Effect Of Reaction Research Articles

Direct Numerical Simulation of Nonequilibrium Effects on Decaying Isotropic Turbulence

The Direct Numerical Simulation of decaying isotropic turbulence is performed with nonequilibrium effects. Oxygen is used as the test gas in the simulations. The individual and combined effects of vibrational relaxation and chemical reactions are studied by considering four different simulation cases. The time evolution of mean thermodynamic properties and turbulent statistics is analyzed. Budgets for turbulent kinetic energy and mean internal energy are computed to explain the dynamics of energy exchange associated with different nonequilibrium effects. The time evolution of enstrophy and turbulent length scales is also studied. The dissociation reaction is found to significantly affect the evolution of mean thermodynamic quantities as well as turbulence. Vibrational relaxation is found to significantly affect the flow in the presence of chemical reactions. The effects of changing the initial conditions on the resulting flowfield are analyzed.

Chemically reacted blood Cu O nanofluid flow through a non-Darcy porous media with radially varying viscosity

The study investigates the flow of a Newtonian Cu O nanofluid through a non-Darcy porous medium with radially varying viscosity, which is crucial for various industries such as pharmaceuticals, chemicals, nuclear, solar, and solar technologies. The peristaltic motion of the nanofluid is studied with thermal radiation and chemical reaction effects, and the viscosity varies with both radius and axial coordinates. The study assumes low Reynolds and long wavelength assumptions and uses the homotopy perturbation technique to obtain a semi-analytical solution of velocity, temperature, nanoparticle concentration, and skin friction. The results show that axial velocity increases with the increase of slip velocity and viscosity parameters, while wave amplitude and chemical reaction parameters increase while nanoparticle concentration decreases. High viscosity parameters allow fluid nanoparticles to gain more active energy and move more freely, which is the main idea behind crude oil refinement. This physical modeling is essential for physiological flows, such as stomach juice flow during endoscope insertion.

Effect of Dufour and chemical reaction on an unsteady magneto hydrodynamics flow past an exponentially moving plate

AbstractThe aim of the study is to measure the Dufour number effects on the flow patterns and heat transfer in an exponentially accelerated infinite vertical plate embedded in a porous medium in the presence of heat source and chemical reaction. Time‐dependent variations in temperature, velocity, and other factors should be taken into consideration due to the flow's unsteadiness. The fluid considered is a gray, absorbing/emitting radiation but nonscattering medium. Using the finite element method, a set of nondimensionless equations is solved analytically. Results are discussed graphically for concentration, temperature, and velocity profiles. Skin friction, Sherwood number, and Nusselt number are also explained for flow parameters through graphs.

Heat and mass transfer characteristics of Al2O3/H2O and (Al2O3+Ag)/H2O nanofluids adjacent to a solid sphere: A theoretical study

A theoretical study is carried out to explore the heat and mass transfer features in the flow of two types nanofluid, i.e., A l 2 O 3 / H 2 O micropolar nanofluid and ( A l 2 O 3 + Ag ) / H 2 O hybrid nanofluid, adjacent to a solid sphere. Furthermore, simultaneous effects of linear thermal radiation and chemical reaction are also explored on the heat and mass transfer characteristics. In mathematical formulation basic conservation laws are utilized along with the Soret and Doufer effects as a coupling agents in the energy and mass concentration equations. The normalized variables are used to transform the governing system of non-linear partial differential equations into the system of dimensionless partial differential equations. Stream function reduces the number of dependent variables and the resulting system is solved numerically by Keller box method. Several plots are presented to explore the impact of involved parameters on the different profiles and engineering interest quantities for both types of fluids. The temperature profile and Nusselt number are large in magnitude for hybrid nanofluid as compared to A l 2 O 3 /water based nanofluid. The heat transfer and mass transfer rates rises with thermal radiation parameter and chemical reaction parameter, respectively.

Heat and mass transfer phenomena for fractal interfacial layer model on metallic-nanomaterials nanofluids flow with chemical reaction effect

