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Marangoni convective MHD flow of SWCNT and MWCNT nanoliquids due to a disk with solar radiation and irregular heat source /
Physica E : Low-Dimensional Systems And Nanostructures, Vol.94, pp.25-30, ISSN: 1386-9477. -
Radiated flow of chemically reacting nanoliquid with an induced magnetic field across a permeable vertical plate /
Results In Physics, Vol.7, pp.2375-2383, ISSN: 2211-3797. -
Radiative heat transfer of nanomaterial on a convectively heated circular tube with activation energy and nanoparticle aggregation kinematic effects
The improvement of the thermal conductivity of the nanoliquid due to the inclusion of a certain amount of nanoparticles is well known. However, the cause of the observed abnormal improvement remains unclear. For this reason, the aggregation kinematics of nanoparticles is significant for evaluating the appropriate thermal effect of particles at the nanoscale. The scope of nanomaterials can be seen in various engineering and industrial fields such as nuclear reactor coolants, heat exchangers, aircraft coolants, microreactor coolants, automobile radiators, solar collectors, etc. Therefore, this study investigates the effects of the aggregation of nanoparticles on radiative nanoliquid flow with activation energy over a horizontal tube subjected to the convective thermal boundary conditions. Experimentally verified correlations of multiwall carbon nanotube aggregation are utilized. The response surface methodology (RSM) is used to determine the optimum levels of the physical parameters to maximize the mass transfer rate of the nanoliquid. The magnitude of the volume fraction and velocity are superior in the absence of aggregation kinematics than in the presence of nanoparticles aggregation mechanism. From the RSM analysis, the maximum Sherwood number obtained is 1.1384 with desirability d = 0.9993. The present results may have applications in nanoliquid-dependent structures, heating/cooling processes, and thermal systems. 2021 Elsevier Ltd -
Significance of nonlinear Boussinesq approximation and non-uniform heat source/sink on nanoliquid flow with convective heat condition: sensitivity analysis
The quadratic convective flow of nanoliquid over an elongating plate subjected to non-uniform heat source/sink, partial slip, and Newton boundary conditions is studied by using the modified Buongiorno model. The correlation for effective thermal conductivity and viscosity of nanoliquid are taken from the experimental work of Corcione. The dimensionless velocity, temperature, rate of heat transport, and mass transport distributions are simulated by solving the nonlinear boundary value problem using the finite difference method. The additional novelty of the present study is an application of response surface methodology to scrutinize the interactive impact of key parameters on the rate of heat transfer. Further, the influence of key parameters is deliberated on various flow fields using the surface and streamline plots. The higher velocities are noticed for the case of nonlinear Boussinesq approximation as compared with the usual Boussinesq approximation. The temperature enhances with a non-uniform heat source/sink aspect. The sensitivity of the heat transfer to the nanoparticle volume fraction remains positive. 2021, The Author(s), under exclusive licence to SocietItaliana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature. -
Nanoparticle aggregation effects on radiative heat transport of nanoliquid over a vertical cylinder with sensitivity analysis
A sensitivity analysis is performed to analyze the effects of the nanoparticle (NP) aggregation and thermal radiation on heat transport of the nanoliquids (titania based on ethylene glycol) over a vertical cylinder. The optimization of heat transfer rate and friction factor is performed for NP volume fraction (1% ? ? ? 3%), radiation parameter (1 ? Rt ? 3), and mixed convection parameter (1.5 ? ? ? 2.5) via the face-centered central composite design (CCD) and the response surface methodology (RSM). The modified Krieger and Dougherty model (MKDM) for dynamic viscosity and the Bruggeman model (BM) for thermal conductivity are utilized to simulate nanoliquids with the NP aggregation aspect. The complicated nonlinear problem is treated numerically. It is found that the temperature of nanoliquid is enhanced due to the aggregation of NPs. The friction factor is more sensitive to the volume fraction of NPs than the thermal radiation and the mixed convection parameter. Furthermore, the heat transport rate is more sensitive to the effect of radiative heat compared with the NP volume fraction and mixed convection parameter. 2021, Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature. -
Sensitivity analysis of heat transfer in nanoliquid with inclined magnetic field, exponential space-based heat source, convective heating, and slip effects
