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The main motive of the instigated mathematical model is to observe the impact of Hall current on the hybrid nanofluid flow over a disk that is rotating. The copper and silver metal nanoparticles have been considered with volume fraction φ1=φ2=0.01(0.01)0.04 and are suspended in water to form the hybrid nanofluid. Diverse characteristics like magnetic field, thermal radiation, and (ESHS) exponential space dependent heat source are incorporated to investigate the nature of the flow. The present mathematical model is initiated with partial derivative equations (PDEs) which are redrafted as ordinary derivative equations (ODEs) with appropriate transformations of similarity. The results are attained through a blend of the Runge-Kutta method, shooting procedure, and the influences of parameters on the flow of nanofluid and hybrid nanofluid are compared and illustrated both as tables and graphs. The present numerical research is unique because by employing a complete quadratic CCD framework using the RSM strategy, the sensitivity and optimization analysis of the heat transmission improvement for the volume fraction, ESHS, and thermal radiation parameters have been performed. The R-squared and adjusted R-Squared are obtained as 100%. The residual graphs and contour diagrams of the same are also shown. The current study establishes that the Hall parameter increases the radial velocity, but it also controls the energy and cross-radial velocity. The rate of heat transmission is increased by thermal radiation even at low levels of ESHS. The rate of heat transmission is more sensitive (0.024670) to the volume fraction of the hybrid nanofluid when ESHS is at an intermediate level. The lowest sensitivity (-1.269967) value towards ESHS is observed For thermal radiation and ESHS parameter values, the heat transmission rate of the mono nanofluid is not as great as that of hybrid nanofluid. The current study finds applications in the generation of hydroelectric power, air cleansing and rotating equipment, healthcare devices, and many other industries.

We scrutinized the influence of nonlinear heat radiation on heat transmission evaluation of Carreau nanofluid and tangent hyperbolic nanofluid streams across a wedge with gyrotactic microorganisms by taking slip situations into consideration in this research article. The necessary nonlinear partial differential formulation is transmuted into non-linear ordinary differential equations by employing appropriate similarity variables, and these equations, including the boundary constraints are resolved in Matlab software utilizing Runge-Kutta fourth order via shooting tactic. A definite description of the framework is achieved by fluctuating the inputs of influential variables of the dependent functions and exhibited via graphs. The inhibiting flow velocity is portrayed by the intensifying inputs of buoyancy ratio, magnetic force, Rayleigh number, and eigenvalue. As a consequence of thermophoresis and Brownian motion of nano-particles, the temperature of the liquids initiates to ascend instantly. Because of differentiated viscous effects, the flow velocity for Carreau nanofluid is slower than that of tangent hyperbolic fluid and the temperature behavior is reversed. Further, the magnitude of skin friction factor for tangent hyperbolic nanofluid is almost half ofs that of Carreau nanofluid.

Present investigation, experimentally probes the influence of utilization of twisted tape turbulator inside a helical tube. Twisted tapes mix the flow and enhance the heat transfer rate. The pitch of twisted tape was considered as variant parameter. Tube was considered to be under constant heat flux. Also, Re number was within the range of 6000–32000 which denotes that flow was the turbulent flow regime. Various parameters including Nu number, friction factor and entropy generation were evaluated. Furthermore, performance evaluation criteria based on first law and second law of thermodynamics together with economic performance parameters were evaluated. The results revealed that by the increment of water flow rate and the decrement of twist pitch the Nu number would face a rise of 66% in comparison with the smooth helical tube. Also, it was found that the application of twisted tape has more effect on frictional entropy generation rather than thermal entropy generation. Finally, the results indicated that the maximum value of ηc was about 1.59 ×10−7 ($/J) which presented up to 2.7 times enhancing in the financial beneficial of the helical tube.

