Heat Transfer Irreversibility Research Articles

Derivation of generalized thermoelectric energy equations and the study of thermoelectric irreversible processes based on energy, exergy, and entransy analysis

AbstractThermoelectric (TE) generation is becoming a valuable and promising research direction. Many researchers have carried out system analysis and performance optimization of thermoelectric technologies based on the generalized thermoelectric energy balance equations. However, it is assumed that TE legs have no heat exchange with the ambient except at the junctions of the hot and cold ends where heat flows in and out. Based on basic thermoelectric effects and fundamental theories of heat transfer, a detailed derivation of the revised generalized thermoelectric energy equations considering convective heat transfer between TE legs and the ambient has been carried out. Irreversible heat transfer processes have been analyzed by employing energy analysis based on the first law of thermodynamics and exergy analysis based on the second law of thermodynamics. The results show that convective heat transfer leads to a decrease in both energy and exergy efficiencies: the rate and magnitude of the decrease in exergy efficiency are greater than those of the decrease in energy efficiency. The exergy efficiency is relatively high despite the low energy efficiency in operation, revealing the features and advantages of thermoelectric generators (TEGs) in low‐grade energy utilization. For TEG efficient operation, the load resistance value should match the system's internal resistance, or at least be greater than that, to avoid a sharp drop in power output and efficiencies. In an attempt at theoretical analysis, the concept of entransy was first introduced into thermoelectric analysis, yielding two concise relational equations which reflect the intrinsic link between Carnot cycle efficiency, energy efficiency, exergy efficiency, and entransy flow transfer efficiency. The entransy analysis based on the index of entransy flow transfer efficiency, together with energy analysis and exergy analysis, may be a novel and valuable guideline for the operation and optimization of TEGs, which needs to be further investigated.

Nanofluids in microchannel heat sinks for efficient flow cooling of power electronic devices

Nanofluids hold significant potential in the field of heat transfer intensification. The objective of this paper is to investigate the thermal-hydraulic characteristics of Ag, SiO2, and Al2O3 nanofluids in rectangular (MC-R), trapezoidal (MC-T), and omega-shaped (MC-O) microchannel heat sinks (MCHSs) through conjugate numerical simulations under a constant heat flux of 100 W/cm2. Water was used as the base fluid, and nanoparticle volume fraction ranged from 0 to 6 %. The average heat transfer coefficient (HTC), Nusselt number, thermal resistance, pressure drop, and pump power as a function of Reynolds number are studied for different nanofluids and cross-sectional shapes in microchannels. The overall performance is also characterized by thermal performance factor, coefficient of performance (COP), and entropy generation analysis. The simulation results show that adding Al2O3 nanoparticles with a volume fraction of 6 % in MC-R at a Reynolds number of 500 results in a substantial 12.3 % increase in the average HTC and an approximately 8 % reduction in total thermal resistance compared to pure water. For the same nanofluid, MC-O exhibits the highest convective HTC, the highest Nusselt number, and the lowest maximum heat sink temperature. The total entropy generation in the MCHSs decreases obviously with increasing Reynolds number. MC-O has the smallest total entropy generation, meaning it has the optimal flow and heat transfer irreversibility. These findings can not only provide valuable guidance for the rational design of MCHSs but also hold significant implications for the effective cooling of microelectronic components via nanofluid-based thermal management technology.

Irreversibility of heat transfer with the curvature effect on peristaltic thrusting of micropolar fluid in a resilient channel in the presence of heat generation: nonlinear analysis

In this work, we perform an investigation of the peristaltic thrusting of an incompressible viscous micropolar fluid in a symmetric resilient channel with consideration of streamline curvature effects and inertia forces. We obtained the partial differential equations for fluid flow in two dimensions for micropolar fluids in addition to the heat equation. These equations have been transformed to another domain by using a transformation between the fixed and wave frames. Asymptotic solutions of have been obtained by using the compatible boundary conditions using the perturbation technique of arbitrary Reynolds number and long-drawn wavelength. The solutions for longitudinal, normal and spin velocities, stream function, heat transfer and rate of working walls have been obtained. The several of biophysical parameters influence has been demonstrated through the graphs. Both time flow rate and pressure gradient relations are obtained. Different characteristics for fluid flow, temperature profile, normal force, microrotation (spin) velocity and Nusslet number are greatly influenced at the channel walls by the presence of micropolar fluid. Trapping and pumping phenomena are further discussed. It is found that the maximum value for the Bejan number occurs near the centre of the channel, i.e. the heat transfer irreversibility dominates around the centre of the channel.

