Improvement In Heat Transfer Rate Research Articles

Artificial neural network (ANN) approach in predicting the thermo-solutal transport rate from multiple heated chips within an enclosure filled with hybrid nanocoolant

This study focuses on enhancing heat and mass transfer in an electronic cooling system such as a rectangular cavity that contains equidistant heated chips along the bottom wall. The cavity of the present study is filled with ethylene glycol (30:70) based hybrid nano coolants of different volume fractions (ϕ) of Multi-walled Carbon Nanotube (MWCNT), Aluminum Oxide (Al2O3), and Copper Oxide (CuO). The set of equations controlling the thermo-solutal natural convection within the enclosure is simulated using the Galerkin weighted residual finite element method (FEM). The study has shown a good agreement of numerical results with different experimental reports within the framework of the present study. A solution space is constructed based on governing parameters such as Rayleigh number, buoyancy ratio, and Lewis number. A hybrid nano-coolant containing ϕMWCNT = 1.5 %, ϕCuO = 0.5 %, and ϕAl2O3 = 2 % showed a 3.11% improvement in heat transfer rate compared to the base fluid, highlighting its potential for thermal management applications. This study also investigates various machine learning models for predicting the heat and mass transfer rate, and an error analysis is conducted on the K-Nearest Neighbour Regressor, Random Forest Regressor, Decision Tree Regressor, and ANN model. The ANN model with 6-50-100-50-2 architecture showcases the best fit with the mean squared error of 0.8923 and an R² value of 99.96 % on testing data. The ANN model exhibits its capability to predict heat transfer and mass transfer rates within the error ranges from 1–2 % and 2–3 %, respectively, even at a strong thermal buoyancy force (Ra = 10⁵). This accuracy showcases a novel use of ANN to efficiently predict thermo-fluidic transport behaviors of hybrid nanofluids, offering a faster alternative to resource-intensive simulations. The present study opens new possibilities for real-time, cost-effective cooling solutions, particularly in microelectronics and renewable energy, while maintaining high prediction accuracy by integrating machine learning with the nanotechnology approach.

Material and Parametric Design Optimization of Improved Heat Transfer Rate of AC Condenser

Air conditioner system is made up of a condenser that removes unwanted heat in an enclosure through the refrigerant and transfers the heat outside. Improving the heat transfer of air conditioning condenser is still a difficult task because of the broader set of materials and various parametric designs involved. Due to this high cost, the experimental set-up cost cannot be modified, instead, simulation analysis was introduced in the optimization process in order to achieve a near-optimal solution. The aim of this research is to improve the heat transfer rate for air conditioning condenser by material and parametric design optimization. The system was designed based on one basic parameter optimization: varying the condenser tube diameter. This variable was changed in order to improve the heat transfer of the condenser. Simulations using Computational Fluid Dynamic (CFD) analysis and thermal analysis were carried out to have a better understanding and distinct visualization of the fluid flow and materials used, and to compare the results. The materials that were used for CFD analysis are R32 and R290, and for thermal analysis are copper (C12200) and aluminum. The analysis was done using Analysis System (ANSYS) software. Different parameters were calculated from the results that were obtained and graphs were plotted between various parameters such as heat flux, static pressure, velocity, mass flow rate and total heat transfer. From the CFD analysis, the result shows that R32 has more static pressure, velocity, mass flow rate and total heat transfer than R290 at a condenser tube diameter of 7mm. In thermal analysis, the heat flux is more for copper (C12200) material at a condenser tube diameter of 7mm than aluminum.