Increasing heat transfer rate in heat exchangers is one of the topics interested by researchers which leads to economic savings. Various methods have been proposed in this field which are categorized into two main groups of active and passive techniques. Despite numerous investigations were conducted in this regards, very rare investigations have probed these methods from the economic viewpoints. Present study was carried out to investigate the effect of volume fraction (VF) of air bubbles on exergo-economic performance of horizontal shell and helically coiled tube exchanger (HSHTE). The air bubbles were injected into shell side via especial method. Holes with certain properties were fabricated on a plastic pipe with diameter of 3 mm for injecting air bubbles. Both counter flow and parallel flow were considered in this investigation. Present study showed that air injection has significant effect on thermal efficiency, exergy destruction and economic performance of the HSHTE. It was found that increment of VF increases number of thermal units, first law efficiently and exergy destruction increase by 4.5, 2.4 and 12.5 times, respectably. Furthermore, best values of Net profit per unit transferred heat load (դp) was about 9.3 × 10−5 ($/J) which presented up to 13% better financial performance in comparison with parallel flow.

In this article, a new approach to study the fractionalized Maxwell fluid is described by the Prabhakar fractional derivative near an exponentially accelerated vertical plate together with exponentially variable velocity, energy and mass diffusion through a porous media is critically examined. The phenomena has been described in forms of partial differential equations along with heat and mass transportation effect taken into account. The Prabhakar fractional operator which was recently introduced is used in this work together with generalized Fick's and Fourier's law. The fractionalized model is transfromed into non-dimensional form by using some suitable dimensionless quantities. The non-dimensional developed fractional model for momentum, thermal and diffusion equations based on Prabhakar fractional operator has been solved analytically via Laplace transformation method and calculated solutions expressed in terms of Mittag-Leffler special functions. Graphical demonstration are made to characterized the physical behavior of different parameters and significance of such system parameters over the momentum, concentration and energy profiles. Moreover, for results validation, comparative study among limiting models derived from fractionalized Prabhakar Maxwell fluid such as fractional and classical fluid models for Maxwell and Newtonian are performed. Further, it is observed from the graphs the valocity curves for classical fluid models relatively higher as compared to fractional fluid models, and fractional approach is more realistic and convenient as compared to classical approach.

Efficient thermal transportation in compact heat density gadgets is a prevailing issue to be addressed. The flow of a mono nanofluid (SiO2/Kerosene oil) and hybrid nanofluid (TiO2 + SiO2/Kerosene oil) is studied in context of Riga wedge. The basic purpose of this work pertains to improve thermal conductivity of base liquid with inclusions of nano-entities. The hybrid nanofluid flow over Riga wedge is new aspect of this work. The concentration of new species is assumed to constitute the base liquid to be non-Newtonian. The fundamental formulation of the concentration laws of mass, momentum and energy involve partial derivatives. The associated boundary conditions are taken in to account. Similarity variables are utilized to transform the leading set of equations into ordinary differential form. Shooting procedure combined with Runge-Kutta method is harnessed to attain numerical outcomes. The computational process is run in matlab script. It is seen that the velocity component f′(η) goes upward with exceeding inputs of modified Hartmann number Mh and it slows down when non-dimensional material parameter αh takes large values. Also, Nusselt number − θ′(0) is enhanced with developing values of Eckert number Ec and Biot number Bi.

In this article, heat source impact on unsteady magnetohydrodynamic (MHD) flows of Prabhakar-like non integer second grade fluid near an exponentially accelerated vertical plate with exponentially variable velocity, temperature and mass diffusion through a porous medium. For the sake of generalized memory effects, a new mathematical fractional model is formulated based on newly introduced Prabhakar fractional operator with generalized Fourier's law and Fick's law. This fractional model has been solved analytically and exact solutions for dimensionless velocity, concentration and energy equations are calculated in terms of Mittag-Leffler functions by employing the Laplace transformation method. Physical impacts of different parameters such as α, Pr, β, Sc, Gr, γ, Gm are studied and demonstrated graphically by Mathcad software. Furthermore, to validate our current results, some limiting models such as classical second grade model, classical Newtonian model and fractional Newtonian model are recovered from Prabhakar fractional second grade fluid. Moreover, compare the results between second grade and Newtonian fluids for both fractional and classical which shows that the movement of the viscous fluid is faster than second grade fluid. Additionally, it is visualized that for both classical second grade and viscous fluid have relatively higher velocity as compared to fractional second grade and viscous fluid.

