Heat Transfer Dynamics Research Articles

Dynamic heat transfer characteristics of printed circuit precooler in supercritical CO2 Brayton cycle

The dynamic characteristics of heat exchangers are critical in supercritical CO2 Brayton cycle, especially in the precooler where significant thermophysical property variations occur. However, few studies have comprehensively analyzed the dynamic heat transfer characteristics in precooler, particularly with respect to the detailed flow and thermal field evolution. A three-dimensional numerical model was developed to study the dynamic performance of a printed circuit precooler, with an emphasis on the impact of thermophysical properties. The study examines responses to abrupt changes in CO2 and water inlet temperature, as well as mass flux variations. Results show that the precooler exhibits rapid response characteristics with mild fluctuations in heat transfer parameters and flow structure. Notably, the large specific heat near the critical point results in minimal variation in CO2 outlet temperature despite abrupt increases in CO2 inlet temperature, thereby enhancing system stability. Conversely, a decrease in CO2 mass flux causes a transition from forced convection to mixed flow, with strengthened buoyancy effects and decreased entropy production. These variations lead to significant changes in CO2 outlet temperature, posing potential challenges to system stability under CO2 mass flux step change conditions. The heat transfer shows a relatively lower response rate to parameter changes of water compared to CO2. Although variations in water parameters have a negligible effect on CO2 heat transfer, they influence the overall heat transfer coefficient. The dynamic heat transfer characteristics of the precooler presented in this paper address research gaps left by 1D numerical and experimental studies, which have provided limited information on flow and thermal fields during dynamic processes. These insights are essential for understanding the dynamic behavior of the entire system.

Significance of 3D rectangular closed domain filled with charged particles and nanoparticles engaging finite element methodology

Abstract This article aims to use passive flow control to analyze the transportation of heat, mass, and charged particles toward a 3D plate. The current problem offers a novel exploration of the flexible domain of non-Newtonian materials, which are well known for their wide range of applications in the engineering and industrial domains. The current study explores the complex dynamics of heat and mass transfer in a fluid that flows over an elongating sheet. The motion of the nanofluid on the surface is caused by the stretching of the 3D plate. The suspension of mixtures of tetra-hybrid nanoparticles can enhance thermal performance and cooling mechanism. Moreover, the 3D model includes modeling of multiple important parameters, such as heat source, thermal radiation, and Hall and Ion slip effects, in Cartesian coordinates for a three-dimensional stretched plate. This comprehensive analysis of various effects offers a new perspective to the field. Partial differential equations represent the emergent phenomena in the problem formulation process. It was estimated that an enhancement of charged particles and motion regarding nanoparticles is enhanced versus an enhancement of charged particles. With the greater power law index, suction, and Weissenberg number, the acceleration of nanoparticles is enhanced.

Thermal analysis of constant surface area tapered helical Coils: Insights from numerical modelling

Helical coils are integral to numerous engineering and domestic applications, from room heaters and vehicle suspensions to nuclear reactors, owing to their high surface area-to-volume ratio that facilitates efficient heat transfer. This study investigates the natural convection heat transfer characteristics of tapered helical coils under radiative heat loss, focusing on both straight and inverted configurations, within an unconfined air medium. The numerical simulations were validated against experimental results with a maximum deviation of 5 % before proceeding to establish the numerical findings. The analysis considers geometric parameters such as non-dimensional pitch (p*), cone angle (θ), and emissivity (ε), along with Rayleigh number (Ra), to elucidate their impact on average Nusselt number (Nu), mass flow rate of air through the coil core, and heat transfer mechanisms. Results reveal distinct behaviors for straight and inverted coils, with varying Ra and θ influencing heat transfer dynamics and airflow patterns. Notably, inverted coils exhibit enhanced heat transfer characteristics compared to straight coils. For straight coils, Nu initially decreases with increasing θ at lower Ra but rises beyond a critical θ at higher Ra due to independent heat dissipation by the coil turns. When θ changes from 0° to 50° at p* = 6, the change in average Nu is approximately 3 % and 10 % for Ra = 108 and 104 respectively. In contrast, for inverted coils, Nu increases with θ across all Ra, owing to the wider top opening facilitating airflow. Furthermore, empirical correlations are developed to predict Nu based on key parameters, achieving high accuracy with deviations of ± 6 % and ± 4 % for straight and inverted coils, respectively. These correlations provide robust tools for optimizing thermal management in diverse applications. Overall, this study contributes significant insights into tapered coil performance, essential for advancing heat transfer technology and design optimization.

