Heat Source Sink Research Articles

Influence of Chemical reaction and heat generation/absorption on Unsteady magneto Casson Nanofluid flow past a non-linear stretching Riga plate with radiation

The use of Casson fluid is of considerable importance in the manufacturing of pharmaceutical products, including the incorporation of china clay and biological fluids such as synovial liquids. Therefore, the primary objective of this work is to examine the characteristics of the Casson fluid flow. The Casson fluid is a non-Newtonian model often used to analyze the unsteady magnetohydrodynamic (MHD) heat and mass transfer in nanofluid flow scenarios across a non-linearly stretched Riga plate. The heat and mass transfer equations include the analysis of radiation and chemical reactions, respectively. Furthermore, the process of heat transmission is intensified by the existence of an external heat source or heat sink. By applying appropriate similarity transformations, the partial differential equations (PDEs) are converted into a set of nonlinear ordinary differential equations (ODEs). These ODEs are then solved numerically by utilizing the Runge-Kutta-Fehlberg-45 method, with the help of a shooting strategy. The validity of the study is determined by a comparative analysis of the present results in relation to prior research. The main objective of this research is to assess the influence of relevant flow parameters on the fluid flow, temperature, and concentration gradients, which will be visually represented and reported in tabular form. The augmentation of the Casson fluid coefficient (β) hinders the advancement of both velocity and temperature. The augmentation of the thermophoresis parameter (Nt) and magnetic factor (M) results in an elevation of θ(η) and a reduction in the curves depicting the volume fraction of nanoparticles. This study establishes a significant connection between many biological and engineering applications, particularly in the analysis of blood samples and the administration of drugs via blood circulation.

Heat transfer study of natural circulation serpentine-shaped loops

Wide range of industrial applications have been utilized natural circulation loops due to heat transport achieved without the aid of any fluid-moving machinery. Moreover, it has been commonly used either two-phase-rectangular- or square-shaped loops owing these geometries promote satisfactory heat transfer and buoyancy forces performance, however, these two geometries require structural elements of considerable size for certain applications. Therefore, this study thoroughly examined a novel design of 10- and 14-elbow-single-phase-serpentine-shaped loops set in vertical configuration for improving cold water dispensers’ systems in a so called side-by-side refrigerator with the size restriction of its cabinet dimensions. Furthermore, when the application was not constricted to the use of water, numerical tests of heat transfer analysis for three working fluids commonly employed in industrial processes, namely, ethylene glycol, ethanol, and air, also was done. Both loops had the same surface area exposed to the heat source and heat sink, along with the total volume within the loops and the pipeline diameter were equal in the two cases. From the procured results, on one hand, when water was used and Reynolds number was increasing, employing the 10-elbow loop, an increase in internal Nusselt number of 24.5% was obtained. On the other hand, when ethanol was used an increase of Nusselt number of 27.28% was achieved. Finally, a great influence of the height of the loop on the increase of buoyancy forces was observed, hence, higher values for Rayleigh number were obtained when 14-elbow loop was utilized instead of 10-elbow loop; nonetheless, higher values of Rayleigh number did not result in greater values of Nusselt number, concluding that a smaller number of elbows promoted a better heat transfer performance under the operation conditions of the present work.

Second law analysis on cross flow of hybrid nanoliquid in a Darcy–Forchheimer medium with thermal radiative flow

This article’s objective is to examine the optimization of entropy in Darcy–Forchheimer cross-hybrid nanofluids as they flow toward a stretchy surface. There is a current because the surface is being stretched. The energy equation is broken down into its component parts including thermal radiation, heat source sink, and convective flow. In this case, copper oxide ( CuO ) and titanium dioxide ( TiO 2 ) are taken into consideration as nanoparticles, while engine oil (EO) is taken into consideration as a continuous phase fluid. In addition, we carried out an investigation into the relative performance of copper oxide ( CuO ) and titanium dioxide ( TiO 2 ) while they were suspended in water engine oil. The application of the second law of thermodynamics allows for the calculation of the rate of entropy optimization. Using a suitable transformation, nonlinear partial differential equations can be transformed into a standard system. In this work, we use the numerical built-in BVP4c solution method to generate numerical results for the derived nonlinear flow equation. Both copper oxide ( CuO ) and titanium dioxide ( TiO 2 ) undergo a graphical analysis of the effects of varying technical factors on entropy optimization, velocity, the Bejan number, and temperature. Numerical computations of the skin friction coefficient and Nusselt number for a range of fascinating parameters are performed for both nanoparticles ( TiO 2 and CuO ) . It is clear from the data that entropy optimization improves as the size of the radiation and porosity estimates reduces. The porosity parameter exhibits direct relationships to both temperature and velocity. Tabular comparisons of the current study with the previously published literature show a high degree of agreement. Copper and titanium oxide nanoparticles are used to increase Engine oil ( EO ) thermal enactment, making it a more useful base fluid. Further, some significant industrial and engineering applications are related to the present problem discourse.

