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The heat transfer rates from the body to the working fluid can be improved through altering geometric configurations of the body and its arrangement in the flow system. One of the arrangements for this purpose is to locate the body at the channel inlet while the convection current opposes it. Since the flow field in the channel inlet influences the heat transfer rates, changing the aspect ratio and inclination of the body is expected to modify the flow field while enhancing the heat transfer rates. Consequently, investigation into the influence of the aspect ratios and tilting angles of the body on the heat transfer rates in the channel flow becomes essential. The paper aims to discuss these issues.

Numerical simulation of flow in a channel with the presence of solid block is carried out. The block aspect ratio is changed while keeping the area of the block constant for all aspect ratios. The tilting angle is also incorporated analysis to examine its effect on the Nusselt number.

The throttling effect of the block at channel inlet accelerates the flow between the channel wall and the block faces. This, in turn modifies the thermal boundary layer around the block. In this case, heat transfer rates increase considerably at the block faces where the flow acceleration suppresses the thermal boundary layer thickness. This is more pronounced for large block tilting angles. The Nusselt number attains low values for the block face opposing to the flow at the channel inlet and the back face of the block. This is attributed to the mixing of the thermal current emanating from the side faces of the block in the region close to the back surface. In this case, thermal boundary layer thickens and the heat transfer rates from the block reduce significantly. The Nusselt number improves with reducing the block aspect ratio, which is particularly true along the side faces of the block. In addition, the influence of the block tilting angle on the Nusselt number is considerable for the low block aspect ratios.

The model study is validated with the previous studies for the drag coefficient. The study covers all the aspects of the flow situations and discusses the resulting fluid field and the heat transfer rates from the block.

It is an interesting work for cooling applications. The block aspect ratio and its tilting angle in the channel influence considerably the flow field and the Nusselt number variation around the block faces.

The cooling technology may be improved through implementing the findings of the current work.

It is an original work and it has never been submitted to other journals.

The purpose of this paper is to establish a three-dimensional flow field model of the Invar alloy laser–metal inert gas (laser–MIG) hybrid welding process to investigate the influence of different heat sources between different layers and to analyze the flow field based on the two different heat source models for the multilayer welding.

The Invar steel plates with 19.5 mm thickness are welded into three layers’ seam using the hybrid laser–MIG welding technology. The flow field based on different heat source models is studied and then used to investigate the influence of different heat sources in different layers during the laser–MIG hybrid welding process. The simulation results of flow field using two different heat source models are compared with experiments.

The flow field simulations results show that using the Gaussian rotating body heat source model to simulate the temperature field is more consistent with the experiment of the hybrid laser–MIG welding where its flow field between different layers better reflects the characteristics of the hybrid laser–MIG welding.

The findings will be useful in the study of a variety of thick-plate laser–MIG hybrid welding process fluid flows.

The purpose of this paper is to study experimentally enhancement of heat transfer in a tube with axial swirling‐flow promoters. The geometric features of flow geometry to improve heat transfer can be selected in order to yield the maximum opposite reduction in heat exchange flow irreversibility by using exergy‐destruction method. The paper seeks to illustrate the use of neural network approach to analyze heat transfer enhancement data for further study in the scope of the experimental program.

For this purpose, 402 experimental measurements are collected. About 225 of those are used as training data for neural networks, the rest is used for testing. Then, these testing results of artificial neural network (ANN) and experimental data are compared. A formula for presenting exergy loses in a tubular heat exchanger is derived first and then the thermodynamic optimum instead of economic optimum is found by minimizing the exergy losses in the system.

Results from all configurations studied show that the heat transfer rate of the heated increases when the swirling‐flow promoter is inserted. From the heat transfer improvement number defined, it is observed that about 100 percent increase in heat transfer rate and five times increase in the pressure drop can be achieved under the condition of constant flow for the single promoter which has three blades, its blade angle is 30° and its location is in the middle of the tube length.

The back‐propagation (BP) algorithm was selected as the neural network algorithm, which uses the generalized delta learning rule. The training time of BP algorithm is considerably long. However, the testing of our neural network is real‐time.

The experimental setup is established to collect the experimental data. It consists of an entrance region, test region (heat exchanger and steam generator), and, flow measurement and control. Also, a software program of neural networks trained BP is written by using Pascal high‐level languages.

An alternative and new approach is proposed in the paper to find optimum flow geometry for a pipe flow with an axial swirling‐flow promoter inserts. It is too difficult to predict the response of a complex physical system that cannot be easily modeled mathematically. The result thus obtained compare well with experimental results, but the computational effort of the ANN and time required in the analysis is much faster as compared. These results show that the ANN can be used efficiently for prediction.

This paper presents the heat transfer enhancement from discrete heat sources using a wavy channel.

The finite element method is utilized to solve the hydrodynamic/thermal problem. The considered geometry consists of a channel formed by two wavy plates with six discrete heat sources placed on upper and lower walls. The global objective is to maximize the heat transfer from the heat sources. The wavy channel enhances heat transfer from the heat sources through the modification of the flow pattern in the channel. The effects of the Reynolds number, Prandtl number, waviness of the wavy wall, and the location of the heat sources on the thermal characteristics of the flow are investigated.