Thermal analysis of MHD unsteady Darcy‐Forchheimer thin film flow in a porous system

AbstractThis study has investigated a Darcy‐Forchheimer thin film flow over an extended horizontal surface with thermal radiation and chemical reaction effects. The governing time‐dependent equations have been non‐dimensionalized using similarity transformations and solved numerically using the fourth‐order Runge‐Kutta method and the shooting technique. The influence of magnetohydrodynamics, non‐uniform heat sourcing, viscous heat radiation, and chemical reactions on temperature, velocity, skin friction, Nusselt, and Sherwood numbers has been examined. Results have shown that porous media, magnetic field, and transient effects decrease the velocity profile, while thermal radiation and variable thermal properties enhance temperature distributions. Findings have indicated that the magnetic field and porosity enhance the skin friction coefficient whereas the heat transfer rate increases with Eckert number and Prandtl number. Rising the chemical reaction parameter from 0.2 to 0.5 rises the mass transfer rate by approximately 9.85%. The thermal analysis of MHD Darcy‐Forchheimer thin film flow in a porous system has been crucial for understanding heat transfer and fluid dynamics in complex environments. It helped in optimizing various engineering processes, such as cooling systems, filtration, and energy conversion, by providing insights into temperature distribution, convective heat transfer, and fluid behavior. This analysis has aided in designing efficient and reliable systems with improved performance and reduced energy consumption.

ANN‐driven insights into heat and mass transfer dynamics in chemical reactive fluids across variable‐thickness surfaces

AbstractThis study investigates the heat and mass transfer dynamics in exothermic, chemically reactive fluids over variable‐thickness surfaces using advanced numerical methods and artificial neural networks (ANN). The importance of understanding these processes lies in their significant industrial applications, such as in chemical reactors and heat exchangers. We transformed nonlinear partial differential equations into ordinary differential equations and used the bvp4c numerical method to generate a comprehensive data set. The ANN model, trained with the Levenberg–Marquardt algorithm, was evaluated for its accuracy in simulating complex fluid dynamics and thermosolutal transport phenomena. Our results revealed that increasing the second‐grade fluid parameter enhanced skin friction by 20.38%, heat transfer rate by 1.16%, and mass transfer rate by 4.06%. The ANN model demonstrated high predictive precision with a validation mean squared error of . These findings highlight the effectiveness of the ANN methodology in providing precise simulations of fluid dynamics, which is crucial for optimizing industrial processes.

Investigation of dynamic start-up and thermal airflow characteristics for air-carrying energy heating and cooling system: Sidewall, ceiling, and composite walls

The dynamic start-up process of the air-carrying energy radiant system (ACERS) is crucial for operation control. The dynamic heat transfer process of sidewall, ceiling, and composite walls for air-carrying energy heating and cooling systems was investigated using field experiments and numerical simulation. A new dynamic start-up model was proposed to rapidly predict the dynamic response time and heat transfer surface temperature for controlling indoor temperature. Six schemes with different thermal flow characteristics resulting from temperature difference and velocity uniformity were quantitatively studied through numerical simulation, which helps determine their rationality. The results show that the dynamic start-up model aligns well with experimental data, with an error of less than 3 %. The fast response time of the air medium heat transfer surface for heating/cooling is short (less than 0.5 h). The ceiling provides better adjustability compared to the sidewall. In the unstable state (Gc < 0), the Gc-related buoyancy has a vertical promotion effect, leading to increased convection and decreased vertical temperature difference in the room. Adding the sidewall heating to the ceiling heating reduces the indoor vertical temperature difference by 23 % for the composite walls heating compared to the ceiling heating. Convection accounts for 27 % of the sidewall heating, which is 2.7 times higher than that of ceiling heating (11 %). Combining the dynamic start-up model with numerical analysis enables rapid prediction and analysis of the thermal performance of ACERS, which can be applied to advanced control and optimization for energy-saving applications.

