concentration at center, while heat and mass transfer rates have opposite behaviors for thermophoresis and Brownian motion. The present results are beneficial to study the entropy generation with various non-Newtonian nanofluid models. The present situation of the proposed problem occurs in various biological and engineering industries.

Unsteady MHD Casson Dissipative Fluid Flow past a Semi-infinite Vertical Porous Plate with Radiation Absorption and Chemical Reaction in Presence of Heat Generation

Unsteady MHD Casson Dissipative Fluid Flow past a Semi-infinite Vertical Porous Plate with Radiation Absorption and Chemical Reaction in Presence of Heat Generation

Chemical reaction and heat source/sink effect on magnetonano Prandtl-Eyring fluid peristaltic propulsion in an inclined symmetric channel

The main emphasis of this article is to examine the peristaltic transport of magnetohydrodynamic (MHD) Prandtl-Eyring nanofluid in an inclined symmetric channel with compliant walls. Nanofluid including thermophoresis and Brownian motion is taken into account. Two-dimensional governing equations for the peristaltic motion of Prandtl-Eyring nanofluid are modeled in the presence of chemical reaction. The resulting dimensionless nonlinear system is numerically solved for velocity, temperature, and concentration. The effects of various dimensionless parameters on fluid flow are featured through graphs. This analysis reveals that the influence of wall tension and wall mass parameters on axial velocity are increasing whereas the impact of wall damping parameter on velocity is decaying. The opposite effect of thermophoresis parameter and Brownian motion parameter on both temperature and heat transfer coefficient are observed. The destructive chemical reaction causes decay in temperature, nanoparticle concentration, and heat transfer coefficient.

P604 Can we reduce intravenous monoclonal antibody observation times without compromising patient safety? A single centre retrospective observational study

Abstract Background Monoclonal antibodies (MAbs) are integral to inflammatory bowel disease (IBD) management. The administration of intravenous (IV) MAbs, infliximab and vedolizumab, for Brighton and Sussex University Hospital patients is via an outpatient clinic. Licensing specifies lengthy observation times; infliximab for induction (infusion 1 to 3) and maintenance (infusion 4 onwards) requires 1 to 2 h observation. Vedolizumab for induction (infusion 1 to 2) requires 2 h observation and maintenance (infusion 3 onwards) 1-h observation. This can affect waiting times; 33% UK patients waited longer than two weeks for infliximab. A reduction in observation times could improve capacity but needs to be done without compromising patient safety. Methods A single centre observational study was conducted. Retrospective data were collected on all current patients receiving infliximab or vedolizumab at BSUH. Data were collected over 12 weeks (April to July 2019); patients seen twice in this period were included once. The presence of reaction from current and previous infusions was determined by patient questioning and patient records review. Reaction occurrence, nature and management were recorded. There is not a grading system for IBD infusion-related reactions. To standardise we used the cancer Common Terminology Criteria for Adverse Events; grade 3 and above is designated severe (grade 5 being death). Results For infliximab 130 patients were reviewed with 2607 infusions administered in total. For vedolizumab 69 patients were reviewed with 557 infusions administered in total. Due to the small sample size significance could not be reached. The survival plot indicates high levels of ‘no reactions’ observed in the first 4 infusions of infliximab 97.7% (+1.6%, -4.7%), and first 3 infusions of vedolizumab 96.9% (+2.3%, −8.8%). Considering capacity over 12 weeks, for infliximab a minimum of 121 could be recouped and 64 h for vedolizumab. Extrapolated this could equate to 740 h per year. Conclusion All reactions occurred within three infusions, were non-severe and managed within the infusion clinic. By removing the observation period from infusion 4 onwards, infusion clinic capacity could be increased but further data from multiple centres are required to prove significance.