Cylindrical solar collectors (CSCs) are getting attraction. Heat extraction part of these instruments consists of a helical tube which transfers thermal energy to working fluid. Enhancement of the heat transfer process within this part leads to enhancement of energy achievement. In this paper, influence of applying helical corrugation on helical absorber was evaluated. The number of corrugations and pitch and height of corrugations were considered as variant parameters. The system was evaluated from different viewpoints and performance of system was analyzed based on performance factor and economic viewpoints. The results revealed that the presence of helical Corrugation could increase heat transfer up to 19%. It was found that Dean number of 3000 could be considered as a critical Dean number from view point of performance factor. The application of the proposed system was more beneficial at Dean numbers below 3000. It was revealed that the application of helical corrugation could provide up to 24% enhancement in economic advantage of the system. Best economic performance was related to case with four starts which had corrugation height and corrugation pitch of 0.002 m and 0.103 m and occurred at Dean number of 2000.

The growth of compact density heat gadgets demands effective thermal transportation. The option of nanofluid plays a dynamic role in this requirement. This research shows the impact of gyrotactic microorganisms on non-Newtonian fluid (Maxwell fluid) passing on the expanding cylindrical surface. The main objective of the present observation is to determine the heat and mass transportation of Maxwell nanofluid. The convective boundary condition and zero mass flux conditions are incorporated. In mathematical derivation, the approximation of the boundary layer is applied. The primal motivation pertains to exaggerating the thermal transport of heat exchangers in industrial processes. To attain the effects of Brownian motion as well as thermophoresis the Buongiorno nanofluid is utilized. By assimilating suitable transformation, the concluding simultaneous for a non-linear set of equations is tackled numerically by hiring Runge-Kutta procedure. The coding is developed and run in the Matlab environment. The leading partial differential system is converted into an ordinary differential system. The role of emerging parameters is elaborated. Also tangible quantities i.e. Skin friction factor, Nusselt number, Sherwood number, and motile density coefficient are enumerated. An accession in the magnetic field causes depreciation in the velocity profile. Where increment in Schmidt number Sc causes a decrement in Sherwood number. The suitable ranges of parameters where increasing or decreasing behavior becomes smooth are taken as 0.0 ≤ M ≤ 6.0, 0.0 ≤ γ ≤ 0.8, 0.7 ≤ Pr ≤ 1.0, 0.1 ≤ Nt ≤ 0.7, 0.01 ≤ Nb ≤ 0.1, 3.0 ≤ Sc ≤ 6.0, 2.0 ≤ Lb ≤ 7.0, 0.1 ≤ Pe ≤ 0.7 and 1.0 ≤ δ ≤ 7.0. The applications of the current study can be seen in chemical and metallurgical industries, the process of thermo-fluid, power generation, executed via condensers, cooling, and heating in large buildings, transportation, etc.

Numerous investigations were conducted to enhance heat transfer in smooth tubes. They have used both active and passive methods. However, very rare investigations have reported the simultaneous usage of active and passive methods. Furthermore, the investigations on entropic behaviors are very rare too. Through present paper, effect of air bubble injection (as active method) together with spring wire turbulator (as the passive method) is probed. The pipe was subjected to a constant heat flux. Spring pitch and fluids flow rates were variable parameters of this study. Four flow levels of 2, 3, 4, and 5 were intended for water and air. The studied parameters were Nusselt number, cost-performance coefficient, and dimensionless exergy destruction. The flow patterns were also assessed. To calculate the Nusselt number and exergy destruction, ambient temperature, pipe surface temperature, water inlet, and outlet temperatures were measured. Results showed that reducing the induced rotational flow by the pitch, affects two-phase flow and leads significant changes flow pattern and two-phase flow motion model. Air bubble injection increased Nu by 40% and dimensionless exergy destruction by 36%.

