Irreversible Flow Research Articles

Thermophysical features of Ellis hybrid nanofluid flow with surface-catalyzed reaction and irreversibility analysis subjected to porous cylindrical surface

This study explores the flow irreversibility of the Ellis hybrid nanofluid (containing CoFe2O4−TiO2 nanoparticles) with homogeneous and heterogeneous reactions to a horizontal porous stretching cylinder. The energy transportation aspects are investigated in terms of the influence of joule heating and viscous dissipation. The slip and convective boundary conditions are levied on the cylindrical surface, and the mathematical flow model is transferred to a system of nonlinear ordinary differential equations using suitable transformations. The highly nonlinear systems of equations are numerically solved using the bvp4c approach in MATLAB. The graphical outcomes are obtained and discussed; it is worth noting that incremental estimations of the curvature parameter show opposite behaviors on the Ellis fluid velocity and entropy generation, i.e., the entropy generation profile increases while fluid velocity decreases. The boundary layer thinning shows resistance to impact by elasticity and magnetic field. Further, as the porosity of the liquid phase increases, the momentum of the boundary layer decreases.

Numerical appraisal of time-dependent peristaltic duct flow using Casson fluid

Interruption of continuous process and decreasing flow rate over time are very common challenges in peristaltic flow. This research takes an initiative to restrain the thermal and fluid flow rate over time by unsteady finite element analysis of Casson fluid flow through a two-dimensional peristaltic duct. The time-dependent flow equation exists in conjugate forced convection and the energy equation consists of radiative heat flux and entropy reduction. The top and bottom walls of the peristaltic duct are considered as contact with air. A circular bolus is set up in the middle of the duct. Four types of Casson fluids like slurry, silicone oil, apple juice, and blood are used as working fluids. The finite element method of Galerkin's residual technique is applied to solve the leading second ordered non-linear partial differential equations with proper border conditions. The effects of pertinent parameters on entropy reduction and thermal transport are analyzed. Results are displayed qualitatively in terms of streamlines, vortex field, and heatline contours as well as quantitatively in the form of average temperature, mean thermal, viscous, and total entropy. The obtained numerical results show that thermal performance and entropy reduction are significantly influenced by forced convection, atmospheric characteristics, internal thermal radiation, and Casson fluids. Approximately 6.99% and 72.13% increment of temperature and flow irreversibility are found for shear stress variation of Casson fluid from thickening to thinning. Decreasing thermal performance of 18.71% and increasing energy loss of 38.07% are noticed within the variation of Casson fluids (slurry, silicone oil, apple juice, and blood). About 14.05% enhancement of thermal transport and 64.91% reduction of total entropy are observed due to increasing internal thermal radiation from 0.5 to 2. The numerical results from this research represent a better thermal and fluid flow rate over time compared to the experimental/existing methodology/numerical research. The obtained flow and thermal transport phenomena expose many attention-grabbing performances which deserve additional investigation on Casson fluid characteristics particularly the continuation of flow rate. A fine approach to the biological peristaltic system is offered by the results.

A Dimension Reduction-Based Multidisciplinary Design Optimization Method for High Pressure Turbine Blades

Abstract The complex aero-thermal coupling between fluid and solid regions within high-pressure turbines makes it important to perform multidisciplinary design optimization of high-pressure turbine blades. However, most published works failed to consider the correlations between blade profiles and cooling structures that could best compromise the aerodynamic and thermal performance of high-pressure turbine blades, and the related optimization problems were so far limited to single- or bi-objective ones. The critical drawbacks of these available studies are mainly due to the reduced accuracies of the adopted methods when dealing with large numbers of design variables and objectives. To tackle these difficulties, a dimension reduction-based multidisciplinary design optimization method is proposed and validated through an aero-thermal design optimization of the NASA-C3X vane with a total of 39 design variables and five performance objectives. The main novelties of this proposed method lie in a hybrid dimension reduction of design space by means of the proper orthogonal decomposition and global sensitivity analysis methods, as well as the integration of the ensemble surrogate model and the reference vector evolutionary algorithm for optimal solutions. The results show that the prediction accuracy of the ensemble surrogate model for each performance objective is enhanced, even though the dimensionalities of design space are reduced. Complicated compromises exist among the five performance objectives under consideration. For NASA-C3X vane, the optimal design helps reduce irreversible flow losses especially wake losses while reducing the volumes with high-temperature and high-temperature gradient near the trailing edge is mainly responsible for the reduced irreversible losses due to heat transfer. The outcomes of this work are particularly relevant for the advanced design optimization methods for high pressure turbines.