Simulation investigation of the oscillatory motion of two elliptic obstacles located within a quarter-circle cavity filled with Cu-Al2O3/water hybrid nanofluid

This study investigates the consequences of introducing a pair of oscillating elliptical obstacles on the natural convection and entropy generation within a quarter-circle cavity that is filled with a water-based hybrid nanofluid. The Galerkin Finite Element Method was utilized to perform numerical simulations on a 2-dimensional cavity, where the outer wall was set to a low temperature and the inner wall was kept at a high temperature, while the other walls were adiabatic. The hybrid nanofluid containing Cu-Al2O3 nanoparticles was used. The impact of changes in the values of dimensionless parameters, such as the Rayleigh number, heated wall length, oscillation frequency, oscillation amplitude, and oscillation period, on the flow and heat transfer within the cavity was examined. Results showed that an increase in the length of the hot source resulted in a decrease in heat transfer rate and that increasing the Rayleigh number led to a significant increase in total entropy generation and heat transfer irreversibility. A drop in the average Bejan number was noted as the Rayleigh number increased, demonstrating the prevalence of entropy caused by fluid friction. The effect of changing the amplitude had a higher impact on the average Nusselt number compared to the frequency value. At low Rayleigh numbers, the average Nusselt number was higher when the elliptical obstacles oscillated in the same direction, while the opposite trend was observed at higher Rayleigh numbers.

Water-based nanofluid flow and heat transfer in thin film over an unsteady stretching sheet: An entropy analysis

The transfer of thermal energy is intrinsically associated with the generation of entropy. Here, we investigate the entropy generation number in nanofluid thin film flow over a radiated stretching sheet subject to different shapes of titanium oxide and copper nanoparticles in base fluid water. In addition, the impact of the magnetic field, viscous dissipation, and Joule heating were also considered. Using a suitable similarity transformation, the momentum and energy equations that describe the flow are converted into ordinary differential equations. These equations are then solved numerically using bvp4c in MATLAB. Graphs and explanations show how different physical parameters affect the velocity profile, temperature distribution, Nusselt number, skin friction coefficient, entropy generation number, and Bejan number. As the Brinkman number went up, fluid friction and Joule loss caused more entropy generation, but the Bejan number showed the opposite trend. In a certain situation, it is also important to note that as the value of the radiation parameter goes up, the irreversibility of heat transfer becomes more important. In addition, spherically shaped nanoparticles have the lowest entropy among all other forms. Hence, nanoparticles have the ability to reduce the amount of energy lost in any physical process and increase the overall productivity of systems. Understanding the flow and heat transmission within a thin film has many practical applications in industry, including aerodynamic lamination of plastic sheets, wire and fiber coating, food processing, annealing and thinning of copper wires, reactor fluidization, and many more.

System design and thermo-economic analysis of a new coal power generation system based on supercritical water gasification with full CO2 capture

To achieve sustainable energy supply and carbon neutral, it is essential to enhance the efficiency and reduce carbon emissions for coal power. In this study, a coal power generation system based on supercritical water gasification (SCWG) with full CO2 capture is proposed. The system achieves autothermal gasification by partial oxidation of coal in the SCWG gasifier. Gasification water is preheated by turbine exhaust, and organic Rankine cycle (ORC) is integrated to recover the waste heat of turbine exhaust. Simulation and thermodynamic analysis models of the system are developed. Results show the energy efficiency and exergy efficiency of system with benchmark parameters reach 52.95 % and 54.11 %, respectively. The largest exergy destruction occurs in gasifier and accounts for 41.36 % of the total exergy loss. Irreversibility of heat transfer mainly occurs in water heat exchanger and ORC, accounting for 4.81 % and 5.59 % of the total loss. Effects of key operating parameters on the system performance are investigated. Results show the optimal turbine exhaust pressure is 0.1 MPa, and higher turbine inlet temperature can enhance the system efficiency. System with reheat configuration shows potential in thermodynamic and economic aspects, and the exergy efficiency of double reheat system is improved from 37.25 % to 45.08 %.