Second law analysis on Ree-Eyring nanoliquid and Darcy Forchheimer flow through a significant stratification in the gyrotactic microorganism

PurposeThe modern day has seen an increase in the prevalence of the improvement of high-performance thermal systems for the enhancement of heat transmission. Numerous studies and research projects have been carried out to acquire an understanding of heat transport performance for their functional application to heat conveyance augmentation. The idea of this study is to inspect the entropy production in Darcy-Forchheimer Ree-Eyring nanofluid containing bioconvection flow toward a stretching surface is the topic of discussion in this paper. It is also important to take into account the influence of gravitational forces, double stratification, heat source–sink and thermal radiation. In light of the second rule of thermodynamics, a model of the generation of total entropy is presented.Design/methodology/approachIncorporating boundary layer assumptions allows one to derive the governing system of partial differential equations. The dimensional flow model is transformed into a non-dimensional representation by applying the appropriate transformations. To deal with dimensionless flow expressions, the built-in shooting method and the BVP4c code in the Matlab software are used. Graphical analysis is performed on the data to investigate the variation in velocity, temperature, concentration, motile microorganisms, Bejan number and entropy production concerning the involved parameters.FindingsThe authors have analytically assessed the impact of Darcy Forchheimer's flow of nanofluid due to a spinning disc with slip conditions and microorganisms. The modeled equations are reset into the non-dimensional form of ordinary differential equations. Which are further solved through the BVP4c approach. The results are presented in the form of tables and figures for velocity, mass, energy and motile microbe profiles. The key conclusions are: The rate of skin friction incessantly reduces with the variation of the Weissenberg number, porosity parameter and Forchheimer number. The rising values of the Prandtl number reduce the energy transmission rate while accelerating the mass transfer rate. Similarly, the effect of Nb (Brownian motion) enhances the energy and mass transfer rates. The rate of augments with the flourishing values of bioconvection Lewis and Peclet number. The factor of concentration of microorganisms is reported to have a diminishing effect on the profile. The velocity, energy and entropy generation enhance with the rising values of the Weissenberg number.Originality/valueAccording to the findings of the study, a slip flow of Ree-Eyring nanofluid was observed in the presence of entropy production and heat sources/sinks. There are features when the implementations of Darcy–Forchheimer come into play. In addition to that, double stratification with chemical reaction characteristics is presented as a new feature. The flow was caused by the stretching sheet. It has been brought to people's attention that although there are some investigations accessible on the flow of Ree-Eyring nanofluid with double stratification, they are not presented. This research draws attention to a previously unexplored topic and demonstrates a successful attempt to construct a model with distinctive characteristics.

Resistance-capacitance thermal models as alternatives to finite-element numerical models in the simulation of thermoelectric modules for electric power generation

This paper demonstrates that resistance–capacitance models provide equal results than models based on finite-element software when predicting the performance of a thermoelectric module under transient-state conditions. Previous papers on this topic fall short as comparing finite-element models with simplified versions of resistance–capacitance models.It was confirmed that resistance–capacitance models replicate results of finite-element models in the simulation of a thermoelectric module under steady-state conditions. Deviations lower than 3 % in electric power and efficiency (ratio of electric power to heat input) are obtained for temperature differences between heat source and heat sink as large as 200 K.Similarly, deviations lower than 3 % are obtained for simulation of a thermoelectric module under transient-state conditions. Resistance-capacitance models not only replicate values, trends and rates of variation predicted by finite-element models under step, linear and sinewave variations in the boundary conditions, but they also do this with negligible computational cost.

