Friction Irreversibility Research Articles

Numerical analysis of entropy generation in a square cavity filled with boron-water nanofluid

The entropy generation and natural convection in a square cavity filled with boron-water nanofluid is numerically investigated under the influence of different nanoparticle volume fractions and buoyancy forces when heated from left vertical wall and cooled from right vertical wall while horizontal walls are insulated. The results are compared with copper (Cu) and aluminum oxide (Al2O3) nanoparticles generally used in the applications. Differential equations are discretized over the SIMPLE algorithm and solved iteratively using the finite control volume method. Entropy generation contours due to heat transfer and fluid friction are presented. Local and average Bejan numbers are also investigated. The results of the study show that the entropy generation increases with the increase in Rayleigh number for all nanoparticles, and fluid friction irreversibility is more dominant in entropy generation with increasing Rayleigh number, and almost all entropy generation is caused by fluid friction in high Rayleigh numbers.

Second Law Analysis for the Experimental Performances of a Cold Heat Exchanger of a Stirling Refrigeration Machine.

The second law of thermodynamics is applied to evaluate the influence of entropy generation on the performances of a cold heat exchanger of an experimental Stirling refrigeration machine by means of three factors: the entropy generation rate , the irreversibility distribution ratio ϕ and the Bejan number based on a dimensionless entropy ratio that we introduced. These factors are investigated as functions of characteristic dimensions of the heat exchanger (hydraulic diameter and length), coolant mass flow and cold gas temperature. We have demonstrated the role of these factors on the thermal and fluid friction irreversibilities. The conclusions are derived from the behavior of the entropy generation factors concerning the heat transfer and fluid friction characteristics of a double-pipe type heat exchanger crossed by a coolant liquid (55/45 by mass ethylene glycol/water mixture) in the temperature range 240 K < TC < 300 K. The mathematical model of entropy generation includes experimental measurements of pressures, temperatures and coolant mass flow, and the characteristic dimensions of the heat exchanger. A large characteristic length and small hydraulic diameter generate large entropy production, especially at a low mean temperature, because the high value of the coolant liquid viscosity increases the fluid frictions. The model and experiments showed the dominance of heat transfer over viscous friction in the cold heat exchanger and and ϕ → 0 for mass flow rates kg.s−1.

RETRACTED: Free convection and entropy generation in a nanofluid-filled star-ellipse annulus using lattice Boltzmann method supported by immersed boundary method

Abstract In the present work, it is aimed to investigate the natural convection numerically. The nanofluid flow and heat transfer in a star-ellipse annulus are investigated. The lattice Boltzmann method is utilized to carry out the numerical simulations. In addition, the Immersed Boundary Method (IBM) is used to treat the Dirichlet and Neumann conditions. The annulus consists a star-shaped cylinder and ellipse cylinder and filled with Cu-water nanofluid. The second law analysis is used to provide local maps of fluid friction irreversibility and heat transfer irreversibility and volumetric entropy generation. The influences of some main parameters including Rayleigh number in a range of 103 to 106, solid volume fraction of nanofluid in range of 0 to 0.03 and eccentricity -0.4

Effect of Thermophysical Property Variation on Entropy Generation towards Micro-Scale

AbstractIn this work, the effect of temperature-dependent thermal conductivity (k(T)) and viscosity (\mu (T)) variation on entropy generation in circular channels with an approach from macro- to micro-scale is numerically investigated. Thermally as well as hydrodynamically fully developed flow of water through the fixed length channels with constant total heat flow rate and total mass flow rate is considered. The effects of k(T) variation and \mu (T) variation on entropy generation are analyzed individually as well as collectively. It is observed that in the case of Constant Property Solutions (CPS) {S_{\mathit{gen},\mathit{tot}}} is maximum at the macro-level; however, in the case of combined k(T) and \mu (T) variations it is maximum at the micro-level. The Bejan number (\mathit{Be}) and irreversibility distribution ratio (φ) are also calculated for asserting the dominance of frictional irreversibility and conduction heat transfer irreversibility. Additionally, the optimum diameter ({D^{\ast }}) corresponding to the optimum number of channels is calculated at minimum total entropy generation. It is observed that {D^{\ast }} is minimum for k(T) variation followed by CPS, \mu (T) variation, and combined k(T) and \mu (T) variations.