Chemical Reaction Influence on General Fluid

This paper focuses on unsteady, two-dimensional, flow boundary layer of a incompressible viscous electrically conducting and absorbing heat fluid along a semi-infinite vertical moving permeable plate in the presence of Chemical reaction and radiation effects. The dimensionless equations are analytically solved using perturbation procedure. The effects of the different flow fluid parameters on velocity, temperature and concentration fields with in the boundary layer have been examined with the help of graphs.

Influence of chemically radiative nanoparticles on flow of Maxwell electrically conducting fluid over a convectively heated exponential stretching sheet

PurposeThis paper aims to examine the influence of radiative nanoparticles on incompressible electrically conducting upper convected Maxwell fluid (rate type fluid) flow over a convectively heated exponential stretching sheet with suction/injection in the presence of heat source taking chemical reaction into account. Also, a comparison of the flow behavior of Newtonian and Maxwell fluid containing nanoparticles under the effect of different thermophysical parameters is elaborated. Velocity, temperature and nanoparticle volume fractions are assumed to have exponential distribution at boundary. Buongiorno model is considered for nanofluid transport.Design/methodology/approachThe equations, which govern the flow, are reduced to ordinary differential equations using suitable transformation. The transformed equations are solved using a robust homotopy analysis method. The convergence of the homotopy series solution is explicitly discussed. The present results are compared with the results reported in the literature and are found to be in good agreement.FindingsIt is observed from the present study that larger relaxation time leads to slower recovery, which results in a decrease in velocity, whereas temperature and nanoparticle volume fraction is increased. Maxwell nanofluid has lower velocity with higher temperature and nanoparticle volume fraction when compared with Newtonian counterpart. Also, the presence of magnetic field leads to decrease the velocity of the nanofluid and enhances the skin coefficient friction. The existence of thermal radiation and heat source enhance the temperature. Further, the presence of chemical reaction leads to decrease in nanoparticle volume fraction. Higher value of Deborah number results in lower the rate of heat and mass transfer.Originality/valueThe novelty of present work lies in understanding the impact of fluid elasticity and radiative nanoparticles on the flow over convectively heated exponentially boundary surface in the presence of a magnetic field using homotopy analysis method. The current results may help in designing electronic and industrial applicants. The present outputs have not been considered elsewhere.

The Impact of Radiation Effect on MHD Stagnation-Point Flow of a Nanofluid over an Exponentially Stretching Sheet in the Presence of Chemical Reaction

The present study is to investigate the effect of the chemical reaction parameter on stagnation point flow of magnetohydrodynamics field past an exponentially stretching sheet by considering a nanofluid. The problem is governed by governing coupled nonlinear partial differential equations with appropriate boundary conditions. The transformed non-dimensional and coupled governing ordinary differential equations are solved numerically using the fourth order Adams-Bashforth Moulton method. The effects of various dimensionless parameters on velocity, temperature and concentration fields are studied and then the results are presented in both tabular and graphical forms.

Thermo-Diffusion and Multi-Slip Effect on an Axisymmetric Casson Flow over a Unsteady Radially Stretching Sheet in the Presence of Chemical Reaction

The objective of this article is to investigate the impacts of thermo-diffusion effect on unsteady axisymmetric Casson flow over a time-dependent radially stretching sheet with a multi-slip parameter and the force of chemical reaction. We employed an established similarity transformation to this non-linear partial differential system to convert it into a system of ordinary differential equations. The numerical results are attained for this system by using KELLER-BOX implicit finite difference scheme. It has great reliability and accuracy even a very short time period for computational simulation. The impacts of influential flow parameters on fluid flow are sketched through graphs and the numerical results are thoroughly argued. The temperature, velocity and wall concentration control parameters are analyzed. (i) It is witnessed that chemical reaction is not favorable to enhance the velocity profile. (ii) Multi-slip parameters vary inversely with velocity profile. (iii) The fluid concentration in its boundary layer decreases with the increase of heavier species, the parameter of the reaction rate and the exponent of power law for fluids having Prandtl number = 10.0, 15.0, 20.0 and 25.0. Moreover, the skin-friction-coefficient factor and Nusselt-number are compared with the published work. A strong numerical solution agreement is being observed.