A conceptual design of a thermal switch capacitor in a magnetocaloric device: experimental characterization of properties and simulations of operating characteristics

The quest for better performance from magnetocaloric devices has led to the development of thermal control devices, such as thermal switches, thermal diodes, and thermal capacitors. These devices are capable of controlling the intensity and direction of the heat flowing between the magnetocaloric material and the heat source or heat sink, and therefore have the potential to simultaneously improve the power density and energy efficiency of magnetocaloric systems. We have developed a new type of thermal control device, i.e., a silicon mechanical thermal switch capacitor (TSC). In this paper we first review recently developed thermal switches based on micro-electromechanical systems and present the operation and structure of our new TSC. Then, the results of the parametric experimental study on the thermal contact resistance, as one of the most important parameters affecting the thermal performance of the device, are presented. These experimental data were later used in a numerical model for a magnetocaloric device with a thermal switch-capacitor. The results of the study show that for a single embodiment, a maximum cooling power density of 970 W m−2 (510 W kgmcm −1) could be achieved for a zero-temperature span and an operating frequency of 5 Hz. However, a larger temperature span could be achieved by cascading multiple magnetocaloric elements with TSCs. We have shown that the compact TSC can be used in caloric devices, even with small temperature variations, and can be used in a variety of practical applications requiring thermal regulation.

Mathematical model establishment and optimum design of a novel cesium thermionic–thermoelectric hybrid generator

Static power sources, such as thermionic energy converters (TEC), thermoelectric generators (TEG), thermophotovoltaic converters (TPV), and alkali metal thermal to electric converters (AMTEC), have enormous potential application in aerospace, military, electronic devices, and low-grade waste heat recovery and utilization. Aiming to further improve the power output and conversion efficiency, any two of them can be cascaded according to the difference in operating temperature. In this study, a novel mathematical model of the static hybrid power generator composed of a cesium thermionic energy converter (CTEC) and a TEG was proposed. The model considered the irreversible heat loss and the additional energy barrier of the CTEC module, and the Thomson effect of the TEG module, synchronously. To obtain the temperature distribution of CTEC and TEG modules, energy balance equations were determined by nonequilibrium thermodynamic analysis. Then, the effects of the output voltage and anode work function of the CTEC, the heat source temperature, and the electric current of the TEG on the output performance were investigated systematically by means of MATLAB. The results indicate that the maximum efficiency of the hybrid generator reaches 26.82% at heat source and heat sink temperatures of 1800 K and 300 K, respectively, which is significantly higher than that of the individual CTEC module (21.28%). This reveals that the waste heat released by the CTEC is utilized effectively in the TEG module, and the increased heat source temperature will further improve the hybrid generator’s power output and efficiency. The output power and efficiency are obviously improved by reducing the anode work function. When ϕC = 1.0 eV, i = 0.005, the power reaches a maximum of 21.61 W at 0.37 V, and the efficiency reaches a maximum of 25.90% at 0.55 V. Moreover, the curve of the output power as a function of conversion efficiency could be used to determine the optimal operating region of the hybrid generator, i,e., Pη < P < Pmax, ηP < η < ηmax, thereby obtaining the thresholds of the hybrid system parameters, i.e., VP < V < Vη, T1,P < T1 < T1,η, T2,P > T2 > T2,η, T3,P > T3 > T3,η and TCs,P > TCs > TCs,η. This study provides a reference for the optimal design and application of a CTEC–TEG hybrid generator in the future.

Chemically and thermally radiated Williamson MHD fluid over porous media with heat source-sink

ABSTRACT The study of the stretching sheet has extensive applications in the field of engineering and technology. Hence, the objective of the present study is to deal with the impact of pertinent parameters on Williamson fluid across a stretchable nonlinear sheet when chemical reaction, varied thermal radiation, and heat source/sink are present. Partial differential equations are used to model the resulting scenario, and after adding the necessary similarity variables, a system of nonlinear ordinary differential equations is formed using flow equations. The reduced ODEs are tackled by applying the fourth-order RK-scheme together with shooting methodology, and the impacts of different system parameters are examined corresponding to the fluid’s velocity, energy, and concentration profile. The important findings are discussed using graphics and they are as follows: As magnetism increases, fluid velocity rises but falls with an increment in buoyancy; the temperature falls with a boost in Grashof number but rises with an inclination in Prandtl number; and fluid reaction concentration declines with the boost in chemical parameter and Schmidt number but rises with an increment in thermophoresis, heat source/sink, and Brownian motion parameter.