Sensitivity analysis of the rate of heat transport in the flow of nanoliquids over an elongated sheet using the response surface methodology (RSM) in combination with the face-centered central composite design. The flow is driven due to the velocity slip and the inclined magnetic field effects. Thermal analysis includes aspects of convective heating, Joule heating, viscous heating, and a space-dependent exponential heat source. The nanoliquid model consists of thermophoresis and random motion mechanisms. A set of coupled partial differential governance equations is rehabilitated into a set of ordinary differential equations using the appropriate transformation. Subsequent nonlinear problem is tackled numerically by utilizing finite difference code that employs the formula of four-stage Lobatto IIIa. The rate of heat transport is scrutinized by adopting RSM for three effectual parameters, namely magnetic field parameter ((Formula presented.)), angle of inclination ((Formula presented.)), and suction parameter (Formula presented.)). The velocity and temperature fields were found to be a decreasing function of an angle of inclination of the magnetic field. The velocity range is inversely related to the suction and flow aspects of velocity. Furthermore, the rate of heat transport is more sensitive to the suction parameter than to the magnetic field and to the angle of inclination of the magnetic field. 2020 Wiley Periodicals LLC -
Significance of inclined magnetic field on nano-bioconvection with nonlinear thermal radiation and exponential space based heat source: a sensitivity analysis
The characteristics of heat transport in nanoliquids under the influence of bio-convection (motile microorganism) have significant applications, since nanoliquids have greater capacity to improve heat transport properties than conventional liquids. With these incredible nanoliquid characteristics, the main objective of current research is to examine the impact of the exponential heat source linked to space and the inclined magnetic force on the nano-bioconvective flow between two turntables. The effect of nonlinear thermal radiation, variable thermal conductivity and viscosity aspects are also considered. The complicated nonlinear problem is treated numerically by using Finite difference method. Optimization procedure implemented via Response surface Methodology for the effective parameters thermophoresis parameter, Hartmann number and radiation parameter on the heat transfer rate. The axial velocity is a dwelling function of the inclined angle of the magnetic field, and the variable viscosity parameter. The temperature profile hikes with an exponential space-related heat source and thermal radiation aspects. Also, the heat transport rate is highly sensitive towards nonlinear thermal radiation parameter compared to the thermophoresis effect and Hartmann number. 2021, The Author(s), under exclusive licence to EDP Sciences, SocietItaliana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature. -
Effects of aggregation on TiO2ethylene glycol nanoliquid over an inclined cylinder with exponential space-based heat source: sensitivity analysis
The current study investigates the impact of nanoparticle (NP) aggregation on nanoliquid flow over an inclined elongating cylinder with an exponential space-related heat source. The dynamic viscosity and thermal conductivity for aggregation structure are modeled by utilizing the Modified Krieger-Dougherty Model and Bruggeman Model correspondingly. The governing equations are solved numerically. Further, the regression model for friction coefficient and heat transport rate is obtained by utilizing the Response Surface Methodology for various space-based heat source parameter (0.5 ? QE? 1.5), mixed convection parameter (1 ? ?? 3) and NPs volume fraction (0.01 ? ?? 0.05). The velocity profile exhibited dual features for different values of curvature parameter and NPs volume fraction. The space-based exponential heat source and mixed convection have an enhancing impact on the skin friction coefficient. It is noticed that the heat transport augments with the addition of nanoparticles. The coefficient of friction is found to be more sensitive to the NPs volume fraction. Further, the heat transport rate is more sensitive toward exponential heat source than NPs volume fraction and mixed convection. 2021, Akadiai Kiad Budapest, Hungary. -
Entropy generation analysis of radiative heat transfer in Williamson fluid flowing in a microchannel with nonlinear mixed convection and Joule heating
In this article, the spectral quasi-linearization (SQLM) method is implemented to solve the complicated differential equations governing the nonlinear mixed convective heat transfer of a Williamson fluid through a vertical microchannel. Unlike the conventional Boussinesq approximation, the quadratic Boussinesq approximation is taken into account in the formulation. The effects of Rosseland thermal radiation, Joule heating, and viscous dissipation are described in the thermal analysis subjected to the boundary conditions of convective thermal heating. The analysis of entropy production is also performed. The importance of various parameters governing velocity, Bejan number, temperature, and entropy generation was explored using graphic illustrations. It was found that the nonlinear density change with a temperature significantly affects the heat transport in the microchannel and thus increases the magnitude of the Bejan number and the production of entropy. Entropy production occurs maximum due to the boundary conditions of convection heating at the walls of the microchannel. Furthermore, due to a stronger viscous heating mechanism, the magnitude of the Bejan number is reduced, while the production of entropy increases significantly. As a limiting case of the problem, a comparison was made with results previously published in the literature and excellent agreement was established. The calculations provide a solid reference point for future CFD models and are relevant to the dynamics of polymers in microfluidic devices and the polymer industries. IMechE 2022. -
