Effect Of Reaction Research Articles

Electrically conducting mixed convective nanofluid flow past a nonlinearly slender Riga plate subjected to viscous dissipation and activation energy

This paper reports the mass and energy transmission characteristics of an electrically conducting mixed convective nanofluid flow past a stretching Riga plate. An additional effect of viscous dissipation, Arrhenius activation energy and heat source is also studied. The energy and mass transmissions are evaluated by a zero-mass flux of nanoparticle and convective boundary conditions. Buongiorno’s relations are proposed for the Brownian motion and thermophoretic diffusion. The similarity substitutions are employed to derive the non-dimensional set of modeled equations. The obtained set of equations is numerically processed via parametric continuation method (PCM). Several flow factors affecting the velocity, energy, and mass distributions are graphically discussed. It has been perceived that the fluid velocity field declines with the influence of velocity power index (m), while improves with the upshot of modified Hartmann number (Q). The effect of Schmidt number and chemical reaction diminishes the concentration profile [Formula: see text]. Furthermore, the energy curve enhances with the effect of thermophoresis factor, Biot and Eckert number.

Numerical study on transient coke deposition and heat transfer characteristics of hydrocarbon fuel in a mini-channel under varying wall heat flux

Dynamic coke deposition has significant influence on flow and heat transfer characteristics of regenerative cooling using hydrocarbon fuel. In the present work, the effect of coke deposition on flow and heat transfer performance of hydrocarbon fuel, n-Decane is numerically investigated under different heating modes including the constant heat flux (CHF), the periodic heat flux (PHF) and staged heat flux (SHF). The results show that as the heating mode varies from CHF to SHF, locally high temperature zones are formed. The flow field structure is varied by dynamic heating condition and coke deposition. The reaction rate of n-Decane also varies periodically with heat flux, resulting in an irregular “S” shaped density distribution. The two main coke precursors i.e., propylene and aromatics are highly sensitive to temperature due to secondary reactions. The thickness of coke deposition increases significantly with time regardless of the heating modes, which indicates that coke deposition process is irreversible. Compared with CHF heating mode, the thickness of coke deposition increases by nearly 25% for the SHF heating mode. Coking mechanism undergoes transition from catalytic coke to lateral coke with increasing temperature. For the CHF heating mode, the heat transfer coefficient increases from 1200 W/(m2·K) to 4400 W/(m2·K) along the flow direction. The PHF and SHF heating modes render higher Nusselt number and heat transfer coefficient than the CHF heating mode as the periodically varying wall heat flux results in locally higher heat flux and smaller temperature difference between the fluid and solid zones. In addition, the thermal conductivity and flow velocity in the regenerative cooling channel are also enhanced for the PHF and SHF heating modes. However, coke deposition leads to serious heat transfer deterioration for PHF and SHF with a decrease of up to 13% in heat transfer coefficient adjacent to the outlet section of the cooling channel. The new heat transfer correlation considering chemical reaction and coke deposition effects of supercritical hydrocarbon fuel is established for different wall heating conditions.

Magnetohydrodynamic stagnation point flow of Williamson hybrid nanofluid via stretching sheet in a porous medium with heat source and chemical reaction

The stagnation point flow of non-Newtonian fluids has several engineering and industrial applications. In this article, we considered the investigation of the magnetohydrodynamic stagnation point flow of Williamson hybrid nanofluid with chemical reaction and energy generation effects over a porous extending sheet. Similarly, the characteristics of radiation and convective boundary conditions are also taken. Presumptions of boundary layer movement of Williamson hybrid nanofluid facilitate the simplification of the essential mathematical equations for the conservation of mass, energy, momentum and concentration. By introducing the similarity variables, the controlling partial differential equations have been transformed into dimensionless ordinary differential equations. Then, the most effective homotopy analysis method is used to approximate the solutions of reduced ordinary differential equations. Graphical calculations are carried out for hybrid nanofluid [Formula: see text] and nanofluid [Formula: see text]. To investigate the impacts of leading parameters, graphs for the quantities are generated. At the boundary, the local skin friction factor, the Sherwood number and the Nusselt number are also determined. According to the outcomes, it is discovered that when the porosity parameter increases the velocity profile of the hybrid nanofluid [Formula: see text] climbs above that of the nanofluid [Formula: see text]. An increase in thermal radiation parameter and Biot number causes a greater thickness of the thermal boundary layer, which in turn raises the temperature of the hybrid nanofluid. Furthermore, the increased chemical reaction decreases the concentration in both [Formula: see text] hybrid nano liquid and [Formula: see text] mono nanofluid cases.