Heat Transfer and Entropy Generation Evaluation on Molten Salt Tank Foundation with Internal Water Cooling

Molten salt tanks are used to store and release thermal energy. Large heat leakage through the molten salt tank foundation to the ground and high temperature of the foundation are detrimental to long-term operation safety. Here we evaluate the heat transfer and entropy generation characteristics of molten salt tank foundations with internal water cooling. Both laminar and turbulent flows reduce the heat leakage efficiently, while the power consumption for the laminar flow is negligible. The effects of the geometrical parameters are presented. Internal fins in the cooling channels decrease the heat leakage significantly. The total entropy generation rate with foundation cooling is higher than that without foundation cooling. The entropy generation rate in the solid domain is much larger than that in the fluid domain and the flow friction irreversibility is tiny. Larger insulation layer thickness decreases the heat leakage and the total entropy generation rate simultaneously. The local entropy generation rate map helps us identify where the most irreversibility is produced. The largest local entropy generation rate for the design with foundation cooling occurs near the solid-fluid interfaces and is much higher than that without foundation cooling.

Two-phase computation of free convection and entropy generation inside an enclosure filled by a hybrid [formula omitted]-[formula omitted]-[formula omitted] water nanofluid having a corrugated heat source using the generalized Buongiorno’s mathematical model: Employment of finite volume method

In this article we studied the entropy generation and natural convection of hybrid nanofluid (Al2O3-TiO2-Cu and Water) in an enclosure containing a central wavy heated source using the generalized Buongiorno’s mathematical model (i.e., two-phase mixture model). Finite volume method has been used to discretize the governing equations. The studied parameters related to this problem are Rayleigh number 103≤Ra≤106, proportion of hybrid nanoparticles 0%≤φ≤5% and dimensionless amplitude of corrugated heater 0≤a≤0.2. It has been found that the increase in the value of corrugated heater amplitude improves the efficiency of hybrid nanofluid heat transfer inside the enclosure so that it enhances compared to the case of straight heater. In addition, it was concluded that increasing the percentage of hybrid nanoparticles in the base fluid raises the rate of heat transfer. The effect of the problem parameters (a and φ) on the heat transfer rate changes with respect to each different values of Rayleigh number, it can be optimized. In addition, the different irreversibility types (entropy due to mass transfer SMT, heat transfer SHT, fluid friction SFF) have been performed for different Ra numbers and corrugations amplitude. It is found that all mean entropies raise by changing the corrugation amplitude from 0 to 0.2 and they are affected significantly by the growth of Ra number and volume fraction of hybrid nanoparticles. The total entropy generation ST was also calculated and plotted. Moreover, the mean Bejan number variation Be- was studied to determinate the dominant irreversibility type. It is found that the mass and heat irreversibility are dominant at low Ra number (104), on the other hand, for the higher Ra number the fluid friction irreversibility is the dominant. Furthermore, the two-phase simulation has been performed for studying the hybrid nanoparticles distribution. It is found that the maximum volume fraction of hybrid nanoparticles is placed on the bottom left and right corners of the cavity and its uniform values situated on the medium of the hybrid nanofluid, while this uniform part becomes wide when increasing Ra number from 104 to 106.

RETRACTED: Using of double distribution function LBM (DDF/LBM) and experimental rheological/thermal measurements of nanofluid for battery thermal management

Abstract The growing demand of electric vehicles (EVs) attracts many researchers to work on the battery thermal management to maintain the temperature of battery package in the desired temperature. In this regard, the present work aims to use the numerical and experimental approaches in order to perform the battery thermal management. The lattice Boltzmann method is used to simulate the fluid flow and heat transfer during free convection in a rectangular cavity included with seven battery cylinders. The battery package and battery are simplified with rectangular cavity and circle cylinder, respectively. The top and bottom walls are kept at constant cold temperature with three different configurations (Smooth, Jagged and Zigzag). In addition, the cavity is filled with SLG (Single Layer Graphene)/water nanofluid which the thermal conductivity and dynamic viscosity are measured experimentally using modern devices. Furthermore, the second law analysis is carried out in order to find the influence of governing parameters including Rayleigh number, nanoparticle concentration (?? = 0.2, 0.4, 0.6, 0.8 and 1.0 mg/ml) and configuration of cavity on the local/total entropy generation. The flow structure, temperature field, local maps of heat transfer irreversibility and fluid friction irreversibility, volumetric magnitude of total entropy generation and average Nusselt number are presented.

