bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the Corrosion Resistance Of Thermal Sprayed Aerospace Coatings Under The Action Of High Current Pulsed Electron Beam
Authors: Wang Hongbo , Ji Xiaolei , Jia Ben 
Published: June 2024

Abstract
Aluminum-based amorphous alloys have excellent mechanical properties and corrosion resistance and are currently used in the form of coating materials for the protection of aircraft surfaces. In this study, AlCoCe alloy and powder are prepared, and then AlCoCe alloy coating is prepared on Q235 substrate by supersonic flame thermal spraying technology, and finally, the surface remelting modification treatment is carried out on the coating by current pulsed electron beam, and the transformation behavior of microstructure of the coating and the change of the corrosion resistance in this process are analyzed by structural characterization and corrosion experiment, to make clear the relationship between the structure of the coating and its corrosion resistance performance. After 15 current pulsed electron beam pulses, the coating surface formed a layer of dense and homogeneous composition of the amorphous structure of the treatment layer, when the number of pulses is higher, due to the heat of the substrate leads to a decrease in the cooling rate, which in turn will lead to the emergence of a crystalline structure of the surface treatment layer.
Analysis of engineering structures and components created using the generative design
Authors: Tkachenko Arseny , Wang Chang Jiang 
Published: June 2024

Abstract
Generative design is an AI-driven process to explore all the possible design variants, it mimics nature’s evolutionary approach to create an optimised final design. Generative design and additive manufacturing are interlinked because additive manufacturing is able to fabricate complex geometries. Generative algorithms have demonstrated their effectiveness in reducing costs, weight and development time across various industries including automotive and aerospace. This paper analysed components and structures to show the advantages of using the generative design method, problems encountered and issues that could be addressed to improve the final designs. Loading conditions, stress concentrations and manufacturability of the generative-designed components were discussed in the paper.
A phase-splitting approach to describe macroscopically non-equilibrium transport in porous media
Authors: Quintard M. , Davit Y. , Wood B. 
Published: June 2024

Abstract
Classical macro-scale dispersion equation cannot correctly represent non-local, non-equilibrium effects, and alternatives had to be proposed to overcome these discrepancies. Two-equation models have been widely used and proved useful to incorporate, to some extent, local non-equilibrium effects. More accurate descriptions may be obtained through the introduction of additional complex terms in the one-equation dispersion equation, e.g. spatial and time convolutions. An alternative more practical route rely on the introduction of a N-equations description. For instance, instead of a two-temperature model, transfers in the solid and/or fluid phase maybe represented by several equations, each one defined by some splitting framework. Splitting of the solid phase has been proposed in the past (multi-rate models). Splitting of the flowing phase has a rustic illustration in the case of the Coats and Smith model, i.e., ”flowing” and ”stagnant” fluid equations. In this paper, we explore further the possibilities offered by N-equations splitting of the flowing phase. The N-equations macro-scale model is developed applying an averaging technique to N-pseudo phases obtained by splitting the flowing phase based on different criteria, e.g. the velocity histogram. Most important model properties are the matrices of dispersion tensors and exchange coefficients, which are provided by a system of specific ”closure” problems. To illustrate this approach, the methodology is applied to Taylor’s dispersion problem, in which non-local effects are produced by pore-scale spatially distributed inlet conditions. The proposed N-equations description was compared to estimates of the N-temperatures obtained from direct numerical simulations. The N-equations model was able to reproduce accurately the dynamic of pore-scale computations, for such reputedly non-homogenizable problems, with a relatively small number of equations.
Impact of one and two partial cooling ducts on temperature rise in transformer windings
Authors: Bulatovič Goran , Bokes Peter 
Published: June 2024

