Prescribed Surface Temperature Research Articles

The impact of a chemical reaction on the heat and mass transfer mechanisms in a dissipative and radiative nanofluid flow over a nonlinear stretching sheet

This paper presents a numerical investigation of the flow of a non-Newtonian tangent hyperbolic nanofluid over a nonlinearly stretched surface, taking into account factors such as thermal radiation, prescribed surface temperature, and a chemical reaction mechanism. Furthermore, the analysis includes the consideration of both viscous dissipation and the influence of a magnetic field within a Darcy porous medium. A mathematical framework for addressing the issue, rooted in the principles of conserving momentum, energy, and mass. The MATHEMATICA tools were employed to apply the shooting technique in order to solve the modeled equations describing the temperature, velocity, and concentration fields of the proposed physical system. Graphs are used to illustrate how certain key parameters affect the profiles of concentration, velocity, and temperature. Data tables are utilized to display information pertaining to the local Nusselt number, local Sherwood number, and local skin friction coefficient. The present results have been confirmed through a comparison with previously published findings. This research holds significant importance as it focuses on the extensive utilization of tangent hyperbolic nanofluids in cooling electronic components that produce substantial heat during their operation. The observed pattern indicates that as the local Weisbsenberg number, magnetic number, local porous parameter, and power law index increase, there is a reduction in the boundary layer thickness. Conversely, in the instances of concentration and temperature distributions, an escalation in these parameters leads to an expansion of the boundary layer thickness.

Photothermoelastic interaction in a two-dimensional semiconductor with nonlocal stress theory

The present contribution enlightens a viable simulation which describes the photothermoelastic interactions for a two-dimensional thermoelastic transversely isotropic thick semiconducting plate due to the presence of a varying heat source. The upper surface of the semiconductor is traction-free, subjected to prescribed surface temperature and prescribed carrier density flux while the lower surface of the plate rests on a rigid foundation and is thermally insulated. In this new model, the conventional Fourier law has been modified assimilating the memory-dependent derivative within a slipping interval in association with the nonlocal stress theory. On utilizing Laplace and Fourier transformation mechanism, the governing equations for displacement, carrier density and temperature have been obtained in the Laplace–Fourier transform domain. In order to have the solutions in the space-time domain, the inversion of the double transform have been carried out numerically based on the method of Fourier series expansion. From the graphical representations corresponding to the numerical results, the significance of effective parameters such as nonlocality parameter, delay-time parameter is discussed. Noteworthy differences in the results have been demonstrated for different kernel functions. Also, the superiority of a nonlinear kernel function and its effectiveness is also reported in the study.

Numerical treatment for double diffusion phenomenon with generalized heat flux effects in 3d nanomaterial flow over bi-directional stretched wall

Current study aims to numerically investigate the bi-directional flow of nanofluids in the presence of Cattaneo–Christov double diffusion for two heat sources, namely, prescribed surface temperature (PST) along with prescribed heat flux (PHF). The conventional mathematical model in partial differential equations (PDEs) of the system have been reduced into an equivalent set of ordinary differential equations (ODEs). The system dynamics in the form of approximate solutions of the ODEs is presented by Adams and Explicit Runge Kutta numerical solvers. For better understanding the influence of physical parameter of interest including Brownian movement parameter, thermophoresis parameter, concentration relaxation parameter, Schmidt number, Prandtl number, thermal relaxation parameter, temperature ratio parameter, stretching ratio parameter and Deborah number on temperature, as well as concentration profiles are presented exhaustively. Appropriateness of the scheme is ascertained through close resemblance of results for different state of the art counterparts with negligible error around 10–05 to 10–09.