Natural convection and variable fluid properties of tangent hyperbolic nanofluid flow with Cattaneo-Christov theories and heat generation

The main aim behind this work is that we have to determine the enhancement that happens in thermal conductivity by using the Buongiorno model of nanofluid when the nanofluid particles are added to the tangent hyperbolic base fluid moving above the stretched surface. The viscosity of tangent hyperbolic nanofluid is assumed to be temperature-dependent. The modified form of the Fourier law of heat conduction motivated us; therefore, the Cattaneo-Christov heat and mass flux model is considered to observe its significance for heat and mass transport. The chemical reaction and heat generation are also considered to determine their influence on temperature and concentration gradients. This study is crucial because of its application in industrial manufacturing processes such as the coating of wire, the thinning of copper, the production of paper, photographic films, hot rolling, and the purification of crude oil. In electronic cooling systems, the efficient dissipation of heat in smartphones, computers, and data centers is critical to preventing overheating. Nanofluids, with their enhanced thermal properties, can significantly improve heat transfer rates, ensuring better performance, stability, and energy savings. The partial governing equations arising from fluid flow, mass, and heat transfer are transformed into ordinary differential equations via appropriate similarity variables. The obtained ordinary differential equations are solved numerically by using the Runge-Kutta Fehlberg method in the MATLAB software. The effects of the emerging parameters are represented through graphs. According to the results, the velocity profile upsurges due to the natural convection parameters and curvature parameter, while the power law index declines the velocity profile. As the Brownian motion coefficient rises, the concentration profile diminishes while the temperature profile increases. Both the concentration and temperature profiles increase for larger values of the thermophoresis parameter. The concentration profile declines for larger values of chemical reaction parameters, and enhancement happens in the temperature region.

Optimization of heat transfer in PCM based triple tube heat exchanger using multitudinous fins and eccentric tube

This study aims to analyze the effect of incorporating a hybrid concept of heat transfer enhancement using extended surfaces and eccentricity of the inner tube in an RT-82 phase change material-based horizontal triple tube heat exchanger. Three types of fins were used, namely longitudinal, arc and triangular shape fins, as per suitability for better heat transfer. Moreover, the concept of eccentricity was also implemented to make PCM melt faster. The novelty of the present study lies in optimizing the heat transfer enhancement by proper placement of the fins and eccentric inner tube arrangement. A conduction-convection model was used to examine the thermal performance of a triple tube heat exchanger. The natural convection of PCM was employed using the Boussinesq approximation. The governing equations were solved using finite volume-based Ansys Fluent 2021 R2 software. The performance study of phase change material was based on transient variation of liquid fraction and average temperature. The optimum model showed a 63.87 % reduction in melting time and a 175.16 % improvement in heat transfer rate compared to a simple triple tube heat exchanger to achieve the unit liquid fraction. It is also observed from the calculation of the Rayleigh number that the conduction became more dominant than the convection phenomenon in the fin based model. The main finding of the present study is the use of triangular fins on the base along with the curved fins at the lower middle section because this arrangement shows high heat penetration capability. The results indicate that fins selection and placement significantly enhance the heat transfer rate.

A parametric study on hydrogen storage in AB5 hydride alloys: Heat and mass transfer, thermodynamics, and design

The design of heat exchangers plays an important role in the performance of solid-state hydrogen storage devices. In this study, three different designs of hydrogen storage devices were investigated, incorporating phase change material (PCM), specifically, RT25HC into their walls in various shapes. A mathematical model, validated using previous experimental data, was employed to calculate heat and mass transfer and determine the reaction time period. The calculations were conducted using ANSYS Fluent, with a constant hydrogen supply pressure of 10 bars and a temperature of 295 K. The absorption properties of the storage reactor were investigated through various parameters such as liquid fraction, hydrogen concentration, and natural convection heat transfer coefficients. Results showed that the geometric structure and PCM distribution significantly impacted the performance of the hydrogen storage devices. Design 1, with a centralized PCM distribution, demonstrated moderate heat transfer rates and a longer reaction time. Design 2, featuring a more distributed PCM layout, improved heat transfer rates and reduced hydrogen kinetics time by 40%. Design 3, which optimized the geometric structure with advanced PCM shapes, achieved the highest heat transfer rates and improved hydrogen kinetics time by 50%. This design also enabled the storage of thermal energy at a high density, ranging from 10.2 J/g to approximately 190.5 J/g. The study provides critical information on the design of efficient solid hydrogen storage processes. The findings suggest significant potential for improved performance in industrial applications such as electric vehicles and domestic energy supply. The high efficiency of the large-scale reactor is due to its well-designed system, which effectively converts chemical energy into thermal energy. Optimizing the reactor geometry and PCM distribution is crucial for achieving superior hydrogen storage and retrieval performance.