Entropy production during natural convection of hybrid nanofluid in an annular passage between horizontal confocal elliptic cylinders

A numerical analysis on entropy production due to natural convection in an annular passage between horizontal confocal elliptic cylinders is studied. The Al2O3-Cu/water hybrid nanofluid is using as a test fluid. The flow by natural convection in the annulus is driven by a gradient of temperature between an internal uniformly heated elliptical cylinder and a cold external elliptical cylinder. The full basic equations describing steady laminar flow of incompressible and Newtonian fluid under the Boussinesq approximation are expressed in the elliptical coordinates system and discretized by the finite volume method using an in-house FORTRAN code. The investigation is carried out to examine the influences of Rayleigh number and hybrid nanoparticles volume fraction on thermo-hydrodynamic characteristics, heat transfer and entropy generation inside the annulus. Obtained results showed that increase of Rayleigh number or use of hybrid nanoparticles in the pure water increases the natural convective flow and the heat transfer rate within the annulus, as well as both thermal and frictional entropy generation. Also, at lower Rayleigh, most of the entropy generation is due to the thermal irreversibility, whereas, at higher Rayleigh, the main contributor to the total entropy generation is that due to the frictional irreversibility.

Entropy generation analysis of Hall current effect on MHD micropolar fluid flow with rotation effect

Entropy generation in form of heat dissipation destroys useful energy which accounts for the underperformance and decrease in the thermodynamic efficiency of a system. Since micropolar fluid is used as a working fluid in many technological and industrial processes, it is therefore necessary to examine the influence of all factors that can enhance entropy production so as to achieve the best energy systems design. In this paper, the influence of Hall current and ion-slip on the entropy generation rate of micropolar fluid is investigated. An applied uniform magnetic field acts in a perpendicular direction to the flow of fluid. The nonlinear coupled partial differential equations used to model the micropolar fluid flow are transformed to ordinary differential equations by using appropriate similarity variables. The differential equations obtained are solved by applying differential transform method. The results for velocity profiles, temperature profile and microrotation are used to determine fluid irreversibility and Bejan number. To get a clearer view of the study, the effects of various parameters such as Hall, ion-slip, magnetic field and coupling number on primary velocity, secondary velocity, temperature profile, microrotation, entropy generation and Bejan number are presented and explained via plots. The results show that entropy generation is reduced as coupling number and magnetic parameter increase, Bejan number receives a boost with increase in coupling number and magnetic parameter. Furthermore, heat irreversibility is more dominant than fluid friction irreversibility at the region close to the channel walls.

Natural convection heat transfer and entropy generation from a heated cylinder of different geometry in an enclosure with non-uniform temperature distribution on the walls

A numerical investigation has been performed to visualize the natural convective heat transfer and nature of entropy generation from a heated cylinder of two separate geometries (circular and square) situated within a square enclosure subjected to non-uniform temperature distributions on the left vertical and bottom walls. The flow inside the enclosure is steady, incompressible and laminar and the working fluid is Newtonian with constant Prandtl number (Pr = 0.71). The results are discussed in terms of the distribution of streamlines and isotherms, surface-averaged Nusselt number and entropy generation, for a different combination of Rayleigh number (103 to 106) and dimensionless wavelength of sinusoidal temperature distribution ( $$0.1 \le \lambda \le 0.7$$ ). It reveals that sinusoidal temperature with higher wavelength enhances the heat transfer. Moreover, the highest value of Nusselt number is obtained in case of enclosure embraces the circular cylinder. Further, the thermal entropy generation is observed to be minimum for sinusoidal temperature distribution with a wavelength of 0.7 irrespective of Rayleigh number. In addition to this, the geometrical configuration of the cylinder has a negligible effect on the variation of fluid friction and thermal irreversibility at higher Rayleigh number. Finally, the circular shape of the embedded cylinder is found to be optimal since it results in maximum heat transfer with least entropy generation.

Entropy generation analysis of mixture nanofluid (H2O/c2H6O2)–Fe3O4 flow between two stretching rotating disks under the effect of MHD and nonlinear thermal radiation

ABSTRACT The flow of water and a mixture of water–ethylene glycol as a base fluid and Fe3O4, as a nanoparticle between two stretching rotating disks, are investigated. The entropy generation has been modelled by the second thermodynamic low. The thermal irreversibility, fluid friction irreversibility and joule dissipation irreversibility are considered in this model. The Lorentz force and Joule heating effect due to a magnetic field and nonlinear thermal radiation have been considered in governing equations. The fifth-order Runge–Kutta method is applied to solve the nonlinear governing equations. The results are compared with those of the previously published papers and show excellent agreement. The effects of Radiation parameter, magnetic field, Brinkman number and volume fraction of nanoparticles on total entropy generation and Bejan number are investigated. Also the effects of the variable parameter on the velocity and temperature profile, skin friction coefficient and Nusselt number are examined. The results are compared with those of the mixture base fluid (water–ethylene glycol) and pure water.