Stabil Kronik Obtrüktif Akciğer Hastalığı Hastalarında Serum Prolidaz ve Karbonik Anhidraz III Düzeylerinin Klinik Önemi

Aim: Chronic obstructive pulmonary disease (COPD) is a disease characterized by irreversible airway flow limitation and chronic airway inflammation. We aimed to investigate the clinical importance of serum prolidase enzyme, which is an indicator of collagen degradation, and Carbonic anhydrase (CA) III enzyme, which has an important function in acid-base regulation, in patients with COPD Methods : In this study, 56 stable COPD patients and 32 healthy subjects without smoking history and comorbidities were included. Serum CA III and prolidase enzyme levels were compared between the two groups. Results: The statistical difference was not found between the two groups in terms of prolidase enzyme levels (p=0.831). There was a statistically significant increase in CA III levels in the COPD group (p=0.001). There were moderate positively correlation between CAIII with partial pressure of carbon dioxide in blood (pCO2) and negatively correlation between CA III with partial pressure of oxygen in blood (pO2) in COPD patients (r:0.302, p<0.025; r:-0.314, p:0.02). Conclusions: We think that there is an important clinical relationship between CA III and COPD, and therefore, CA III may be a candidate biomarker in the follow-up of COPD.

Optimization and thermodynamic analysis of rib arrangement and height for microchannels with sharkskin bionic ribs

Here, four novel arrangements of microchannels with sharkskin-inspired bionic ribs were proposed to enhance heat transfer with a low pressure drop, as well as to reduce the irreversibility of flow and heat transfer compared to that in a smooth rectangular microchannel (SRM). The arrangements featured either equal (E) or non-equal (N) rib lengths and parallel (P) or staggered (S) rib positions, and were labeled as EP, ES, NP, and NS accordingly. The flow and heat transfer characteristics of these microchannels were then investigated in the laminar flow regime (Re = 50–1000). The results showed that NS performed the best overall at each condition, compared with EP, ES, and NP. Meanwhile, a performance evaluation plot showed that NS had the best energy savings and a large slope at H = 0.06 mm. Entropy generation analysis further confirmed that H = 0.06 mm was the optimum bionic rib height. The minimum enhanced entropy generation number, N s,a, for NS was 0.43 at H = 0.06 mm and Re = 770, indicating better energy utilization compared to other microchannels at this operating condition. The results from this study illustrate the potential of bionics in improving the design of microchannel structures.

Viscous dissipation effect on forced convective transport of nanofluids in an asymmetrically heated parallel-plate microchannel

This study intends to investigate the effects of viscous dissipation on the Alumina-water nanofluids transport in an asymmetrically heated microchannel, accounting for Brownian motion and thermophoresis mechanism. An iterative algorithm deploying Runge-Kutta fourth order method was set up to solve the governing equations numerically. Viscous dissipation shifts the highest concentration and lowest fluid temperature away from the adiabatic wall and redistributes the spatial variation of thermal conductivity and viscosity, retarding the Nu as its effect strengthens. It is noteworthy that the trends of Nusselt number variation with an increasing nanoparticle bulk concentration, and Brownian and Themophoretic diffusivity ratio, N BT , highlight the competition between the enhanced thermal diffusion effect and the hindered heat convection by a larger flow resistance. A Brinkman number, Br larger than 0.02 alters the Nu pattern of variation with N BT . Viscous dissipation leads to more pronounced effects of particle migration on the concentration and temperature distribution in particular. Assuming negligible viscous dissipation, Nusselt number deteriorates beyond an Alumina concentration of 3.65 vol %. while Titania-water nanofluids showed an opposite trend. The total entropy generation, caused by fluid flow irreversibility predominantly, amplifies with an increasing nanoparticle concentration, more significantly when the concentration is below 6.5 vol %., for Br = 0.1. Conversely, an increase in Brownian to Thermophoretic diffusivity ratio, N BT , lessens the entropy generation.