Soret and Dufour Effects on MHD Convective Flow Past a Vertical Plate Through Porous Medium

The objective of the present paper is to investigate the soret and dufour effect of Kuvshinshiki fluid on MHD free convection flow past a vertical porous plate with heat and mass transfer in the presence of chemical reaction. The velocity, temperature and concentration are obtained by using a perturbation technique. The results have been discussed graphically and numerically for various values of the flow parameters by using Matlab.

Free Radiation and Mass Transfer Effects on Mhd Convection Flow Along a Moving Vertical Porous Plate with Suction And Chemical Reaction in Presence of Soret and Dufour Effects

The paper discusses the take a look at of the Radiation and chemical response of the moving vertical permeable plate embedded in a permeable medium at the MHD boundary layer by taking into consideration the impacts of Soret and Dufour and the heat source. Equations supervise the flow are coupled andunraveled numerically utilizing Runge - Kutta fourth request strategy and Newton Raphson shooting method. The impact of different controlling Parameters on the speed, temperature, cognizance, pores and skin-rubbing coefficient, Nusselt range and Sherwood range are pointed out in detail. The findings are compared with available data obtained through analytical procedures and found to be in concurrent with the latter.

Effects of Chemical Reactions on the Local Hydrodynamics in Slurry Bubble Column Reactors Operating under Typical Fischer-Tropsch Process Conditions – Ii

AbstractOur rigorously validated Computational Fluid Dynamics (CFD) model (Basha et al. 2016) was previously used to predict the effects of gas sparger designs and internals configurations on the local hydrodynamics in a pilot-scale and a conceptual large-scale slurry bubble column reactors (SBCRs) (Basha and Morsi 2018). In this study, the CFD model was used to predict the effect of incorporating the F-T reaction kinetics on the local hydrodynamics in the pilot-scale (0.3-m ID, 3-m height) and the overall performance of the pilot-scale and an industrial-scale (5.8-m ID, 42-m height) SBCRS, both operating under F-T conditions with iron catalyst.In the pilot-scale SBCR, the CFD simulations were carried out with catalyst concentrations of 5, 10 and 15 vol% and three H2/Co ratios of 1, 1.5 and 2, at temperature of 443 K, pressure of 20.5 bar and a superficial gas velocity of 0.24 m/s. The predictions showed that the presence of chemical reactions decreased the gas holdup and the Sauter mean bubble diameters along the reactor height by an average of 15.4 % and 17.63 %, respectively and strengthened the liquid circulations near the reactor wall. The predictions also showed that the CO and H2conversions increased with increasing the catalyst concentration, and the pilot scale SBCR could produce a maximum of 1.87 tons/day of C5+products at a catalyst concentration of 15 vol%.In the commercial-scale SBCR, the CFD simulations were conducted at a catalyst loading of 10 vol% at a temperature of 528 K, pressure of 29 bar and four superficial gas velocities of 0.12, 0.24, 0.3 and 0.4 m/s. The calculations were completed, however, the contours of the local hydrodynamics were not extracted due to computational and memory limitations associated with generating graphics of such a large and complex reactor geometry. The predictions showed that the CO conversions were 48 %, 59 %, 58 % and 55 %; the H2conversions were 36 %, 51 %, 56 % and 54 % and the C5+products yields were are 275, 576, 627 and 654 ton/day at the superficial gas velocities of 0.12, 0.24, 0.3 and 0.4 m/s, respectively. When comparing the CFD model predictions with those of the 1-D empirical model developed by Sehabiague et al. (Sehabiague et al. 2015) at a superficial gas velocity of 0.24 m/s and catalyst loading of 10 %, the CFD model was found to predict lower CO conversion, higher H2conversion and higher C5+yield.