Second law analysis for nanofluid flow in mini-channel heat sink with finned surface: a study on fin geometries

In this numerical work, a second law analysis is carried out for the nanofluid flow and heat transfer in the mini-channel with finned surface. The mini-fins with various geometries, including trapezoidal, square, triangular, and sinusoidal, are located on the bottom surface of the mini-channel. The effects of mini-fins geometry, mini-fins number, Reynolds number, and solid volume fraction of nanoparticles on the temperature and velocity distributions, frictional and thermal irreversibilities, and Bejan number inside the mini-channel are studied. The numerical method is validated with the experimental data. The results show that the sinusoidal, triangular, square, and trapezoidal mini-fins generate up to 66.23%, 61.87%, 59.21%, and 57.80%, respectively, lower thermal irreversibility as compared with the smooth mini-channel. Among mini-fin geometries, the triangular mini-fins generate the maximum frictional irreversibility, while the trapezoidal mini-fins provide the minimum frictional irreversibility. The frictional irreversibility increases about 108.56%, while the thermal irreversibility decreases up to 46.33% as the mini-fin number increases from one to nine. The thermal irreversibility diminishes about 49% by boosting the Reynolds number from 100 to 500. Usage of nanofluid increases both frictional and thermal irreversibilities. Finally, the thermal irreversibility is a dominant term in the total irreversibility and the effects of frictional irreversibility can be ignored.

Numerical investigation of forced convection heat transfer and flow irreversibility in a novel heatsink with helical microchannels working with biologically synthesized water-silver nano-fluid

This paper aims to evaluate the hydrothermal and irreversibility behaviour of a biological water-Ag nano-fluid in a new heatsink with helical microchannels. Two-phase mixture model is applied to precisely simulate the behavior of nanofluid in the nanoadditive concentration (φ) range of 0–1% and Reynolds number (Re) range of 500–1500. The influences of φ and Re on the convective heat transfer coefficient, CPU surface temperature, pumping power, as well as the irreversibilities due to heat transfer and fluid friction are examined. The findings depict that boosting the Re and φ augments the performance of heatsink by intensifying the convective heat transfer coefficient of the working fluid which favourably declines the CPU surface temperature and the heat transfer irreversibility and importantly results in the temperature uniformity of the CPU surface. However, intensification in Re adversely affects the pumping power, the fluid friction and total irreversibilities in the system. Furthermore, it is revealed that the nano-fluid always has a superior cooling performance as compared with the pure water. Finally, it is found that the best hydrothermal performance of the nano-fluid in the proposed heatsink occurs at Re = 1500 and φ = 1%, while the minimum total irreversibility occurs at Re = 500 and φ = 1%.

The effect of inlet temperature on the irreversibility characteristics of non-Newtonian hybrid nano-fluid flow inside a minichannel counter-current hairpin heat exchanger

The goal of this work is to examine the influence of entering temperature on the entropy generation characteristics of a minichannel hairpin heat exchanger with counter-flow configuration. The working fluids are water and hybrid water–Fe3O4/carbon nanotubes (CNTs) nano-fluid (NF) that flows through the annulus side and tube side of the heat exchanger, respectively. It is assumed that the NF is non-Newtonian, and its thermal conductivity and viscosity are temperature dependent. The impact of volume fraction of Fe3O4 ($$\varphi_{\text{FF}}$$) and CNT nanoadditives ($$\varphi_{\text{CNT}}$$) as well as the Reynolds number of NF ($$Re_{\text{nf}}$$) on the Bejan number and irreversibilities due to heat transfer and fluid friction are also assessed. It was found that augmenting the temperature difference between the fluids entering the heat exchanger results in a decrease in the frictional irreversibility and an increase in the global thermal and total irreversibilities and global Bejan number. Additionally, the outcomes depicted that the global frictional and total irreversibilities and the global Bejan number intensify by boosting the $$Re_{\text{nf}}$$ and $$\varphi_{\text{CNT}}$$, while the increase of $$\varphi_{\text{FF}}$$ first leads to the reduction and then the increase of these parameters.

