Entropy Generation Analysis Research Articles

Heat transfer and entropy generation analysis in the buoyancy-driven flow of Fe3O4-MWCNT/water hybrid nanofluid within a square enclosure in the presence of fins using machine learning

Heat transfer and entropy generation analysis in the buoyancy-driven flow of Fe3O4-MWCNT/water hybrid nanofluid within a square enclosure in the presence of fins using machine learning

Heat transfer and entropy generation analysis of ternary nanofluid

Abstract In light of the rising demand for improved heat transfer in thermal systems, this work offers a unique technique for boosting heat transfer capacity and reducing entropy generation using a ternary nanofluid. Moreover, constant pressure gradient, magnetic field, Joule heating, and thermal radiation also contribute to the flow dynamics. The 2D mathematical model is solved numerically using a finite difference method and the simulations are done in MATLAB. The obtained results show that ternary nanoparticles not only increase the thermal rates but are also helpful in maintaining the irreversibility of a system. It is also observed that the heat transfer of the base fluid increased by 7.5%, 8.3%, and 8.5% on adding TiO2, CuO-TiO2, and MgO-CuO-TiO2 nanoparticles, respectively.

Heat Transfer and Entropy Generation in Vibrational Flow: Newtonian vs. Inelastic Non-Newtonian Fluid

A computational method is employed to solve heat transfer and entropy generation within a circular pipe. The thermal boundary condition assumes a constant wall temperature, while viscosity is taken to be dependent on temperature. A power-law type shear-thinning fluid is utilized in the analysis, with sinusoidal vibration applied horizontally perpendicular to the flow direction. Temperature distributions across the pipe are illustrated. Additionally, the entropy generation rate over the entire fluid volume under vibration was examined, comparing the results between steady flow and vibrational flow for both types of fluids. It was found that radial mixing is more pronounced in non-Newtonian fluids as vibration increases the strain rate, which is higher for low Reynolds numbers. The research provides a quantitative analysis of heat transfer and entropy generation for both Newtonian and shear-thinning fluids at different Reynolds numbers. It was observed that the effectiveness of superimposed vibrational flow is limited, especially for low Reynolds numbers and flow behavior index characteristic of shear-thinning fluids.

Irreversibility analysis of radiative TiO2+Al2O3+Cu/H2O ternary nanofluid flow over a bidirectional stretching sheet with cattaneo-christov heat flux: nanotechnology applications

Ternary nanofluids demonstrate better heat transfer characteristics in contrast to conventional liquids and typical hybrid nanofluids. These are applied in sophisticated cooling systems for electronics, heat exchangers, and automotive engines, along with renewable energy systems such as solar collectors, where efficient heat transfer plays a crucial role. The aim of this research is to investigate the movement of a Casson ternary nanofluid passing through a bidirectional exponential sheet by employing the innovative Cattaneo-Christov heat flux concept. The utilization of the energy equation considers thermal radiation, viscous dissipation, and heat source/sink effects, with the integration of chemical reaction effects into the concentration equation. An analysis of entropy generation is utilized to evaluate the thermodynamic irreversibility within the system. The conversion of transport equations involves a transformation from partial to ordinary differential equations, followed by a numerical solution utilizing the BVP4C solver embedded in the MATLAB package R2022b. The impacts of developed factors on thermal, concentration, and velocity behavior, as well as engineering quantities, are thoroughly explored graphically. The outcome reveals that the velocity gradients diminish as magnetic fields intensify, while it amplified by the Hall factor. The rise in temperature of ternary nanofluid correlates with elevated levels of radiation, and Brownian motion. Concentration intensifies with the rapid development of thermophoresis influences. Heightened values of the Reynolds and Brinkman numbers give rise to amplified entropy production but a decrease in the Bejan number. The ternary nanofluid displays a remarkable 8.92% increase in skin friction on the x-axis and y-axis, influenced by the potent Darcy-Forchheimer factor. The rates of mass and heat transfer in nanofluids undergo a decrease of 8.58% and 12.52%, respectively, due to the heightened influence of Brownian motion and Eckert number. The results could provide valuable insights into the performance of ternary nanofluids in various industrial environments under specific conditions.