The time‐fractional ISPH method for fin circular rotation on MHD bioconvection flow of oxytactic microorganisms and NEPCM within a hexagonal‐shaped cavity

AbstractThis work investigates the bioconvection flow of oxytactic microorganisms and nanoparticle‐enhanced phase change material (NEPCM) within a hexagonal‐shaped cavity containing a rotated cross fin, utilizing the incompressible smoothed particle hydrodynamics (ISPH) method based on a time‐fractional derivative. The study considers the circular rotation of an inner cross fin and the presence of two rectangular heat sources on the plane walls inside the hexagonal cavity. The novelty of this work is its integration of a hexagonal‐shaped cavity with a rotated cross fin and the use of a time‐fractional derivative in the ISPH method to analyze bioconvection flow, offering new insights into the interaction between microorganism motion and heat transfer dynamics in complex geometries. The effects of Darcy, Hartmann, Lewis, Peclet, Rayleigh, and bioconvection Rayleigh numbers on isotherms, heat capacity ratio, microorganism density, velocity fields, and average Nusselt number are analyzed. The key findings demonstrate the significant impact of Rayleigh and bioconvection Rayleigh numbers in enhancing heat distribution and velocity fields, thereby significantly influencing microorganism motion. Due to Lorentz forces, the velocity field decreases by with an increase in the Hartmann number from 0 to 50. The resistance of the nanofluid's velocity becomes apparent as the Darcy number decreases. Increasing Lewis and Péclet numbers cause the microorganisms to shift towards the cavity's boundaries.

Impact of vertical thermal vibration on heat transfer dynamics in a dual-channel-driven cavity under zero-gravity condition

Impact of vertical thermal vibration on heat transfer dynamics in a dual-channel-driven cavity under zero-gravity condition

Experimental and numerical study on ferrohydrodynamic and magneto-convection of Fe3O4/water ferrofluid in a sudden expansion tube with dimpled fins

BackgroundThis study experimentally and numerically addresses magnetohydrodynamic forced convection including dimpled fins, Fe3O4/water ferrofluid, and DC magnetic field. In this research, focusing on the thermo-hydraulic performance improvement of a sudden expansion tube. It has been used different inlet diameters, dimple sizes, ferro nanoparticle concentrations, and magnetic field strengths to examine the heat transfer and fluid dynamics characteristics of the system. MethodsThe study consists of two parts, i) experimental and ii) numerical. Steady-state, incompressible, Newtonian flow were considered but chemical reaction, viscous dissipation, buoyancy, and radiative heat transfer were neglected in this study. On the other hand, numerical solutions were carried out for single-phase method. This study was first compared with the studies in the literature on the flow in a sudden expansion tube without dimpled fins and the error rate was found to be less than 10 %. In the analysis, dimpled fins with d=3, 5, and 7 mm at each P=15 mm (P/d=5.0, 3.0, and 2.14) have been used. As working fluid, Fe3O4/water ferrofluid with volume concentration of φ=1.0 % and 2.0 % have been analyzed. Additionally, DC magnetic fields, which strength of Ha=0.1, 0.3, 0.5, 1.1, 3.2, and 5.3 (B =0.01, 0.03, 0.05, 0.1, 0.3, and 0.5T), have been applied on the sudden expansion tube surface as external force. Significant findingsDimpled fins enhance the heat transfer by disrupting the boundary layer and forming secondary flows, while the ferrofluid increases the thermal conductivity and viscosity of the base fluid. Based on these explanations, dimpled fins increased the convective heat transfer rate at the rate of 96.0 % compared with smooth tube. In addition, Fe3O4/water ferrofluid with φ=2.0 % performed the highest performance and performance evaluation criteria increased by 8.5 %. The magnetic field also contributes to the heat transfer enhancement by inducing Lorentz force and mixing the flow. Excessive increasing of magnetic field strength adversely affected the system performance, and the highest performance evaluation criterion is acquired at Ha=3.2 by increasing 3.9 %. Compared with smooth tube, compound effect of dimpled fins, Fe3O4/water ferrofluid, and magnetic field improved the average Nusselt number and performance evaluation criterion at the rate of 279.8 % and 207.9 %, respectively.