Considering the thermal processes with the help of smart heat recovery, this study proposes a novel auxiliary trigeneration system for a ship based on the waste heat of its engine to produce electricity, cooling, and freshwater. The system consists of a regenerative organic Rankine cycle (RORC) with R600 working fluid, a lithium-bromide/water single-effect absorption chiller, and a humidification dehumidification (HDH) desalination unit. A multi-heat recovery technique is implemented in the design framework, having a well-organized waste-to-energy system. Technical 3E (energy, exergy, and exergoeconomic) analysis together with a multi-criteria optimization using a genetic algorithm is conducted. Furthermore, a parametric study is employed regarding the impact of changing design parameters, namely, pinch point temperature difference of the high recovery vapor generator (HRVG), turbine inlet pressure, and top temperature of the HDH on the thermodynamic and exergoeconomic criteria. The results indicated the high sensitivity of the outputs from varying the turbine inlet pressure. Besides, the optimum net output power, cooling, and generated freshwater are calculated to be 783.9 kW, 959.8 kW, and 98.1 m3/day, respectively. Also, the optimum energy and exergy efficiencies and total cost per unit exergy are computed to be 58.4%, 43.0%, and 0.1494 $/kWh, respectively.

In the present study, the natural convection flow of water with Nano-encapsulated phase change material (NPCM) was simulated inside an insulated chamber, which a pair of pipes were considered as a heater and cooler sources with the boundary condition of uniform temperature. The NPCM's core was made of n-nonadecane with melting temperature of 30.44°C. This core has ability to change the liquid-solid phase to transfer heat between the heater and the cooler sources. Current simulation was steady state and was solved by SIMPLE algorithm based on FVM to investigate the effects of Rayleigh number, volume fraction and location of phase change zone on the convective heat transfer coefficient. Observations showed that, phase change of NPCM occurs at low Rayleigh numbers but had no effect on the convective heat transfer coefficient, but it was directly related to the thermal conductivity of mixture. Moreover, adding volume fraction of NPCM 0.02 into water increased the convective heat transfer coefficient by 10.43%, 19.1% and 18.3% compared to pure water for Rayleigh numbers 102,104,and106, respectively.

The free convection of Cu-water nanofluid is simulated and investigated inside a square heat exchanger chamber in the presence of MHD magnetic field. The Buongiorno model with the effects of Brownian and thermophoresis motion is considered to nanoparticles distribution inside the chamber. The geometry consists of a square chamber with two cylinders on the right and left sides as heater and cooler in order to create the buoyancy force, respectively. These cylinders represent hot and cold pipes, and the walls of the chamber are heat and mass insulation. the FVM with SIMPLE algorithm are used for velocity and pressure coupling. In current two-phase simulation, the effects of Rayleigh number, Hartmann number, inclination angle of chamber and volume fraction on streamline contours, isothermal lines, Lorentz force lines, nanoparticle distribution and Nusselt number are investigated. By modeling the motion of nanoparticles and evaluating it, a nanoparticle transport zone was observed. The diffusion effects of thermophoresis were significant in this zone. The nanoparticles were thrown from the hot cylinder to the cold cylinder. The application of a magnetic field enlarged the nanoparticle transport zone. However, increasing the Rayleigh number and decreasing the inclination angle of the enclosure caused the nanoparticles to disperse evenly.

Performance enhancement of energy storing unite is a very important issue in renewable energy systems. In the present investigation, L shaped fins with two different orientations and various geometrical properties were considered to enhance the solidification performance inside a vertical enclosure. Furthermore, effect of two types of Nano-particles with different concentrations were evaluated. It was found that the application of downward L shaped fin is better than upward form in solidification process. Also, results revealed that case with same length in vertical and horizontal part of L shaped fin has best performance. Furthermore, results presented that there is no need to use high cost Nano-particles of Cu because low cost Nano-particles of Al2O3 have better performance in considered issue. Best performance was related to case 3 which had 12.3% enhancement in the solidification time. Also, between the downward fins, the best case was related to case 8 which provided about 21.5% reduction in the solidification time. Furthermore, it was found that the application of AL2O3 with concertation of 2% and case 8, provided about 27% improvement in the total melting time when compared to the Base case.