Steady streaming flow induced by active biological microstructures; application to small intestine villi

Physiological transport of fluid at small scales is often achieved by microscopic active fingerlike structures. It is recognized that they have to move in a non-symmetric fashion in order to break the symmetry of creeping flow and to induce a net movement of the fluid. However, in the limit of low, but non-vanishing, Reynolds number, irreversible flow on long time scales could also be generated by symmetric oscillations of these microstructures. Inspired by small intestine villi, we reported three dimensional direct numerical simulations of the irreversible part of the flow, namely steady streaming flow (SSF), generated by an array of oscillating fingerlike structures. In order to capture these second order flow phenomena, the algorithm was based on a combination of lattice-Boltzmann methods with two relaxation times and the smoothed profile method. SSF was confined inside a steady viscous boundary above the villi. Two steady vortices at the tip of the villi characterized this flow which induced mass transfers between the bulk and the periphery. Strikingly, the spatial extension of these vortices was not solely governed by the Stokes boundary layer but also by the lateral confinement between the villi. Moreover, secondary vortices outside the steady boundary layer were also observed. These findings were rationalized in a state diagram showing three regimes of SSF. Finally, orders of magnitude showed that SSF should contribute to the transport of particles, such as bacteria or nano-particles, on a layer a few hundred micrometers above the villi and on a time scale of few minutes.

Irreversible entropy production rate in a parametrically driven-dissipative system: The role of self-correlation between noncommuting observables

In this paper, we explore the emergence of the Wigner entropy production rate in the stationary state of a two-mode Gaussian system. The interacting modes dissipate into different local thermal baths. Also, one of the bosonic modes evolves into the squeezed-thermal state because of the parametric amplification process. Using the Heisenberg-Langevin approach, combined with quantum phase space formulation, we get an analytical expression for the steady-state Wigner entropy production rate. It contains two key terms. The first one is an Onsager-like expression that describes heat flow within the system. The second term resulted from vacuum fluctuations of the baths. Analyses show that self-correlation between the quadratures of the parametrically amplified mode pushes the mode towards the thermal squeezed state. It increases vacuum entropy production of the total system and reduces the heat current between the modes. The results imply that, unlike other previous proposals, squeezing can constrain the efficiency of actual non-equilibrium heat engines by irreversible flows.

The effect of non-ionizing excitations on the diffusion of ion species and inter-track correlations in FLASH ultra-high dose rate radiotherapy

Purpose. We present a microscopic mechanism that accounts for the outward burst of ‘cold’ ion species (IS) in a high-energy particle track due to coupling with ‘hot’ non-ion species (NIS). IS refers to radiolysis products of ionized molecules, whereas NIS refers to non-ionized excitations of molecules in a medium. The interaction is mediated by a quantized field of acoustic phonons, a channel that allows conversion of thermal energy of NIS to kinetic energy of IS, a flow of heat from the outer to the inner core of the track structure. Methods. We perform step-by-step Monte Carlo (MC) simulations of ionizing radiation track structures in water to score the spatial coordinates and energy depositions that form IS and NIS at atto-second time scales. We subsequently calculate the resulting temperature profiles of the tracks with MC track structure simulations and verify the results analytically using the Rutherford scattering formulation. These temperature profiles are then used as boundary conditions in a series of multi-scale atomistic molecular dynamic (MD) simulations that describe the sudden expansion and enhanced diffusive broadening of tracks initiated by the non-equilibrium spectrum of high-energy IS. We derive a stochastic coarse-grained Langevin equation of motion for IS from first-principle MD to describe the irreversible femto-second flow of thermal energy pumping from NIS to IS, mediated by quantized fields of acoustic phonons. A pair-wise Lennard-Jones potential implemented in a classical MD is then employed to validate the results calculated from the Langevin equation. Results. We demonstrate the coexistence of ‘hot’ NIS with ‘cold’ IS in the radiation track structures right after their generation. NIS, concentrated within nano-scale volumes wrapping around IS, are the main source of intensive heat-waves and the outward burst of IS due to femto-second time scale IS-NIS coupling. By comparing the transport of IS coupled to NIS with identical configurations of non-interacting IS in thermal equilibrium at room temperature, we demonstrate that the energy gain of IS due to the surrounding hot nanoscopic volumes of NIS significantly increases their effective diffusion constants. Comparing the average track separation and the time scale calculated for a deposited dose of 10 Gy and a dose rate of 40 Gy s−1, typical values used in FLASH ultra high dose rate (UHDR) experiments, we find that the sudden expansion of tracks and ballistic transport proposed in this work strengthens the hypothesis of inter-track correlations recently introduced to interpret mitigation of the biological responses at the FLASH-UHDR (Abolfath et al 2020 Med. Phys. 47, 6551–6561). Conclusions. The much higher diffusion constants predicted in the present model suggest higher inter-track chemical reaction rates at FLASH-UHDR, as well as lower intra-track reaction rates. This study explains why research groups relying on the current Monte Carlo frameworks have reported negligible inter-track overlaps, simply because of underestimation of the diffusion constants. We recommend incorporation of the IS-NIS coupling and heat exchange in all MC codes to enable these tool-kits to appropriately model reaction-diffusion rates at FLASH-UHDR. Novelty. To introduce a hypothetical pathway of outward burst of radiolysis products driven by highly localized thermal spikes wrapping around them and to investigate the interplay of the non-equilibrium spatio-temporal distribution of the chemical activities of diffusive high-energy particle tracks on inter-track correlations at FLASH-UHDR.