Heat Transfer and Entropy Generation on Free Convection Airflow inside a T-shaped Cavity Considering Inner Obstacles

In this study, a numerical analysis of heat and entropy generation on free convection of airflow is performed inside a T-shaped cavity with and without circular obstacles. The T-shaped cavity is formed with two symmetrically isothermal rectangular blocks. A cold temperature is maintained on the cavity's upper wall. The adiabatic walls are connected to heated wall at constant temperature. It is assumed that the flow is laminar, 2-D, and steadily incompressible. The finite element analysis is employed for solving the governing equations. The calculated results are compared and validated with the other published works. The dimensionless velocity (streamlines) and temperature (isotherms) are calculated and illustrated for varying Rayleigh numbers. It is found that the average Nusselt number at the heated walls and entropy generation inside the cavity increase with the increment of Rayleigh numbers. Moreover, the thermal performance effects on natural convection flow are investigated with circular obstacles inside the enclosure. Five cases without and with circular obstacles regarding the boundary conditions are investigated. It is found that the thermal performance of the cavity can be improved by adding two circular obstacles with cool boundary conditions. It is evident that the innovative structure by adding two circular obstacles with cool boundary conditions gives higher average Nusselt number and entropy generation whereas lower Bejan numbers for varying Rayleigh numbers. The study is performed for and . Jagannath University Journal of Science, Volume 11, Number 1, June 2024, pp. 186−202

Entropy generation analysis and thermal performance of absorber tube in parabolic trough solar collector inserted with eccentric structure insert

To address the issue of uneven heat transfer in parabolic trough solar collectors, this study introduces an innovative insert (composed of vortex generators) layout. The vortex generators are strategically placed in areas with high heat flux density, while their number is reduced in regions with low heat flux density. By adjusting the position of the central rod, the inserts are defined as three different layout strategies (central structure, low eccentric structure, and upper eccentric structure), and their thermal performance is analyzed. The differences in fluid flow and heat transfer induced by different structures are also compared. The results show that the upper eccentric structure can induce unevenly distributed high-intensity mixing vortices, and through the ejection and sweeping movements of these vortices, the high-temperature fluid in areas with high heat flux density is transported to positions with low geothermal flow. Among all the studied configurations, the upper eccentric structure achieves a Nusselt number increase ranging from 1.16 to 2.34 times and a friction number value increase between 1.47 and 5.38 times. In terms of heat transfer performance, the highest value is 1.43 when the number of vortex generators is 6 and Reynold number is 13,750. Additionally, the thermal performance of the inserted tubes is analyzed using the field synergy principle and entropy generation method.

Analysis of heat generation and viscous dissipation with thermal radiation on unsteady hybrid nanofluid flow over a sphere with double-stratification: Case of modified Buongiorno's model

PurposeThis work uses entropy generation analysis to numerically analyze magnetohydrodynamics (MHD) unsteady flow, heat and mass transfer. The study considers changing viscosity, thermal radiation, viscous dissipation, mass suction, heat generation, and stratification processes in a hybrid nanofluid around a spinning sphere. A two-phase nanofluid flow model (Buongiorno model) is used to tackle the current challenge. Both the free stream velocity and the sphere's angular velocity changed over time. Design/methodology/approachThe case study's complicated partial differential equations are transformed into simpler ordinary differential equations utilizing similarity transformation. Implementing the fourth-order Runge-Kutta Fehlberg method with a shooting scheme in MATHEMATICA has allowed us to get numerical solutions for ordinary differential structures. FindingsThe many aspects of these regulated physical characteristics have been elucidated and thoroughly examined via the use of charts and tables. For increasing values of unsteadiness parameter, the velocity profiles in the x-direction grow while they decrease in the z-direction. On the other hand, the temperature profile exhibits a dual pattern, and the concentration profile decreases. As the chemical reaction parameter climbs from 0.25 to 1.0, the Sherwood number for the nanofluid rises by 6721.39% and for the hybrid nanofluid, 3818.9%. When Nr increases from 0.2 to 0.8, nanofluid Nusselt number climbs 22.5% and hybrid nanofluid's Nusselt number rises 21.9%. The Brinkmann number and nanoparticle volume percentage are strongly associated with entropy production. Entropy generation is dual for the temperature difference, magnetic, radiation, and changeable viscosity parameters. The findings are also compared to those from the existing literature and are in excellent agreement with them.