Effect of surface roughness on heat transfer and entropy generation of mixed convection in nanofluid

In this study, mixed convective heat transfer and entropy generation of Al2O3-water in a lid-driven square cavity with roughness elements on the bottom surface have been studied. The vertical sidewalls of the cavity are adiabatic, and horizontal walls are maintained at a constant temperature, while the top wall is moving at a constant velocity. Various Reynolds numbers, Rayleigh numbers, and nanoparticles concentrations have been considered. The wavy bottom wall of the cavity is determined by the number and amplitude of the roughness elements. It has been observed that the larger amplitude reduces the heat transfer rate while increasing the total entropy generation and the average Bejan number (Beavg). Conversely, the roughness elements reduce the heat transfer rate and total entropy generation while increasing Beavg. It has been further observed that the amplitude has a greater effect on the entropy generation and Beavg than the number of roughness elements. In addition, increasing the Reynolds and Rayleigh numbers increases the average Nusselt number and total entropy generation, while reducing Beavg. Addition of nanoparticles in a base fluid increases the heat transfer while minimizing the total entropy generation. Beavg rises with nanoparticle concentrations. The lowest entropy generation for nanofluid could be achieved at the low Rayleigh number and Reynolds number with a fixed number and amplitude of the roughness elements. In the cases studied, total entropy generation is greatly affected by heat transfer irreversibility while fluid friction irreversibility plays a minor role in the total entropy generation enhancement.

Numerical analysis of natural convection heat transfer and entropy generation in a porous quadrantal cavity

Purpose The purpose of this paper is to analyze the natural convection heat transfer and irreversibility characteristics in a quadrantal porous cavity subjected to uniform temperature heating from the bottom wall. Design/methodology/approach Brinkmann-extended Darcy model is used to simulate the momentum transfer in the porous medium. The Boussinesq approximation is invoked to account for the variation in density arising out of the temperature differential for the porous quadrantal enclosure subjected to uniform heating on the bottom wall. The governing transport equations are solved using the finite element method. A parametric study is carried out for the Rayleigh number (Ra) in the range of 103 to 106 and Darcy number (Da) in the range of 10−5-10−2. Findings A complex interaction between the buoyant and viscous forces that govern the transport of heat and entropy generation and the permeability of the porous medium plays a significant role on the same. The effect of Da is almost insignificant in dictating the heat transfer for low values of Ra (103, 104), while there is a significant alteration in Nusselt number for Ra ≥105 and moreover, the change is more intense for larger values of Da. For lower values of Ra (≤104), the main contributor of irreversibility is the thermal irreversibility irrespective of all values of Da. However, the fluid friction irreversibility is the dominant player at higher values of Ra (=106) and Da (=10−2). Practical implications From an industrial point of view, the present study will have applications in micro-electronic devices, building systems with complex geometries, solar collectors, electric machinery and lubrication systems. Originality/value This research examines numerically the buoyancy driven heat transfer irreversibility in a quadrantal porous enclosure that is subjected to uniform temperature heating from the bottom wall, that was not investigated in the literature before.

Entropy generation analysis of convective airflow in a solar updraft tower power plant

AbstractThe main objective of this numerical investigation is to interpret the entropy generation for free convection airflow in a solar tower updraft system. The ground surface is subjected to uniform hot temperature and the collector cover is maintained at lower constant temperature while the chimney wall is adiabatic. Two dimensionless equations of steady laminar free convective airflow are discretized using the finite volume approach. Numerical solutions were accomplished for different values of the Rayleigh number. Results are given in terms of isotherms, velocity magnitude, local entropy generation associated with thermal and fluid friction, local total entropy generation and local Bejan number contours for Rayleigh number ranging between 103 and 108. The reported results show that thermal and frictional irreversibilities are proportional to the Rayleigh number. Also, it was found that, at lower Rayleigh, total irreversibility is attributable to the thermal irreversibilities and occurs essentially in the collector section. At higher Rayleigh, frictional irreversibilities are increased significantly and become the dominant source of irreversibility in the solar tower, and the chimney section is the main contributor in the total irreversibility in the system.