This study presents a comprehensive investigation into the intricacies of single-phase simulation concerning the behavior of fractal interfacial magnetized metallic chemical-reactive nanoparticles within fluid systems. The research focuses on unraveling the multifaceted phenomena associated with heat and mass transfer in complex nanoscale environments. To achieve this, we employ numerical techniques to address the intricate fluid flow problems that arise due to the presence of these nanoparticles. Fractal complexities are linked to critical phenomena, such as mixing and mass transport, at the turbulent/non-turbulent interface of shear layers and boundary layers. This study primarily concentrates on the phenomena of heat and mass transfer, with a focus on estimating thermal conductivity models that have significant impacts on the flow of metallic nanofluids under convective conditions. The combination of a high thermal conductivity model with a novel interfacial fractal theory reveals a substantial effect on heat and mass transfer enhancement. Furthermore, this research explores hybrid types of porous channel geometries under the combined influence of magnetohydrodynamics and chemical reaction mechanisms in the presence of metallic nanoparticles. A comprehensive numerical analysis of higher-order nonlinear differential equations is conducted, which exposes the flow field’s behavior concerning momentum, energy, and mass transfer. These insights are envisioned through single-phase simulations of nanofluids. The influence of the nanoparticles’ radius and diameter is found to play a significant role in thermal performance, with nanoparticles ranging from 1% to 8% exhibiting a notable impact on thermal conductivity. Highlights A new mathematical relation of mass, as well as heat transfer for metallic-nanomaterial being affected by thermal conductivity (T.C.), has been established. The important role of the physical number is observed under the effect of T.C. and heat and mass transfer through orthogonal porous surfaces. An injection/suction, as well as an expansion/contraction phenomenon related to the porous surface is observed.

Neural networking-based analysis of heat transfer in MHD thermally slip Carreau fluid flow with heat generation

The formulation of heat transfer in non-Newtonian fluid models remains a topic of great interest for researchers. The ultimate flow differential equations in this direction are non-linear and hence difficult to solve analytically. Therefore, we offer state of the art determination of film effectiveness (heat transfer coefficient) by using artificial intelligence (AI). To be more specific, the Carreau fluid model is formulated at a flat surface along with thermal slip, heat generation, velocity slip, chemical reaction, and magnetohydrodynamics (MHD) effects. The developed equations are reduced by the application of the Lie symmetry approach and solved by the shooting method. The artificial neural networking model is built by using 132 sample values of the Nusselt number (NN) as an output. Porosity parameter, Prandtl number, magnetic field parameter, and heat production parameter are all inputs. 92 (70 %) is designated for training, whereas 20 (15 %) is designated for validation and testing. The Levenberg-Marquardt algorithm is used to train the neural network. The constructed artificial neural networking (ANN) is best to predict the NN at a flat surface. It is observed that for large Prandtl numbers, the magnitude of the Nusselt number is greater for porous surface, but the converse is true for magnetic field parameter.

Investigation of Magnetized Casson Nanofluid Flow along Wedge: Gaussian Process Regression

An unsteady two-dimensional magnetized Casson nanofluid flow model is constructed over a wedge under the effect of thermal radiation and chemical reaction. The multiple slip effects are also assumed near the surface of the wedge along with the convective boundary restrictions. This study investigates the application of soft computing techniques to address the challenges posed by the complexity of problem modeling and numerical methods. Traditional approaches incorporating various model factors may struggle to provide accurate solutions. To resolve this issue, Gaussian process regression (GPR) is employed to predict the solution of the proposed flow model. With the help of the numerical shooting method together with Runge–Kutta–Fehlberg fourth-fifth-order (RKF-45) reference data, the GPR model is trained. The numerical simulation illustrated that the Casson fluid parameter β and the unsteadiness parameter S strengthen the friction factor, and the heat transfer rate is enhanced as the radiation parameter Rd becomes larger. In addition, the Biot numbers Bi1 & Bi2 lead to strengthen nanoparticle temperature; an opposite behavior is noticed with the skin friction coefficient S˜fxRex0.5, heat transfer rate H˜tx Rex0.5, and nanoparticle transfer rate C˜txRex0.5. The GPR model with the exponential Kernel function provided better performance than other functions on both training and checking datasets to predict S˜fxRex0.5,H˜tx Rex0.5, and C˜txRex0.5. Statistical metrics including RMSE, MAE, MAPE, MSE, R2, and R are employed to check the accuracy and convergences of the predicted and numerical solutions obtained through GPR and RKF-45. It is observed that all three GPR models had an R2 value of higher than 0.9. The proposed study demonstrates the advantages of employing soft computing methods (GPR) to effectively analyse the behavior of complex flow models.

Study of an unsteady magnetohydrodynamic‐free convective flow under parabolic ramped temperature and concentration in the presence of Soret and heat sink

AbstractThe purpose of this paper is to investigate the effects of Soret, thermal radiation, and chemical reaction on an unsteady magnetohydrodynamic free convective flow past an impulsively initiated semi‐infinite vertical plate with heat sink under parabolic ramped temperature and parabolic ramped concentration. Using some nondimensional parameters, the flow boundary equations in this case are first converted to dimensionless equations. The closed‐form Laplace transform technique is employed here to solve the partial differential equations and get the solutions for fluid velocity, temperature, and concentration. The velocity, temperature, and concentration of the fluid tend to vary with the effect of various flow factors. These changes are graphically represented and analyzed. Differences in skin friction, Nusselt number, and Sherwood number for the different relevant parameters are also recorded. The Soret number hikes the fluid velocity and concentration. The rate of heat transfer, mass transfer, and momentum transfer improves due to the application of parabolic ramped conditions.