Investigation of double-PCM based PV composite wall for power-generation and building insulation: Thermal characteristics and energy consumption prediction

The integration of phase change material (PCM) with building-integrated photovoltaic (BIPV) presents a compelling approach to enhance solar energy utilization and mitigate indoor thermal loads, contributing to energy-efficient and low-carbon building development. Traditional BIPV-PCM structures, however, struggle to balance PV efficiency and thermal insulation, particularly with varying PCM wall positions. To address this situation, this study introduces a novel double-PCM BIPV composite envelope (BIPV-dPCM). An experimentally validated dynamic heat transfer model was developed and used to perform a comparative simulation analysis with three reference systems to quantify the energy-saving potential of the BIPV-dPCM, focusing on PV output and wall insulation effectiveness metrics. Further dimensionless parametric analysis were carried out to investigate the systematic performance of the two PCMs at different relativities. In addition, the coupled working mechanism of the BIPV-dPCM system concerning the power generation performance and thermal insulation performance under transient variations is explored. It was found that the BIPV-dPCM showcases superior thermoelectric coupling performance compared to three alternative enclosures. Incorporating two PCMs significantly enhances electrical exergy efficiency by 11.66 % and thermal exergy efficiency by 1.54 %, surpassing other reference systems. The increase in PCM latent heat ratio has a limited effect on performance gain. Notably, as the PCM thickness ratio exceeds 1, the decline in P value decelerates, for every 0.5 increment in the g, the P value diminishes by merely 0.2 %. The ideal h is identified between 1 and 1.5, with 1.5 being optimal for energy conservation objectives. Additionally, the self-sufficiency coefficient (SSC) of the BIPV-dPCM remains robust, sustaining a range of 55 % to 65 % over prolonged periods. This study offers novel perspectives and serves as a design reference for optimizing building energy systems and enhancing cooling efficiencies in subtropical climates.

Unravelling molecular interactions in various alcohol-water binary mixtures using femtosecond laser-induced thermal lens spectroscopy

The FTLS (femtosecond laser-induced thermal lens spectroscopy) technique was utilized to explore the photothermal response and heat transfer dynamics in various water-based binary mixtures containing monohydric and polyhydric alcohols. Our results highlight the significant influence of intermolecular hydrogen bonding interactions and the molecular properties of the mixture constituents on the photothermal behavior of both pure solvents and their binary mixtures. Notably, we observed distinct effects of water inclusion on the heat transfer characteristics of monohydric alcohols (such as methanol and ethanol) compared to polyhydric alcohols (such as ethylene glycol (Etg) and glycerol (Gly)). This discrepancy can be attributed to the formation of unique molecular structures via hydrogen bonding interactions, which effectively hinders the natural molecular dynamics of short-chain length alcohols. Conversely, polyhydric alcohols like Etg and Gly exhibit contrasting photothermal characteristics due to their extensive intermolecular hydrogen bonding. Our investigations reveal that molecular attributes, such as chain length and the number of hydroxyl (-OH) groups, play a crucial role in altering the heat transfer mechanisms and thermal lens signal characteristics of the mixtures. These findings emphasize the sensitivity of FTLS as a probe for understanding the effects of intermolecular hydrogen bonding interactions on the molecular dynamics and thermo-optical properties of aqueous-alcoholic solutions.

