bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fractional diffusant model of a multicomponent inhomogeneous gas mixture as a basis for the diffusant approximation
Authors: Burakhanov B M 
Published: December 2021

AbstractIt can be shown that for a correct description of the motion of an inhomogeneous multicomponent mixture of gases, such concepts as a multi-velocity continuum and interpenetrating motion are not enough. This is the basis for the introduction of the concept of “poly-velocity motion”. The reason for the need to use this concept is that to describe the motion of each component of an inhomogeneous mixture, it is necessary to use not one, but two velocity fields. The use of two velocity fields to describe the motion of a mixture component is the basis for constructing a fractional model of the mixture component, in which each component is divided into two fractions. This model serves as the basis for constructing the proposed fractional diffusant model of a multicomponent inhomogeneous gas mixture.
The phenomenon of relay race molecular transfer of the amount of motion and its relationship with the diffusion phenomenon
Authors: Burakhanov B M 
Published: December 2021

Abstract
The very fact of molecular transfer of the amount of motion, including in an ideal gas in an equilibrium state, has long been well known. However, this fact is still not realized as a physical phenomenon of transfer, equivalent to such transfer phenomena as diffusion, thermal conductivity and viscosity. The key concept used in this paper when describing the phenomenon of relay race molecular transfer of the amount of motion is the concept - “molecular relay race type of motion”. A molecular relay race model of an ideal gas in an equilibrium state is proposed, as well as a molecular relay race model of a mixture of two ideal gases at constant temperature and pressure. It is shown that the value of the velocity modulus of diffusion flows is one of the physical characteristics of the mixture as a whole. It is also shown that the total density of the substance carried by the diffusion flows is many orders of magnitude less than the total density of the inhomogeneous multicomponent mixture.
Study of the factors that determine the transfer of water and organic compounds into the gas phase from aqueous solutions in a discharge with a liquid cathode
Authors: Chistolinov A V , Khromov M A , Yakushin R V , Gadzhiev M Kh , Tyuftyaev A S 
Published: December 2021

Abstract
A study was performed to investigate the transfer of organic compounds and water from an aqueous solution to the gas phase under the action of a direct current discharge, in which an aqueous solution that contains organic compounds plays the role of a cathode. The effect of the area of the free surface of a liquid in various reactors, as well as the effect of the stirring mode of a solution near the surface of a liquid on the rate of transfer of water and organic compounds under the action of a discharge of this type, have been investigated. It is shown that a change in the area of the free surface of a liquid has no significant effect on the rate of transfer of water and organic compounds from solution to the gas phase under the action of a direct current discharge with a liquid cathode. It is shown that the stirring mode and the temperature of the solution, on the contrary, have a very significant effect on the rate of nonequilibrium transfer of both water and organic compounds from solution to the gas phase under the action of a discharge with a liquid cathode.
Flow control in cavity by means of sDBD actuator
Authors: Kazanskii P N , Moralev I A , Selivonin I V 
Published: December 2021

Abstract
This paper presents results of controlling the hydrodynamic cavity pulsations by plasma sDBD actuators. The study was held at flow velocity 36 m/s. The discharge was organized near the upstream edge of cavity. The discharge pulse energy was 0.03 J, Excitation of resonant modes, whose frequency coincides with the modulation frequency of the discharge, is obtained. Also, in the case of the detuned discharge operation, locking of the cavity to the discharge modulation frequency occurs.
Influence of the surface DBD parameters on the streaks development in the boundary layer
Authors: Yarantsev D , Selivonin I , Moralev I 
Published: December 2021

Abstract
The effect of the filamentary barrier discharge parameters on the boundary layer streaks generation and instability was studied. The streaks are formed near the constricted discharge channels due to vortices formation driven by spanwise Coulomb volume force. The secondary instability of the streaky structures can lead to the laminar-turbulent transition of the boundary layer. This work demonstrates that supply voltage parametrs affect the period of the constricted channels and thus the streaks transversal period within the boundary layer. For the various streaks periods, different modes of streak instability are shown to dominate.
Variations of nanoparticle layer properties during nucleate pool boiling
Authors: Okawa Tomio , Nakano Koki , Umehara Yutaro 
Published: December 2021