Outlining the impact of discrete filling of metal foams on thermodynamic performance

The desire of this paper is to present the numerical analysis of thermodynamic performance of high porosity metal foams with discrete filling inside the horizontal pipe. The heater is embedded on the pipe’s circumference and is assigned with known heat input. To enhance heat transfer, aluminum metal foam of 10 PPI (pores per inch) with porosity 0.95 is filled into the pipe. In filling, two kinds of arrangements are made. In the first arrangement, the metal foam is filled adjacent to the inner wall of the pipe (Model (1–3)), and in the second arrangement, the metal foam is located at the center of the pipe (Model (4–6)). So, six different models are inspected for different fluid velocities (0.7–7 m/s) under turbulent flow conditions. Darcy Extended Forchheimer (DEF) is combined with local thermal non-equilibrium (LTNE) models for estimating the flow features and heat transfer via metal foams and initially validated with experimental outcomes. The application of the second law of thermodynamics via metal foams is the novelty of current investigation. In the study, the thermal performance is assessed in terms of heat transfer enhancement ratio and heat transfer performance ratio, and the thermodynamic performance is evaluated based on exergy and irreversibility analysis. In the analysis, the parameters like mean exergy based Nusselt number (Nue), heat transfer and flow frictional irreversibility are considered for the evaluation. The overall thermal performance and exergy transfer found higher in Model (1–3) than the Model (4–6) respectively. The flow and heat transfer irreversibility found less in Model (1–3) than the Model (4–6) respectively. The superior thermodynamic performance is obtained from the metal foam filled cases than from the clear pipe. In that, Model-2 suits the best configuration for designing the thermal system.

Optimizing geometrical structure of a residential parabolic solar collector relying on hydrothermal assessment and second law analysis

Researchers are interested in the optimization of thermal systems due to the rising demand towards renewable and green energy to reduce greenhouse gasses and expenses. To achieve this, the present work aims to conduct the numerical modeling on the residential scale trough solar collector. For this purpose, the lattice Boltzmann method is employed with special treatment for the curved physical boundaries. To enhance the thermal capability of the solar collector, the CuO-water nanofluid is utilized, which its thermal conductivity is estimated using Koo–Kleinstreuer and Li (KKL) model. Furthermore, the Brownian motion effect on the dynamic viscosity is taken into account. In addition, the local and volumetric second law analysis is performed. Besides, the heat line visualization is done to capture the path-line of heat energy within the solar collector. The thermal distribution, flow field, local entropy production (i.e. fluid friction irreversibility and heat transfer irreversibility maps), volumetric entropy generation, Bejan number, and average Nusselt number are the studied items in terms of the governing parameters. The Rayleigh number (103 ≤ Ra ≤ 106), CuO nanoparticle concentration (φ = 0, 0.01, 0.02, 0.03, 0.04) and four structural design of the solar collector (Single-pipe, Double-pipe, Triple-pipe, Quadruple-pipe) are assumed as the governing parameters.

Experimental investigation of entropy generation in a pipe heat exchanger with turbulence generator inside and on the outside

The thermal performance of a pipe heat exchanger can be improved with the use of turbulator inserts. This is accompanied with a drop in pressure because of secondary swirl flow creation in the exchanger. A number of experiments were performed to find the entropy formation with twisted tape inserts inside a tube and helical ribs over the outside of a tube heat exchanger. A counter flow system with water being used as a working fluid was used. The simple pipe validation was performed using standard correlations, and the findings were found to be within an acceptable range. As the Reynolds number was increased, it was discovered that the irreversibility of heat transfer gets increased. As the twist ratio falls, the entropy created due to friction increased. The Bejan number demonstrates that the formation of entropy is mostly attributable to the irreversibility of heat transport rather than the irreversibility of fluid friction. A Bejan value close to one suggests that there is a significant irreversibility of heat transfer in all instances.

Presentation of entropy due to heat transfer irreversibility of MHD Williamson fluid over an inclined channel

The non-Newtonian characteristic of the fluid flow phenomena has several applications in industries and the production of engineering gadgets. Based upon the role, the present work deals with the flow of Williamson nanofluid past two inclined parallel sheets. Further, the influence of radiating heat due to thermal radiation, Ohmic heating because of the magnetization, and inclined angle on Williamson fluid are presented, which are vital for the heat transfer enhancement. The proposed study became novel due to the scrutiny of entropy for the irreversibility processes within the system that is obtained due to heat transfer. The designed model with dimensional form is developed by converting to dimensionless forms with the help of similarity transformations. The finalized transformed equations are handled analytically using the Homotopy perturbation method (HPM). Heat irreversibility is calculated by inserting the observed values into entropy generation and Bejan number. The suggested method of solution for the momentum profile is verified by comparing it to a previously published numerical result in some limited circumstances, and great agreement is found. The result reveals that the entropy generation is enhanced near the upper wall of the channel for the magnetized particle but thermal radiation attenuates it, however, the fluid temperature boosts up for the enhanced coupling constraint i.e. for the existence of Eckert number.

