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This paper seeks to conduct a numerical study to investigate heat transfer in turbulent, unconfined, submerged, and inclined impinging jet discharged from a slot nozzle, utilising finite volume code FLUENT.

Two re‐normalisation group k‐ε and the basic Reynolds stress models by using enhanced wall treatment for near wall turbulent modelling were applied and the local Nusselt numbers were compared with experiments. The enhanced wall treatment solves the fully turbulent region and viscous sublayer by considering a single blended function of both layers.

In inclined impinging jet by movement of stagnation point to the uphill side of the impinging plate, the location of the maximum Nusselt number moves to the uphill side of the plate. However, this movement increases by increasing of H/D and by decreasing of Reynolds number and inclination angle. For a flat plate impinging jet, the results were found to be less than 8 per cent different and for inclined impinging jet, more sensitive to H/D, 5‐20 per cent different in comparison with experiments. In addition, the flow streamlines were consistent with location of the heat transfer peak on the impinging surface.

Reynolds numbers in range of 4,000‐16,000, the ratio of nozzle height to hydraulic diameter of the nozzle (H/D) in range of 4‐10, and inclination angle of air jet and plate in range of 40‐90° were considered.

A unique achievement of this study in comparison with experimental data was locating the exact peak of the local Nusselt number on impinging plate by change of Reynolds number, H/D, and inclination angle.

The purpose of the present study is to investigate the flow and turbulence characteristics of a turbulent wall jet flowing over a surface inclined with the horizontal and to investigate the effect of variation of the angle of inclination of the wall on the flow structure of the wall jet.

The high Reynolds number two-equation κ− model with standard wall function is used as the turbulence model. The Reynolds number considered for the present study is 10,000. The Reynolds averaged Navier-Stokes (RANS) equations are used for predicting the turbulent flow. A staggered differencing technique employing both contravariant and Cartesian components of velocity has been applied. Results for distribution of wall static pressure and skin friction, decay of maximum streamwise velocity, streamwise variation of integral momentum and energy flux have been compared for the cases of α=0°, 5°, and 10°.

Flow field has been represented in terms of streamwise and lateral velocity contours, static pressure contour, vorticity contour and streamwise velocity and static pressure profiles at different locations along the oblique offset plate. Distribution of Reynolds stresses in terms of spanwise, lateral and turbulent shear stresses, and turbulent kinetic energy and its dissipation rate have been presented to describe the turbulent characteristics. Similarity of streamwise velocity and the velocity parallel to the oblique wall has been observed in the developed region of the wall jet flow. A decaying trend is observed in the variation of total integral momentum flux in the developed region of the wall jet which becomes more evident with increase in oblique angle. Developed flow region has indicated trend of similarity in profiles of streamwise velocity as well as velocity component parallel to the oblique wall. A depression in wall static pressure has been observed near the nozzle exit when the wall is inclined and the depression increases with increase in inclination. Effect of variation of oblique angles on skin friction coefficient has indicated that it decreases with increase in oblique angle. Growth of the outer and inner shear layers and spread of the jet shows linear variation with distance along the oblique wall. Decay of maximum streamwise velocity is found to be unaffected by variation in oblique angle except in the far downstream region. The streamwise variation of spanwise integral energy shows increase in oblique angle and decreases the magnitude of energy flux through the domain. In the developed flow region, streamwise variation of centreline turbulent intensities shows increased values with increase in oblique angle, while turbulence intensities along the jet centreline in the region X<12 remain unaffected by change in oblique angles. Normalized turbulent kinetic energy distribution highlights the difference in turbulence characteristics between the wall jet and reattached offset jet flow. Near wall velocity distribution shows that the inner region of boundary layer of the developed oblique wall jet follows a logarithmic profile, but it shows some difference from the standard logarithmic curve of turbulent boundary layers which can be attributed to an increase in skin friction coefficient and a decrease in thickness of the wall attached layer.

The study presents an in-depth investigation of the interaction between the jet and the inclined wall. It is shown that due to the Coanda effect, the jet follows the nearby wall. The findings will be useful in the study of combined flow of wall jet and offset jet and dual offset jet on oblique surfaces leading to a better design of some mechanical jet flow devices.

The data on round jets in still air and in a general stream are analysed to determine the spread of the jet and the decay of the axial velocity distribution. The temperature distributions for heated jets are treated in the same way. Methods of model test technique for jets and jet aircraft are discussed; it is shown that the jet momentum is the most important quality in the representation of hot jets. Illustrations of the effect of jets on neighbouring surfaces, including the Coanda effect, are given, and finally an examination of the effect of jets on aircraft stability is made.