Prescribed thermal effects on the dynamics of radiative and chemically reactive hyperbolic tangent nanofluid

ABSTRACT The dynamics of hyperbolic tangent nanofluid, coupled with thermal radiation and chemical reactions, find extensive applications in various fields, including drying processes, oil emulsions, ceramics, prevention of crop damage from freezing, and dehydration processes. Therefore, the primary objective of the present contribution is to scrutinize the dynamic behavior of hyperbolic tangent nanofluid with consideration for both chemical reactions and thermal radiation effects subject to a prescribed thermal system. To model the nanofluid’s behavior, we have employed Buongiorno’s nanofluid model, which incorporates random motion and thermo-diffusion of nanostructured particles. The thermal performance of the hyperbolic tangent nanofluid is analyzed under two boundary conditions: prescribed surface temperature (PST) and prescribed heat flux (PHF). To facilitate the analysis, we have transformed the transport PDEs in Cartesian configuration into ODEs. Subsequently, we have employed the highly efficient HAM (homotopy analysis method) to solve the obtained system. The study explores the influence of various flowing constraints on key configurations such as temperature formation, velocity formation, concentration formation, local drag formation, Nusselt number, and Sherwood number. Notably, the Nusselt number diminishes with the inclusion of thermo 0.2 ≤ N t ≤ 1.1 and Brownian 0.3 ≤ N b ≤ 1.1 diffusions of nanoparticles, while it increases with an escalation in the thermal radiation 0.0 ≤ R d ≤ 2.5 parameter.

Entropic behavior in bidirectional flow of CeO2-ZnO/water hybrid nanofluid with prescribed surface temperature/heat flux aspects

PurposeThe present study aims to encompass the bidirectional magnetized flowing of a hybrid-nanofluid over an unsteady stretching device with the inclusion of thermal radiation and entropy generation. Brick-shaped nanoparticles (zinc-oxide and ceria) are suspended in water, serving as the base-fluid to observe the performance of the hybrid mixture. The Maxwell thermal conductivity relation is employed to link the thermophysical attributes of the hybrid mixture with the host liquid. Additionally, a heat source/sink term is incorporated in the energy balance to enhance the impact of the investigation. Both prescribed-surface-temperature (PST) and prescribed-heat-flux (PHF) conditions are applied to inspect the thermal performance of the hybrid nanofluid.Design/methodology/approachThe transport equations in Cartesian configuration are transformed into ordinary differential equations (ODEs), and an efficient method, namely the Keller-Box method (KBM), is utilized to solve the transformed system. Postprocessing is conducted to visually represent the velocity profile, thermal distribution, skin-friction coefficients, Bejan number, Nusselt number and entropy generation function against the variations of the involved parameters.FindingsIt is observed that more entropy is generated due to the increases in temperature difference and radiation parameters. The Bejan number initially declines but then improves with higher estimations of unsteadiness and Hartmann number. Overall, the thermal performance of the system is developed for the PST scenario than the PHF scenario for different estimations of the involved constraints.Originality/valueTo the best of the authors' knowledge, no investigation has been reported yet that explains the bidirectional flow of a CeO2-ZnO/water hybrid nanofluid with the combined effects of prescribed thermal aspects (PST and PHF) and entropy generation.

EMHD flow and convective heat transfer over a prescribed surface temperature (PST) and prescribed heat flux (PHF) heating condition

Mixed convection describes the combined effects of free and forced convection. It’s used extensively in technical projects including solar collectors, electronics, and nuclear power plants. When buoyancy force dominates the forced convective process or when forced flow dominates the free convective process, such a process is taking place. The authors of this study pondered the situation in which a non-Newtonian micropolar fluid flows steadily and incompressible past an expanding sheet. We have used elements of EMHD, velocity slip, and mixed convection to achieve this. The set of equations administered flow of fluid is converted into ordinary differential equation by suitable variables. MATLAB software’s bvp4c code is used to find the solutions of reduced equations. The influence of different parameters on velocity profile and temperature profile are illustrated. From the outcomes, it is stipulated that the increasing parameter the and temperature distributions exhibit an increasing trend. Additionally, when we increase the value of we see a decreasing trend in the temperature distribution for both the and instances.