Melting performance improvement of phase change materials with thermal energy storage unit using nanoparticles

The world is facing two major problems today, as imbalance of supply and demand of the energy and the continues deterioration of the environment. Latent thermal energy storage with phase change material plays a vital rule in resolving this problem. The current study investigates the numerical simulation of phase change material with novel fins configuration in the triplex-tube storage unit. But their low thermal conductivity is the main problem by affecting the energy storage. To enhance the heat transfer rate within the system, novel longitudinal triangular and traditional rectangular fins with a combination of hybrid nanoparticles (Cu-TiO2) are employed. In summary, utilizing novel fins to improve heat transfer rate in conjunction with nanoparticles is highly effective for improving the phase change material melting process in thermal energy storage systems. The usage of nanoparticles speeds up the melting rate 33.5%- Case A, 20%-Case B, 19.4%-Case C, and 18% for Case D. Moreover, when compared to rectangular-shaped fins, the use of longitudinal triangular -shaped fins accelerates the PCM melting rate. For instance, the melting rate in Case C (fins with longitudinal triangular form) is higher than in Case F (fins with a rectangle shape).

Optimizing heat transport in a permeable cavity with an isothermal solid block: Influence of nanoparticles volume fraction and wall velocity ratio

Abstract This study examines the influence of wall velocity ratio on mixed convective heat transport in a permeable cavity containing an isothermal solid block at its center. The analysis considers the characteristics of various flow variables, i.e., Darcy number, wall velocity ratio, Richardson number, and volume fraction of suspended nanoparticles, on heat transport and material flow characteristics. The principal equations are solved implementing the semi-implicit method for pressure linked equations algorithm, and the outcomes are compared with existing literature. The study shows that rising estimations of Darcy number, velocity ratio, Richardson number, and nanoparticles volume fraction lead to improved heat transfer rates. For example, at high Richardson number (100) and solid volume fraction (0.05), increasing the velocity ratio from 0.5 to 1.5 results in a 6% (5%) upsurge in heat transport rate. Conversely, at smaller Richardson number (0.01), the heat transport rate upsurges by 29% (28%). Similarly, at high Darcy numbers and low wall velocity ratios, a 3% (4%) escalate in heat transport rate is observed with an increase in nanoparticles concentration from 0 to 0.05, while a 9% (8%) increase in thermal performance is achieved at low Darcy numbers. The study emphasizes the importance of optimizing the combination of nanoparticles volume fraction, Darcy number, velocity ratio, and Richardson number to maximize thermal performance in the porous cavity.

Experimental investigation of the effect of angled fins on the energy and exergy efficiencies of solar stills: A comparison between double slope and pyramid solar stills under Tunisia weather conditions

Solar stills play a crucial role in addressing the scarcity of potable water, particularly in remote areas. However, traditional solar still designs are often inefficient, with limited productivity and high energy consumption. One approach to enhancing the efficiency of solar stills is to use finned absorber plates, which can increase the heat transfer area and improve heat transfer rates, thereby enhancing evaporation and overall productivity. This study investigates the impact of different configurations of angled fins on the energy and exergy efficiencies of solar stills, focusing on Pyramid Solar Still (PSS) and Double Slope Solar Still (DSSS) designs. Energy efficiency was calculated over several days to determine the effect of the number of angled fins ((3 × 3), (3 × 5), and (3 × 7) fins) on the performance of both solar stills and to compare the two configurations. The most favorable results were obtained using an absorber plate featuring (7 × 3) angled fins in PSS. The desalination systems equipped with finned absorber plates with (7 × 3) angled fins achieved approximately 43.22 % and 46.25 % greater productivity for the PSS and DSSS, respectively, compared to absorber plates without fins. In this configuration with (7 × 3) angled fins, the PSS system recorded an energy efficiency of 37.84 %, while the DSSS system achieved a rate of 31.93 %. The PSS desalination system with an absorber plate without angled fins achieved an energy efficiency of 26.18 %, while the similarly equipped DSSS system attained an energy efficiency of 22.39 %. Regarding exergy efficiency, the PSS showed an average daily exergy efficiency without angled fins of 1.94 %, but using (7 × 3) angled fins boosted this to 2.66 %, the highest value observed. Likewise, the DSSS’s exergy efficiency started at 1.54 % without fins but reached 2.15 % with (7 × 3) fins. Overall, though, the PSS consistently outperformed the DSSS in terms of both energy and exergy efficiency across the various absorber plate configurations. These findings underscore the effectiveness of using finned absorber plates to enhance the evaporation rate and improve the overall efficiency of solar stills.