Results indicate that the wavy channel significantly enhances the heat flow out of the heat sources, with heat sources located at the minimum channel cross sections having the best performance. The Nusselt number increases with an increase in Reynolds number and waviness of the wavy channel. The higher Prandtl number has a positive effect on the heat flow out of the heat sources. The heat transfer enhancement can reaches as high as 120 percent for high Reynolds numbers and waviness of the channel.

The combination of wavy plates and optimum placement of heat sources can lead to better, less expensive thermal management of heat sources in electronic devices.

The concept of a heat function is introduced to visualize the path of heat flow in a buoyancy‐driven turbulent flow heated vertical flat plate. The velocities and the temperature field near the vertical plate are predicted numerically, using an algebraic flux model of turbulent heat transport. As an accurate prediction of the turbulent heat flux is required in order to predict the heat function in the flow field, the use of an algebraic flux model for the turbulent heat transport θu_i, is made as compared with a simple eddy diffusivity hypothesis. The algebraic flux expression was closed with a low‐Re‐number‐k‐ε — θ² —_θ model. The solution ofthe 4 equation low‐Re‐number‐k‐ε — θ² — ε_θ model predicts very well the local Nusselt number along the plate height as well as the velocity and the temperature field near the wall when compared with the experiments. Then the partial differential equation for the heat function is numerically solved to show the true path of heat flow in the buoyancy‐driven turbulent flow field near a heated vertical plate.

To study the thermal performance of both co‐current and counter‐current parallel flow heat exchangers. The hot stream is assumed to flow in the middle of two cold streams and exchange heat with them.

The dimensionless governing equations are derived based on the conservation of energy principle and solved using FEM based on subdomain collocation method and Galerkin's method. The results show that the subdomain collocation method is more accurate than the Galerkin's method, as observed when the results obtained are compared with the analytical results for the classical two‐fluid heat exchangers.

The results are presented in terms of effectiveness and number of transfer units (Ntu) for different values of the governing parameters. The governing parameters are the Ntu, the heat capacity ratios, the overall heat transfer coefficient ratio, and the inlet temperatures parameter. The results show that the effectiveness of the three‐fluid heat exchanger is always higher than that of classical two‐fluid flow heat exchanger for fixed values of the governing parameters. The results also show that for fixed values of the governing parameters, the effectiveness of the counter‐current is higher than the co‐current parallel flow three‐fluid heat exchangers.

One‐dimensional governing equations are derived based on the conservation of energy principle. The ranges of the governing parameters are: Ntu (0:5), the heat capacity ratios (0:1,000), the overall heat transfer coefficient ratio (0:2), and the inlet temperatures parameter (0:1).

Both co‐current and counter‐current parallel flow heat exchangers are used in the thermal engineering applications. The design and performance analysis of these heat exchangers are of practical importance.

This paper provides the details of the performance analysis of co‐current and counter‐current parallel flow heat exchangers, which can be used in thermal design.

This paper aims to investigate the thermal performance of equivalent square and circular thermal systems and compare the heat transport and irreversibility of magnetohydrodynamic (MHD) nanofluid flow within these systems.

The research uses a constraint-based approach to analyze the impact of geometric shapes on heat transfer and irreversibility. Two equivalent systems, a square cavity and a circular cavity, are examined, considering identical heating/cooling lengths and fluid flow volume. The analysis includes parameters such as magnetic field strength, nanoparticle concentration and accompanying irreversibility.

This study reveals that circular geometry outperforms square geometry in terms of heat flow, fluid flow and heat transfer. The equivalent circular thermal system is more efficient, with heat transfer enhancements of approximately 17.7%. The corresponding irreversibility production rate is also higher, which is up to 17.6%. The total irreversibility production increases with Ra and decreases with a rise in Ha. However, the effect of magnetic field orientation (γ) on total EG is minor.

Further research can explore additional geometric shapes, orientations and boundary conditions to expand the understanding of thermal performance in different configurations. Experimental validation can also complement the numerical analysis presented in this study.

This research introduces a constraint-based approach for evaluating heat transport and irreversibility in MHD nanofluid flow within square and circular thermal systems. The comparison of equivalent geometries and the consideration of constraint-based analysis contribute to the originality and value of this work. The findings provide insights for designing optimal thermal systems and advancing MHD nanofluid flow control mechanisms, offering potential for improved efficiency in various applications.

The purpose of this study is to investigate the influence of enclosure shape on magnetohydrodynamic (MHD) nanofluidic flow, heat transfer and irreversibility in square, trapezoidal and triangular thermal systems under fluid volume constraints, with the aim of optimizing thermal behavior in diverse applications.

The study uses numerical simulations based on a finite element-based technique to analyze the effects of the Rayleigh number (Ra), Hartmann number (Ha), magnetic field orientation (γ) and nanoparticle concentration (ζ) on heat transfer characteristics and thermodynamic entropy production.