Unsteady magnetized flow of micropolar fluid with prescribed thermal conditions subject to different geometries

Due to realistic implementations of heat transfer flows, this study communicates with the two cases of the prescribed thermal process. A comparative analysis of the time-dependent flow of a micropolar fluid between two problems of linear stretching sheet and exponential stretching sheet is demonstrated. In the context of the linear stretching sheet, the investigation covers situations involving prescribed surface temperature (PST) and prescribed heat flux (PHF). Likewise, for the exponential stretching sheet, the study examines cases of prescribed exponential order temperature (PEST) and prescribed exponential order heat flux (PEHF). For both problems, the two cases of the thermal process are examined for heat transfer analysis considering joule heating and nonlinear thermal radiation. The two-dimensional flow in the presence of a variable magnetic field is explored for both the linear and exponential stretching sheet problems. Graphical representations are employed to provide a comparative illustration of flow properties concerning relevant parameters for both cases. From the graphical and tabular analysis, we deduce that an exponential stretching sheet provides more consequential results as compared to a linear stretching sheet. Furthermore, the material parameter demonstrates an increase in the velocity field for both of the considered sheets.

Entropy generation analysis of CNT‐based nanofluid flows induced by a moving plate

AbstractCarbon nanotubes have garnered considerable interest from academia and industry due to their unique properties and potential applications. This study examines fluid flow induced by a plate moving at a constant velocity towards/receding from normal stagnation point flow. The plate's surface is immersed with ethylene glycol and two types of carbon nanotubes: single‐walled and multi‐walled. The Reynolds number, proportional to the plate's velocity, governs the flow. Thermal transport analysis includes Ohmic heating, heat source/sink effects for constant wall temperature and prescribed surface temperature, and entropy generation analysis. Similarity ansatz is used to obtain non‐dimensional ordinary differential equations, and numerical and asymptotic solutions are computed using MATLAB's bvp4c routine (finite difference‐based approach). By varying the relevant parameters, the study interprets the behavior of entropy generation, Bejan number, skin frictions, Nusselt number, flow, and energy profiles. The numerical solutions are observed to match their asymptotic behaviors within an intermediate range of small and large Reynolds numbers for the wall stress parameter. The magnetic parameter produces a resistive force that reduces fluid flow but enhances the system's energy. Moreover, understanding the flow and heat transfer characteristics of CNT‐based nanofluids induced by a moving plate can provide insights into the design and optimization of thermal systems, including efficient heat exchangers used in power generation, chemical, and petrochemical industries.

Influence of PST and PHF heating conditions on the swirl flow of Al+Mg+TiO2 ternary hybrid water-ethylene glycol based nanofluid with a rotating cone

Swirl flow heat exchangers are commonly used in industrial processes such as power generation, chemical processing, and refrigeration. They can be used for both heating and cooling applications and can be designed to handle a wide range of fluid flow rates and temperatures. This study investigated the influence of PST (prescribed surface temperature) and PHF (prescribed heat flux) heating conditions on the swirl flow of Al+Mg+TiO2 ternary hybrid water-ethylene glycol (50/50) based nanofluid with a heated rotating cone. The governing ordinary differential equations were derived from the partial differential equations using the proper similarity transformations. The problem was solved using the Shifted Legendre Collocation Method (SLCM), which is a powerful numerical method. The results showed that the PST heating conditions had a significant impact on the flow and heat transfer characteristics of the ternary hybrid nanofluid. Under PHF heating conditions, the swirl velocity distribution was leading to a noteworthy influence. The use of the Al+Mg+TiO2 ternary hybrid water-ethylene glycol based nanofluid resulted in a significant enhancement in the convective heat transfer coefficient. The SLCM method provided accurate and efficient numerical solutions for the problem, demonstrating its suitability for simulating complex fluid flow and heat transfer problems.