Abstract
The nanoparticle layer detachment during nucleate pool boiling and its influences on heat transfer surface properties were explored experimentally. The material of the heat transfer surface was copper and the nanoparticle layer was formed on the heat transfer surface by nucleate boiling in the water-based TiO2 nanofluid. It was found that the detachment of the nanoparticle layer during nucleate boiling in pure water is significant. In the present experiment, more than half of nanoparticles deposited on the heated surface were detached before the CHF condition was reached. The thickness and roughness decreased accordingly. However, the wettability and wickability that are the influential parameters on the CHF value were maintained even after the occurrence of nanoparticle layer detachment and deteriorated only after the CHF condition was reached. It is therefore considered that the onset of CHF brings qualitative change to the capillary suction performance of the layer of nanoparticles. In exploring the effect of the nanoparticle layer properties on the nucleate boiling heat transfer, sufficient attention should be paid to the variation of the nanoparticle layer properties during nucleate boiling.
Heat transfer and exergy analysis of flow boiling evaporation in u-bend channel
Authors: Jatau T , Bello-Ochende T 
Published: December 2021

Abstract
This study presents, a numerical method used to evaluate the exergy analysis of flow boiling evaporation of R134a in a U-bend channel using entropy generation criterion which is concerned with the degradation of exergy during the process due to irreversibilies (entropy generation) contributed by heat transfer and pressure drop. The simulations were conducted with the heat flux of 15 kW/m2, mass fluxes of 200-600 kg/m2s of R134a at the saturation temperature of 15 °C. Three(3) different geometries sizes of U-bend channel’s diameter 6, 8 and 10 mm with the bend radius of 10.2 mm were utilized. The Volume of Fluid (VOF) multiphase flow formulation was used in Ansys Fluent. The results show that the entropy generation increases with increase in mass fluxes due to irreversibilies contributed by the heat transfer coefficient and pressure drop as mass fluxes increase. Based on the size of the U-bend channel, the entropy generation was found to increase as the diameter of the channel increases. The numerical results were compared with the data in the open literature and there was a good agreement.
Pool boiling performance of laser-textured surfaces with time-dependent wettability
Authors: Zupančič Matevž , Gregorčič Peter , Golobič Iztok 
Published: December 2021

Abstract
In last years, the direct laser texturing proved as environmentally friendly, scalable, flexible and efficient approach for surface functionalisation by creating appropriate surface features for enhanced boiling performance. When metal surface is laser-processed in open (oxygen-containing) atmosphere, it oxidizes and becomes (super)hydrophilic. However, it is well known that the wettability transition towards (super)hydrophobic state occur, if such a surface is exposed to the presence of hydrophobic contaminants. When water is used as a working fluid, this wettability transition can have a significant effect on nucleate boiling performance, which is investigated in this work.
Pool boiling of nanofluids on biphilic surfaces
Authors: Pontes P , Freitas E , Fernandes D , Teixeira A , Ferreira R , Bellmann S , Cautela R , Moita A. S. , Bahadur V , Miranda J , Lima R , Ribeiro APC. , Moreira ALN 
Published: December 2021

Abstract
This study addresses the combination of customized surface modification with the use of nanofluids, to infer on its potential to enhance pool boiling heat transfer. Hydrophilic surfaces patterned with superhydrophobic regions are prepared and used to act as surface interfaces with nanofluids (water with gold, silver and alumina nanoparticles) and infer on the effect of the nature and concentration of the nanoparticles in bubble dynamics and consequently in heat transfer processes. The main qualitative and quantitative analysis was based on extensive post-processing of synchronized high-speed and thermographic images. The results show an evident benefice of using biphilic patterns, but with well-stablished distances between the superhydrophobic regions. Such patterns allow a controlled bubble coalescence, which promotes fluid convection at the hydrophilic surface between the superhydrophobic regions, which clearly contributes to cool down the surface. The effect of the nanofluids, for the low concentrations used here, was observed to play a minor role.
Numerical simulation of dropwise condensation over hydrophobic surfaces using vapor-diffusion model
Authors: Suzzi N , Croce G 
Published: December 2021