The key findings reveal that the geometrical design significantly influences fluid velocity, heat transfer and irreversibility. Trapezoidal thermal systems outperform square systems, while triangular systems achieve optimal enhancement. Nanoparticle concentration enhances heat transfer and flow strength at higher Rayleigh numbers. The magnetic field intensity has a significant impact on fluid flow and heat transport in natural convection, with higher Hartmann numbers resulting in reduced flow strength and heat transfer. The study also highlights the influence of various parameters on thermodynamic entropy production.

Further research can explore additional geometries, parameters and boundary conditions to expand the understanding of enclosure shape effects on MHD nanofluidic flow and heat transfer. Experimental validation can complement the numerical simulations presented in this study.

This study provides valuable insights into the impact of enclosure shape on heat transfer performance in MHD nanofluid flow systems. The findings contribute to the optimization of thermal behavior in applications such as electronics cooling and energy systems. The comparison of different enclosure shapes and the analysis of thermodynamic entropy production add novelty to the study.

Thermo-magnetic convective flow analysis under the impact of thermal radiation for heat and entropy generation phenomena is an active research field for understanding the efficiency of thermodynamic systems in various engineering sectors. This study aims to examine the characteristics of convective heat transport and entropy generation within an inverted T-shaped porous enclosure saturated with a hybrid nanofluid under the influence of thermal radiation and magnetic field.

The mathematical model incorporates the Darcy-Forchheimer-Brinkmann model and considers thermal radiation in the energy balance equation. The complete mathematical model has been numerically simulated through the penalty finite element approach at varying values of flow parameters, such as Rayleigh number (Ra), Hartmann number (Ha), Darcy number (Da), radiation parameter (Rd) and porosity value (e). Furthermore, the graphical results for energy variation have been monitored through the energy-flux vector, whereas the entropy generation along with its individual components, namely, entropy generation due to heat transfer, fluid friction and magnetic field, are also presented. Furthermore, the results of the Bejan number for each component are also discussed in detail. Additionally, the concept of ecological coefficient of performance (ECOP) has also been included to analyse the thermal efficiency of the model.

The graphical analysis of results indicates that higher values of Ra, Da, e and Rd enhance the convective heat transport and entropy generation phenomena more rapidly. However, increasing Ha values have a detrimental effect due to the increasing impact of magnetic forces. Furthermore, the ECOP result suggests that the rising value of Da, e and Rd at smaller Ra show a maximum thermal efficiency of the mathematical model, which further declines as the Ra increases. Conversely, the thermal efficiency of the model improves with increasing Ha value, showing an opposite trend in ECOP.

Such complex porous enclosures have practical applications in engineering and science, including areas like solar power collectors, heat exchangers and electronic equipment. Furthermore, the present study of entropy generation would play a vital role in optimizing system performance, improving energy efficiency and promoting sustainable engineering practices during the natural convection process.

To the best of the authors’ knowledge, this study is the first ever attempted detailed investigation of heat transfer and entropy generation phenomena flow parameter ranges in an inverted T-shaped porous enclosure under a uniform magnetic field and thermal radiation.

This study aims to investigate the impact of different heater geometries (flat, rectangular, semi-elliptical and triangular) on hybrid nanofluidic (Cu–Al₂O₃–H₂O) convection in novel umbrella-shaped porous thermal systems. The system is top-cooled, and the identical heater surfaces are provided centrally at the bottom to identify the most enhanced configuration.

The thermal-fluid flow analysis is performed using a finite volume-based indigenous code, solving the nonlinear coupled transport equations with the Darcy number (10^–5 ≤ Da ≤ 10^–1), modified Rayleigh number (10 ≤ Ra_m ≤ 10⁴) and Hartmann number (0 ≤ Ha ≤ 70) as the dimensionless operating parameters. The semi-implicit method for pressure linked equations algorithm is used to solve the discretized transport equations over staggered nonuniform meshes.

The study demonstrates that altering the heater surface geometry improves heat transfer by up to 224% compared with a flat surface configuration. The triangular-shaped heating surface is the most effective in enhancing both heat transfer and flow strength. In general, flow strength and heat transfer increase with rising Ra_m and decrease with increasing Da and Ha. The study also proposes a mathematical correlation to predict thermal characteristics by integrating all geometric and flow control variables.

The present concept can be extended to further explore thermal performance with different curvature effects, orientations, boundary conditions, etc., numerically or experimentally.

The present geometry configurations can be applied in various engineering applications such as heat exchangers, crystallization, micro-electronic devices, energy storage systems, mixing processes, food processing and different biomedical systems (blood flow control, cancer treatment, medical equipment, targeted drug delivery, etc.).

This investigation contributes by exploring the effect of various geometric shapes of the heated bottom on the hydromagnetic convection of Cu–Al₂O₃–H₂O hybrid nanofluid flow in a complex umbrella-shaped porous thermal system involving curved surfaces and multiphysical conditions.