Consistent ramifications of prescribed surface temperature and prescribed heat flux boundary conditions for the slip flow of Walter B fluid in a stretching channel

ABSTRACT The present work delves into the Walter B fluid flow across the channel with the elongating enclosures when enthralled by linear radiation. The magnetic field is contemplated throughout the examination. The fluid suction and injection is permitted through the lower permeable wall. The slip regime is confined at the boundaries of the channel. Heat transfer in the channel is brought to light under two heating processes, namely prescribed surface temperature and prescribed surface heat flux case. The modeled equations are non-dimensionalized and then solved by the Runge-Kutta Fehlberg method in association with shooting scheme. Results deduce that the Reynolds number magnifies the velocity in the channel. Under two different heat boundary conditions, it is recorded that temperature is more pronounced for prescribed surface temperature case than prescribed heat flux. Flow profile for the varying viscoelastic parameter deciphers that at the lower end of the channel, the velocity is augmented and reverse response is recorded at the upper half of channel. Entropy profile magnifies with the augmentation of the magnetic parameter and shows depleting nature for higher Reynolds number. Examining the Walter B fluid flow in the channel enclosed with stretchable walls deliberates the flow of blood in the arterial wall under the exertion of strong magnetic field.

Energy optimization of aluminum alloys on engine oil-based nanofluid flow

The growing demand for energy calls for efficient utilization of natural energy resources in developing useful work. Thermodynamic irreversibility deals with the disorderliness in any system. This work investigates the energy optimization of a cylinder experiencing stretching and rotation immersed with aluminum alloys (AA7072-AA7075) in engine oil-based nanofluid. The Maxwell nanofluid model is employed to check the thermophysical properties of nanofluids. Heat transfer occurred at the cylinder’s surface by considering the constant and prescribed temperature. Forced convection is due to a stretchable rotating boundary, while natural convection is owing to a thermal gradient in the system. The dimensionless ordinary differential equations are obtained by using the appropriate ansatz and solved numerically through the bvp4c technique. A comparison profile of constant wall temperature and prescribed surface temperature shows that entropy generation and Bejan number are reduced for the former and increased for the latter, while thermal transport exhibits an opposite behavior. The axial and azimuthal wall stress parameters diminished due to an increment in Reynolds number. The heat transport rate is comparatively higher for AA7075/Engine oil than AA7072/Engine oil.

Semi-Numerical Investigation of Boundary Layer Flow and Heat Transfer of Magnetohydrodynamics Nano-Fluid Flow in Presence of Chemical Reaction Over a Non-Isothermal Porous Medium

Abstract The technical brief presents, analysis of boundary layer flow and heat transfer in nanofluids under the influence of magnetic field, thermal radiation and chemical reaction over non-isothermal stretching surface through permeable porous medium. The self-similarity equations obtained from governing equations are solved using shifted Chebyshev and Haar wavelet collocation methods. The prescribed surface temperature, prescribed heat flux cases and impact of various flow governing parameters are discussed in detail. The established results are compared with earlier results and are comparable.

Comparative appraisal of mono and hybrid nanofluid flows comprising carbon nanotubes over a three-dimensional surface impacted by Cattaneo–Christov heat flux

Carbon nanotubes (CNTs) are nanoscale tubes made of carbon atoms with unique mechanical, electrical, and thermal properties. They have a variety of promising applications in electronics, energy storage, and composite materials and are found as single-wall carbon nanotubes (SWCNTs) and double-wall carbon nanotubes (DWCNTs). Considering such alluring attributes of nanotubes, the motive of the presented flow model is to compare the thermal performance of magnetohydrodynamic (MHD) mono (SWCNTs)/Ethylene glycol) and hybrid (DWCNTs- SWCNTs/Ethylene glycol) nanofluids over a bidirectional stretching surface. The thermal efficiency of the proposed model is gauged while considering the effects of Cattaneo-Christov heat flux with prescribed heat flux (PHF) and prescribed surface temperature (PST). The flow is assisted by the anisotropic slip at the boundary of the surface. The system of partial differential equations (PDEs) is converted into a nonlinear ordinary differential system by the use of similarity transformations and handled using the bvp4c numerical technique. To depict the relationship between the profiles and the parameters, graphs, and tables are illustrated. The significant outcome revealed that the fluid temperature rises in the scenario of both PST and PHF cases. In addition, the heat transfer efficiency of the hybrid nanoliquid is far ahead of the nanofluid flow. The truthfulness of the envisioned model in the limiting scenario is also given.