A study on heat transfer in three-dimensional nonlinear convective boundary layer flow of nanomaterial considering the aggregation of nanoparticles
Thermal systems of solar collectors, electronic cooling, nuclear reactors, and combustion operate at high thermal conditions, and in such circumstances, the density relation of the working fluids with the thermal field may not be linear. The working fluid features are significantly affected by nonlinear density temperature fluctuations. Therefore, a theoretical study of the quadratic Boussinesq approximation (with quadratic density temperature [QDT] variation) and quadratic Rosseland radiation on the three-dimensional boundary layer dynamics and heat transport of ethylene glycol-based titania nanomaterial is carried out. The phenomenon of the kinematics of nanoparticle aggregation is also analyzed by considering modified models proposed by MaxwellBruggeman and KriegerDougherty for thermal conductivity and dynamic viscosity. The flow is induced by the elongation of a flexible flat plate in two directions. A comparison of heat transfer features of linear elongation of the plate and nonlinear elongation of the plate is conducted. The Rosseland radiative heat flux is studied in three different forms. The governing nonlinear equations are treated using apt nondimensionalization, stretching transformation, and then by using the Richardson extrapolation method. The results are presented via plots to analyze the impact of key parameters involved in the model. The magnitude of the nanomaterial temperature is enhanced due to the kinematics of nanoparticle aggregation. Among linear, quadratic, and nonlinear forms of Rosseland radiative heat flux, the quadratic radiative heat is more suitable when QDT is considered. A positive relationship is found between heat transfer and volume fraction and a positive relationship is observed between heat transfer and the QDT factor. The magnitude of the velocities and thermal field is higher for flow driven due to the linear elongation of the plate than the nonlinear case. 2021 Wiley Periodicals LLC -
Heat transfer optimization of hybrid nanomaterial using modified Buongiorno model: A sensitivity analysis
Sensitivity analysis of the heat transfer rate in the flow of the hybrid nanoliquid C2H6O2?H2O (base liquid) +MoS2?Ag (nanoparticles) over a wedge using the Response Surface Methodology (RSM) is carried out. The nanomaterial is modeled using the modified Buongiorno nanofluid model (MBNM) that considers the major slip mechanisms and the effective properties of the hybrid nanoliquid. Two distinct heat sources- linear thermal heat source and an exponential space-dependent heat source are taken into account. The governing nonlinear two-point boundary-layer flow problem is treated numerically. The effects of pertinent parameters on the flow fields in the boundary layer region are represented graphically with suitable physical interpretations. The exponential heat source and slip mechanisms are used to study the sensitivities of the heat transfer rate. Both heat source mechanisms lead to an improvement in the temperature profile, in which the effect of the exponential space-related heat source is predominant. The Brownian motion parameter was found to be the most sensitive to the heat transfer rate. 2021 -
Significance of Joule heating and viscous heating on heat transport of MoS2Ag hybrid nanofluid past an isothermal wedge
The problem of flow and heat transport of magneto-composite nanofluid over an isothermal wedge has not been addressed in the literature up to yet. Thus, this article features the laminar transport of Newtonian composite nanomaterial (C2H6O2H2O hybrid base liquid + MoS2Ag hybrid nanoparticles) in the presence of exponential space- and temperature-dependent heat source past an isothermal wedge. An incompressible and electrically conducting fluid is assumed. The effects of Joule heating and viscous heating are also accounted. Single-phase nanofluid model and boundary layer approximation are utilized to govern the equations of flow and heat transport phenomena. The solution of the simplified coupled system of dimensionless constraints is obtained by using the RungeKuttaFehlberg method based on the shooting technique. Detailed analysis of active quantities of interest has been presented and discussed. The interesting physical quantities (friction factors and Nusselt number) are estimated. Also, the slope of the data point is calculated in order to estimate the amount of decrease/increase in physical quantities. 2020, Akadiai Kiad Budapest, Hungary. -
Heat transfer enhancement due to nanoparticles, magnetic field, thermal and exponential space-dependent heat source aspects in nanoliquid flow past a stretchable spinning disk