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.

Integrating ISPH simulations with machine learning for thermal radiation and exothermic chemical reaction on heat and mass transfer in spline/triangle star annulus

This work integrates incompressible smoothed particle hydrodynamics (ISPH) with machine learning (ML) to examine the uses of two different domain shapes, spline star-domain, and triangle star-domain, on double diffusion of nano-encapsulated phase change material (NEPCM). The effects of thermal radiation and exothermic chemical reactions are conducted in this work. The hexagonal-shaped is located inside the center of the star-shape carrying (Th&Ch). The left/right walls of the star shape are kept at (Tc&Cc) and the other walls have an adiabatic condition. It is recommended to examine the smoothness of closed curves in the heat and mass transfer by changing the triangle to spline curves. The present investigations of transmission of heat and mass of NEPCM within a complicated star shape can be employed in cooling systems of electronic/battery, heat exchangers, food processing, and chemical engineering. The ISPH simulations are executed for the pertinent parameters, Darcy number, Frank-Kamenetskii number, Rayleigh number, Dufour number, Soret number, and thermal radiation parameter. The performed simulations showed the significance of the spline star domain compared to the triangle star domain in smoothening the nanofluid flow and double-diffusive convection in an annulus. Frank-Kamenetskii number is a promising factor in the enhancement of heat transfer and controlling the phase change zone within an annulus. At a spline-star cavity, the maximum velocity rises by 32.32 % and 54.95 % when the Frank-Kamenetskii number grows from 0 to 5, and thermal radiation increases from 0 to 5. Soret number works effectively in enhancing the distribution of concentration at large temperature differences. Machine learning plays a vital role in many engineering applications. Hence, ML's powerful capabilities to predict the average Nu‾ and Sh‾. In the proposed ML model, the dimensionless time and thermal radiation parameter are used as input to the ML model, while their corresponding numeral estimated values of Nu‾ and Sh‾ are used as output targets for the ML model. The values of Nu‾ and Sh‾ are predicted by the suggested ML model with a comparatively small error less than 1 %.

Importance of Activation Energy on Magnetized Dissipative Casson-Maxwell Fluid through Porous Medium Incorporating Chemical Reaction, Joule Heating, and Soret Effects: Numerical Study

In recent decades, the study of non-Newtonian fluids has attracted the interest of numerous researchers. Their study is encouraged by the significance of these fluids in fields including industrial implementations. Furthermore, the importance of heat and mass transfer is greatly increased by a variety of scientific and engineering processes, including air conditioning, crop damage, refrigeration, equipment power collectors, and heat exchangers. The key objective of this work is to use the mathematical representation of a chemically reactive Casson-Maxwell fluid over a stretched sheet circumstance. Arrhenius activation energy and aspects of the magnetic field also have a role. In addition, the consequences of both viscous dissipation, Joule heating, and nonlinear thermal radiation are considered. The method transforms partial differential equations originating in fluidic systems into nonlinear differential equation systems with the proper degree of similarity which is subsequently resolved utilizing the Lobatto IIIA technique’s powerful computing capabilities. It is important to recall that the velocity profile drops as the Maxwell fluid parameter increases. Additionally, the increase in the temperature ratio parameter raises both the fluid’s temperature and the corresponding thickness of the boundary layer.

Effects of second order chemical reaction on MHD forced convection Cu, Ag, and Fe3O4 nanoparticles of Jeffrey Nanofluid over a moving plate in a porous medium in the presence of heat source/sink

Effects of second order chemical reaction on MHD forced convection Cu, Ag, and Fe3O4 nanoparticles of Jeffrey Nanofluid over a moving plate in a porous medium in the presence of heat source/sink

Effect of chemical reaction with heat and mass transfer over an inclined plate

Effect of chemical reaction with heat and mass transfer over an inclined plate

Chemical Reaction Effects on the Flow of Titanium Dioxide–Water in a Mixed Convective Nanofluid along an Inclined Plate in a Porous Medium