Abstract
Dropwise condensation of humid air over hydrophilic and hydrophobic surfaces is numerically investigated using a phenomenological, Lagrangian model. Mass flux through droplets free surface is predicted via a vapor-diffusion model. Validation with literature experimental data is successfully conducted at different air humidities and air velocities. The accuracy of the implemented condensation model is compared with a standard analogy between convective heat and mass transfer, showing that the latter is not able to predict heat transfer performances in the investigated air velocity range.
Thermal performance deterrence caused by PCM inclusion in firefighting garments: The other side of the story
Authors: Fonseca A , Neves S F , Campos J B L M 
Published: December 2021

Abstract
Firefighters usually encounter high heat flux exposures, which can cause severe burns. The addition of a phase change material (PCM) layer into a firefighting garment assembly has proven to be beneficial as it lowers the garments temperature during the fire exposure. However, after the fire exposure, accumulated heat in the PCM garment is discharged towards skin and environment which can have a negative influence on thermal performance. In this study, a one dimensional numerical approach was used to study the effect of environment parameters (ambient convective heat flux) as well as PCM parameters (latent heat, melting temperature) on the thermal performance of the firefighting garment, after the fire exposure. It was concluded that the amount and phase change temperature at which latent heat is discharged had a significant effect on thermal performance, depending on the heat exposure scenario. For high – intensity exposures, skin damage is promoted by an increase in both properties whilst for low intensity exposures, a decrease in melting temperature would promote greater skin damage. The results outlined in this paper could aid in the manufacture of PCM firefighting garments, as skin damage due to PCM resolidification might be an important parameter to take into account when maximizing thermal performance.
Fire behaviour of a Carbon/Nomex honeycomb sandwich composite used in aircraft interior
Authors: Papadogianni V , Romeos A , Perrakis K , Panidis T 
Published: December 2021

Abstract
Fire behaviour of a carbon/Nomex honeycomb composite, used as ceiling panel in aircraft interiors, was investigated in Cone Calorimeter at different incident heat fluxes, ranging from 20 to 70 kW/m2. The material exhibited good fire performance with relatively low amount of heat release and long ignition times. Combustion of the material at 40 kW/m2 proceeded in one stage, while at higher heat fluxes two stages were observed. The burning mechanisms and char formation during thermal decomposition at different heat fluxes was also examined. The long tail after flame-out in heat release curves and the significant increase of CO production and mass loss were analysed with respect to char residue.
Comparison of finite volume and one dimensional network methodologies for thermal management of lighting applications
Authors: Joshi P S 
Published: December 2021

Abstract
Signify is focused on building a state-of-the-art, innovative and sustainable solutions for industries, homes, buildings, and communities. In the last decade or so there has been a considerable shift from using traditional incandescent luminaires to highly efficient, cheaper, and robust LED (Light Emitting Diode) based lighting fixtures. LEDs are semiconductor devices and thus their life depends largely on operating temperatures. Thermal management of the lighting fixture, therefore, becomes crucial for the overall performance. Heat sinks are designed for given operating conditions for better thermal management. With the improved LED efficiencies there are two alternatives that the product designer can opt for namely, to increase the lumen output for the present fixture or to reduce the overall heat sink size. To assist the product designer in this aspect, the present paper reports the thermal management of lighting luminaries using two different modelling techniques such as Finite Volume Method (FVM) and One Dimensional (1D) resistive network analysis. These two modelling techniques are employed to predict the temperature profiles on the luminaire and then compared them with the actual test results. The processing time, accuracy, and method of implementation for both these techniques are then discussed.
Experimental study of a natural convection flow in a cubic enclosure with a partially heated inner block
Authors: Weppe Alexandre , Moreau Florian , Saury Didier 
Published: December 2021