The main objective of this manuscript is to glance into the assets of nanoparticles in the stream of generalized micropolar fluid and Carreau fluid against an intensified elongated surface. In order to assess, the heat and mass diffusion occurrences, the Cattaneo-Christov implications are also experienced in the temperature and concentration computations. In contrast to prior studies, rheological attributes on non-Newtonian fluids are depicted by engaging micropolar fluid and Carreau liquid that reflect a clear difference of transport phenomena. By minimizing the number of independent factors, the regulating equations are transmuted into non-dimensional types, that are then tackled numerically using the RK-4 algorithm along with the shooting strategy. For velocity, micro-rotation, temperature and concentration distributions, a visualization evaluation of the entangled flow parameters is executed. It has been revealed that expanding magnetic and micropolar constraints enhance micro-rotation velocity. The unsteadiness parameter enhances all three physical quantities, surface drag force, Nusselt number, and Sherwood number.

This communication explores the significance of suction/injection for gravity modulation mixed convection in micropolar fluid flow due to an inclined sheet in the presence of magnetic field and thermal radiation. In recent years, very extensive modern technological applications have rise the interest in mixed convection controlled by g-jitter forces associated with microgravity. The novelty of the present study is effects of g-jitter on dynamics of micropolar fluid adjustable inclination to the sheet taken into account. Mathematical formulation based on usual laws of conservation is non dimensionalized with emerging parameters through implementation of similarity transform to yield a corresponding set of partial differential equations. In the face of convective non linearity combined with coupling due to mixed convection and micropolarity, a finite element discretization is harnessed to be coded and run on Matlab platform. The credibility of numerical procedure is assured for its acceptable adoption with the established results. The growing strength of amplitude of modulation is showing proportional decrease and increase in the fluctuation of heat transfer and skin friction coefficients, and the fluctuation of reduced skin friction factor, couple stress, and Nusselt number improves with larger inputs of amplitude. These findings would be helpful to experts dealing with upper space heat transportation, performance of materials such as crystals and effectiveness of chemical catalytic reactors.

This manuscript uncovers the heat and mass transfer of an unsteady tangent hyperbolic nanofluid flow across an extensible Riga wedge under the effects of stagnation point, heat source, and activation energy. The flow computations with modified Hartmann numbers are embedded in this investigation particularly in the unsteady tangent hyperbolic liquid stream scenario. The focus pertains to augment heat conduction in the bulk liquid as heat and mass transport media. The implications of controlling parameters on non-dimensional speed, temperature, as well as concentration profiles are visually portrayed. The governing partial differential equations are modified into non-dimensional forms by reducing the number of independent factors, which are then pursued numerically utilizing the Runge-Kutta method with the shooting tool. The velocity of Newtonian fluid improves as the magnitude of wedge angle parameter βw rises, although it is marginally lower than that of tangent hyperbolic fluid, the temperature of Newtonian fluid intensifies substantially faster than that of tangent hyperbolic fluid for higher values of βw. The skin friction factor increases with alterations to the Hartmann parameter, Weissenberg factor, wedge angle parameter as well as suction parameter. The percentage increase in skin friction factor is 13.3 and 21.93 when modified Hartmann number takes input in the range 0 ≤ Mh ≤ 0.2 and unsteady parameter 0.1 ≤ A ≤ 0.5. The Schmidt number, chemical change, and wedge angle parameters are all designed to boost the Sherwood number.