Slip and chemical reaction effects on the peristaltic rheology of a viscoplastic liquid in different wave frames: application of a high-permeability medium

Slip and chemical reaction effects on the peristaltic rheology of a viscoplastic liquid in different wave frames: application of a high-permeability medium

Evaluation of homogeneous-heterogeneous chemical response on Maxwell-fluid flow through spiraling disks with nonlinear thermal radiation using numerical and regularized machine learning methods

ABSTRACT The present study addresses the effects of nonlinear thermal radiation and heat fall/rise on the thermal radiated viscoelastic fluid flow through spiraling disks with a homogeneous and heterogeneous chemical response. The properties of the Cattaneo-Christov heat flux model, a revised model of conventional Fourier’s law that predicts thermal relaxation properties, are examined in detail. The rotation of both the disks in the same and opposite directions is evaluated. The effect of heterogeneous-homogeneous chemical reactions is also considered in the present communication, making the study reasonably adaptable. The coupled partial differential equations, such as energy, momentum, and concentration, are transformed into ordinary differential equations by von Kármán variables. The outcomes of the present work confirm that flow behavior is reversed due to stretching action. Velocity and pressure profiles are reduced with the impact of Deborah’s number. In addition, it is noticed that increasing heterogeneous-homogeneous reaction parameters decreases the fluid concentration. Numerically computed values are compared with the predicted results using L.R. regularized L.R. and regularized S.V.R. It is observed that the regularized L.R. method outperformed the other two machine learning methods. Graphical illustrations of axial, radial, and tangential flows and concentration and temperature profiles are illustrated in graphs.

RISMiCal: A software package to perform fast RISM/3D-RISM calculations.

Solvent plays an essential role in a variety of chemical, physical, and biological processes that occur in the solution phase. The reference interaction site model (RISM) and its three-dimensional extension (3D-RISM) serve as powerful computational tools for modeling solvation effects in chemical reactions, biological functions, and structure formations. We present the RISM integrated calculator (RISMiCal) program package, which is based on RISM and 3D-RISM theories with fast GPU code. RISMiCal has been developed as an integrated RISM/3D-RISM program that has interfaces with external programs such as Gaussian16, GAMESS, and Tinker. Fast 3D-RISM programs for single- and multi-GPU codes written in CUDA would enhance the availability of these hybrid methods because they require the performance of many computationally expensive 3D-RISM calculations. We expect that our package can be widely applied for chemical and biological processes in solvent. The RISMiCal package is available at https://rismical-dev.github.io.

A NUMERICAL STUDY ON MHD FLOW OF A CASSON FLUID PASSING THROUGH A VERTICAL CONE WITH SUCTION VELOCITY AND THERMO-DIFFUSIVE EFFECTS.

A mathematical model is developed for an unsteady MHD flow of a Casson fluid passing through a vertical cone with the effect of chemical reaction, thermal radiation, thermos-diffusive ef-fects and additionally with the influence of suction velocity. The non-dimensional governing equation of the fluid problem are solved numerically by fi-nite difference method. Numerical solution of ve-locity, temperature, and concentration along with the influence of different parameters are obtained and their nature is described graphically. The re-sults of the study indicate a considerable effect of parameters on velocity, temperature, concentra-tion. The rate of heat and mass transfer along with skin friction has also been influence by the existing parameters.

Chemical reaction effect across the moving flat plate with heat generation and MHD flow of Maxwell fluid with viscous dissipation

In this paper, the investigation centered on examining a Maxwell fluid’s convective double diffusive flow carefully considers factors such as chemical reactions, radiation, and the presence of a permeable moving flat plate. Additionally, the study encompassed the effects of heat generation and magnetohydrodynamics (MHD). The governing equations, initially expressed as partial differential equations, were converted into ordinary differential equations using a similarity transformation technique to facilitate the analysis. The computational power of MATLAB’s BVP4C software was harnessed to solve this resultant system of ODEs efficiently. The outcomes of this investigation were presented in the form of graphical representations that vividly depicted the behavior of the flow field, energy conservation, and concentration profiles under various parameter combinations. The research findings were thoughtfully summarized in a table, offering a comprehensive overview of temperature, velocity, and mass profiles across various parameters. These parameters included the Deborah number, chemical reaction rate, Eckert number, Lewis number, Prandtl number, porosity parameter, and MHD parameter. A notable discovery emerging from this study was the inverse relationship observed between nondimensional concentration contours and the magnitude of the chemical reaction rate. Simultaneously, it was observed that higher values of the Maxwell fluid led to a rise in the thickness of the temperature boundary layer. These findings offer valuable insights into the intricate interplay of physical and chemical phenomena in convective flows involving complex fluid properties and boundary conditions. The temperature outline diminishes as the heat generation rate increases, while the concentration profile declines with an elevation in the chemical reaction rate.