Entropy generation in Casson nanofluid flow over a lubricated wall in the presence of induced magnetic field and activation energy

ABSTRACT The research on entropy generation in a mechanical system is quite imperative owing to its immense applications in the production of advanced cooling devices and medical appliances. The basic need on this research is how to optimize the irreversibilities within the systems and channelize that energy towards the benefit. This study elucidates the entropy generation analysis of a Casson nanofluid near a stagnation point over a lubricated vertical wall. A thin film of shear-thinning liquid with power law index of 0.5 is employed on the wall to ensure the lubrication. The effect of induced magnetic field and the chemical reaction stimulated by the activation energy is also incorporated within the flow. The non-linear PDEs of the substantive problem along with the compatible interfacial and boundary conditions are reverted into ODEs with the aid of suitable similarity transformation, and then cracked numerically using the sixth-order Runge Kutta method assisted with Nachtsheim–Swigert shooting practice. One of the significant findings reveals that the fluid friction irreversibilities in the entropy generation are diminished with the magnetic parameter and the Casson parameter, whereas the thermal irreversibility predominates over the total entropy generation for the escalating values of the activation energy parameter.

Entropy generation analysis of unsteady MHD nanofluid flow in a porous pipe

This article presents a numerical investigation into the entropy production of nanofluids flowing through a porous medium in a permeable conduit, focusing on water-based solutions containing Titanium Carbide (TiC) and Silicon Carbide (SiC) nanoparticles. These nanoparticles are selected for their heat transfer properties. The flow system's governing equations are developed and solved using the Runge-Kutta-Fehlberg method. The study examines the influence of key nondimensional parameters, including the solid volume fraction of nanoparticles, radiation parameters, and Reynolds number, on temperature, velocity profiles, and entropy generation. The results show that Silicon Carbide-water nanofluids perform efficiently in terms of heat transfer and entropy minimization. Additionally, Silicon Carbide exhibits low skin friction at the pipe wall, with this effect increasing as the solid volume percentage of nanoparticles rises. The study also indicates that irreversibility due to heat transfer becomes more significant near the pipe wall as the solid volume fraction decreases and increases with higher radiation parameters and Reynolds number. These findings are presented graphically and in tabular form to illustrate the physical significance of the problem.

Multiple solutions and temporal stability for ternary hybrid nanofluid flow between non‐parallel plates with entropy generation analysis

Multiple solutions and temporal stability for ternary hybrid nanofluid flow between non‐parallel plates with entropy generation analysis

Significant statistical model of heat transfer rate in radiative Carreau tri-hybrid nanofluid with entropy analysis using response surface methodology used in solar aircraft

The recent advancement of technologies focuses on the use of solar-based heat radiation and nanotechnology. The primary source of heat is solar energy, which is obtained by absorbing sunlight. In addition, solar thermal planes, photovoltaic cells, and sun-based hybrid nanofluids all help to harness solar energy. Therefore, main concern of the study is to explored the two-dimensional Engine oil-based Carreau tri-hybrid nanofluid (SiO2 (silica dioxide), MOS2 (Molybdenum disulfide), Fe3O4(black iron oxide)) flow via a stretching sheet within solar wings. The flow phenomena of the non-Newtonian fluid enrich for the effects of radiant energy and the external heat source. By adopting similarity transfiguration, the dimensional partial main flow equations are changed into nonlinear dimensionless ordinary differential equations. The most effective and powerful tool of the semi-analytical method ADM (Adomain Decomposition Method) is utilized to solve the nanofluid flow problem. The uniqueness of the proposed study arises due to the analysis of entropy generation obtained by various irreversibility processes. The graphical illustration of outcome of various governing parameters on velocity, temperature, entropy terms and engineering quantities have been presented and theoretically analyzed. The findings reveal that The Carreau ternary hybrid nanofluids enhance the system's thermal conductivity for optimal temperature regulation in solar aircraft and better heat dissipation. The use of Carreau ternary hybrid nanofluids significantly reduces entropy generation, which implies a more reversible process, enhancing the overall efficiency of the energy conversion systems in solar aircraft. The heat flow of the system is accurately reflected by the chosen variables and their interactions, as demonstrated by the constructed model's strong statistical significance. For real-world applications, this improves the model's predictability and dependability.