Thermal case examination of inconstant heat source (sink) on viscous radiative Sutterby nanofluid flowing via a penetrable rotative cone

To improve heat transfer, this work provides a unique theoretical mathematical model of ternary hybrid nanofluid. In this analysis, the tri-hybrid nanoparticles TiO2, Al2O3, and AA7072 are submerged in ethylene glycol (EG), resulting in the mixture TiO2+Al2O3+AA7072/EG. The tri hybridity nanofluid is considered 3-D flowing via a rotate permeable cone embedded in Darcy-Forchheimer porousness material in the existence of fluctuating temperature generating (sink) and current radiate fluxing. The Keller box scheme (KBS) is exploited to resolve the liquid flowing and temperature equations numerically after converting them to ordinary differential equations employing similarity transformations. The results are graphed, and it is shown that the tri-hybrid nanofluid (THNF) has superior thermal conductance to the hybrid nanofluid (HNF) and that the fluid's velocity and temperature develop as a consequence of enlargement in thermal radiative fluxing and variable thermal conductivity effects. Raising values of De and Fr decline drag friction but drag friction coefficient values are improved as a result of positive variation in M,Re,ς, and λ. It is apparent that the rate of heat transference amplifies owing to magnification in QT, QE and Rd but the heat transfer rate diminishes due to magnification in Re and Fr. Incremental change in volume fraction of nanoparticles φ=0.005to0.03 delivers more heat in the case of tri-HNFs TiO2+Al2O3+AA7072 in contrast to ethylene glycol based TiO2+Al2O3 fluid. The optimal percentage error diminishes for the drag friction phenomenon from 1.4% up to 1.1% by adopting De from 1 to 1.5 and λ=0.5. The percentage error in terms of heat transfer rate is getting smaller from 3.6% to 3.0% because of a positive change in QT by keeping Rd=1.5.

Thermal characterization of heat source (sink) on hybridized (Cu–Ag/EG) nanofluid flow via solid stretchable sheet

Abstract The goal of this research is to consider the thermal impact on varied convection flow in hybrid nanofluids with heat generation over a two-dimensional heated flat around a stretchable sheet. The flow is considered steady and incompressible while the stretchable sheet is assumed an impermeable. Two distinctive nano-level particles are considered, namely copper (Cu) and silver (Ag) with ethylene glycol base fluid. The boundary layer was generated on a stretchable sheet surface by mixed convection flow in hybrid nanofluids. Ideally, the sink and source are thermal reservoirs of internal thermal capacities. This means you can extract or reject heat from them without changing their temperature. To make a study of thermodynamic systems like heat engines and refrigerator systems, the governing equations were solved numerically with Keller-box methodology depending on the implicit finite-difference technique. Research findings were worked with the parameters of mixed convection, Prandtl number, nanoparticle volume fraction, through various non-dimensional parameters, and heat generation. Especially for thermal generation enhancement, the fluidity and thermal dispersal get elevated. Even though the flowing behavior and the thermal dispersal of hybridity fluids with the combinations of Cu and Ag nanoparticles were similar, their values are distinct, which reflect in graphical displays. The hybrid nanofluidity gets improved with the volume variation of nanoparticles if the ϕ \phi value is 0.01 ≤ ϕ ≤ 0.05 0.01\le \phi \le 0.05 and if the flow profile value decreases ϕ h {\phi }_{{\rm{h}}} , where 0.01 ≤ ϕ h ≤ 0.05 0.01\le {\phi }_{{\rm{h}}}\le 0.05 as the dispersal of temperature enhances when the nanoparticle nanofluid constraint is improved.