An inclined plate is being approached by a mixed convective boundary layer nanofluid flow of titanium dioxide–water through a porous medium. A numerical analysis has been done to investigate the effects of chemical reactions on the considered nanofluid flow. With the aid of a system of governing partial differential equations, a set of nonlinear ordinary differential equations for taking into consideration nanofluid flow have been derived using appropriate matching transformations. The Runge–Kutta method, as well as the Nachtsheim and Swigert Shooting method, is applied to numerically resolve the group of subsequent nondimensionalized equations. The associated numerical result was then successfully compared with the available published literature in a few unique, limited circumstances. Based on the considered nanofluid flow characteristics for heat as well as mass transfer, the effects of the Schmidt number, the permeability, and the chemical reaction parameters of the titanium dioxide–water nanofluid flow have been examined, assessed, and presented for velocity in conjunction with the local skin friction coefficient, temperature in conjunction with the local Nusselt number, as well as concentration in conjunction with the local Sherwood number. Numerical results reveal that the local Sherwood number Sh, as well as the local Nusselt number Nux, increase, whereas the local skin friction coefficient Cf decreases due to the increase in the chemical reaction parameter Krp.

DARCY-FORCHHEIMER FLOW OF A CONDUCTING MICROPOLAR FLUID AT A STRETCHING SHEET WITH CONVECTIVE BOUNDARY CONDITIONS

In this paper we study the Darcy-Forchheimer flow of a magnetohydrodynamic (MHD) micropolar fluid over a stretching surface with convective boundary conditions. The effects of viscous dissipation, thermal radiation, activation energy, and chemical reaction, along with Dufour and Soret effects, are considered and analyzed. By using a suitable similarity transformation, the governing partial differential equations (PDEs) are converted into a system of nonlinear coupled ordinary differential equations (ODEs). The non-linear ODEs are solved numerically by a shooting technique with the bvp5c MATLAB package. The effects of the physical parameters on the velocity, the micro-rotation, the temperature, and the concentration fields are analyzed through graphs and tables. The present results are validated with the results in the existing literature for some special cases. It is observed that an increase in the magnetic strength leads to a decrease in the velocity field. However, the thermal radiation parameter and the Eckert number significantly boost the temperature distribution. The concentration field is improved by the activation energy parameter. We believe that this investigation has a definite bearing to industries such as heat exchangers and lubricant refining process.

MHD Williamson fluid flow on an extending sheet with thermophoresis and chemical reaction

This research investigates the steady, two-dimensional, incompressible flow of a pseudoplastic Williamson fluid subjected to a linearly stretched sheet. The study incorporates the effects of magnetic fields, chemical reactions, and thermophoresis on fluid behavior. By applying boundary layer techniques and similarity transformations, the governing equations are simplified for numerical analysis. The MATLbvp4c solver is employed to solve the reduced equations. The obtained results are visually represented and thoroughly discussed to comprehend the model's physical characteristics. The investigation highlights the magnetic field's influence, chemical reaction, and impact of thermophoresis particle deposition on the flow behavior of Williamson fluid over the extended sheet. Findings: Moreover, significant roles are found for chemical reactions and thermophoresis parameters in determining the fluid concentration near the boundary layer. It is observed that an increase in the chemical reactions and thermophoresis parameters results in a reduced thickness of the fluid concentration near the boundary layer. Notably, an increase in Schmidt value also diminished the thickness of the fluid concentration close to the boundary layer. MHD parameter significantly influences the fluid's velocity and temperature near the surface. It has been noted that an increase in the MHD parameter decreases the fluid?s velocity and increases the temperature near the surface. The impact of skin friction coefficient and Nusselt number and the impact of mass transfer coefficient on Williamson fluid will be discussed. The findings acquired are examined in relation to existing research and the correlation is provide as table.

Computational investigation of chemical and non-equilibrium effects on the Richtmyer–Meshkov instability

In order to study the reactive Richtmyer–Meshkov instability (RMI) at a microscale, we have implemented a direct simulation Monte Carlo (DSMC) method which is recently developed for resolving thermal–chemical processes at the scale of molecular motions. The method allows efficient simulations of polyatomic reactions and non-equilibrium processes without violation of the detailed balance which is generically suffered by the conventional algorithms and leads to failure of local thermal equilibrium eventually. With attainment of essential accuracy, the effects of nonequilibrium and chemical reactions on the evolution of two-dimensional (2D) RMI at the microscale are investigated. The results show that the nonequilibrium effect slows down the heat release of chemical reactions and strengthens the viscous and diffusive effects for the mixture and shock conditions tested, which inhibit the growth of the RM instability. The heat release via combustion, however, can substantially increase the RMI growth due to induced baroclinic torque. Consequently, the intricate coupling of these effects nonlinearly dominates the development of RMI at the microscale. Therefore, the influence of nonequilibrium conditions where the translational energy is higher than that of the internal modes of polyatomic molecules, specifically the vibrational energy, in the post-shock region should be considered. The procedure provides a paradigm for further research in pursuit of accurate evaluation of microscopic processes and the resulted performance in supersonic combustion that plays a key role in the development of hypersonic vehicles.