Boundary layer formations over a stretchable heated cylinder in a viscoelastic fluid with partial slip and viscous dissipation effects

An exact similarity solution is worked out for fluid motion in the vicinity of a cylindrical surface in an electrically conducting viscoelastic fluid obeying the Jeffrey model. Cylindrical surface expands axially with linear velocity and has a prescribed surface temperature. The present analysis focuses on the partial slip assumption which gives rise to a nonlinear case Robin-type (mixed) boundary condition in axial velocity. In contrast to a previously published study (J. Mech., vol 31, pp. 69–78, 2015) which only reported local similarity solutions in no-slip case, the present work provides an exact similarity analysis by defining a quadratic surface temperature. The effects of the magnetic field and Joule heating on the momentum and thermal transport phenomena are also scrutinized. A numerical routine is used to solve the equation accurately for a wide range of fluid parameters, including ranges that could not be handled by previous approximate analytical methods that were limited to the no-slip limit. The influences of viscoelasticity and partial slip on the flow behavior are investigated, and the coefficient of skin friction for a Jeffrey fluid is calculated. Obtained results are consistent with the previously published works under special situations. The case of flat surface, which can be obtained as a limiting case of the model, is not even explored in the past.

Radiative simulation of non-Newtonian MHD fluid over a boundary-driven multi-physical curved mechanism: Keller–Box evidence

This study is numerically driven to ascertain the flow of two-dimensional heat transfer of an incompressible electrically conducting non-Newtonian fluid over a continuous power-law stretching curved surface. The flow model considers rheological fluid viscosity using curvilinear (r −, s −) coordinates. The energy equation for the curved mechanism is examined in two streams: the prescribed surface temperature and the prescribed heat flux. Surface frictional heating is influenced by thermal radiation and viscous dissipation. Similarity transformations are executed to reduce partial differential equations into ordinary differential equations. The Keller–Box shooting method with the Jacobi iterative techniques is numerically computed for the degenerated nonlinear system of the boundary value problem. The associated boundary-layer thickness and flow fields- velocity and temperature are analyzed against characterizing parameters. Significant results are obtained and discussed with graphical plots showing that fluid velocity can be controlled by virtue of fluid parameters and stretching power index. These results are useful in polymer dynamics involving the melting and manufacturing of stretchable sheets.

A comparative analysis of the time-dependent magnetized blood-based nanofluids flows over a stretching cylinder

This article explores the analysis of magnetized blood-based nanofluids flows over an extending cylinder. The nanofluid contains copper, copper oxide and iron oxide nanoparticles which are mixed with blood. The mathematical model has been built-up in partial differential equations (PDEs) form and then changed into ordinary different equations by mean of suitable similarity variables and then has been evaluated by homotopy analysis method (HAM). The convergence of the applied technique is presented in graphical form. During the solution process, the influences of physical parameters like magnetic parameter, unsteadiness parameter, curvature parameter and thermal relaxation time parameter on the flow profiles have been investigated and depicted in Figures and Tables. The correctness of the present model has also been presented in tabular form. The results show that the greater curvature factor reduces the radius of cylinder due to which thickness of layer becomes thin at the boundaries and therefore the velocity distribution declines, while the greater curvature parameter has the increasing impact on the temperature distribution for constant wall temperature (CWT) case and decreases the temperature distribution for prescribed surface temperature (PST) case.

Vapor buoyancy increases clear-sky thermal emission

The molar mass of H2O (18 g mol−1) is smaller than that of dry air (29 g mol−1), which makes humid air lighter than dry air with the same temperature and pressure. This vapor buoyancy (VB) effect has been traditionally considered small in large-scale climate dynamics and even neglected in some leading climate models. Here, using theory and aquaplanet simulations with prescribed surface temperatures, we show that VB increases tropospheric air temperature, and that the warmer atmosphere emits more clear-sky thermal radiation by about 2–4 W m−2 in the dry subtropical areas, a significant radiative effect. We then analyze Coupled Model Intercomparison Project Phase 6 simulations with prescribed sea surface temperatures and realistic topography. The results show that VB can increase clear-sky thermal radiation by up to 5 W m−2 over the ocean and about 15 W m−2 over the subtropical arid land regions. The radiative effect over arid land is amplified by a substantial increase of surface temperature due to VB. Our results highlight the role of VB in regulating Earth’s energy balance both at the top of the atmosphere and at the land surface. This study points to new ways to improve climate models and their simulated energy balance.