The effect of chemical reaction on thermo-solutal magneto-convection under non-equilibrium temperature conditions

The effect of chemical reaction on thermo-solutal magneto-convection under non-equilibrium temperature conditions

Numerical study of film cooling in single-element injector gaseous CH4/O2 rocket engine with coupled wall function

The investigation of film cooling in CH4/O2 rocket engines holds paramount importance in the advancement of rocket propulsion. However, the wall heat flux is always overestimated in numerical simulation processes. Hence, this article proposes a numerical framework that employs the Reynolds averaged Navier–Stokes method to simulate the single-element gaseous CH4/gaseous O2 combustion chamber, which is the basis for rocket engine simulations. The coupled wall function that considers chemical reaction effects is introduced to enhance the accuracy of wall heat flux prediction. The impact of utilizing a coupled wall treatment on the prediction of wall heat flux and its fundamental parameters are examined. In addition, a single-element combustion chamber experiment is performed to validate the simulation. The results demonstrate that the implementation of the coupled wall function hardly influences the main flow characteristics, whereas the wall heat flux calculated with general wall functions shows an overestimation, which can be reduced by the coupled wall function. Finally, the case with a coupled wall function can improve the cooling efficiency with greater accuracy and the cooling systems with optimized design. The proposed numerical framework and the findings of the study provide profound insights that can improve the design and optimization of rocket engines.

Computer Simulation of Heat and Mass Transfer Effects on Nanofluid Flow of Blood Through an Inclined Stenosed Artery With Hall Effect

Abstract The present study deals with the analysis of heat and mass transfer for nanofluid flow of blood through an inclined stenosed artery under the influence of the Hall effect. The effects of hematocrit-dependent viscosity, Joule heating, chemical reaction and viscous dissipation are taken into account in the governing equations of the physical model. Non-dimensional differential equations are solved using the finite difference method, by taking into account the no-slip boundary condition. The effects of different thermophysical parameters on the velocity, temperature, concentration, shear stress coefficient and Nusselt and Sherwood numbers of nano-biofluids are exhaustively discussed and analysed through graphs. With an increase in stenosis height, shear stress, the Nusselt number and the Sherwood number are computed, and the impacts of each are examined for different physical parameters. To better understand the numerous phenomena that arise in the artery when nanofluid is present, the data are displayed graphically and physically described. It is observed that as the Hartman number and Hall parameter increase, the velocity drops. This is as a result of the Lorentz force that the applied magnetic field has generated. Blood flow in the arteries is resisted by the Lorentz force. This study advances the knowledge of stenosis and other defects’ non-surgical treatment options and helps reduce post-operative consequences. Moreover, ongoing research holds promise in the biomedical field, specifically in magnetic resonance angiography (MRA), an imaging method for artery examination and anomaly detection.

Sensing of magnetic field effects in radical-pair reactions using a quantum sensor

Magnetic field effects (MFE) in certain chemical reactions have been well established in the last five decades and are attributed to the evolution of transient radical pairs whose spin dynamics are determined by local and external magnetic fields. The majority of existing experimental techniques used to probe these reactions only provide ensemble averaged reaction parameters and spin chemistry, hindering the observation of the potential presence of quantum coherent phenomena at the single molecule scale. Here, considering a single nitrogen-vacancy (NV) center as quantum sensor, we investigate the prospects and requirements for the detection of MFEs on the spin dynamics of radical pairs at the scale of a single and small ensembles of molecules. We employ elaborate and realistic models of radical pairs, considering their coupling to the local spin environment and the sensor. For two model systems, we derive signals of MFE detectable even in the weak coupling regime between a radical pair and an NV quantum sensor and observe that the dynamics of certain populations, as well as coherence elements, of the density matrix of the radical pair are directly detectable. Our investigations will provide important guidelines for the potential detection of spin chemistry of biomolecules at the scale of a single and small ensembles of molecules. Published by the American Physical Society 2024

Fluid sustainability by the effect of microrotational flow and chemical reactions in a vertical channel