Abstract
In many industrial contexts, buoyancy driven flows are the only cooling strategy in case of breakdown of the forced convection cooling system. In order to study those flows in a simplified configuration, a buoyancy-driven flow is generated inside a cubic enclosure by a partially heated block (Ra = 1.4 × 109). The flow is studied experimentally in the vertical median plane, in the part of the enclosure where the flow is generated i.e. close to the heated side of the block. Velocity fields, mean profiles and RMS statistics are analyzed. The results show the presence of boundary layer flows with a central zone nearly at rest and stratified. RMS velocities are intensified with elevation.
Thermal conditions for the formation of self-assembled cluster of droplets over the water surface
Authors: Fedorets Alexander A , Dombrovsky Leonid A , Shcherbakov Dmitry V , Frenkel Mark , Bormashenko Edward , Nosonovsky Michael 
Published: December 2021

Abstract
The effect of temperature profile of the water layer surface on the formation and structure of a levitating droplet cluster is studied in the paper. The laboratory experiments indicate that a local temperature maximum of water is a necessary condition for the formation of a cluster. A quantitative criterium of transformation of a monolayer of randomly positioned microdroplets to a self-assembled cluster of relatively large droplets is obtained.
Development of measurement setup for thermal conductivity at high temperatures using the parallel hot-wire
Authors: Nonneman Jasper , Couvreur Kenny , Vancoillie Andrey , Paepe Michel De 
Published: December 2021

Abstract
An experimental setup is built to determine the thermal conductivity of a mixture of KNO3 and NaNO3 with a ratio of 54-46m% which is used in high temperature thermal storage systems. The measurement principle is based on the transient parallel hot-wire method which is described in the standards NBN B 62-202 and ISO 8892-2. The setup is designed to measure the thermal conductivity around the melting temperature (<300°C). Measurements within the liquid region show faulty results caused by natural convection within the sample. The measured thermal conductivity within the solid region is 0.5466-0.5529W/mK close to the melting point and 0.7174W/mK at room temperature, which shows a decreasing thermal conductivity with increasing temperature in the solid region.
A comparison of postprocessing methods for hot film sensors for the heat transfer analysis of impinging jet flows
Authors: Murphy Paula , Persoons Tim , O’Shaughnessy Seamus , Murray Darina 
Published: December 2021

Abstract
The aim of this investigation is to optimise the data post-processing techniques associated with hot film sensors when intended to be used as a means of accurate, high-resolution heat flux measurement. More specifically, this project focuses on the performance of hot film sensors operated in a constant temperature anemometer bridge, used in conjunction with impinging jet air flows. The characteristic heat transfer behaviour in this impinging jet flow provides the reference against which the heat flux data attained using the hot film sensor is compared. As part of this investigation, three hot film calibration methods are examined for a range of sensor overheat values: (A) a wall shear correction method, (B) a physical quasi 1-D conduction model and (C) a physical quasi 2-D fin conduction model. The results show that the method C, when used in conjunction with a 5 K sensor overheat, best replicated that of the reference heat flux sensor for the jet configurations investigated.
Research on xylitol crystallization by shearing and seeding for its use as a phase change material
Authors: Delgado Mónica , Navarro Miguel , Lázaro Ana , Boyer Séverine A E , Peuvrel-Disdier Edith 
Published: December 2021

Abstract
As thermal energy storage is becoming more important, new materials are being studied. Sugar-alcohols (SA) are very promising as phase change materials (PCM) because they are non-toxic, affordable and their latent heat is high. However, undercooling and low crystallization rates are some of the problems present in these materials. The SA studied in this work is xylitol, and using a microscope connected to a transparent counter-rotating shear cell, the effect of secondary nucleation is studied, as well as the crystallization rate of xylitol and how undercooling affects it. From the results, it is deduced that a proper seed preparation and handling is needed. The crystal structure is also studied, using XRPD diffractograms and differential scanning calorimetry.
An experimental study of the temperature evolution of a single fin submerged in a phase changing material during melting at different heat fluxes
Authors: Tassenoy R , Beyne W , Plas W , Lecompte S , De Paepe M 
Published: December 2021