Numerical investigation of entropy generation in a solar parabolic trough collector using supercritical carbon dioxide as heat transfer fluid

• A Three-dimensional numerical thermal model is developed for solar Parabolic trough collector with s-CO2 as a heat transfer fluid. • Non-uniform solar heat flux calculated using Monte Carlos Ray Tracing based Optical Tool. • Entropy generation is calculated using the local temperature and velocity fields. • Optimal inlet boundary conditions were obtained for the s-CO2 as heat transfer fluid in the solar parabolic trough collector. Parabolic trough collector (PTC) is a widely used and efficient Concentrating Solar Power (CSP) technology for generating solar thermal power. Supercritical CO 2 (s-CO 2 ) is a heat transfer fluid (HTF) that shows good promising for use in solar PTC for further improvement in its efficiency and operations. A numerical thermal model is developed to understand the performance of s-CO 2 as an HTF in a solar PTC. The local temperature and velocity fields were used to calculate the entropy generated within HTF due to finite temperature differences and fluid flow friction. A commercially available LS-3 parabolic trough collector is used for the analysis with a modified receiver. An optical analysis tool based on Monte Carlo Ray tracing is used to calculate non-uniform heat flux distribution around the circumference of the PTC receiver. Entropy generated at various operating pressures, inlet temperatures, and inlet Reynolds number using s-CO 2 as HTF is calculated and analyzed. Results showed that entropy generated in the PTC receiver is reduced to a minimum at optimal Reynolds number for each of the operating pressures and inlet temperatures of the HTF. The Bejan number estimates the contribution of entropy generated due to heat transfer irreversibilities to the entropy generated due to heat transfer and fluid flow irreversibilities which is between 0.2 and 0.4 at high flow rates and close to 1 at low flow rates. Exergy efficiency analysis supported the optimized inlet boundary conditions.

PANDORA`S BOX OR «NO-REFLOW» PHENOMENON (CLINICAL CASE)

It has been established that successful repefusion of ocluded infarct-dependent coronary artery (IDCA) during percutaneous coronary intervention does not mean restoration of myocardial perfusion. This «no-reflow» phenomenon is known from the studies of R. Kloner, C. Ganote, R. Jennings (1974). They were among the first to note only a partial restoration of coronary blood flow after the reperfusion of mechanically occluded for 90-180 minutes coronary artery in dogs. The authors considered damage to the capillary endothelium, edema of the damaged wall and extravasal tissues, and protrusion into the capillary cavity to be the cause of this phenomenon.
 The frequency of the phenomenon of «no-reflow» after the successful restoration of coronary blood flow in the IDCA varies between 5 - 40% of all cases. The development of this phenomenon was an unfavorable prognostic factor, primarily in terms of mortality and deterioration of the functional state of the left ventricle.
 The pathophysiology of the «no-reflow» phenomenon remains poorly understood. Obviously, it has a multifactorial nature and cannot be described by any one mechanism.
 Analyzing the phenomenon of «no-reflow», it is noted that in spite of the reperfusion of IDCA, there are pronounced pathophysiological changes in the microcirculatory tract, the essence of which is to block myocardial perfusion in the area of myocardial infarction.
 During the COVID-19 pandemic, the number of patients with myocardial infarction increased, including an increase in the number of diagnosed «no-reflow» and «slow-flow» phenomena, which is associated with the impact of SARS СOVID-19 virus on the myocardium, namely the development of microvascular damage.
 There is currently no specific therapy for the prevention and treatment of «no-reflow» phenomen that would be recommended for patients with STEMI.
 This article presents a clinical case of the phenomenon of «no-reflow» in patient B., 56 years old, who complained of severe chest pain, irradiation in the left shoulder and lower jaw, shortness of breath, general weakness. History of hypertension, coronavirus PCR +. Troponin I - 5.4 ng/ml. According to the electrocardiogram: elevation of the ST segment in II. III, aVF leads. At the time of contrast infusion during stenting of infarct-dependent right coronary artery, its slow filling was recorded - the phenomenon of «no-reflow» TIMI 0, MBG-0. The patient was discharged from the hospital in satisfactory condition under the supervision of a family doctor.
 Conclusions:
 