Numerical Investigation of Heat Exchanger Enhancement for a Staggered Arrangement with Corrugated Rods in Front

The heat exchanger is used in many industrial and engineering activities.Where, numerous applications confirms on a large heat transfer rate. However, the twisted tube is one of heat transfer rate enhancement methods. Also, the turbulent flows are often used instead of laminar for enhancement heat transfer rate. Therefore, the tube arrangement can be used in a suitable way for utilized this purpose. The shape features of tubes in the heat exchangers are very important for enhancing their performance. As well, the pressure drop and heat transfer rate have a remarkable effect on the thermal efficiency of the heat exchanger. In this research, a numerical investigation with a new way for heat exchanger tube staggered arrangement is presented. Where new solid spiral rods with oval sections are inserted in front of main tubes to induce high turbulent flow intensity as well as redistribution airflow over exchanger tubes. However, the new air distribution will help the airflow pressure over all the tubes to push the thermal boundary symmetrically behind the tubes. Therefore, two different sectional tubes were presented (circular and elliptical). These cross-sectional areas for both types have the same values. The main tubes have no twisted to prevent decreases in pressure. The numerical analysis used the K- ε model at a low Reynolds number to the simulation of this situation. Where, the eddy will generate in the vicinity region to pipe walls due to twisted pipe as well as the obstruction the cross flow. However, there are a good improvement of heat transfer rate without spend any energy depending on the control the shape and arrangement of pipes. The results show that the corrugated rod will increase the Nusselt number at different values of Reynolds. However, the elliptic tube gives the best results for heat transfer rate and maximum Nusselt number. The results compared with others works and give a good agreement.

Unfolding some numerical solutions for the magnetohydrodynamics Casson–Williamson nanofluid flow over a stretching surface

Abstract This research focuses on exploring the significance of chemical reactions and thermal radiation on the magnetohydrodynamic (MHD) flow of a Casson–Williamson nanofluid (CWNF) over a stretching sheet. The objective is to comprehend how these factors influence the flow and heat transfer. A mathematical model, comprising partial differential equations adjusted into ordinary differential equations (ODEs) via utilizing some transformation. These ODEs are then tackled by MATLAB’s BVP4C method, which is part of the finite difference technique. Results are verified by comparison with existing literature and are depicted visually and in tabular format. Additionally, the study explores the effects of external factors such as magnetic fields and the Lewis number on parameters like Nusselt number, friction factor, and Sherwood number. Furthermore, heat generation in MHD CWNF is analyzed, along with a thorough evaluation of heat transfer near a stretching sheet with a permeable layer. The findings suggest that growing Brownian motion factor (Nb) and thermophoresis coefficient (Nt) enhance the rate of heat transfer, signifying improved heat transfer rates. Similarly, higher Nt values are associated with enhanced Sherwood numbers, indicating better mass transfer. Conversely, higher Nb values lead in lower local Sherwood numbers. Physically, an increase in Brownian motion causes significant displacement of nanofluid particles, boosting their kinetic energy and thereby enhancing heat generation within the boundary layer. It is noted that the Eckert number (Ec) reflects the impact of different Ec values on temperature distribution. As Ec increases, there is a proportional increase in fluid temperature due to frictional heating, which stores heat energy within the fluid. This effect becomes more pronounced for non-linear stretching surfaces, demonstrating the response of the thermal region to viscous dissipation. Viscous dissipation has the potential to enhance convective heat transfer, leading to amplified temperature distribution and thickening of the thermal layer.