Pressure drop prediction for R407C fluid during flow evaporation in horizontal pipes using Kalman Filter

The estimation of pressure drop in systems involving two-phase fluids holds a substantial influence over system design, energy efficiency, heat transfer dynamics, and the overall system performance. Existing correlations in the current literature exhibit considerable errors, primarily attributable to the diverse characteristics of flow patterns inside the pipe. This work presents a discussion on the pressure drop of the R-407C fluid in horizontal pipes during two-phase flow, along with the application of the Kalman Filter to improve the estimations produced by well-known correlations. The initialization data used were obtained through equations created based on experimental data and considering the influence that diameter, mass velocity, and saturation pressure have on the pressure drop. The correlations used as a basis for the calculations were selected from the literature, considering the lowest percentage error observed in the pressure drop estimation. Experimental data of pressure drop where compared with the results the obtained by using the correlation alone and in combination with a Kalman Filter. For tubes with a diameter greater than 1.5 mm, applying the correlation together with the Kalman Filter resulted in a Mean Absolute Relative Deviation (MARD) of 15.71, whereas using the correlation alone yielded a MARD of 28.26. For tubes with diameters of 1.5 mm or less, the MARD values were 12.12 and 62.90, for the combination of correlation and the Kalman Filter and for the correlation alone, respectively. These results underscore the viability of the Kalman Filter as an effective tool for improving the accuracy of pressure drop calculations in horizontal tubes.

The Development of Simulation and Optimisation Tools with an Intuitive User Interface to Improve the Operation of Electric Arc Furnaces

The paper presents a novel decision support system designed to improve the efficiency and effectiveness of decision-making for electric arc furnace (EAF) operators. The system integrates two primary tools: the EAF Simulator, which is based on advanced mechanistic models, and the EAF Optimiser, which uses data-driven models trained on historical data. These tools enable the simulation and optimisation of furnace settings in real time and provide operators with important insights. A key objective was to develop a user-friendly interface with the Siemens Insights Hub Cloud Service and Node-RED that enables interactive management and support. The interface allows operators to analyse and compare past and simulated batches by adjusting the input data and parameters, resulting in improved optimisation and reduced costs. In addition, the system focuses on the collection and pre-processing of input data for the simulator and optimiser and uses Message Queuing Telemetry Transport (MQTT)communication between the user interfaces and models to ensure seamless data exchange. The EAF Simulator uses a comprehensive mathematical model to simulate the complex dynamics of heat and mass transfer, while the EAF Optimiser uses a fuzzy logic-based approach to predict optimal energy consumption. The integration with Siemens Edge Streaming Analytics ensures robust data collection and real-time responsiveness. The dual-interface design improves user accessibility and operational flexibility. This system has significant potential to reduce energy consumption by up to 10% and melting times by up to 15%, improving the efficiency and sustainability of the entire process.

A fixed point analysis of fractional dynamics of heat transfer in chaotic fluid layers

This manuscript aims to analyze the chaotic fluid layer heating from below, using the Atangana–Baleanu derivative to characterize the existence and uniqueness of this chaotic model based on the provided fixed point data. First, with suitable examples, we demonstrate the existence and uniqueness of fixed point solutions within the framework of controlled metric spaces. Secondly, we study the chaotic behavior of water with various Rayleigh numbers by experimenting with it while keeping a constant Prandtl number. Furthermore, the role of the Rayleigh number in magnifying chaotic behaviors is examined, with graphical simulations demonstrating the effect of different fractional orders of the Atangana–Baleanu derivative. This research provides insights into the dynamics of chaotic systems and their practical applications in controlled situations.

An empirical analysis of hybrid MHD ferrofluid unsteady flow of two-dimensional heat transfer across a porous channel

This research investigates the heat transfer dynamics of a two-dimensional, incompressible, laminar, magnetohydrodynamics, time-dependent flow of a hybrid ferromagnetic fluid with radiation and irregular heat source/sink conditions through two porous channels. The study investigates the unique capability of ferromagnetic solid nanoparticles to improve the thermal efficiency of the host fluid, with potential applications in medicine such as drug targeting, cell separation, and magnetic resonance imaging. A mathematical model is developed as a nonlinear partial differential equation (PDE), which is subsequently converted into a nonlinear ordinary differential equation (ODE) using similarity transformations. The numerical solution is obtained using the 4th-order Runge-Kutta method implemented in Mathematica software. We analyze the impact of various nondimensional factors on the numerical results, including skin friction coefficient and Nusselt number, as well as graphical results depicting the velocity and temperature profiles of the hybrid ferrofluid. Boosting the film thickness parameter (λ) improves the heat transfer rate at the bottom of the porous channel. Raising the irregular heat source/sink parameters ( A * and B * ) and causing opposite impacts on the heat transfer rate at the bottom porous channel. Higher the radiation (R) values, the temperature profile behaves oppositely in both porous channels. The analysis reveals that the hybrid ferrofluid exhibits a higher rate of heat transfer compared to the ferrofluid.