Abstract
We apply our quasi-1D model to the temperature rise in oil-filled transformer foil windings with two symmetric partial ducts. We compare the results with a two-dimensional FEM simulation. To compare the results to industrial tests we try to find a relationship between the effective values for heat transfer coefficients of different foil windings. Finally, we compare the effectiveness of adding one vs two partial cooling ducts to the winding.
Experimental investigation of phase change material (PCM) thermal energy storages with and without metal foam at different temperatures
Authors: Fareedi AR , Khoso AQ , Khan H , Buonomo B , Manca O , Nardini S 
Published: June 2024

Abstract
This paper presents an experimental investigation of phase change materials (PCM) thermal energy storage. The experimental unit consists of a square channel with a single flow stream having distilled water as a heat exchange fluid. RT-42 is used as a thermal energy storage and the overall system is designed in two configurations i.e. with and without aluminium metal foam having a porosity of 95%. Each configuration is analysed and compared for two temperature variations i.e. at 55 °C and 65 °C, respectively. The study reveals that the heat storage rate in metal foam (MF) integrated PCM thermal energy storage is enhanced to ~3-4 times as compared to the setup without metal foam. In metal foam PCM energy storage, the temperature distribution is uniform and heat transfer is due to conduction as well as convection, while in case of pure PCM, there exist a temperature gradient within the thermal storage and the heat transfer is slower due to convection phenomenon. It is also observed that the heat transfer rate for 65 °C is comparatively greater than that of 55 °C for both systems as the higher operating temperatures lead to higher heat flux. However, operating at high temperatures is less feasible as the setup is more prone to PCM leakages.
A 3D symmetry-preserving simulation of a concentrated photovoltaic thermal (CPVT) solar collector
Authors: Santos D , Rigola J , Castro J , Trias F X 
Published: June 2024

Abstract
In this work, a general collocated and unconditionally stable framework on unstructured meshes for solving Conjugate Heat Transfer (CHT) problems is presented by means of preserving the underlying symmetries of the continuous differential operators, thus not introducing uncontrolled artificial numerical dissipation to our system. Then, this framework is applied to solve a Concentrated PhotoVoltaic Thermal (CPVT) Solar Collector. Furthermore, a new boundary condition is implemented to consider the heat transfer between enclosed elements, including radiation. The model is validated using experimental data.
A coupled point particle two-phase heat and mass transfer model for dispersed flows based on Boundary Element Methods
Authors: Gomboc T , Zadravec M , Ravnik J , Hriberšek M 
Published: June 2024

Abstract
In dispersed multiphase flow processes we encounter coupled heat, mass and momentum transfer between the disoersed and the continuous phase. In the context of the subdomain Boundary Domain Integral Method (BDIM) solution of the Navier-Stokes equations a two-way coupling model is presented based on the use of the elliptic fundamental solution and the Dirac delta function properties which leads to accurate evaluation of the heat and mass point particle source impacts on the continuous (air) phase. In addition, the two-phase flow case under consideration is extended to the case of porous spherical particle drying with internal moving drying front, which is solved by the Boundary Element Method (BEM).
An experimental investigation of forced convective liquid immersion cooling of a 12-cell li-ion battery module
Authors: Salter D W , Bachelier G , Kumavat P S , Trimble D , O’Shaughnessy S M 
Published: June 2024

Abstract
This study details an experimental investigation of forced convective liquid immersion cooling of lithium-ion batteries. Twelve Samsung INR 18650 20S cylindrical cells, each with a nominal voltage of 4.2 V and nominal capacity of 2 Ah, are placed in a 4-in-series, 3-in-parallel arrangement inside a polycarbonate chamber. The cells are immersed in the dielectric fluid SF-33 and are discharged at C rates in the range of 1C to 4C. Temperature sensors placed along the body of each cell near the electrodes monitor their thermal behaviour during experiments. Results show that liquid immersion cooling is an effective method to maintain all cell temperatures within the desired temperature range of 15°C to 35°C for all cases tested, maintaining temperature differences within individual cells to ≤1.5°C, and those between cells to ≤3°C. This research contributes to the understanding of thermal management strategies for lithium-ion batteries, particularly in scenarios involving high discharge rate applications.
Thermal analysis of an integrated motor drive with a switching cell array power converter
Authors: Grespan M , Busquets-Monge S , De Les Valls E Mas , Jordà X , Di Francisco M Raya , Angeli D 
Published: June 2024