Dynamics of gyrotactic microorganisms for chemically reactive magnetized 3D Sutterby nanofluid flow comprising non-uniform heat sink-source aspects

This presents a theoretical and computational evaluation of the unsteady 3D Bioconvection flow of Sutterby fluid, which has non-linear nonlinear radiation features as well as gyrotactic microorganisms, illuminating the novelty of the work. Furthermore, the influences of magnetic field, activation energy, chemical reactions, mixed convection and non-uniform heat sink-source are likewise indebted. Boundary layer theory is entreated to progress the elementary PDEs designed for microorganism field, momentum, nanoparticles concentration and energy also then condensed to the extremely nonlinear ODEs through the variable’s transformation. Numerical solutions for the existing investigation are obtained by bvp4c method in MATLAB software. Numerical calculations intended for Sherwood number, density number of microorganism and wall heat transfer are correspondingly accompanied. The graphic illustrations for exemplifying features of diverse embryonic parameters on dimensionless measures are designated systematically. It is fascinating to observed that the concentration as well as microorganism field is progressed for developed approximations of the bioconvection Rayleigh number and the magnetic parameter. The temperature of the fluid develops as a implied reaction to the magnetic parameter, the radiation parameter, Biot number and temperature ratio parameter.

MHD flow and heat transfer of micropolar nanofluid on a linearly stretching/shrinking porous surface

In this paper, there is considered incompressible steady two-dimensional laminar MHD boundary layer flow, heat and mass transfer characteristics of micropolar nanofluid across a linearly stretching/shrinking porous surface. The effects of the magnetic, thermal slip, mass slip and heat source sink parameters are also considered. By applyingn appropriate similarity variables, the system of governing partial differential equations associated to micropolar nanofluid flow is transformed into a system of non - linear ordinary differential equations. The resulting equations are numerically solved in the Maple software by using shooting technique. The impact of the different applied parameters on skin friction, couple stress, Nusselt and the Sherwood numbers along the related profiles are determined for both stretching and shrinking cases of the surfaces. It was observed that with an increase in suction and magnetic parameters, the fluid velocity decreased. An increment in the thermal slip, the fluid temperature decreased and nanoparticles concentration decreases as the mass slip parameter is enhanced. An increase in concentration decreases but temperature increases. While, concentration and temperature both increase due to increase in thermophoresis parameter, and concentration also increases by increase in rate of chemical reaction. Thus, suction at the boundary and magnetic parameter acted as flow controlling parameter. It is believed that this type of investigation is very much helpful for the manufacturing of complex fluids and also for cleaning oil from surfaces.

Effect of Double-Diffusive Stagnation point flow of Eyring– Powell Nanofluid on a Slender Stretching Sheet with Non-uniform heat Source Sink and Inclined Magnetic Field

In the present paper, the effects of an inclined magnetic field and a non-uniform heat source sink on a double diffusive convective stagnation point flow in a slender stretching sheet are studied. The suitable similarity transformation is utilized for the conversion of nonlinear differential equations. These converted equations are solved by means of Differential Transformation method (DTM) with the support of symbolic software Mathematica. Further, the effects of appropriate parameters on velocity profile, solute, nanoparticle concentration and temperature profiles are shown graphically with some suitable discussions. It is found that velocity decreases with a rise of magnetic parameter. Because applying the uniform magnetic field normal to the flow direction gives rise to Lorentz force. This force has the tendency to slow down the velocity of the fluid in the boundary layer. Also non-uniform heat source sink parameters enhance the thermal profile of the system. But, opposite behavior can be seen in solute and nanoparticle concentration profiles. Such results can be useful in design and structure of materials, where implementation of variable thickness decreases the weight of stretched element and boosts the usage of materials.

Multi objective ecological optimization of an irreversible Stirling cryogenic refrigerator cycle

The primary objective of the current study is to demonstrate the multi-objective, ecological optimization of an irreversible Stirling cycle-based cryogenic refrigerator. The novelty of the work lies in the ecological optimization of the system, where irreversibilities are considered during the study and the thermal reservoirs have finite energy. The heat source and heat sink exchange energy with the working fluid and respective thermodynamic processes are carried out. The aim is to maximize the ecological objective function and the ecological coefficient of performance, and the effect of design variables on the objective function is investigated. The heat sink capacitance rate, temperature ratio, heat source, and sink capacitance rates, and effectiveness of the hot and cold side heat exchangers are regarded as the design variables. A heat transfer search algorithm is used to optimize the objective functions, and multiple optimal solutions are presented using the Pareto optimal curve. The multi-criteria decision technique TOPSIS is employed to select the ideal solution. For an ideal point selected through TOPSIS, the system works at an optimum ECF and ECOP of 787 W and 5.9, respectively. The ECOP of the system for the current study is 1.81 times and 4.03 times higher than the existing literature. However, the maximum ECF of 1797 W or maximum ECOP of 17.2 can be obtained for the given constraints of design variables.