A unified approach for the thermodynamic comparison of heat pump cycles

The flexible heat pump cycle introduces a heat storage device into the Evans-Perkins cycle to recover, store, and reuse part of the sensible heat carried by the hot liquid refrigerant from the condenser, achieving a higher coefficient of performance than the latter. In this paper, we develop a unified approach, namely cycle superposition to allow comparison of the flexible heat pump cycle with other performance-enhancing cycle layouts including two-stage cycles with intercooling, subcooling, flash gas removal, or their combinations. We show that under ideal conditions, the flexible heat pump cycle is thermodynamically similar to two-stage heat pump cycles with full subcooling or flash gas removal, but no intercooling. From the energy recovery perspective, the two-stage cycles recover and reuse some sensible heat carried by hot liquid refrigerant simultaneously using their high-stage compressor, whereas the flexible heat pump cycle decouples the recovery and reuse of such heat in time using a heat storage. However, the irreversible heat transfer via real heat exchangers during charging and discharging processes will reduce the benefits of the flexible heat pump cycle. The effectiveness of all these performance-enhancing methods strongly depends on the characteristics of refrigerants.

Dual pressure condensation heating high temperature heat pump using eco-friendly working fluid mixtures for industrial heating processes: 4E analysis

To make better use of waste energy for the industrial heating processes, dual pressure condensation heating high temperature heat pump system (DPS) is proposed, to achieve the purpose of step heating. Meantime, environmental-friendly working fluid hydrocarbons are selected as the components of the mixtures. The energy, exergy, environmental and economic (4E) analysis models are established, and the system performance is optimized, compared with single-stage (SS) system and fossil fuel-fired boilers. There is an optimal intermediate water temperature corresponding to the highest system energy efficiency. The maximum COP of 5.29 is achieved when R600a/R601a (50/50) is adopted, improved by 18.23% and 24.18% compared with DPS and SS systems using pure working fluid. By using zeotropic working fluid, the irreversible heat transfer loss can be significantly reduced. The overall exergy loss with R600a/R601a (50/50) is 21.68–41.27% and 12.26–16.69% lower than pure SS and pure DPS systems, respectively. In terms of environmental and economic aspects, DPS with zeotropic working fluid shows excellent performance. In comparison with boiler, pure DPS and pure SS system, the reduction of carbon emissions through the whole lifetime is 81.22%, 15.35% and 20.04%, and the life cycle cost is decreased by 93.91%, 9.70–15.05%, and 27.89–38.07%.

Thermally developing combined electroosmotic and pressure-driven flow of Phan–Thien–Tanner fluids in a microchannel

We present semi-analytical solutions for the hydrodynamically developed and thermally developing flow of a non-Newtonian fluid through an isothermal rectangular microchannel. The fluid motion is actuated by the combined consequences of the electroosmotic and pressure-gradient forces. For the rheological behavior of the non-Newtonian fluid, we have used the simplified Phan–Thien–Tanner viscoelastic model. Going beyond the Debye Hückel linearization approximation, we have used the full-scale solution for the electrical double-layer potential equation to obtain the exact analytical solutions for the velocity, flow rate, and shear rate parameters. In contrast, the temperature distribution and heat transfer for the thermally developing flow have been obtained by solving the energy equation numerically considering the effects of volumetric heat generation due to Joule heating and viscous dissipation. We find that a larger value of the viscoelastic set ε̃Wĩk2 contributes toward the net gain in flow rate. Both the normal and shear stress increase for increasing ε̃Wĩk2, while the shear viscosity reduces with a degree of surface charging. The average shear viscosity reduces with the degree of surface charging and at higher ε̃Wĩk2 values. The heat transfer is enhanced for augmenting ε̃Wĩk2, although the thermal entrance region gets contracted for a pure electroosmotic flow at higher Peclet numbers. Our study reveals that the heat transfer rate can be amplified by effectively modulating the degree of surface charging and ε̃Wĩk2. We have also carried out an entropy generation analysis, which shows the dominance of heat transfer irreversibility over fluid friction irreversibility. We believe that the present research will offer essential approaches for designing advanced energy-efficient microchannels appropriate to modern industrial applications using viscoelastic fluids.