Artificial intelligence and numerical study of the heat transfer and entropy generation analysis of NEPCM-MWCNTs-Water Hybrid Nanofluids inside a quadrilateral enclosure

In the present investigation, the primary objective is to assess the synergistic impact of a novel hybrid nanofluid composed of nano-enhanced phase change material, multi-walled carbon nanotubes, and water. The governing equations are transformed into dimensionless forms for a more generalized analysis. To solve the problem, the Galerkin finite element method is employed, offering a robust numerical approach. A dataset of 1000 records was created by numerically solving the model for various combinations of control parameters. Using the dataset, a neural network was trained to learn the relationship between control parameters and heat transfer rate. The evaluation outcomes are comprehensively illustrated through key parameters, including local and average Nusselt numbers, total entropy generation, contours, and streamlines in the range of 103<Rayleigh number<105, 0<nanotube concentration<0.025, 0<nano capsule concentration <0.025, and 0.1<non-dimensional fusion temperature <0.7. Remarkably, the results indicate a substantial improvement in the heat transfer rate of the suspension for a hybrid concentration of 5%, showcasing an impressive 13% enhancement in contrast to the water host fluid's performance. Notably, the observed rise in entropy generation is relatively moderate, only a 5% increase.

Entropy generation analysis on MHD mixed convective flow of couple stress MWCNT$MWCNT$–Ag/C2H6O2$\text{Ag/C}_{2}\text{H}_{6}\text{O}_{2}$ hybrid nanofluid with variable properties in a vertical channel

Entropy generation analysis on MHD mixed convective flow of couple stress MWCNT$MWCNT$–Ag/C2H6O2$\text{Ag/C}_{2}\text{H}_{6}\text{O}_{2}$ hybrid nanofluid with variable properties in a vertical channel

Impacts of binary chemical reaction with activation energy on MHD thermally radiating blood based hybrid nanofluid flow through shrinking-stenotic artery: Entropy generation and stability analysis

This study investigates numerically the heat and mass transport with entropy generation of MHD human blood as a hybrid nanofluid at the surface of a porous stenotic shrinking artery in the presence of velocity slip and convective boundary conditions. This study aims to examine the influence of thermal radiation and binary chemical reactions with activation energy by adopting gold and silver nanoparticles as nanomaterials for drug delivery as they exhibit potential drug transport and imaging properties for treating stenosed arteries. Initially formulated as partial differential equations (PDEs), the model is adeptly transformed into ordinary differential equations (ODEs) via established similarity transformations. Subsequently, a numerical solution employing the bvp4c built-in solver in MATLAB mathematical software unravels crucial physical quantities’ behaviors across various parameter configurations. Remarkably, this study reveals the presence of two potential solutions due to the contracting of the artery, among which only one exhibits physical stability. Dual solutions can only be found within the critical values of suction (Sλ) parameters. The critical values Sλ from computation are 2.1850, 2.1318 for Au/Blood nanofluid, and Au − Ag/Blood hybrid nanofluid, respectively. Also, the stability of blood flow is achieved by finding the lowest eigenvalue. A minimum eigenvalue (β1) that is positive denotes the upper stable solution branch, whereas a minimal eigenvalue that is negative indicates the bottom unstable solution branch. Notably, the findings underscore the efficacy of enlarging velocity and thermal conductance in the presence of gold and silver nanoparticles. A noteworthy finding of this study reveals that elevated thermal radiation and thermal Biot number significantly increase the temperature within the hybrid blood nanofluid system, highlighting the role of these parameters in thermal management within the circulatory system. Also, increasing the curvature parameter, activation energy, and concentration Biot number enhances blood concentration in the stenosed artery. However, opposite effects are observed with increasing Schmidt number and binary chemical reaction parameter in the first stable solution branch, indicating a delicate balance in optimizing these parameters. The entropy through the blood flow was found to increase with the magnetic field, the curvature of the artery, and thermal radiation. These results benefit the human circulatory system and may help prevent heart attacks.

Entropy generation analysis of dusty fluid with peristalsis in asymmetric channel with slip effects

Entropy generation analysis of dusty fluid with peristalsis in asymmetric channel with slip effects

Unsteady-state entropy generation analysis of the counter-flow dew-point evaporative coolers