Experimental study on transient flow characteristics in an equal-height-difference passive heat removal system for ocean nuclear power plants

The equal-height-difference passive heat removal system (EHDPHRS) utilizes the ocean as the heat sink for infinite heat dissipation and has broad application prospects in ocean nuclear power plants. However, the equal height difference between the heat source and heat sink is susceptible to severe flow instability. In this study, a fully visualized experimental facility was constructed to analyze the transient flow characteristics in the EHDPHRS. The experimental results revealed three typical two-phase natural circulation flow modes in the EHDPHRS. The formation mechanism of each flow mode was analyzed using thermal–hydraulic parameters. The results revealed that the flow mode is determined by the steam–water direct contact condensation and reverse flow of subcooled water, and both factors promote each other. Moreover, condensation-induced water hammer (CIWH) was found to be the most severe flow instability in the EHDPHRS. CIWH events can lead to violent pressure peaks and reduce the natural circulation capacity. In addition, when the occurrence position of CIWH events is concentrated at the pipe outlet, the influence of CIWH events on the two-phase natural circulation flow capacity gradually decreases. These research results aid in the optimal design of the EHDPHRS and prevention and control of CIWH events.

Investigation of Thermal Performance of Ternary Hybrid Nanofluid Flow in a Permeable Inclined Cylinder/Plate

This article comprehensively investigates the thermal performance of a ternary hybrid nanofluid flowing in a permeable inclined cylinder/plate system. The study focuses on the effects of key constraints such as the inclined geometry, permeable medium, and heat source/sink on the thermal distribution features of the ternary nanofluid. The present work is motivated by the growing demand for energy-efficient cooling systems in various industrial and energy-related applications. A mathematical model is developed to describe the system’s fluid flow and heat-transfer processes. The PDEs (partial differential equations) are transformed into ODEs (ordinary differential equations) with the aid of suitable similarity constraints and solved numerically using a combination of the RKF45 method and shooting technique. The study’s findings give useful insights into the behavior of ternary nanofluids in permeable inclined cylinder/plate systems. Further, important engineering coefficients such as skin friction and Nusselt numbers are discussed. The results show that porous constraint will improve thermal distribution but declines velocity. The heat-source sink will improve the temperature profile. Plate geometry shows a dominant performance over cylinder geometry in the presence of solid volume fraction. The rate of heat distribution in the cylinder will increase from 2.08% to 2.32%, whereas in the plate it is about 5.19% to 10.83% as the porous medium rises from 0.1 to 0.5.

Perturbation methodology for electromagnetic radiative fluxing of chemical reactive Casson fluid flow under heat source (sink) effectiveness

In this paper, magnetohydrodynamics of a Casson fluid flow is inspected with the presence of thermal radiation and chemical reaction. Employing the perturbation procedure, the modeling equations are tenacious; the graphs are acquired to illustrate the results. The Casson fluid velocity increases as the perturbation parameter increases. Grashof values for heat and mass transport enhanced Casson fluid velocity. Increasing Casson, magnetic, heat source, and radiation parameters reduce the flow velocity. Prandtl number, heat source, and radiation parameter all reduced the temperature profiles. Chemical reaction parameters lowered the concentration profiles. The skin friction enhances with Casson parameter impact. However, the skin-friction coefficient, Sherwood and Nusselt numbers reduce with an increment in the perturbation parameter. In certain cases, this study’s answers agreed well with the previous literature. Casson liquid with a magnetic region using mixed convection by an exponential vertical boundary layer is the novelty of the work.