The purpose of this paper is to detail an innovative new equipment enhancement for use in the horizontal processing of printed circuit boards (PCBs).

The paper describes a non‐contact laminar or streamline flow process chamber. It also describes a transport and guiding method suitable for both thick and thin materials and expands on the mechanics and fluid dynamics that further reduce equipment length and operating cost.

The new process chamber and its related enhancements result in a faster and more uniform chemical reaction than is obtainable with conventional flood chambers. This enables the equipment to have reduced length and to offer reduced operating costs.

The paper presents a new approach to horizontal processing that can offer reduced equipment footprints and reductions in operating costs.

This study aims to present a numerical analysis of the behavior of the electric field and flow field characteristics under electrohydrodynamics (EHD) force. The influence of the jet airflow under the EHD force is investigated when it impacts the inclined flat plate.

The high electrical voltage and angle of an inclined flat plate are tested in a range of 0–30 kV and 0–90^°, respectively. In this condition, the air is set in a porous medium and the inlet jet airflow is varied from 0–2 m/s.

The results of this study show that the electric field line patterns increase with increasing the electrical voltage and it affects the electric force increasing. The angle of inclined flat plate and the boundary of the computational model are influenced by the electric field line patterns and electrical voltage surface. The electric field pattern is the difference in the fluid flow pattern. The fluid flow is more expanded and more concentrated with increasing the angle of an inclined flat plate, the electrical voltage and the inlet jet airflow. The velocity field ratio is increased with increasing the electrical voltage but it is decreased with increasing the angle of the inclined flat plate and the inlet jet airflow.

The maximum Reynolds number, the maximum velocity field and the maximum cell Reynolds number are increased with increasing the electrical voltage, the inlet jet airflow and the angle of the inclined flat plate. In addition, the cell Reynolds number characteristics are more concentrated and more expanded with increasing the electrical voltage. The pattern of numerical results from the cell Reynolds number characteristics is similar to the pattern of the fluid flow characteristics. Finally, a similar trend of the maximum velocity field has appeared for experimental and numerical results so both techniques are in good agreement.

This study aims to focus on understanding how different jet angles and Reynolds numbers influence the phase change materials’ (PCMs) melting process and their capacity to store energy. This approach is intended to offer novel insights into enhancing thermal energy storage systems, particularly for applications where heat transfer efficiency and energy storage are critical.

The research involved an experimental and numerical analysis of PCM with a melting temperature range of 22 °C–26°C under various conditions. Three different jet angles (45°, 90° and 135°) and two container angles (45° and 90°) were tested. Additionally, two different Reynolds numbers (2,235 and 4,470) were used to explore the effects of jet outlet velocities on PCM melting behaviour. The study used a circular container and analysed the melting process using the hot air inclined jet impingement (HAIJI) method.

The obtained results showed that the average temperature for the last time step at Ф = 90° and Re = 4,470 is 6.26% higher for Ф = 135° and 14.23% higher for Ф = 90° compared with the 45° jet angle. It is also observed that the jet angle, especially for Ф = 90°, is a much more important factor in energy storage than the Reynolds number. In other words, the jet angle can be used as a passive control parameter for energy storage.

This study offers a novel perspective on the effective storage of waste heat transferred with air, such as exhaust gases. It provides valuable insights into the role of jet inclination angles and Reynolds numbers in optimizing the melting and energy storage performance of PCMs, which can be crucial for enhancing the efficiency of thermal energy storage systems.

The purpose of this study is to numerically analyze the convective heat transfer features for cooling of an isothermal surface with a cavity-like portion by using CuO-water nano jet. Jet impingement cooling of curved surfaces plays an important role in practical applications. As compared to flat surfaces, fluid flow and convective heat transfer features with jet impingement cooling of a curved surface becomes more complex with additional formation of the vortices and their interaction in the jet wall region. As flow separation and reattachment may appear in a wide range of thermal engineering applications such as electronic cooling, combustors and solar power, jet impingement cooling of a surface which has a geometry with potential separation regions is important from the practical point of view.

Numerical simulations were performed with a finite volume-based solver. The study was performed for various values of the Reynolds number (between 100 and 400), length of the cavity (between 5 w and 40 w), height of the cavity (between w and 5w) and solid nano-particle volume fraction (between 0 and 4 per cent). Artificial neural network modeling was used to obtain a correlation for the average Nusselt number, which can be used to obtain fast and accurate predictions.