Effect of a Sinusoidal Temperature Profile on Entropy Generation Due to Double-Diffusive Natural Convection in a Square Partly Porous Cavity

Abstract In this paper, entropy generation due to double-diffusive natural convection inside a partly porous enclosure under sinusoidal wall heating is numerically analyzed. The resulting dimensionless coupled partial differential equations are discretized using the finite volume method (FVM), while the pressure–velocity coupling is handled using the SIMPLE algorithm. To ensure the validity of the results obtained from the in-house FORTRAN code, a comparison is made with previous numerical and experimental works. The results of the study indicate that the dimensionless thickness of the porous layer (Δ), the thermal conductivity ratio (Rk), the angle of inclination of the cavity (α), and the buoyancy ratio (N) are critical factors in determining local distribution and global maximum value of entropy generation due to heat transfer and fluid friction. In contrast, their effect on entropy generation induced by concentration is insignificant, except for the buoyancy ratio parameter, where an enhancement of the global maximum of entropy generation is observed by increasing N. Moreover, it is found that Sψ (max) experiences a sharp decline as Δ varies from 0.2 to 0.8, resulting in a reduction of about 67% for the case with N=10 and 83% for the case with N=1. These results highlight the importance of carefully controlling system parameters to minimize energy losses and maximize system efficiency in heat transfer and fluid flow systems.

Entropy and exergy analysis of coupled radiative heat transfer and heat conduction: A new thermodynamics approach

This study presents a new approach for evaluating the thermodynamic efficiency of a coupled radiative and conductive heat transfer process with an internal heat source. In this approach, the exergy balance equation is derived, and the exergy augmentation rate due to the internal heat source is found to be the sum of the exergy of the system output to the environment surroundings, the exergy stored in the system, and the exergy consumption rate due to the irreversibility of heat transfer in the system. The exergetic efficiency of the coupled heat transfer process is then obtained according to the radiative exergy balance equation. Based on the above theoretical derivation, we carry out a thermodynamic analysis of an example including five coupled heat conduction-radiation transfer systems with a uniform internal heat source and different boundary conditions. The variations in the numerical results are discussed according to the exergy balance principle, and the behaviours of the exergy components over time under transient conditions are analysed. Our numerical results show that increasing the area of the adiabatic boundary and reducing the heat loss of the system should be considered when designing heat-transfer systems (as the exergetic efficiency increases from 0.515 to 0.617). The larger the area of the adiabatic boundary of the system, the stronger the effect of increasing this area on the overall optimisation. When a system has two adiabatic boundaries, a symmetrical arrangement of the adiabatic boundaries is suggested, although this is much less effective than increasing the number of adiabatic boundaries.

Cilia and electroosmosis induced double diffusive transport of hybrid nanofluids through microchannel and entropy analysis

Abstract A mathematical model is presented to analyze the double diffusive transport of hybrid nanofluids in microchannel. The hybrid nanofluids flow is driven by the cilia beating and electroosmosis in the presence of radiation effects and activation energy. Cu–CuO/blood hybrid nanofluids are considered for this analysis. Phase difference in the beatings of mimetic cilia arrays emerge symmetry breaking pump walls to control the fluid stream. Analytical solutions for the governing equations are derived under the assumptions of Debye–Hückel linearization, lubrication, and Rosseland approximation. Dimensional analysis has also been considered for applying the suitable approximations. Entropy analysis is also performed to examine the heat transfer irreversibility and Bejan number. Moreover, trapping phenomena are discussed based on the contour plots of the stream function. From the results, it is noted that an escalation in fluid velocity occurs with the rise in slippage effects near the wall surface. Entropy inside the pump can be eased with the provision of activation energy input or by the consideration of the radiated fluid in the presence of electroosmosis. The results of the present study can be applicable to develop the emerging thermofluidic systems which can further be utilized for the heat and mass transfer at micro level.

Qualitative modeling of solar panel cooling by nanofluid jets: Heat transfer and second law analysis

The present paper highlights heat transfer and entropy generation due to mixed convection for an inclined channel. The channel is heated by its upper wall and cooled by two jets of nanofluids penetrating through its lower wall. The studied configuration is chosen to model, in qualitative way, a cooling system for photovoltaic panel. The set of partial differential equations that governing the flow was numerically solved using COMSOL software. Effects of the inclination angle of the channel, Reynolds number and nanoparticles fraction, on heat transfer, hydrodynamic and created entropy are examined. The inclination angle, the Reynolds number and the nanoparticle fraction are ranging from 0° to 30°, from 50 to 150 and from 0% to 8% respectively. It was found that the effect of the angle of inclination, on heat transfer and thermal irreversibility, is weak and that it cannot exceed 2%. Whereas the nanofluid concentration and the Reynolds numbers alter at once the created entropy and the heat transfer. Results show an increase of nearly 15% of Nusselt number and thermal irreversibility when the nanoparticle concentration reaches 8%. The local irreversibility maps reveal that the created entropy is significantly localized at the impact locations of the cooling jets. Since irreversibility is synonymous with the aging of the system, which naturally leads to usury, it can be concluded that the channel may be damaged at these locations.