Thermal and electrical contact resistances of thermoelectric generator: Experimental study and artificial neural network modelling

Thermal and electrical contact resistances (TCR and ECR) of thermoelectric generator (TEG) exert essential impacts on its performance. In this study, through a series of experiments these two important properties have been estimated in a wide range of thermal and mechanical conditions, and with different interfacial materials. The magnitudes of the overall TCR were found in the range of (1.12–2.00) × 10–3 m2⋅K/W with air, (0.82–1.81) × 10–3 m2⋅K/W with graphene sheet, and (3.61–8.37) × 10–4 m2⋅K/W with thermal grease as interfacial materials when the heat-source temperature varied from 348.15 K to 598.15 K and the imposed pressure load from 266 kPa to 1266 kPa. Importantly, the detailed TCRs at different locations across the TEG system were also analyzed. The dominant components, which occupy more than 80 % of the overall TCR, have been identified at the interfaces of the thermoelectric module contacting the heat source and heat sink. In our experiment, the corresponding ECRs under the same working conditions were (1.03–1.52) × 10–9 Ω⋅m2, (0.56–9.60) × 10–10 Ω⋅m2, and (1.05–6.23) × 10–10 Ω⋅m2, respectively. Moreover, it is revealed that the TEG system delivered better performance at relatively low TCR and ECR when it operated at a high heat-source temperature, a large pressure load and using thermal grease as interfacial material. In addition to these experimental findings, a novel fully-connected feed-forward artificial neural network (ANN) model was also proposed to predict the overall TCR. It is shown that such an ANN model, as a promising approach, can achieve a cost-effective TCR prediction in good accuracy, with the mean square error and correlation coefficient being 2.36 × 10–9 and 99.4 %, respectively. These numerical and experimental results in this study will be of particular value for future TEG design and optimization.

Dynamics of gyrotactic microorganisms for modified Eyring Powell nanofluid flow with bioconvection and nonlinear radiation aspects

This analysis investigates the features of the mixed convection phenomenon for modified Eyring Powell fluid based on Buongiorno’s relation of nanofluid. The moment of gyrotactic micro-organisms and bioconvection analysis is considered in this analysis. Energy expression incorporates the aspects of nonlinear radiation and heat sink source. Furthermore, convective heat transportation analysis and no mass flux relations are incorporated into the modeling of physical problems. The governing system represents that the rheological expression of modified Eyring Powell nanofluid is simplified and then through a transformation procedure is reduced to ODEs. The transformed ODEs are then tackled through the bvp4c technique. Important physical parameters are elaborated through graphs. Gradients of microorganisms and temperature are discussed against emerging physical parameters. Nanofluid temperature intensifies for the biot number and radiation parameter, while the quite opposite behavior of nanofluid is detected against Prandtl number. The moment of gyrotactic micro-organisms dwindles for larger bioconvection Lewis number.

Magnetized Cross tetra hybrid nanofluid passed a stenosed artery with nonuniform heat source (sink) and thermal radiation: Novel tetra hybrid Tiwari and Das nanofluid model

Researchers around the planet are attempted to explore the influence of various non-Newtonian fluids with the mono and dihybrid nanoparticles in the status of blood flowing arteries to investigate the heat transference aspect for the cure of various diseases. Current examination is created to investigate the effect of extended novel tetra hybrid Tiwari and Das nanofluid model on blood flow arteries with consideration of Cross non-Newtonian fluid model. Heat transference assessment has been taken with the insertion of impacts like heat source/sink, viscous dissipation, Joules heating as well as nonlinear thermal radiation. PDE are designed to investigate the momentum of blood flowing and temperature analysis. The governing PDE are converted into ODE with the application of similarity conversions and furthermore managed these ODE numerically with the utilization of MATLAB builtin bvp4c scheme. The obtained outcomes are studied numerically as well as graphically in the case of diverse dimensionless variables ranges between 0.5≤M≤2, 0.1≤We≤4, 0.1≤n≤1.5, 0.1≤γ≤2, 0.5≤Rd≤2, 19≤Pr≤22, 0.1≤θw≤1.5, 0.1≤Ec≤2.1, 0.5≤U≤2, 0.5≤W≤2 versus velocity, temperature, wall frictional factor and heat transition rate. From obtained outcomes it is reflected that the surface drag phenomenon weakens by the boost of a Weissenberg number and an increment variation in magneto force provides a resistance against the fluid flow. Temperature within the arteries intensifies by the advantage of a thermal radiation and viscous dissipation.