It was observed that cavity geometrical parameters of the cooling surface can be adjusted to change the flow field and convective heat transfer features. When the cavity length is low, significant contribution of the inclined wall of the cavity on the average Nusselt number is achieved. As the cavity length and height increase, the average Nusselt number, respectively, reduce and slightly enhance. At the highest value of cavity height, significant changes in the convective flow features are obtained. By using nanofluids instead of water, enhancement of average heat transfer in the range of 35-46 per cent is obtained at the highest particle volume fraction.

In this study, jet impingement cooling of an isothermal surface which has a cavity-like portion was considered with nanofluids. Addition of this portion to the impingement surface has the potential to produce additional vortices which affects the fluid flow and convective features in the jet impingement heat transfer. This geometry has the forward-facing step for the wall jet region with flow separation reattachment in the region. Based on the above literature survey and to the best of the authors’ knowledge, jet impingement cooling for such a geometry has never been reported in the literature despite its importance in practical thermal engineering applications. The results of this study may be useful for design and optimization of such systems and to obtain best performance in terms of fluid flow and heat transfer characteristics.

The purpose of this paper is to explore the flow and heat transfer characteristics of the jet impingement onto a conical heat sink and evaluate the ability of heat transfer enhancement.

A numerical study of the flow and heat transfer of liquid impingement on cone heat sinks was conducted, and transition SST turbulence model was validated and adopted. The flow and thermal performances were investigated with the Reynolds number that ranges from 5,000 to 23,000 and cone angle that ranges from 0° to 70° in four regions.

Local Nusselt numbers are large, and pressure coefficients drop rapidly near the stagnation point. In the conical bottom edge, a secondary inclined jet was observed, thereby introducing a horseshoe vortex that causes drastic fluctuations in the curves of the flow and heat transfer. The average Nusselt numbers are higher in a conical protuberance than in flat plates in most cases, thus indicating that the heat transfer performance of jet impingement can be improved by a cone heat sink. The maximum increase is 13.6 per cent when the cone angle is 60°, and the Reynolds number is 23,000.

The flow and heat transfer behavior at the bottom edge of the cone heat sink is supplemented. The average heat transfer capacity of different heat transfer radii was evaluated, which provided a basis for the study of cone arrays.

The purpose of this study is to analyze the nonhomogeneous model on the mixed convection of Al2O3–Fe3O4 Bingham plastic hybrid nanofluid in a ventilated enclosure subject to an externally imposed uniform magnetic field. Entropy generation and the pressure drop are determined to analyze the performance of the heat transfer. The significance of Joule heating arising due to the applied magnetic field on the heat transfer of the yield stress fluid is described.

The ventilation in the enclosure of heated walls is created by an opening on one vertical wall through which cold fluid is injected and another opening on the opposite vertical wall through which fluid can flow out.

This study finds that the inclusion of Fe₃O₄ nanoparticles with the Al₂O₃-viscoplastic nanofluid augments the heat transfer. This rate of enhancement in heat transfer is higher than the rate by which the entropy generation is increased as well as the enhancement in the pressure drop. The yield stress has an adverse effect on the heat transfer; however, it favors thermal mixing. The magnetic field, which is acting opposite to the direction of the inlet jet, manifests heat transfer of the viscoplastic hybrid nanofluid. The horizontal jet of cold fluid produces the optimal heat transfer.

The objective of this study is to analyze the impact of the inclined cold jet of viscoplastic electrically conducting hybrid nanofluid on heat transfer from the enclosure in the presence of a uniform magnetic field. The combined effect of hybrid nanoparticles and a magnetic field to enhance heat transfer of a viscoplastic fluid in a ventilated enclosure has not been addressed before.

A simplified method for estimating the aerodynamic properties of thin flapped aerofoils influenced by high velocity jet sheets is developed. It is assumed that the main flow around the aerofoil does not influence the velocity distribution in the jet. Considering also the effect of the mixing with the surrounding air, a real jet is supposed to be replaced by an appropriate aerodynamic model, having a linear downstream distribution of velocity adopted on the basis of test data. Both thin aerofoil and the jet sheet are adequately replaced by vortex distributions,so that the lift and the pitching moment of the aerofoil influenced by the jet may be evaluated in the usual manner. Comparison with some available experimental results shows that the proposed semi‐empirical method gives good agreement with experiment.