Computational Irreversibility Analysis in Transient Flow of a Non-Newtonian Fluid through a Channel with Porous Walls

A second law analysis is explored to investigate the irreversibility properties in a transient, porous channel flow of a viscous, incompressible, and non-Newtonian fluid. The non-Newtonian fluid model is of a Generalized Newtonian Fluid type with no elastic properties but with shear-thinning viscosity. Additionally, given that the flow is non-isothermal, the viscosity is therefore expectedly also assumed to be temperature dependent. The porous channel is subjected to constant suction and injection of fluid through the walls. Computational solutions for the underlying fluid dynamical equations, based on robust finite difference numerical techniques, are developed and implemented in time and space. We demonstrate the effects of the embedded fluid flow and heat transfer parameters on the fluid velocity and temperature profiles. We also explore the competing effects of heat transfer irreversibility versus fluid friction irreversibility. The major observations are that, in the flow regions where the maximum velocity obtains, heat transfer irreversibility significantly dominates over the otherwise insignificant fluid friction irreversibility. It is also observed that, in those flow regions away from the region of maximum velocity, the opposite scenario obtains, and hence fluid friction irreversibility significantly dominates over heat transfer irreversibility. Along the channel walls, fluid friction irreversibility notably dominates over heat transfer irreversibility. The possibility that certain parameter choices may lead to reverse scenario is not discounted.

Analysis of Micro-Hybrid and Casson-Hybrid Nano-Convective and Radiative Fluid Flow in an Inclined Channel

The underlying intension of this study is to oversee the entropy generation due to Casson-micropolar hybrid nanofluid flow in an inclined microchannel. Magnesium oxide (MgO) and Zirconium oxide (ZrO2) nanoparticles are considered with a base fluid of polyethylene glycol (PEG). The proposed system of nonlinear differential equations is numerically solved with a shooting procedure (R-K 4th order). Outcomes obtained for the velocity f (ζ), the micro rotation g (ζ), the Bejan number Be, the Entropy generation Ns, and the temperature distribution θ (ζ) are elucidated via graphs. A comparative study of obtained results with previously published results are also discoursed. One of the interesting outcomes of this study is found to be—an increase in the radiation reduces the fluid temperature at the center of the microchannel and the Bejan number profiles postulate that the heat transfer irreversibility dominates around the center of the microchannel.

Magneto-nanofluid flow in cylinder-embedded discretely heated-cooled annular thermal systems: Conjugate heat transfer and thermodynamic irreversibility

The present work investigates magnetohydrodynamics-driven thermal-fluid flow characterization in cylinder-embedded annular thermal systems subjected to peripheral differential heating. It explores Al2O3/water nanofluid flow-associated heat transfer and entropy generation in the presence of a magnetic field and a conducting cylindrical obstruction (block). The consequence of various obstruction sizes on thermo-fluid flow behavior is also analyzed. The transport equations are handled by a finite element-based solver. The thermal-flow analysis is carried out for the relevant vital parameters such as Rayleigh number (Ra), Hartmann number (Ha), magnetic field orientation (γ), and obstruction size. Through the investigation, it is found that Nusselt number (Nu) is greatest when the internal conducting block size is the least. It can thus be inferred that flow circulation plays a dominant role in determining the Nu value. Heat flow dynamics described by the heatlines, as well as flow structure examined by the streamlines, are found to vary depending upon the obstruction size, and the field orientation (γ). Furthermore, the total entropy generation figures out that when the buoyant forces within the thermal systems are low, the entropy generation is uniform along the periphery; however, when the buoyant forces take a significantly higher value, the contours of entropy generation are seen to be more concentrated near the discretely heated and cooled walls. It is seen that if the inner conducting body size increases, the overall entropy production significantly increases. Finally, a generalized single mathematical correlation is developed for both heat transfer and entropy generation. This thermal system configuration has practical relevance and the present findings could enrich the understanding of pre-existing concepts in the area of thermal systems pertaining to effective heat-exchanging devices.