This study explores the heat transfer characteristics of nanoliquid flowing over a rotating disk in the presence of the applied magnetic field and convective boundary condition. The nanoliquid is flowing due to the rotation of the disk with uniform stretching of a disk along the radial direction. Effects of ESHS (exponential space-related heat source) and THS (thermal-related heat source) are the focal concern of this article. The effective thermal conductivity of ethylene glycol (EG)-based graphene oxide (GO) nanoliquid is estimated by using Nans model whereas effective dynamic viscosity is calculated through Brinkman model. The partial differential system which governed the problem is transformed by using Von-Karman stretching transformations to the ordinary differential system. The subsequent two-point ODBVP (ordinary differential boundary value problem) is treated numerically. The consequence of effective parameters of the problem on different flow fields is illustrated graphically. The numerical values of shear stress and heat transfer rate (Nusselt number) are also calculated. Further, the slope of the data points is determined to quantify the outcome. Validation of the present results is made by direct comparison with the available results and an excellent agreement is found. It is found that the rate of heat transfer increased with nanoparticle volume fraction at the rate 0.4153 and the friction factor increased by increasing nanoparticle volume fraction at the rate 3.0681. The fluctuation rate of Nusselt number due to the variation of the ESHS parameter is almost three times more than that of THS parameter. 2020, Akadiai Kiad Budapest, Hungary. -
Effectiveness of Hall current and exponential heat source on unsteady heat transport of dusty TiO2-EO nanoliquid with nonlinear radiative heat
The problem of exponential heat source across a flowing nanofluid (TiO2-EO; titanium oxide-Engine oil) containing tiny dust particles on a deformable planar plate has been an open question in meteorology. In this paper, the boundary layer transient two-phase flow of dusty nanoliquid on an isothermal plate which is deforming with time-dependent velocity in the presence of exponential heat source is studied. The impacts of Hall current, nonlinear radiative heat and an irregular heat source (temperature based heat source and exponential space-based heat source) are also accounted. Dusty nanofluid is the composition of dust particles and nanoliquid (TiO2-EO). Using relevant transformations, the system of PDEs is rehabilitated to the system of ODEs and then treated numerically. Exploration of the impacts of pertinent parameters on velocity and temperature fields is performed via graphical illustrations. Numeric data for skin friction factor and the Nusselt number is presented and their characteristics are analyzed/quantified through the slope of linear regression via data points. 2019 Society for Computational Design and Engineering -
RayleighBard convection in a non-Newtonian dielectric fluid with MaxwellCattaneo law under the effect of internal heat generation/consumption
Purpose: The study of instability due to the effects of MaxwellCattaneo law and internal heat source/sink on Casson dielectric fluid horizontal layer is an open question. Therefore, in this paper, the impact of internal heat generation/absorption on RayleighBard convection in a non-Newtonian dielectric fluid with MaxwellCattaneo heat flux is investigated. The horizontal layer of the fluid is cooled from the upper boundary, while an isothermal boundary condition is utilized at the lower boundary. Design/methodology/approach: The Casson fluid model is utilized to characterize the non-Newtonian fluid behavior. The horizontal layer of the fluid is cooled from the upper boundary, while an isothermal boundary condition is utilized at the lower boundary. The governing equations are non-dimensionalized using appropriate dimensionless variables and the subsequent equations are solved for the critical Rayleigh number using the normal mode technique (NMT). Findings: Results are presented for two different cases namely dielectric Newtonian fluid (DNF) and dielectric non-Newtonian Casson fluid (DNCF). The effects of Cattaneo number, Casson fluid parameter, heat source/sink parameter on critical Rayleigh number and wavenumber are analyzed in detail. It is found that the value Rayleigh number for non-Newtonian fluid is higher than that of Newtonian fluid; also the heat source aspect decreases the magnitude of the Rayleigh number. Originality/value: The effect of MaxwellCattaneo heat flux and internal heat source/sink on Rayleigh-Bard convection in Casson dielectric fluid is investigated for the first time. 2020, Emerald Publishing Limited. -
Heat and mass transfer effects on non-newtonian fluid flow over an unsteady stretching surface with viscous dissipation and thermal radiation
This paper analyzes the flow, heat and mass transfer characteristics of non-Newtonian Casson fluid towards an unsteady permeable stretching surface. An external transverse magnetic field is applied normal to the sheet. The effects of viscous dissipation and thermal radiation are considered in energy equation. Rosseland approximation is used to model the radiative heat transfer. With the aid of similarity transformations, the unsteady boundary layer equations are transformed into a set of non-linear ordinary differential equations. Numerical solutions of resulting non-linear differential equations are solved by using efficient fourth-fifth order Runge-Kutta Feldberg method. The obtained numerical results are compared and found to be in good agreement with previously published results. Behavior of emerging parameters on velocity, temperature and concentration profiles are discussed and presented graphically. Further, variation of the reduced skin friction coefficient, Nusselt and Sherwood number against physical parameters in graphical and tabular form are presented and discussed in detail. It is found that the effects of thermal radiation and viscous dissipation are favorable for thickening the thermal boundary layer. 2018 Pushpa Publishing House, Allahabad, India. -