Nanoparticle shape factor impact on double diffusive convection of Cu-water nanofluid in trapezoidal porous enclosures: A numerical study

Enclosures that contain both fluid and porous regions are utilized in various industries and geophysical processes to enhance heat and mass transfer. These enclosures find applications in fields such as geothermal engineering, drying of porous solids, cooling of electronics, metal solidification, and many others. In line with the motivation behind these applications, the present study explores double diffusion in the naturally convective flow of water-based nano fluid saturated in the trapezoidal porous enclosure and containing Copper (Cu) nano particles. The impact of uniformly applied radiative heat flux and nano particle shape factor is also accounted. A numerical investigation was carried out using a finite difference methodology integrated into a computational MATLAB code for numerical simulation. The simulation aimed to study the effect of nanoparticle shape factor on the effectiveness of a porous medium, which is exposed to two distinct objectives: enhancing heat transfer and optimizing mass transfer within a fluid-saturated porous medium. This research conducts a meticulous parametric exploration, underscoring the pivotal roles played by Darcy number (Da), nanofluid shape factor (m), Rayleigh number (Ra), thermal radiation (Rd), buoyancy ratio (Nr), and Lewis number (Le) in shaping the dynamics of flow, heat, and concentration transfer. The analysis of Nusselt and Sherwood numbers reveals that changing the shape of nano-particles from spheres to bricks increases the heat flux and mass flux coefficients by approximately 0.33% and 1.37% respectively. The results show a significant increase in Nusselt and Sherwood numbers, with blade-shaped nanoparticles demonstrating approximately a 2.97% and 10.82% improvement, respectively, compared to sphere-shaped nanoparticles. The outcome of this analysis yields an exhaustive dataset encompassing Nusselt and Sherwood numbers can be written as mathematical functions based on the parameters we talked about earlier.

Heat and mass transfer dynamics in curved Ш-Chip: ISPH simulations and ANN analysis

This research investigates heat and mass transfer behavior in nano-enhanced phase change materials (NEPCM) within reactive systems using incompressible smoothed particle hydrodynamics (ISPH) coupled with artificial neural network (ANN) predictions. It introduces a novel model comprising six vertical rods and one curved rod, forming a unique Ш-Chip configuration. The complexity of the NEPCM model demonstrates its relevance in fluid dynamics and heat transfer analyses applicable across diverse fields including food processing, electronics cooling, chip manufacturing, heat exchangers, and solar energy systems. The study explores the influence of various dimensionless parameters such as the Frank-Kamenetskii number (Fk), Hartmann number (Ha), Soret and Dufour numbers (Sr&Du), Lewis number (Le), Rayleigh number (Ra), and fractional order parameter (α) on heat and mass transfer phenomena. Heat/mass sources from embedded vertical and curved rods filled with NEPCM are considered within the model. An artificial neural network (ANN) model employing a multilayer perceptron (MLP) structure is utilized to accurately predict the average Nusselt (Nu‾) and Sherwood (Sh‾) numbers, demonstrating its applicability in fluid dynamics and heat transfer analyses. Key insights highlight the role of Fk and Ra in enhancing convection flow and nanofluid velocity within the curved Ш-Chip. Furthermore, variations in Ha lead to observable velocity reductions due to intensified Lorentz forces, while increased Le values result in decreased velocities as thermal diffusion becomes dominant. The fractional order parameter (α) aids in the transition from unsteady to steady state. The unique configuration of the curved Ш-Chip, combined with the incorporation of heat/mass sources from embedded particles, offers promising applications across diverse fields such as food processing, electronics cooling, chip manufacturing, heat exchangers, and solar energy systems. This research underscores the crucial role of understanding the pertinent parameters to ensure the effective development of systems tailored to specific needs. Additionally, it emphasizes the practical value of employing ANN models in predictive modeling to tackle the complexities encountered in engineering applications.