Abstract
In modern electric propulsion systems the electric motor is tightly integrated with the power converter and control unit. These so called Integrated Motor Drives can allow for vast improvements in efficiency and volume reduction, due to the elimination of redundant electric components, and the shared case and cooling system between the motor and the power converter. The cooling systems used in these applications must be carefully designed as the motor and power electronics components may feature greatly different temperature limits. This work discusses the development of a thermal model for an integrated motor drive composed by a six phase permanent magnet motor with hairpin windings and a switching-cell-array-based multilevel power converter. The system is modelled by means of a lumped parameter thermal network which includes an accurate model of the motor stator and rotor, as well as the arrangement of the power switches on the converter boards. The conductive resistances are simply obtained from geometric data and material properties. Instead, the convective resistances are evaluated by means of empirical models available in the literature and a CFD model for the cooling jacket. The developed model is employed to assess the feasibility of the presented arrangement of motor and power electronics components from the thermal point of view.
Improvement of the modelling of the conduction-radiation flash method by a fully stochastic approach. A numerical validation
Authors: Seyer L , Enguehard F , Rochais D 
Published: June 2024

Abstract
Three different numerical models for simulating the well-known experimental flash method are presented and compared. These models consider conduction-radiation coupling and are applied within a one-dimensional grey semi-transparent slab enclosed between two opaque surfaces. The first model (A) is deterministic, dating back to about a decade, and is based on three assumptions regarding radiation transfer: isotropic intensity within each of the two hemispheres, the scattering phenomenon is supposed to be isotropic, and linearization of terms involving differences of temperatures to the fourth power. The other two models are completely new and do not make these assumptions. While the first one (B) is purely deterministic and serves as a reference for validation, the other one (C) is fully stochastic, and is the focus of this paper. A comparison shows excellent agreement between (B) and (C), validating our new model of interest (C). On the other hand, (A) exhibits significant discrepancies with the other two, highlighting the importance of its limiting assumptions.
Numerical modeling of a confined falling liquid film sheared by a gas flow in a plate heat exchanger of an NH3/H20 absorption chiller
Authors: Sleiman J , Collignon R , Phan H T , Stutz B 
Published: June 2024

Abstract
In recent years, the demand for cooling has seen a substantial increase, primarily due to rising summertime temperatures. Conventional mechanical compression air conditioners have played a predominant role in fulfilling this demand, albeit at the cost of significant electricity consumption. In response, absorption chillers have emerged as an eco-friendly alternative, powered by sustainable heat sources like solar energy or industrial waste heat. The present work is conducted within the framework of developing compact absorption chillers incorporating plate heat exchangers. It builds upon prior research by improving an existing numerical model for falling film plate heat exchangers within an NH3/H2O absorption chiller. This former numerical model evaluates the coupled heat and mass transfer between the liquid film and the vapor flow while excluding hydrodynamic interactions at the liquid-vapor interface. The current investigation aims to address compactness and cost-efficiency limitations in absorption chillers. The consequences of operation within confined spaces were numerically evaluated. An innovative analytical model was developed to quantify the influence of the interactions at the liquid-vapor interface. Shear stress and interfacial perturbations were considered compared to the classical Nusselt model, enabling the evaluation of the changes in the average film thickness and the flooding phenomenon. This analytical model was then added to the previously developed heat and mass transfer model. The numerical model was applied to both the desorber and absorber units. The results show that increased confinement has minimal effects on the transfer coefficients. Additionally, an approach is suggested for estimating flooding in confined spaces and the results are compared with various correlations available in the literature.
Experimental investigation of the supercritical heat transfer of the low GWP refrigerant R1234ze(E): calibration and validation of test rig
Authors: Van Nieuwenhuyse J , Lecompte S , De Paepe M 
Published: June 2024