Accurate LBM appraising of pin-fins heat dissipation performance and entropy generation in enclosures as application to power electronic cooling

Purpose The purpose of this paper is to carry out an in-depth analysis of heat dissipation performance by natural convection phenomenon inside light-emitting diode (LED) lamps containing hot pin-fins because of its significant industrial applications. Design/methodology/approach The problem is assimilated to heat transfer inside air-filled rectangular cavity with various governing parameters appraised in ranges interesting engineering application and scientific research. The lattice Boltzmann method is used to predict the dynamic and thermal behaviors. Effects of monitoring parameters such as Rayleigh number Ra (103-106), fin length (0-0.25) and its position, pin-fins number (1-8), the tilting-angle (0-180°) and cavity aspect ratio Ar (0.25-4) are carried out. Findings The rising behaviors of the dynamic and thermal structures and heat transfer rate (Nu), the heatlines distribution and the irreversibility rate are appraised. It was found that the flow is constantly two contra-rotating symmetric cells. The heat transfer is almost doubled by increasing Ra. A lack of cooling performance was identified between Ar = 0.5 and 0.75. The inclination 45° is the most appropriate cooling case. At constant Ra, the maximum stream-function and the global entropy generation remain almost unchanged by increasing the pin number from 1 to 8 and the entropy generation is of thermal origin for low Ra, so that the fluid friction irreversibility becomes dominant for Ra larger than 105. Research limitations/implications Improvements may include three-dimensional complex geometries, accounting for thermal radiation, high unit power and turbulence modelling. Such factors effects will be conducted in the future. Practical implications The cooling performance/heat dissipation in LED lamps is a key manufacturing factors, which determines the lifetime of the electronic components. The best design and installation give the opportunity to increase further the product shelf-life. Originality/value Both cooling performance, irreversibility rate and enclosure configuration (aspect ratio and inclination) are taken into account. This cooling scheme will give a superior operating mode of the hot components in an era where energy harvesting, storage and consumption is met with considerable attention in the worldwide.

Study on fluid flow and heat transfer in fluid channel filled with KKL model-based nanofluid during natural convection using FVM

PurposeA comprehensive study on the fluid flow and heat transfer in a nanofluid channel is carried out. The configuration of the channel is as like as quarter channel. The channel is filled with CuO–water nanofluid.Design/methodology/approachThe Koo–Kleinstreuer–Li model is used to estimate the dynamic viscosity and consider the Brownian motion. On the other hand, the influence of nanoparticles’ shapes on the heat transfer rate is considered in the simulations. The channel is included with the injection pipes which are modeled as active bodies with constant temperature in the 2D simulations.FindingsThe Rayleigh number, nanoparticle concentration and the thermal arrangements of internal pipes are the governing parameters. The hydrothermal aspects of natural convection are investigation using different approaches such as average Nusselt number, total entropy generation, Bejan number, streamlines, temperature fields, local heat transfer irreversibility, local fluid friction irreversibility and heatlines.Originality/valueThe originality of this work is investigation of fluid flow, heat transfer, entropy generation and heatline visualization within a nanofluid-filled channel using a finite volume method.

Effects of radiation and magnetic field on mixed convection stagnation-point flow over a cylinder in a porous medium under local thermal non-equilibrium

Heat transfer enhancement and entropy generation are investigated in a nanofluid, stagnation-point flow over a cylinder embedded in a porous medium. The external surface of cylinder includes non-uniform transpiration. A semi-similarity technique is employed to numerically solve the three-dimensional momentum equations and two-equation model of transport of thermal energy for the flow and heat transfer in porous media. The mathematical model considers nonlinear thermal radiation, magnetohydrodynamics, mixed convection and local thermal non-equilibrium in the porous medium. The nanofluid and porous solid temperature fields as well as those of Bejan number are visualised, and the values of circumferentially averaged Nusselt number are reported. The results show that thermal radiation significantly influences the temperature fields and hence affects Nusselt and Bejan number. In general, more radiative systems feature higher Nusselt numbers and less thermal irreversibilities. It is also shown that changes in the numerical value of Biot number can considerably modify the predicted value of Nusselt number and that the local thermal equilibrium modelling may significantly underpredict the Nusselt number. Magnetic forces, however, are shown to impart modest effects upon heat transfer rates. Yet, they can significantly augment frictional irreversibility and therefore reduce the value of Bejan number. It is noted that the current work is the first systematic analysis of a stagnation-point flow in curved configurations with the inclusion of nonlinear thermal radiation and local thermal non-equilibrium.