Dynamics of heat transport in flow of non‐linear Oldroyd‐B fluid subject to non‐Fourier's theory

AbstractTo study non‐Fourier heat and mass transport in the stagnation point flow of magnetized Oldroyd‐B fluid due to stretching cylinder, the Cattaneo–Christov heat flux model is used in this investigation. Further, as the controlling agents for thermal and solutal transport in the fluid flow, the heat generation/absorption source and chemical reaction are also considered. The formulations of a such physical phenomenon are going to form the PDEs. Through appropriate similarity variables, these governing partial differential equations for flow and energy transport are converted into the ordinary differential. The analytical series solutions are obtained through the use of a homotopic approach. The graphical upshots are conducted for velocity fields, temperature, and concentration distributions. In addition, energy transport analysis is performed for two kinds of surface heating mechanisms, namely the prescribed surface temperature (PST) and constant wall temperature (CWT). The outcomes of the current investigation revealed that a higher rate of heat transfer is observed in the case of CWT as compared to PST. Moreover, the increasing values of thermal and solutal relaxation time parameters reduce the heat and mass transport in the fluid flow, respectively.

Entropy formation analysis for magnetized UCM fluid over an exponentially stretching surface with PST and PSHF wall conditions

<abstract> <p>This article aims to demonstrate the formation of entropy due to variable thermal conductivity, radiation, and fluid friction irreversibilities for a three-dimensional upper-convected Maxwell (UCM) fluid. The fluid motion occurs as a result of exponential stretching sheets. Separate discussions are held regarding the entropy generation related to the prescribed surface temperature and prescribed surface heat flux. Additionally, the heat transport mechanism is examined in the presence of thermal radiation. The governing physical situation is first modeled and then solved by using the homotopy analysis method to acquire the solution. The physical importance of relevant flow parameters is shown graphically and in tabular form. It is noted that the entropy generated is reduced with an increase in the thermal radiation parameter. Streamline patterns are also drawn for two- and three-dimensional UCM fluid models. Finally, the current analytical solution is found to be in agreement with the solutions in the literature.</p> </abstract>

Thermal progression via bi-directional stretching surface for unsteady dynamics of magnetized elastico-viscous nanofluid subject to variable thermal conditions: a comprehensive analysis

Countless utilization of elastico-viscous nanomaterials in industrial and engineering processes pulled our attention to examine the unsteady dynamics of an elastico-viscous nanofluid over a bi-directionally expandable plate with the aspects of simultaneous heat mechanisms, namely, prescribed surface temperature and prescribed heat flux. Additionally, nanoparticles characteristics are added in the system through a well-reputed Buongiorno nanofluid model. Furthermore, supremacies of magnetic field, Forchheimer medium and internal heat consumption/generation are also comprehensively analyzed. An appropriate group of variables is opted to exchange the governing equalities into ordinary differential equations before finding the analytical solution through homotopy analysis method. Spectacular outcomes for heat plus mass transports against various approximations of involved parameters are intercepted through tables. Temperature plus concentration summaries are portrayed for acceptable ranges of involved parameters. Finally, marvelous outcomes are linked with previously published data to authenticate the whole parametric scrutiny. It is noted that escalating selections of elastico-viscous and heat distribution indices reduce the temperature and concentration fields. Nanofluid temperature has reduced with the escalation of thermal index and nanoparticles concentration has boosted with the growth of thermodiffusion parameter (). Residual errors plots explicate the endorsement of the results obtained through the present exploration.