ABSTRACT The analysis of fluid sustainability and mass transfer features is an important research subject in mathematics, physics, and engineering science. Also, the traditional discipline of fluid dynamics gains a new dimension with the introduction of the idea of microrotational flow, which is the localized circulation of fluid around a rotating axis. The incorporation of this innovative approach with chemical interactions in a vertical channel offers significant potential for developing the study of fluid sustainability. This work investigates the dynamics of microrotational flow and chemical reactions using the numerical techniques. Thus, the present analysis examines the sustainability of fluid flow by combining microrotation and chemical reaction impacts. The proposed mechanism is mathematically expressed using the governing equations and the nonlinear coupled equations are solved analytically with suitable walls and conditions of the interface. The obtained solutions exhibit the nature of different parameters for the microrotational flow, velocity, and concentration fields. The findings are graphically shown and noted that the vortex viscosity parameter increases the microrotation flow speed and reduces the fluid velocity. Thermal Grashof number enhances the fluid flow. The presence of a chemical reaction parameter suppresses the fluid flow. Furthermore, the achieved solutions are in good agreement with the earlier literature.

Improving the prediction of elemental sulfur solubility in sour gas mixtures by modifying cubic equations of state

So far, several correlations have been developed to forecast the solubility of sulfur in various mixtures of acid gases with different concentrations of hydrogen sulfide. These correlations are correlative methods requiring experimental sulfur solubility data to tune their model parameters. Besides, correlative methods have many restrictions and are useable only for a limited range of operating conditions. Another approach for predicting sulfur solubility is applying equations of state. The predictive ability of equations of state has made them a powerful tool to more accurately perform the equilibrium phase calculations of acid gas mixtures in a vaster operating range. The major problem of the equations of state is the inaccurate characterization of their parameters for elemental sulfur due to its chemical complexity. In this study, the performance of three cubic equations of state is evaluated for forecasting the solubility of elemental sulfur in different acid gas mixtures. The main idea which is supposed to be put forward for rectifying defects of cubic equations of state is to model the trend of errors propagated in predicting the solubility of sulfur. Indeed, the effect of sulfur chemical reactions is ignored, and a generalized correction function is developed to compensate for deviations arising from the simplification assumptions. Subsequently, the results predicted by modified equations of state are compared to experimental sulfur solubility data and previously existing methods. Finally, a case study is performed on a sour gas reservoir sample to predict precipitation P-T curve and to calculate sulfur solubility changes with the pressure and temperature reduction throughout the gas well. Predicted results revealed the proposed correction function could significantly decrease the solubility calculations obtained from the modified equations of state under 5.6%, which is a good achievement compared to their original versions.

Numerical computation of magnetic field with melting heat and homogeneous-heterogeneous chemical reaction effects on oblique stagnation flow of variable viscosity micropolar Fe3O4 nanofluids

The complex micro-structural characteristics of electro-conductive sol gel materials require simultaneous consideration of magneto-hydrodynamics, micro-rheology and also physico-chemical phenomena. In this editorial, a mathematical model is therefore developed to simulate the steady-state, oblique (non-orthogonal) stagnation flow of electro-conductive micropolar magneto-nano-liquid flow impacting on an extending horizontal plane under the impact of transverse magnetic field. To capture the sophisticated physico-chemistry, the simultaneous presence of homogeneous and heterogeneous chemical reactions is considered. Viscosity depending upon temperature is taken into consideration with Reynolds’ exponential model. Tiwari-Das and Maxwell-Garnett nano-liquid models are deployed which modifies density, thermal conductivity and electrical conductivity with volume fraction of nano-sized particles.

Catalytic effects on peristaltic flow of Jeffrey fluid through a flexible porous duct under oblique magnetic field: Application in biomimetic pumps for hazardous materials

Homogenous and heterogeneous reactions play an essential role in polymer production, combustion, ceramic production, catalysis, distillation, and biochemical procedures. As a result of this advancement, a mathematical model is developed to examine the role of catalytic chemical reaction effects on the magneto-hydrodynamic peristaltic transport in a flexible divergent duct containing a non-deformable porous medium as a model for complex hazardous waste bio-inspired pumping mechanisms. The Jeffrey model is utilized to simulate strong non-Newtonian characteristics. Additional multi-physical features included in the model are heat generation, thermal radiation, Hall current, and complaint wall properties along with an inclined (oblique) magnetic field. The long wavelength and low Reynolds number approximations are deployed to transform the primitive conservation equations from a moving boundary problem to a fixed frame. Appropriate transformations are then utilized to render the model dimensionless. The exact solutions are obtained for stream function and velocity. Further, the R-K-Fehlberg integration scheme is applied to solve the energy and concentration equations. Velocity, temperature, concentration, skin friction, and Nusselt number profiles are visualized graphically. Streamline patterns are also included to capture bolus dynamics. Validation with previous simpler studies has been included. A detailed appraisal of key control parameters on transport characteristics is conducted. It is found that velocity is suppressed with elevation in the damping force parameter while it is enhanced with an increment in regime permeability i. e. Darcy number. Both homogeneous and heterogeneous reactions are observed to exert a significant impact on the species concentration. The volume of the trapped fluid bolus size is shown to be an increasing function of the peristaltic wave amplitude ratio. The present work generalizes existing studies to consider catalytic effects on dissipative peristaltic pumping of the Jeffrey fluid with heat generation and radiative flux, aspects which have been neglected in a single model previously. The simulations are relevant to better characterize the complex transport phenomena in nuclear reactor waste transport via biologically inspired pumping designs.