Enhancing energy efficiency and heat transfer performance of engine oil flow through hybrid nanoparticles in convergent/divergent channel

Engine oil (EO) is employed as a lubricant in various machinery engines. Efficient heat transfers are a fundamental requirement for all processes. To improve heat transfer rates and reduce the energy loss caused by high temperatures, this study focuses on incorporating Iron Oxide (Fe3O4) and Cupper Oxide (CuO) into the engine oil as suspended particles. However, the focus of this research paper is to analyze entropy generation in a convergent/divergent channel that contains a hybrid nanofluid. Mathematical modeling is utilized to present the continuity, momentum, and energy equations. Using the resemblance transformation variables, the governing dimensional partial differential equations (PDEs) are transformed into a system of non-dimensional ordinary differential equations (ODEs), which are then resolved in ascending order through the BVP4c scheme. The graphical results illustrate the effects of various parameters on fluid velocity, temperature, entropy generation, and Bejan number. The study explores changes in velocity profiles under different Hartmann numbers, revealing opposing variations in divergent and convergent channels. Velocity profiles exhibit similar patterns when varying the porosity parameter. In the convergent passage, a higher porosity parameter results in a higher temperature field. Entropy rises against Eckert and Hartmann numbers in both Convergent and Divergent cases. These insights aid in designing and optimizing machinery engines.

Bio-convection of ternary magnetized nanoparticles thermal conductivity in chemical reaction and activation energy flow with Darcy Forchheimer permeable across a double porous medium

This research focuses on investigating the impact of magnetized nanoparticles’ heat and mass transfer process two-dimensional (2D) porous medium ternary hybrid Magnetohydrodynamics (MHD) ferrofluid flow through a two movable permeable porous surface, with a specific emphasis on the Darcy Forchheimer effect, activation energy, and chemical reaction parameters. Recently, motile microorganisms have become a significant area of interest in the study of heat and mass transfer. This study employs colored plots to analyze the optimum heat transfer over a double porous plate by altering different physical parameters. Using the shooting technique, the study provides numerical solutions to nonlinear systems of equations by transforming the partial differential equations (PDE) into ordinary differential equations (ODEs) via the dimensionless similarity transformation. Tables and graphs demonstrate how the governing parameters impact velocity, temperature, mass concentration profiles, and motile microorganisms, as well as physical quantities like skin friction coefficient, Nusselt number, Sherwood number, and motile number. Ternary hybrid ferrofluid exhibits a significantly improved heat transfer rate compared to both Ferro and hybrid ferrofluid. The convective flux of heat and mass transfer experiences a decrement with an escalation in the values of the activation energy (E) parameter. The presence of positive values for both the similarity variable (n) and Exothermic/Endothermic parameter (λ) leads to an enhancement in the flow of thermal transfer on both porous surfaces. This research will have far-reaching implications in various fields, including coolant technology in the manufacturing industry, heat dissipation in electronic modules, high-performance computing cooling facilities, the automotive sector, and space applications.

Numerical study of flow and thermal characteristics of pulsed impinging jet on a dimpled surface

This research comprehensively investigates the flow and thermal characteristics of a pulsating impinging jet over a dimpled surface. It analyzes the impact of key parameters (e.g., inlet velocity pulsation functions, pulsation frequency, amplitude, dimple pitch, dimple depth, Reynolds number) on flow patterns and heat transfer. Validated computational fluid dynamics and the Re-normalization group turbulence model are employed to accurately simulate complex turbulent flow behavior. Local and average heat transfer coefficients are calculated and compared to steady impingement cases, revealing the potential benefits of pulsation for heat transfer enhancement. The study also examines how pulsation-induced flow modulation and thermal mixing affect heat transfer mechanisms. Results indicate that combining fluctuating flow with a dimpled surface can improve heat transfer rates. In summary, increasing pulsation amplitude consistently enhances heat transfer, while the effect of frequency varies between impinging and wall jet zones.