The surging demand for air conditioning, especially in hot climates, underscores the urgency of strategies aimed at curbing fossil fuel reliance and fostering energy saving strategy. Despite the longstanding utility and advantages of the conventional mechanical vapor compression refrigeration system, sustainability hurdles persist owing to its pronounced electricity demand. While evaporative cooling, harnessing water evaporation, emerges as a more efficient alternative, its efficacy is contingent upon environmental conditions. Addressing this, dew-point evaporative cooling (DPEC) presents an innovative direction, showcasing superior efficiency by directing supply air into a wet channel. This study delves into the thermodynamic losses within a counter-flow configured DPEC system, employing a transient entropy generation model rooted in the second law of thermodynamics to provide a comprehensive analysis of DPEC’s performance. Key findings that emerged from this study reveal that (1) the transient entropy generation is intricately distributed across different layers of the dew point evaporative cooling (DPEC) system, including dry air, wet air, the channel plate, and the water film; (2) Parametric analyses highlight the significant impact of factors on entropy generation, inlet air temperature has a minimal effect on system efficiency, but higher temperatures increase thermal losses. Excessive humidity limits evaporative potential, while low humidity significantly increases entropy generation. The system performs optimally at a working ratio of 0.3 and lower air velocities (within the inlet air velocity range of 0.6 to 2.2 m/s). Channel length has little impact, while the system is more sensitive to channel height, with a height of 2.5–3.5 mm being conducive to better performance. Experimental validation demonstrates the model’s accuracy in predicting system performance. The research contributes to a deeper understanding of DPEC systems, offering insights for achieving optimal operating conditions and enhancing overall efficiency in the pursuit of sustainable development.

Energy characteristic of cavitation in a centrifugal pump based on entropy generation analysis

Energy characteristic of cavitation in a centrifugal pump based on entropy generation analysis

Numerical study of fluid flow and entropy optimization subject to second order slip condition across a permeable curved surface

The entropy generation analysis has great significance in the industrial sectors with heat transmission and fluid flows, for evaluating the irreversibility aspect of a system in heat transfer operations. The numerical simulation of entropy generation and the nanofluid flow across a permeable curved surface subject to cross-diffusion and irregular heat source/sink is reported in the current investigation. The thermodynamics 2nd law is used to simulate the entropy optimization. The flow phenomena are mathematically described by partial differential equations (PDEs), which are derived in a curvilinear coordinate system. The system of ODEs (ordinary differential equations) is derived by using the similarity conversion, which is further numerically calculated through the parametric continuation method (PCM) using MATLAB software. The results reveal that the velocity slip and curvature parameters improve the velocity profile whereas the inverse effect is observed against the surface permeability parameter. It can also be noticed that the entropy optimization enhances with the variation in Brinkman number and temperature ratio parameter. The impact of Schmidt number and chemical reaction decline the mass transmission ratio.

Numerical analysis of magnetohydrodynamic mixed convection and entropy generation in a curvelinear lid-driven cavity with carbon nanotubes and an adiabatic cylinder

Mixed convection convection is a vital subject and it is beneficial in many engineering applications. The current paper addresses this subject with a novel geometry and very vital variables including magnetohydrodynamic influences on the forced/free convection as well as the reproduction of irreversibilities in an enclosure filled with water/carbon nanotubes (CNT) and a nonadiabatic cylinder. The top wall is split from the middle and moves in different directions to drive the isotherms which are generated from the bottom wall and cold from the vertical surfaces. The numerical analysis was carried out using finite element method; the variables are Reynolds number (40–200), Richardson number (0.01–10), Hartmann number (0–62), inclined magnetohydrodynamic angle (0–60), volume concentration (0–0.08) while Prandtl number has kept constant at 6.2. The results show that the transformation of heat, as well as the fluid flow, are largely influenced by the change of variables, where increasing Reynolds number, Richardson number enhances heat and increases the flow circulation. Furthermore, heat transfer enhances by 57 % when increasing Ri from 0.1 to 10 at Re=41 and this enhancement increases to 62.5 % at Re = 200. Furthermore, increasing the concentration of the carbon nanotube can cause heat transfer but decrease the circulation of the fluid. In contrast, the transfer of heat as well as the flow streams are remarkably decreased with the increase of the Hartmann at zero inclination angle; however, the value of the Nusselt average increases with the increase of the inclination angle. Moreover, the value of Nusselt average decreses by 34.7 % when increasing Ha from 0 to 62 at Re = 200. Furthermore, the total entropy generation increases as Richardson number, Reynolds number, and volume concentration increase; in contrast, detraction with the rise of the MHD.

A comprehensive investigation and optimization of superheat degree on performance of supersonic nozzle by considering non-equilibrium condensation and entropy generation analysis

A comprehensive investigation and optimization of superheat degree on performance of supersonic nozzle by considering non-equilibrium condensation and entropy generation analysis