A reduced-order model of thermo-viscoelastic filaments in a material extrusion process

High-resolution and high-efficiency simulations are a great challenge in a material extrusion process. This paper developed a reduced-order thermo-viscoelastic model based on discrete differential geometry. This model successfully simulated the dynamic behaviors, heat transfer, and deformations of filaments during the material extrusion with high computational efficiency. The kinematics of filaments was constructed using a centerline and time-parallel frame combined scheme, and the dynamic system was derived based on the elastic and viscous potential energies of stretching, bending, and twisting. A Newmark implicit algorithm was applied to solve the dynamic equations of the model, and a collision detection and response strategy for filaments was proposed. The convergence, accuracy, and efficiency of this model were validated and tested from various aspects. This model was then utilized to examine the impact of printing parameters on the temperature distribution and sagging deformation of an overhanging filament, and its extended applications were further demonstrated.

Suction and double stratification effect on unsteady MHD heat transfer nanofluid flow over a flat surface

The objective of the current work is to examine the influence of suction on the unsteady Magnetohydrodynamic (MHD) thermal and mass transfer of a nanofluid flow past a flat sheet in the occurrence of double stratification. The governed highly non-linear PDEs along with corresponding appropriate boundary circumstances are first converted into dimensionless system by the use of similarity translations. The numerical methodology used for solving the transformed ordinary differential equations (ODEs) is often known as the Keller box procedure. This study investigates and visually represents the impact of non-dimensional factors such as Hartman number, Prandtl number, Suction, Eckert number, unsteadiness factor, thermal and solutal stratification on the distributions of velocity, concentration, temperature, drag force, Nusselt, and Sherwood number. The numerical calculation and graphical presentation are conducted to evaluate the impacts of several significant quantities on the flow model. It has been discovered that a rise in the suction parameter leads to an enhancement in the velocity gradient, while simultaneously causing a reduction in the concentration and temperature profiles. The outcomes of the study could have implications for various engineering and industrial applications that control and manipulate fluid flows and heat transfer. The results of the research may have ramifications for a wide range of industrial and engineering applications that control and regulate heat transfer and fluid dynamics.

Investigating crossflow interactions in multi-perforation cooling systems: Experimental and numerical insights

This study investigates the effects of employing a multi-perforation cooling system on crossflow interactions, utilizing both numerical simulations and experimental methods. A 30° inclined multi-perforation cooling system is applied on a heated flat plate as part of the experimental setup. Large Eddy Simulation (LES) is utilized for Computational Fluid Dynamics (CFD) calculations to analyze the impact of multi-perforation on heat transfer dynamics. Validation is conducted by comparing the results with experimental investigations. The study encompasses both aerodynamic and thermal considerations, employing Particle Image Velocimetry (PIV) and infrared techniques for analysis, while wall heat flux is measured using electrical discharge. Experimental data on film cooling are collected through these methods, focusing on the impact of blowing ratio (M) and the number of open jet rows (R). The LES-based CFD simulations accurately predict the trajectory of the cooling film. Notably, the influence of flow through the multi-perforation on the primary flow is observable across both configurations of open jet rows (4R and 8R near the wall). The outcomes substantiate the formation of a cooling film emanating from the jet’s fourth row (4R configuration), thereby validating the LES simulations. Visualization of wall temperatures illustrates the formation of a cooling film, discernible through the visible heat distribution from row 4R. However, discrepancies arise in predicting the adiabatic cooling efficiency towards the exit of the 4R region and the commencement of the 8R region, potentially attributed to the alterations induced by the additional multi-perforated injection. The novelty and the main objective of this study is to evaluate the impact of the variation of geometric parameters between the jets and the main flow on the dispersion of the jets themselves. A novel function, tailored to the temperature evolution of the cooling gas, is employed for data analysis. Two geometry configurations, featuring varying open hole areas, are evaluated. The film-cooled heat transfer coefficient, depicted by the Nusselt number, and the adiabatic film cooling efficiency results, serve to appraise the film cooling efficacy of the configurations.