 The phenomenon of «no-reflow» is a topical and unresolved issue of myocardial revascularization in real clinical practice.
 The most common prerequisite for the development of the phenomenon of «no-reflow» after myocardial revascularization is late hospitalization, and aggravating circumstances - comorbid pathology (COVID-19, hypertension, diabetes).
 This clinical case is interesting because the patient with lesions of the lower left ventricular wall PCI was complicated by the phenomenon of «no-reflow», as evidenced by the slowing of ST segment resolution, lack of myocardial perfusion, parietal thrombosis throughout the RCA.
 Further search for ways to prevent and treat irreversible blood flow syndrome after successful reperfusion of infarct-dependent coronary artery is needed.

Analysis of process efficiency: Role of flow and thermal characteristics on entropy production and heat transfer rates for thermal convection in porous beds confined within triangular configurations with hot slanted walls

Flow and heating characteristics associated with heat transfer rates vis-a-vis entropy generation based on flow and thermal irreversibilities are numerically studied for thermal convection in the porous bed confined within various configurations of triangular enclosures. The triangular configurations involve various vertex angles ( and ) with three tilt positions (configurations 1–3) subjected to a linear heating pattern of the slanted walls. Numerical studies are carried out for various dimensionless parameters (Prm and Dam ) at fixed Ram . Simulation results infer that the triangular configuration 3 [configuration 3: triangle is tilted perpendicularly from horizontal position (configuration 1 or 2)] involving is the optimal configuration based on the larger rate of heat transfer and moderate entropy production at larger porosities () for buoyancy dominant scenarios () irrespective of Prm .

Five performance indicators for a universal generalized irreversible steady flow cycle including seven specific refrigeration cycles

Five performance indicators for a universal generalized irreversible steady flow cycle including seven specific refrigeration cycles

Magnetic energy spectrum produced by turbulent dynamo: Effect of time irreversibility

We consider the kinematic stage of evolution of magnetic field advected by turbulent hydrodynamic flow. We use a generalization of the Kazantsev–Kraichnan model to investigate time irreversible flows. In the viscous range of scales, the infinite-time limit of the spectrum is a power law, but its slope is more flat than that predicted by the Kazantsev model. This result agrees with numerical simulations. The rate of magnetic energy growth is slower than that in the time-symmetric case. We show that for high magnetic Prandtl turbulent plasma, the formation of the power-law spectrum shape takes very long time and may never happen because of the nonlinearity. We propose another ansatz to describe the spectrum shape at finite time.

Water-pumping and purifying hydrogels driven by diurnal temperature variation

Diurnal temperature variation is an untapped energy source, although it has seldom been exploited as such. In this study, a novel system of thermo-responsive hydrogels uses diurnal temperature variation as the only power source to pump and purify water. Water is pumped at night and released during the day using an anisotropic xylem-mimetic structure whose composite phase functions as a water channel valve. The water-pumping efficiency ranges from 78% to 92%, and the weights of the pumped water per cycle are 2–3 times larger than those of the pumping materials. The anisotropic structure and the hydrophobic silicone phase are critical in determining pumping efficiency, which allow irreversible water flow upon temperature variation. Seasonal and regional temperature changes can be matched using thermo-responsive hydrogels with different volume transition temperatures. Purification of dye-contaminated water and separation of oil–water mixtures are also successfully achieved based on the hydrophilic and the pollutant-adsorbing nature of hydrogels. Since temperature changes even faster than the diurnal temperature cycle can also power this water pumping and purification system, this novel mechanism could provide a new operational solution for future water management.