Combined Effect of Structured Surface and Biosurfactant in Pool Boiling Heat Transfer Enhancement

An attempt has been made to explore the combined effect of structured surfaces (segmented finned surface and uniform cross-section surface) and Rhamnolipid biosurfactant to improve heat transfer rate in pool boiling. Experimental investigations were performed at normal atmospheric condition and till reaching critical heat flux. The results shows that the segmented finned surface has shown better heat transfer than plain surfaces, with a 200% increase in heat transfer coefficient. In contrast, a uniform cross-section surface showed an improvement in heat transfer coefficient of 107% over a plain surface. The reasons for better thermal performance in segmented finned configuration can be associated to the reduced surface tension of the working fluid increasing more nucleation sites. Additionally, better rewetting phenomena and bubble evolution from the segmented finned surface have also assisted in improving the heat transfer rate. Moreover, the pool boiling results of all the heating surfaces with surfactant solution is compared with pure water. It has been observed that all heating surfaces have performed better with surfactant solution compared to pure water. However, the CHF obtained on all heating surfaces with surfactant solution were lesser than pure water. Low CHF is due to the foamability of the surfactant solution.

Nonlinear buoyancy driven MHD Reiner–Rivlin nanoliquid flow with quadratic radiation

The present study investigates the dynamics of Reiner–Rivlin nanofluid flow past an inclined flat plate considering quadratic radiation, external magnetic field and nonlinear buoyancy. Appropriate similarity transformations are employed to transform the mathematically modeled equations and are then resolved using the finite-difference based bvp5c scheme, which implements the four-stage Lobatto IIIa formula, in MATLAB. A comparative study between the transport phenomena of non-Newtonian and Newtonian case is also performed. It is observed that the Newtonian case exhibit higher solutal and thermal fields when compared to the non-Newtonian case. However, the results are reversed in the case of velocity profile. The Reiner–Rivlin nanofluid has improved heat transfer rate and drag coefficient characteristics than the Newtonian fluid. Augmentations in the inclination angle descend the velocity profile and ascend the thermal and solutal fields. The increment in the radiation parameter and Hartmann number causes an increment in the nanoliquid temperature. It is also observed that the velocity profile is directly proportional to the changes in the buoyancy ratio. Moreover, the present study has applications in the field of plasma studies, aerodynamics, and cooling systems.

Heat transfer enhancement of electronic devices by using flexible printed circuit boards

In this paper, heat transfer in electronic equipment was studied numerically and experimentally, by investing in the flexible printed circuit board and changing the board’s orientation, which is the substrate of the electronic equipment from a vertical to a horizontal position. ANSYS Fluent software has been used to solve the continuity, momentum, and energy equations with the three-dimensional, unsteady, laminar and incompressible flow. In this study, the oscillatory motion equation was used as a boundary condition to represent the motion of the flexible board. In the experimental aspect of this study, a simulation of an ASUS motherboard (X399-A) with dimensions (30 x 25) cm and a Core i9 CPU with a fully working power of 130W was used to study the enhancement of heat transfer in the electronic devices by test rig specially made for this study. The results show that the flexible board’s enhancement in the heat transfer was (7%) vertically and (7.6%) horizontally compared with the rigid board for the same working conditions. The horizontal position is better than the vertical of the two types of rigid and flexible board, with improved heat transfer rates of (2.7%) and (3%); correlation Equations of the Nusselt number from experimental results are presented.

A numerical study on the thermal response of biodegradable ferrous oxide/aluminium oxide nanofluid flow past an unsteady contracting permeable cylinder: A comparative analysis

Esters that are considered natural come from renewable sources like vegetable or animal oils or other bio-based materials. Due to natural esters' great biodegradability, lack of toxicity, and high flash point, their use in industrial applications has been expanding quickly in recent years. The current study, thus numerically investigates an unsteady laminar flow and heat transfer of biodegradable nanofluids past over a shrinking cylinder of time dependent radius. Natural Ester (NE) is used as the base fluids, and two nanoparticles such as Fe3O4 (ferrous oxide) and Al2O3 (aluminium oxide) are used to create different combinations of nanofluids. The unsteady Navier-Stokes equations are used to model it, and similarity solutions are introduced to solve the problem. A MATLAB built-in package BVP4c has been employed to tackle the problem. The physical behavior of the solution has been explored in terms of parametric analysis and graphical demonstration and the validation of present solutions is reported by the comparative benchmark with already available results in a limiting sense. Our findings demonstrate that Fe3O4 biodegradable nanofluids are capable of carrying and dispersing thermal energy more effectively, resulting in improved heat transfer rates compared to Al2O3 biodegradable nanofluids.