Abstract
Heat transfer of supercritical refrigerants is applied in practical systems such as the transcritical organic Rankine cycle or supercritical heat pump. The concept of supercritical heat transfer is not new and has already been studied and applied for decades in several applications. However, results on one fluid cannot be directly translated to another one. This is because the thermohydraulic behavior of fluids is heavily influenced in the near-supercritical region due to sudden variations in the thermophysical properties when the fluid is heated or cooled close to its critical point. For refrigerants under horizontal flow, the research is limited. Most studies in literature are on small diameter tubes and on R134a, which has a high global warming potential. Therefore, an experimental test rig has been built to measure the supercritical heat transfer of low global warming potential refrigerants over a large temperature and pressure range in the supercritical region. In this work, the calibration and validation of this test rig is presented using the refrigerant R1234ze(E). The test section consists of a 4 m long horizontal tube with an inner diameter of 22.9 mm, equipped with thermocouples at both the tube wall and in the bulk of the flow, and is heated by resistance wires wrapped around the tube. For the calibration, the temperature profiles under both non-heating and heating conditions are evaluated. For the validation, the average Nusselt numbers obtained through experiments under subcritical conditions are compared to the average Nusselt numbers calculated based on the Dittus-Boelter and Gnielinski correlation.
Improving virtual heat transfer description of developed and undeveloped annular gap flows at high Taylor numbers
Authors: Žnidarčič Anton , Katrašnik Tomaž 
Published: June 2024

Abstract
Increased power densities of electric machines are, amongst other factors, related also to the increase of the rotors’ rotating velocities. These can be combined with axial flow to improve the heat transfer in the annular gap. The resulting high rotating and axial velocities are characterized with high Taylor (Ta) and Reynolds (Re) numbers. Such flow regimes are currently not yet thoroughly described. The reasons are in the complex interactions between the operating conditions, annular gap geometry and the conditions at the gap inlet, which affect the flow development in the gap. Each of these impacts varies between different electric machines, adding to the complexity of description. To address this, a numerical study based on 3D CFD simulations is performed. The study accounts for the impacts of the flow conditioning at the entrance to the annular gap and the possibility that the small scale turbulent structures might not be well resolved at high Ta numbers. Thus, different inflow configurations are applied using both RANS and LES models. The results are compared with available experimental and numerical data and provide a valuable insight into the requirements for reliable heat transfer description in the increasingly interesting flow conditions.
On a proper tensorial subgrid heat flux model for LES
Authors: Trias F X , Gorobets A , Oliva A 
Published: June 2024

Abstract
In this work, we aim to shed light on the following research question: can we find a subgrid-scale (SGS) heat flux model with good physical and numerical properties, such that we can obtain satisfactory predictions for buoyancy-driven turbulence at high Rayleigh numbers? This is motivated by our previous findings showing the limitations of existing SGS heat flux models for LES. On one hand, the most popular models rely on the eddy-diffusivity assumption despite their well-known lack of accuracy in a priori studies. On the other hand, the gradient model, which is the leading term of the Taylor series of the SGS flux, is much more accurate a priori but cannot be used as a standalone model since it produces a finite-time blow-up. In this context, we firstly aim to reconcile accuracy and stability for the gradient model. To do so, it is expressed as a linear combination of regularized (smoother) forms of the convective operator. The new alternative form can indeed be viewed as an approximate deconvolution of the exact SGS flux. Moreover, it facilitates the mathematical analysis of the gradient model, neatly identifying those terms that may cause numerical instabilities, leading to a new unconditionally stable non-linear model that can indeed be viewed as a stabilized version of the gradient model. In this way, we expect to combine the good a priori accuracy of the gradient model with the stability required in practical numerical simulations.
Experimental and numerical pressure drop investigation of a protruding tube microchannel heat exchanger
Authors: Settati Mohamed , Oliet Carles , Sanmarti Oriol , Oliva Assensi 
Published: June 2024