Increasing use of fossil fuels has led to serious consequences on the environment including global warming, pollution, and increased costs of heating systems. This indicates the importance of improving the efficiency of devices used in heating and air conditioning systems such as heat exchangers. In this study, it was tried to enhance the performance of the heat exchanger by simultaneous use of a flat tube as a central tube of the heat exchanger and dual conic turbulator. In addition to plain conical turbulator, the influence of the conical turbulator with aerodynamic geometry was investigated on the heat transfer and pressure drop. Finally, economic evaluation of the studied cases was done based on the thermal performance enhancement factor (TEF) and the net profit of unit transferred heat load (ηp). Tests were conducted in the hot water flow rate ranging 0.033–0.0678 L/s while cold water flow rate was kept constant at 0.166 L/s. The results indicated that the heat transfers and exergy loss of the flat tube heat exchanger with a dual modified conical turbulator was up to 33% and 30% higher than the plain tube heat exchanger, respectively. Also, a heat exchanger with a modified dual turbulator with convergent embellishment (case B) selected as the economic case and has the highest TEF and ηp . It was revealed that the application of enhanced conical turbulator would lead in the increment of ηp up to 1.26 times.

A two-stage ORC (Organic Rankine Cycle) is being proposed for the recovery and utilization of low-grade heat from single flash geothermal power plant exhaust flue fluids. The working fluids for two-stage the recovery system are R227ea and R116. The impact of essential design parameters such as inlet temperature of the cycle, ambient temperature, geothermal turbine inlet pressure, geothermal condensation temperature on system performance are investigated using thermodynamic mathematical models regarding energy and exergy efficiencies as the objective function. The addition of the recovery section to the base cycle improves the thermal efficiency from 0.2023 to 0.2178, a 7.66% improvement in this critical metric. Furthermore, the exergy efficiency rises from 0.55044 to 0.5803, representing a 15.04% boost in exergy efficiency. Furthermore, the system's overall output rises from 7690 kW to 9898 kW, representing a substantial gain of 28.71%. The suggested recovery system's cycle has a lower LEC than a single flash geothermal cycle from an economic standpoint. LEC Reduced from $ 0.125 per kilowatt to $ 0.108 per kw, a cost savings. As a result, including a recovery section in the basic single flash geothermal cycle will significantly improve system performance.

Filled square cross-section shape is the common conventional structure for n-type and p-type legs of thermoelectric generators. However, other cross-section shapes with hollow structure can significantly increase the output power of thermoelectric generator. However, mechanical strength and economic considerations may still remain as the significant challenges and factors. Hence, in this research, different hollow cross-section leg shapes are investigated for thermoelectric generator from all thermal, economic, exergetic and mechanical viewpoints simultaneously through a 3D validated numerical simulation. Output voltage/power, energy-efficiency, exergy efficiency, Von-Mises stress, and the dollar/watt value are calculated for all mentioned structures and optimum conditions are identified. As a sample result, the triangular shape leg is able to generate up to 100% more power and better conversion/exergy efficiency (compared to the rectangular) at maximum input heat flux while mechanically less reliable design. Many other remarkable and interesting findings are provided in this manuscript.

Through the present investigation, the thermal and power output of novel-shaped solar panels are evaluated. For the cooling of the mentioned forms, forced air flow was utilized. Three novel shapes, of Pyramid, Hexagonal, and Conical which had the equal lateral surface were considered. For the simulation, an open source CFD software was utilized. The lateral surfaces were put under identical amount of heat flux. Air as the coolant fluid was injected with constant inlet temperature from the trapdoors at the bottom of different shaped structures. Three different values of heat flux and air injection rate were evaluated for each shape. The outcomes presented that the conical shaped solar panel exhibits better thermal performance than other geometries. Furthermore, conical form finds the least temperature that was about 10.5 °C less than that of the pyramid-shaped panel. Furthermore, it was revealed that the corners of pyramid and hexagonal-shaped solar panels have higher temperature. Also, it was found that the efficiency of conical shaped panel was up to 8.4% more than that of pyramid-shaped panel.