Two-phase flow of dusty Casson fluid with Cattaneo-Christov heat flux and heat source past a cone, wedge and plate
This article addresses the boundary layer flow and heat transfer in Casson fluid submerged with dust particles over three different geometries (vertical cone, wedge and plate). The aspects of Cattaneo-Christov heat flux and exponential space-based heat source (ESHS) are also accounted. At first, the partial differential equations are transformed into a set of ordinary differential equations via appropriate similarity transformations. Resulting equations are solved via shooting method coupled with the Runge-Kutta-Fehlberg-45 integration scheme. The consequences of dimensionless parameters on velocity and temperature fields of both fluid and dust particles phase are analyzed. The rate of increment/decrement in the skin friction as well as the Nusselt number for various values of physical parameters are also estimated via slope of linear regression line using data points. 2018 Trans Tech Publications, Switzerland. -
Exponential heat source effects on the stagnation-point heat transport of Williamson nanoliquid with nonlinear Boussinesq approximation
The nonlinear two-point partial differential boundary value problem associated with the nano-pseudoplastic material flow and heat transport subject to nonlinear Boussinesq approximation is computed and explored statistically. Heat transportation features are analyzed by the consideration of an exponential space-related heat source and the Buongiorno model of nanofluids. The boundary-driven expressions of the physical phenomenon are coupled and highly complicated due to the consideration of nonlinear convection terms. Reasonable variables are employed to reform the partial differential equations into a system of ordinary differential expressions and are solved numerically. Furthermore, correlation and regression techniques are employed for the statistical evaluation of the phenomenon. The probable error is implemented to calculate the reliability of the computed correlation factors. The exponential index and Schmidt number are positively correlated with the reduced skin friction coefficient whereas the other parameters are negatively correlated with it. The heat transfer rate is improved predominantly by the nonlinear thermal convection parameter. The temperature is enhanced by the intensification of the exponential-based heat source factor. The temperature and concentration profiles are boosted by incrementing the Biot number values. 2021 Wiley Periodicals LLC -
Statistical analysis of stagnation-point heat flow in Williamson fluid with viscous dissipation and exponential heat source effects
This analysis explores the effect of the novel exponential space-dependent heat generation factor on the stagnation-point Williamson fluid flow over a stretchable surface. The heat transport phenomenon is carried out by the addition of viscous and Ohmic dissipations. Similarity transformations are applied to the nonlinear system of partial differential expressions that arise by the flow. The nonlinear ordinary differential system hence obtained is solved to visualize the role of different constraints graphically. Statistical methods such as correlation, probable error, and regression are utilized. The probable error is evaluated to calculate the reliability of the computed correlation factors. The study reveals that the velocity phenomenon is reduced by incrementing the Weissenberg parameter. The velocity of the hydromagnetic liquid is lesser than the velocity of magnetohydrodynamic fluid flow. Also, the higher heat generation factor gives a boost to the temperature of the flowing material. 2020 Wiley Periodicals LLC -
Significance of quadratic thermal radiation and quadratic convection on boundary layer two-phase flow of a dusty nanoliquid past a vertical plate
Boundary layer two-phase flow of particulate Al2O3-H2O nanoliquid over a vertical flat plate is studied numerically subjected to the aspects of quadratic thermal convection and quadratic thermal radiation. The Khanafer-Vafai-Lightstone monophasic nanofluid model (KVL model) and Saffman's dusty fluid model are used for the equations governing the flow of dusty nanoliquids. The quadratic Boussinesq approximation is used together with the Prandtl's boundary layer approximation. The non-linear problem is treated with the finite difference method. Surface plots and streamlines are presented to visualize the results. A comparison of linear thermal radiation, quadratic thermal radiation, and nonlinear thermal radiation is performed. Among the three types of radiation, the greatest heat transfer is observed in nonlinear thermal radiation followed by quadratic thermal radiation and linear thermal radiation. Also, in the presence of quadratic convection, the heat transport, and velocity field get enhanced. It is found that the presence of Al2O3 nanoparticles of 3% volume concentration in particulate water effectively advances the heat transport of the system. However, heat transport gets reduced by increasing the mass fraction of dust particles. Furthermore, in the presence of a transverse magnetic field, the velocity of the dusty nanoliquid gets reduced. 2020