Abstract
An experimental and numerical fluid flow study in a micro heat exchanger (microHEX) is conducted in this work to investigate its pressure drop characteristics. The microHEX sample presents a high degree of protrusion of the microchannels inside the inlet and outlet manifolds (Lprot
/Dm
=0.7), a large manifold-to-branch area aspect ratio (Am/As
=37), and a very small flow division in each microchannel (β=1/34). These features configure T-junctions that differ completely from the conventional ones in the literature. Experimental measurements of the microHEX pressure drop were performed for the Reynolds range of 300-2200. The numerical methodology combines a 1D model to evaluate the pressure drop of a single microchannel, adding minor entrance and exit losses due to the change of section and direction. A CFD numerical simulation evaluates the particular pressure loss associated with the dividing T-junction towards the protruded microchannel. The numerical simulation pressure drop results compared well with the experimental measurements, reporting a difference of 3.11% for an initial case. An extension of the work will soon cover all the collected experimental cases.
Experimental investigations of the potential of organic salt solutions for application in pressure-retarded osmosis
Authors: Dietrich F , Cieślikiewicz Ł , Furmański P , Łapka P 
Published: June 2024

Abstract
Pressure-retarded osmosis (PRO) is a process that enables useful work generation from the salinity difference of solutions. The literature most often considers using PRO with natural sodium chloride (NaCl) solutions such as seawater and river water or industrial solutions such as seawater desalination concentrate. Open cycle systems, which are dependent on the available source of streams feeding the system, are most often analyzed. In such systems, the full PRO potential as a power generation method cannot be explored due to the existing limitations of natural and industrial NaCl solutions. The second approach, found less frequently in scientific publications, is closed-cycle systems. They allow more extensive manipulation of the feed and draw stream parameters and the use of optimized synthetic solutions. This allows optimization of the process precisely for the intended applications. Furthermore, engineered solutions of various compositions can be used in closed-cycle systems, which opens new ways of increasing the system performance and application potential. The research described in this article is focused on the experimental evaluation of PRO potential for generating useful work by applying solutions of organic salts under varying conditions. The chemical compounds used were selected based on their theoretical performance, ease of use, and availability. The developed experimental stand allows full control over the temperature of the feed and draw solution streams. The studies were conducted without back-pressure, in a configuration typical of the forward osmosis process, with solution circulation on both sides of the membrane. As a result, the effect of solution temperature and concentration on water flow through the membrane was determined, and permeate flow is directly related to achievable work in the PRO process. The obtained results were compared to the system performance with NaCl solutions under the same conditions to evaluate potential gains.
Numerical simulation of drop impingement onto superheated textured walls
Authors: Sontheimer Henrik , Ho Anh Tu , Elsäßer Leon , Stephan Peter , Gambaryan-Roisman Tatiana 
Published: June 2024

Abstract
Spray cooling stands out as a suitable method for cooling of high-end electronic devices. Texturing of the surface can further increase the cooling performance. Understanding the flow dynamics and heat transport during the impingement of a single drop is crucial to gain an in-depth insight into complex phenomena governing spray cooling. In this study, the influence of textured walls on drop impingement dynamics and heat transfer is investigated. Numerical simulations are conducted within the OpenFOAM framework. Our solver accounts for evaporation, conjugate heat transfer and a dynamic contact angle. We study wall topographies comprised of cubes, rectangular grooves, pyramids and triangular grooves. Our results reveal that textured surfaces significantly increase both wetted area and contact line length compared to a smooth wall, with cubes demonstrating the best performance. Furthermore, we observe a significant increase in heat flow during the sessile drop phase. This study lays the foundation for designing surfaces that optimize heat transfer for drop impingement and spray cooling.