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The purpose of this paper is to develop a numerical model to simulate the flow field as well as the conjugate heat transfer during unsteady cooling of a flat plate with a single submerged water jet. At wall temperatures above the liquid boiling point, the vapor formation process and the interaction of the vapor phase with the developing jet-flow field are included.

The time-dependent flow and temperature distribution during all occurring boiling phases as well as the local and temporal distribution of the heat transfer coefficient on a flat plate can be simulated.

The influence of the liquid jet flow rate (10,800=Re_d=32,400) and the nozzle distance to the plate (4=H/d=20) on the transient cooling process are analyzed. This includes the time-dependant positions of the transition regions between the boiling phases on the plate as well as the temperatures at these transition regions. Additionally, the local heat transfer rates are a direct result of the unsteady cooling simulation.

A single model approach is developed and utilized to simulate the unsteady cooling process of a flat plate with an impinging water jet including all occurring boiling phases.

The aim of this paper is to present a Eulerian–Lagrangian model of aircraft ground deicing that avoids the scale’s dispersion problem caused by the great distance between the spray nozzle and the surface to be deiced. Verification is done using the case of a hot particle liquid spray impinging on a horizontal flat plate. The impinged particles flow outwards radially from the impingement zone and form a hot film wall. The computed wall heat distribution is verified. In the end, an inclination spray’s angle study is presented.

The problem is divided into two regions. First, a 3D region is created for the evolution of the Lagrangian particles spray. A second 2D region is provided for the formation of a liquid film. The two regions exchange mass, momentum and energy through an interface. Heat losses are modelled through particles and liquid-film cooling and evaporation, particles splash and heat transfer to a fixed temperature plate.

For a chamber pressure of 1 bar, the predicted spray penetration is within 10 per cent of the experimental results. For this study case, the heat transfer is maximized with an inclination angle of approximately 30° of the spray.

The model presented makes it possible to simulate the impingement and heat transfer of a large-scale liquid spray with a reasonable computational cost. To the best of the authors’ knowledge, this model is a first attempt of the computational fluid dynamics simulation of ground deicing.

A numerical solution for ‘running wet’ aircraft anti‐icing systems is developed. The model includes breakup of the water film, which exists in regions of direct impingement, into individual rivulets. The wetness factor distribution resulting from the film breakup and rivulet configuration on the surface are predicted in the numerical solution procedure. The solid wall is modelled as a multi‐layer structure and the anti‐icing system used is of the thermal type utilizing hot air and/or electrical heating elements embedded within the layers. Details of the calculation procedure and the methods used are presented.

The purpose of this study is to numerically investigate the effect of jet impingement, magnetic field and nanoparticle shape (sphericity) on the hydrodynamic/heat transfer characteristics of nanofluids over stationary and vibrating plates.

A two-dimensional finite volume method-based homogeneous heat transfer model has been developed, validated and used in the present investigation. Three different shapes of non-spherical carbon nanoparticles namely nanotubes, nanorods and nanosheets are used in the analysis. Sphericity-based effective thermal conductivity of nanofluids with Brownian motion of nanoparticles is considered in the investigation. Moreover, the ranges of various comprehensive parameters used in the study are Re = 500 to 900, St = 0.0694 to 0.2083 and Ha = 0 to 80.

The hydrodynamic/heat transfer performance of jet impingement in the case of vibrating plate is 298 per cent higher than that of stationary plate at Re = 500. However, for the case of vibrating plate, a reduction in the heat transfer performance of 23.35 per cent is observed by increasing the jet Reynolds number from 500 to 900. In the case of vibrating plate, the saturation point for Strouhal number is found to be 0.0833 at Re = 900 and Ha = 0. Further decrement in St beyond this limit leads to a drastic reduction in the performance. Moreover, no recirculation in the flow is observed near the stagnation point for jet impingement over vibrating plate. It is also observed that the effect of magnetic field enhances the performance of jet impingement over a stationary plate by 36.18 per cent at Ha = 80 and Re = 900. Whereas, opposite trend is observed for the case of vibrating plate. Furthermore, at Re = 500, the percentage enhancement in the Nuavg values of 3 Vol.% carbon nanofluid with nanosheets, nanorods and nanotubes are found to be 47.53, 26.86 and 26.85 per cent when compared with the value obtained for pure water.

The present results will be useful in choosing nanosheets-based nanofluid as the efficient heat transfer medium in cooling of high power electronic devices. Moreover, the obtained saturation point in the Strouhal number of the vibrating plate will help in cooling of turbine blades, as well as paper and textile drying. Moreover, the developed homogeneous heat transfer model can also be used to study different micro-convection phenomena in nanofluids by considering them as source terms in the momentum equation.