Abstract
An experimental setup has been designed to study a single cylindrical fin placed in a cylindrical enclosure filled with phase changing material (PCM). The heat flux to the fin is measured at the top of the fin. The temperature evolution at different fin heights is measured by thermocouples placed internally in the fin. The evolution of these temperatures has been studied for different heat fluxes. This provides insight in the contribution of the different fin heights to the total heat transfer to the PCM during the different stages of the melting process. As such they can be used to assess the effectiveness of the fin over its length. After approximately 6h, the fin temperature stabilizes during melting. Due to the temperature drop over the fin, the bottom temperature reached is significantly lower than the temperature at the top and the contribution of this lower part to the total heat transfer is lower as well. For heat fluxes higher than 3805±75 W/m2, the steady-state temperatures at fin locations in contact with the melting PCM are similar. For low heat fluxes, this steady-state temperature is not reached during a 12h experiment. Longer experiments are thus needed to study the steady-state behaviour at these lower heat fluxes.
Numerical approach for fluids flow and thermal convection in microchannels
Authors: Ajeeb Wagd , Oliveira Monica S A , Martins Nelson , Sohel Murshed S M 
Published: December 2021

Abstract
The heat transfer performance of conventional thermal fluids in microchannels is an attractive method for cooling devices such as microelectronic applications. Computational fluid dynamics (CFD) is a very significant research technique in heat transfer studies and validated numerical models of microscale thermal management systems are of utmost importance. In this paper, some literature studies on available numerical and experimental models for single-phase and Newtonian fluids are reviewed and methods to tackle laminar fluid flow through a microchannel are sought. A few case studies are selected, and a numerical simulation is performed to obtain fluid flow behaviour within a microchannel, to test the level of accuracy and understanding of the problem. The numerical results are compared with relevant experimental results from the literature and a proper methodology for numerical investigation of single-phase and Newtonian fluid in laminar flow convection heat transfer in microscale heat exchangers is defined.
Conjugate heat transfer from a microchannel embedded impingement cum film cooled-flat plate
Authors: Jaiswal A K , Mahapatra P S , Prasad B V S S S 
Published: December 2021

Abstract
A computation fluid dynamics analysis is presented to investigate the effect of placing a microchannel inside a flat plate. A microchannel embedded flat plate with 250 angled 175 film holes in staggered form is considered in the present work. A Conjugate heat transfer analysis is done to determine the efficiency of cooling. Simulations were carried out, and subsequently, a parametric study was conducted to observe the effect of variation of blowing ratios. The temperature distribution is observed to be more uniform due to the presence of the microchannel, resulting in a lesser thermal gradient in the solid plate. It is also noted that overall effectiveness increases with the blowing ratio. The maximum increase in overall effectiveness due to the microchannel is about 30% for the blowing ratio of unity.
Critical evaluation of nanofluids and ionanocolloids as heat transfer fluids
Authors: Fabre Elaine , Sohel Murshed S M 
Published: December 2021

AbstractNanofluids and ionanocolloids are potential heat transfer fluids with remarkable thermophysical properties. The main difference between these two types of fluids remains in the base fluid used, which significantly impacts their performances. In this work, an attempt of a critical evaluation of the most relevant characteristics of both fluids is presented and the main challenges of their application are discussed.
Effect of Nanoparticle Deposition on the Thermal Performance of Evaporator in Thermosyphons
Authors: Donepudi T , Korobko A V , Peeters J W R , Fateh S 
Published: December 2021

Abstract
Rapid advancements in technology have led to the miniaturization of electronic devices which typically dissipate heat fluxes in the order of 100 W/cm2. This has brought about an unprecedented challenge to develop efficient and reliable thermal management systems. Novel cooling technologies such as Two-Phase Thermosyphons that make use of nanofluids provide a promising alternative to the use of conventional systems. This article analytically estimates the effects caused by nanoparticles that deposit on the evaporator surface and their effect on the heat transfer process.