Darcy-Forchheimer nanofluid flow and heat transfer with convective boundary conditions: Insights from differential transform method

In this work, we use the sophisticated differential transform method (DTM) to derive solutions to the complicated momentum, heat, and mass transfer equations that characterize Darcy-Forchheimer nanofluid flow over a stretching surface with convective boundary conditions. The investigation includes the nuanced effects of heat sources and chemical reactions and also addresses the synergistic effects of Brownian motion and thermophoresis. By applying an appropriate similarity transformation, the governing partial differential equations (PDEs) are gracefully transformed into an elegant system of nonlinear coupled ordinary differential equations (ODEs), a problem that is ingeniously solved using DTM. The veracity of our results is underpinned by a careful validation against previous scientific work that illuminates the path to scientific clarity. As the mathematical tapestry unfolds, the enchanting interplay of physical parameters on fluid dynamics is revealed, manifesting in visually captivating graphs and illuminating tables. Of particular note is the transformative influence of the magnetic parameter, which stages a ballet in which an increase in skin friction and the Nusselt number causes a diminuendo. Meanwhile, the solutal concentration decreases as the Brownian motion, Lewis number, and chemical reaction parameters increase, while it waltzes in reverse harmony with the thermophoresis parameter. Beyond equations and diagrams, this investigation promises to cast a luminous beacon on practical realms, imparting invaluable insights for industries ensconced in the realm of heat exchangers, the alchemy of lubricant refining processes, and the grand tapestry of scientific and engineering domains.

Magneto-Stefan blow enhanced heat and mass transfer flow in non-Newtonian ternary hybrid nanofluid across the nonlinear elongated surface

The present article explores the flow and heat transfer properties of a non-Newtonian ternary nanofluid over a nonlinear stretched surface by considering magnetic, chemical reaction, and Stefan blow effects. The ternary nanoliquid considered here are of three distinct nanoparticles such as Ag, MoS2, and SiO2 due to their high thermal conductivity, thermal stability and lubricating particles each dispersed in a base fluid (H2O). Using similarity transformations, the governing partial differential equations (PDEs) that describe the flow, heat transfer, and nanoparticle concentration distribution are turned into a system of ordinary differential equations (ODEs). In order to deal with this system, the shooting strategy is utilized – a numerical method renowned for its efficacy in solving nonlinear boundary value problems. Furthermore, the effects of critical parameters such as the Jeffrey parameters, magnetic field strength, Stefan blow parameter, and nanoparticle volume percentage on flow and heat transmission characteristics are comprehensively investigated. It is observed that the velocity field augments when Stefan blow parameter Sb > 0 (mass blowing) and reduces when Sb < 0(mass suction). It is noteworthy to observe that an increase in the Prandtl number (Pr) corresponds to a decrease in the temperature field. The findings of this research possess the potential to provide practical ramifications in diverse technical, biomedical, and industrial sectors, including but not limited to polymer processing and nanomaterial creation. These findings hold significant value in situations where precise control of fluid flow and heat transfer is essential for maximizing overall performance and efficiency.

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.

Chemical Reaction and Dufour Effects on MHD Flow of Cu-TiO2 Nanofluids Past an Unbounded Vertical Porous Moving Plate

The effects of chemical reaction, radiation absorption, diffusion thermo on MHD free convective flow of a nanofluid bounded by porous medium past a semi-infinite flat plate are analyzed. The plate is moved with a constant velocity, temperature and the concentration are assumed to be fluctuating with time harmonically from a constant mean at the plate. The solutions of the governing equations are evaluated by using the perturbation technique. We have considered the nano-fluids namely Cu-water and TiO2-water nanofluids. The effects of governing flow parameters on velocity, temperature and concentration are discussed through graphs. For engineering interest, we evaluated the skin friction, Nusselt number and Sherwood number and computationally discussed.