A brief review of the application of ferrofluids and magnetic fields in solar energy systems

Solar energy devices must constantly work at a suitable thermal efficiency in order to be economical. On the other hand, it has been found that ferrofluids and magnetic fields can improve heat transfer rates in energy conversion systems. Therefore, they have the potential to enhance the performance of solar-based devices. This investigation examines recent studies on the application of ferrofluids and magnetic fields in solar devices. Ferrofluids and magnetic fields are introduced and their most widely used areas are described. The studies conducted on the applications of magnetic fields and ferrofluids in PV and PV/T systems are reviewed, and the most important factors affecting the efficiency of these systems are classified. It is clear that magnetic nanofluids in the presence of a magnetic field will always perform better compared to the state without a magnetic field and pure water. The most critical parameters for improving the performance of these systems are the magnetic field intensity, ferrofluid flow rate, the direction of the magnetic field and its rotation, and the volume fraction of nanoparticles in ferrofluid. Among solar devices integrated with magnetic fields, flat-plate solar collectors have the best compatibility in improving system performance even at higher induction intensities such as 1 T (10,000 G). This can increase the outlet temperature up to 100 °C in low volume fractions and improve the thermal efficiency of the system by up to 40 %.

Experimental Investigation to Improve Heat Transfer Rate of Transformer Oil Using Cuo Nanoparticles

In this research, we employed a statistical experimental design approach, specifically the Taguchi method using an L9 orthogonal array robust design, to optimize experimental conditions. Our aim was to maximize the Heat Transfer coefficient of CuO-Transformer oil Nano fluid. We carefully selected three controllable factors with different levels: Concentration of Nanoparticles (0.1, 0.2, and 0.3g/lit), Size of nanoparticles (10, 15, and 20 Nm), and Ratio of Surfactant weight to Nano particles weight (0.1, 0.5, and 1).Our analysis of the results highlighted the significant role played by the Size of nanoparticles in influencing the heat transfer coefficient of the Nano fluid, accounting for approximately 88.852% of the variation. We determined the optimal settings for these three factors to maximize the heat transfer coefficient: Concentration of Nano particlesof0.2g/lit, Size of Nano particles of 10 Nm, and Ratio of Surfactant weight to Nano particles weight of 1. The Heat transfer coefficient predicted by ANOVA under these optimized conditions was 559.443W/m2 K and by regression model was 549.45 W/m2 K.To validate our findings, a confirmation test was conducted at these optimal conditions, and the results demonstrated a high degree of consistency between the experimental and predicted values.

Heat Transfer Enhancement by Mitigating the Adverse Effects of Crossflow in a Multi-Jet Impingement Cooling System in Hexagonal Configuration by Coaxial Cylindrical Protrusion—Guide Vane Pairs

A novel compound multi-jet impingement system for enhanced cooling of a flat surface by augmenting its area with cylindrical protrusions (CPs) equipped with coaxial guide vanes (CGVs) and reducing deflection of jets by crossflow has been developed for high-heat removal applications. The cooling performance of coaxial circular jets impinging on the top faces of CPs placed in hexagonal configuration on a flat plate is evaluated by three-dimensional (3D) computational fluid dynamics (CFD) simulations. Jets impinging on the top faces of the protrusions are directed to their lateral faces and then to the base plate by the CGVs around the protrusions, resulting in up to 62.8% improvement in heat transfer rate with a minor increase in pressure drop. Effects of protrusion height and diameter on the pressure drop and cooling performance are studied for jet Reynolds (Re number range of 5000–20,000. Due to both shortened jet impingement lengths as the height of protrusions is increased and directing the expended fluid away from the impinging jets by CGVs, adverse effects of jet–crossflow interactions on cooling performance and fluid pumping power are significantly reduced. Performance evaluation criterion (PEC) of the novel compound multi-jet impingement cooling system (CMJICS) can be as high as 1.52.