Impingement of jet over two different plate types such as stationary and vibrating is completely analyzed with the use of a validated in-house FVM code. A complete investigation on the influence of external magnetic field on the performance of plate type configuration is evaluated. The three fundamental shapes of carbon nanoparticles are also evaluated to obtain sphericity based hydrodynamic/heat transfer performance of jet impingement.

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.

This paper aims to study the heat transfer phenomenon occurring between heated walls and impinging fuel, showing the strict relationship between cooling effect after impingement and enhancing of wallfilm formation. The study focuses on a fundamental task in terms of pollutant emissions in internal combustion engines, aiming at giving a major contribution to the optimization of energy conversion systems in terms of environmental impact.

The paper is based on experimental campaigns relevant at taking measurements of an impinging spray over a heated wall in a confined vessel. The results, in both qualitative and quantitative terms (measurements of liquid and vapour radial penetration and thickness), are numerically reproduced by a computational model based on a Reynolds Averaged Navier Stokes approach, properly validated through customized sub-models.

The paper provides quantitative results about the agreement between radial penetration and vapour thickness between measurements and simulation, achieved by taking into account the cooling effect determined by the fuel impingement. This validation of the numerical model allows the author to give more considerations about the link between wall temperature and wallfilm formation.

This paper presents an original approach for the simulation of wall heat transfer, by imposing a boundary condition at the wall that may consider the heat conduction and temperature cooling given by fuel impingement in both lateral and normal directions. The classical Dirichlet boundary condition, characterized by imposing a fixed temperature value, is, instead, replaced by an approach based on calculating the unsteady process that couples the heat fluxes between the fluid and the solid material and within the solid itself.

This paper aims to introduce a three-dimensional smoothed particle hydrodynamics (SPH) framework for simulating supercooled large droplets (SLD) dynamics at aeronautical speeds.

To include the effects of the surrounding air, a multiphase model capable of handling high density-ratio problems is adopted. A diffusive term is incorporated to smooth the density field and avoid numerical instabilities. Additionally, a particle shifting technique is used to eliminate anisotropic particle distributions.

The framework is validated against low-speed droplet impingement experimental results and then applied to the droplet impingement at high speeds typical of SLD conditions. Preliminary parametric studies are conducted to investigate the post-impact splashing. It is observed that a thicker water film can decrease the crown diameter and a smaller impact angle can suppress upward and forward splashing.

A three-dimensional multiphase SPH framework for SLD dynamics at a wide range of impact speed is developed and validated. The effects of particle resolution, water film thickness and impact angle on the post-impact crown evolution are investigated.

Porous media can provide excellent performance in thermal energy transport applications. This study aims to optimise the square porous slabs (placed in the middle of the channel) parameters to enhance the cooling performance of the jet-impingement microchannel heat sink.

Three levels of each design parameters, i.e. porous slab side, porous slab height, type of material, permeability and quadratic drag factor, are studied; and an L₂₇ orthogonal array is adopted to generate the design points in the specified design space. Optimum designs of the porous media slabs are achieved to minimise the maximum-wall temperature, thermal resistance and pressure drop and maximise the average heat transfer coefficient and figure of merit (FOM).

Results exhibited that the porous media material and permeability are the most, whereas drag factor is the least significant factors with respect to the overall performance of the heat sink. The optimum value of FOM for the proposed hybrid heat sink model belongs to the set of design variables, i.e. 0.4 mm slab side, 0.6 mm slab height, 5 × 10⁻¹¹ m² permeability, 0.21 drag factor and copper as substrate material.

This study proposes a novel design and a hybrid approach to investigate and optimise the hydrothermal performance of jet impingements on porous slabs inserted in the microchannels.

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 study is to investigate the effects of film holes’ arrangements and jet Reynolds number on flow structure and heat transfer characteristics of jet impingement conjugated with film cooling in a semicylinder double wall channel.

Numerical simulations are used in this research. Streamlines on different sections, skin-friction lines, velocity, wall shear stress and turbulent kinetic energy contours near the concave target wall and vortices in the double channel are presented. Local Nusselt number contours and surface averaged Nusselt numbers are also obtained. Topology analysis is applied to further understand the fluid flow and is used in analyzing the heat transfer characteristics.

It is found that the arrangement of side films positioned far from the center jets helps to enhance the flow disturbance and heat transfer behind the film holes. The heat transfer uniformity for the case of 55° films arrangement angle is most improved and the thermal performance is the highest in this study.

The film holes’ arrangements effects on fluid flow and heat transfer in an impingement cooled concave channel are conducted. The flow structures in the channel and flow characteristics near target by topology pictures are first obtained for the confined film cooled impingement cases. The heat transfer distributions are analyzed with the flow characteristics. The highest heat transfer uniformity and thermal performance situation is obtained in present work.