Finite Element Simulation of Multiple Slip Effects on MHD Unsteady Maxwell Nanofluid Flow over a Permeable Stretching Sheet with Radiation and Thermo-Diffusion in the Presence of Chemical Reaction

The aim of the present study is to investigate the multiple slip effects on magnetohydrodynamic unsteady Maxwell nanofluid flow over a permeable stretching sheet with thermal radiation and thermo-diffusion in the presence of chemical reaction. The governing nonlinear partial differential equations are transformed into a system of coupled nonlinear ordinary differential equations with the aid of appropriate similarity variables, and the transformed equations are then solved numerically by using a variational finite element method. The effects of various physical parameters on the velocity, temperature, solutal concentration, and nanoparticle concentration profiles as well as on the skin friction coefficient, rate of heat transfer, and Sherwood number for solutal concentration are discussed by the aid of graphs and tables. An exact solution of flow velocity, skin friction coefficient, and Nusselt number is compared with the numerical solution obtained by FEM and also with numerical results available in the literature. A good agreement between the exact and numerical solution is observed. Also, to justify the convergence of the finite element numerical solution, the calculations are carried out by reducing the mesh size. The present investigation is relevant to high-temperature nanomaterial processing technology.

Thermal-diffusion and diffusion-thermo effects on squeezing flow of unsteady magneto-hydrodynamic Casson fluid between two parallel plates with thermal radiation

Present numerical study examines the heat and mass transfer characteristics of unsteady magneto-hydrodynamic squeezing flow of Casson fluid between two parallel plates with viscous and Joule dissipation effects in the presence of chemical reaction. The influence of Soret and Dufour parameters on squeezing flow is investigated along with thermal radiation and heat source/sink effects. The heat and mass transfer behaviour of squeezing flow is analysed by considering the rheological Casson fluid model. The present physical problem is governed by the set of nonlinear coupled time-dependent partial differential equations (PDEs). The method of similarity transformation approach is used to reduce the system of PDEs to a system of nonlinear ordinary differential equations (ODEs). Further, the Runge–Kutta fourth order integration scheme with shooting method (RK-SM) is used to solve the reduced ODEs. Numerical computations are performed for different sets of control parameters. The non-Newtonian flow behaviour of Casson fluid is presented in terms of graphs and tables. It is remarked that the temperature field is enhanced for increasing values of Hartmann number. Also, increasing Casson fluid parameter increases the velocity field. Concentration field is diminished for enhancing values of Soret parameter. Finally, the comparison between present similarity solutions and previously published results shows the accuracy of the current results.

ВЛИЯНИЕ КИСЛОРОДА В НАТРИИ НА ПРОНИЦАЕМОСТЬ НАТРИЯ В СТАЛЬ

And widely used on the nuclear power plants (NPP) sodium is the most studied. The vital issue limiting its application is powerful exothermic interaction with water. Temperature of a torch of burning of sodium at contact with water vapor reaches 1600 K. The problem of protection of steel tubes against destruction at emission of water vapor in sodium is solved by timely detection of a small leak today. Generally in contact with sodium threefold oxides are stable. Penetration of sodium into steel leads to damage of structural material in the presence of chemical reaction with formation of ferro-chromates of sodium and is defined by oxygen level in sodium of existence of these compounds. Formation of compounds of sodium with iron and chrome in steel at its contact with sodium hydroxide submits to dependence on time in degree 0.5 that testifies to the diffusive mechanism of interaction. Penetration of sodium into steel 10X18H9, 10X18H10T with formation of the Na (FexCr1-x)O2 compound on a surface there were also zones with the volume structure aligned (α) in deeper layers as a result of contact with NaOH during 6 h at 1000 K made about 250 microns. At the same time, NaCrO2 on the surface of chrome for lack of iron does not exceed 30 microns and has anticorrosive properties and also high electrical resistance (about 1 megohm). It is shown that the distilled sodium gets in steel 10X2M and 10X18H10T at 923 and 1023 K to for 500 h on depth less than 2 microns, i.e. it is occluded in blankets and has no significant effect on properties of steel.