Influence of pore-crack environment on heat propagation of underground coalfield fire: A case study in Daquanhu, Xinjiang, China

The development of pores and cracks in coalfield fire area promote the abnormal temperature, the greenhouse effect, and the release of toxic gases. It is of great significance to study the dynamic distribution characteristics of temperature field and concentration field of typical gas products in a coalfield fire area under different pore-crack environments for revealing the spreading law of underground coalfield fire. In this paper, the combined effect of coal combustion chemical reaction, heat energy transmission, flue gas seepage and pore-crack environment were considered. Taking Daquanhu coalfield fire area as an example, an optimized multi-field coupling model, which included the chemical reaction of coal combustion, convection heat transfer in cracks, heat transfer in porous media, gas seepage and improved partial differential equation of pore-crack evolution was constructed. The coalfield fires area was divided into combustion zone, caving zone, sagging subsidence zone, crack zone. The evolution law of temperature field, CO2 concentration field in the coalfield fire area under different air leakage and geological crack conditions was analysed. The results showed that the temperature development of coalfield fire is divided into rapid heating stage and stable development stage. At the rapid heating stage, the greater the air leakage flow was, the faster the maximum temperature rise in the combustion zone. At the stable development stage, with the air leakage decreased, the thermal buoyancy increased. The greater the number of cracks was, the greater the area of the drying zone (673.15 K < T < 1073.15 K) closed to the crack zone. The influence of crack environment on heat flux in the sagging subsidence zone and crack zone was obvious. The total heat flow in the crack zone was about 25 times that in the caving zone. The relationship between the maximum temperature in the combustion zone and the CO2 concentration at the crack outlet showed an exponential model (ExpGro1 exponential model). The area spread by coalfield fire increased linearly with the rang of surface temperature abnormal. The research results provided a basis for judging the spread trend of coalfield fire and extracting coalfield fire of heat energy.

Numerical simulation of the thermo-hydro-chemical coupling in enhanced geothermal systems: Impact of SiO2 dissolution/precipitation in matrix and fractures

The hydraulic properties of reservoir matrix and fractures, as well as the production performance of enhanced geothermal systems, can be significantly affected by chemical dissolution and precipitation. Therefore, chemical reaction effects must be considered when exploiting dry hot rock resources. To investigate the impact of chemical effects, this study incorporates the dissolution/precipitation process of silica in the reservoir matrix and fractures and establishes a thermo-hydro-chemical coupling dual-well model that includes a main fracture and multiple secondary fractures. Results indicate that under-saturation injections increase the mechanical aperture of the main fracture by up to 0.066 mm and permeability by up to 217.3 % over a 30-year production period. Oversaturation injections decrease the mechanical aperture by up to 0.035 mm and permeability by up to 66.1 %. Reservoir matrix permeability exhibits a noticeable zonal distribution, with a maximum increase of 22.6 % in the under-saturation injection and a maximum decrease of 4.1 % in the saturation injection over a 30-year production period. Chemical reactions have a significant impact on the average production pressure. Neglecting chemical reactions in the matrix may result in overestimation or underestimation of changes in production pressure. These results provide a reference for the sustainable production of EGS in the long term.

A STUDY ON MHDJEFFREY FLUID FLOW PAST A VERTICAL POROUS PLATE WITH MULTIPLE BOUNDARIES UNDER THE EFFECT OF CHEMICAL REACTION

In non-Newtonian fluid flow Jeffrey fluid is the one which describes stress relaxation very well. This paper is mainly focused on analytical investigation of unsteady heat and mass transfer rate through porous medium in the presence of magnetic field along with radiation/absorption, heat generation/ absorption and homogeneous chemical reaction effects. The coupled linear partial differential equations are turned to ordinary equations by super imposing solutions with steady and time dependent transient part. Finally, the set of ordinary differential equations are solved with a perturbation method to meet the inadequacy of boundary condition. The effect of different parameters on the flow is described with the help of graphs and tables. This investigation is the fluctuation of velocity appears near the plate due to the presence of sink and presences of elastic element as well heat source reduces the skin friction. Impact of Jeffery parameter leads to decrease the fluid velocity. The heavier species with low conductivity reduces the f low within the boundary layer.