Information retrieval and criticality in high-dimensional parity-time-symmetric systems

Recently, impressive progress has been made in the study of non-Hermitian systems with parity-time symmetry, such as observations of topological properties of physical systems and criticality at exceptional points. A crucial aspect of parity-time symmetric nonunitary dynamics is the information flow between the system and the environment. In this paper, we use the physical quantity, distinguishability between quantum states, to uniformly quantify the information flow between low-dimensional and high-dimensional parity-time symmetric non-Hermitian systems and environments. The numerical results show that the oscillation of quantum state distinguishability and complete information retrieval and can be obtained in the parity-time-unbroken phase. However, the information decays exponentially in the parity-time-broken phase. The exceptional point marks the criticality between reversibility and irreversibility of information flow, and the distinguishability between quantum states exhibits the behavior of power-law decay. Understanding these unique phenomena in nonunitary quantum dynamics provides an important perspective for the study of open quantum systems and contributes to their application in quantum information.

Information retrieval and criticality in high-dimensional parity-time-symmetric systems

Recently, impressive progress has been made in the study of non-Hermitian systems with parity-time symmetry, such as observations of topological properties of physical systems and criticality at exceptional points. A crucial aspect of parity-time symmetric nonunitary dynamics is the information flow between the system and the environment. In this paper, we use the physical quantity, distinguishability between quantum states, to uniformly quantify the information flow between low-dimensional and high-dimensional parity-time symmetric non-Hermitian systems and environments. The numerical results show that the oscillation of quantum state distinguishability and complete information retrieval and can be obtained in the parity-time-unbroken phase. However, the information decays exponentially in the paritytime-broken phase. The exceptional point marks the criticality between reversibility and irreversibility of information flow, and the distinguishability between quantum states exhibits the behavior of power-law decay. Understanding these unique phenomena in nonunitary quantum dynamics provides an important perspective for the study of open quantum systems and contributes to their application in quantum information.

Inherent Irreversibility of Mixed Convection within Concentric Pipes in a Porous Medium with Thermal Radiation

This work investigated the thermal putrefaction and inherent irreversibility in a steady flow of an incompressible inconstant viscosity radiating fluid within two concentric pipes filled with a porous medium. Following the Brinkmann-Darcy-Forchheimer approach, the nonlinear differential equations governing the model were obtained. The model boundary value problem was addressed numerically via a shooting quadrature with the Runge-Kutta-Fehlberg integration scheme. The effects of diverse emerging parameters on the fluid velocity, temperature, skin friction, Nusselt number, entropy generation rate and the Bejan number are provided in graphs and discussed in this paper.

Channel flow of a Jeffrey fluid in a porous space with entropy generation

AbstractThe present investigation reveals the Poiseuille flow of an incompressible Jeffrey fluid involving two heated parallel plates. The nonlinear model is proposed by incorporating Brownian motion vis‐a‐vis, viscous dissipation, and suction/injection, which are also taken into consideration. However, numerical treatment is based on fourth‐order Runge–Kutta shooting integration method and applied for the solution of the system of governing equation. As a novelty, the entropy analysis due to the flow irreversibility of the system is carried out, and also a computational result of the Bejan number is also elaborated. The impacts of various thermo‐physical pertinent specifications such as velocity, temperature are examined thoroughly and interpreted through graphs.

Magnetic-field- and thermal-radiation-induced entropy generation in a multiphase nonisothermal plane Poiseuille flow.

The effect of radiative heat transfer on the entropy generation in a two-phase nonisothermal fluid flow between two infinite horizontal parallel plates under the influence of a constant pressure gradient and transverse noninvasive magnetic field have been explored. Both fluids are considered to be viscous, incompressible, immiscible, Newtonian, and electrically conducting. The governing equations in Cartesian coordinates are solved analytically with appropriate boundary conditions to obtain the velocity and temperature profile inside the channel. Application of a transverse magnetic field is found to reduce the throughput and the temperature distribution of the fluids in a pressure-driven flow. The temperature and fluid flow inside the channel can also be noninvasively altered by tuning the magnetic field intensity, temperature difference between the channel walls and the fluids, and several intrinsic fluid properties. The entropy generation due to the heat transfer, magnetic field, and fluid flow irreversibilities can be controlled by altering the Hartmann number, radiation parameter, Brinkmann number, filling ratio, and ratios of fluid viscosities and thermal and electrical conductivities. The surfaces of the channel wall are found to act as a strong source of entropy generation and heat transfer irreversibility. The rate of heat transfer at the channel walls can also be tweaked by the magnetic field intensity, temperature differences, and fluid properties. The proposed strategies in the present study can be of significance in the design and development of next-generation microscale reactors, micro-heat exchangers, and energy-harvesting devices.