Phase transformations in metastable liquids combined with polymerization.

This paper is concerned with the theory of nucleation and growth of crystals in a metastable polymer melt with allowance for the polymerization of a monomer. A mathematical model consisting of the heat balance equation, equations governing the particle-radius distribution function and the polymerization degree is formulated. The exact steady-state analytical solutions are found. In the case of unsteady-state crystallization with polymerization, the particle-size distribution function is determined analytically for different space-time regions by means of the Laplace transform. Two functional integro-differential equations governing the dimensionless temperature and polymerization degree are deduced. These equations are solved by means of the saddle-point technique for the evaluation of a Laplace-type integral. The time-dependent distribution function, temperature and polymerization degree at different polymerization rates and nucleation kinetics are derived with allowance for the main contribution to the Laplace-type integral. In addition, the general analytical solution by means of the saddle-point technique and an example showing how to construct the analytical solutions in particular cases are given in the appendices. The analytical method developed in the present paper can be used to describe the similar phase transition phenomena in the presence of chemical reactions. This article is part of the theme issue 'Heterogeneous materials: metastable and non-ergodic internal structures'.

Entropy optimization in flow of Williamson nanofluid in the presence of chemical reaction and Joule heating

Flow of Williamson nanofluid over a stretching sheet is addressed. Entropy generation is modeled by second thermodynamics law. Present model examines the momentum, heat, mass and entropy generation. Joule heating, viscous dissipation and chemical reaction are considered in the modeling. Fluid is conducting electrically through applied magnetic field. Optimal homotopy analysis method is implemented for the solutions. Series solutions convergence by residual errors is ensured. Outcomes of magnetic parameter. Prandtl number, Brownian motion, chemical reaction parameter, thermophoresis and Brinkman number are examined. Moreover coefficient of skin friction and heat transfer rate (Nusselt number) are computed and examined. Heat transfer rate by Brownian parameter is increased. Furthermore entropy generation rate increases for higher magnetic parameter.

Three-component chemical model of nonideal plasma: accounting for interparticle interaction corrections in the presence of chemical reactions

Three-component chemical model of nonideal plasma: accounting for interparticle interaction corrections in the presence of chemical reactions

Heat and Mass Transfer of MHD Stretched Nanofluids in the Presence of Chemical Reaction

Heat and Mass Transfer of MHD Stretched Nanofluids in the Presence of Chemical Reaction

The study of MHD Nano fluid flow with chemical reaction along with thermophoresis and Brownian motion on boundary layer flow over a linearly stretching sheet

The two-dimensional steady boundary layer flow, of a nanofluid past a stretching sheet with a convective boundary condition in the presence of chemical reaction has been studied. The equation of volume fraction concentration consists of the Brownian motion and the thermophoresis effects. The governing equations are simplified via boundary value approximation and some similarity variables and solved using the Runge-Kutta fourth order method with shooting technique and homotopy perturbation method (HPM) with Pad� approximation (HPM-Pad�). All the salient parameters on the temperature and concentration profiles have been studied and details are given graphically. Thus the results found in this study are being compared with the previously published study, where an excellent agreement is achieved. As presented on tables. It is found that the reduced Nusselt number is a decreasing function of both generative and destructive chemical reaction γ. While the reduced Sherwood number is a decreasing function when chemical reaction parameter, γ0.

Radiation Effect on MHD Stagnation-point Flow of a Nanofluid over an Exponentially Stretching Sheet in the Presence of Chemical Reaction

The effect of chemical reaction parameter on magnetohydrodynamic boundary layer flow of nanofluid past an exponentially stretching sheet is presented. An appropriate set of similarity transformations are used to transform the governing partial differential equations (PDEs) into a system of nonlinear ordinary differential equations (ODEs). The resulting system of ODEs is solved numerically by using the 4th order Adam’s - Moultan method along with shooting technique. The numerical results are analyzed by graphs for different parameters which appear in the solution affecting the MHD mixed convection stagnation point.