Heat Transfer - Science topic

Natural convection and heat transfer in triangular cavities are widely used in the thermal engineering of buildings and heat dissipation in electronic devices. In this study, we analyze dimensionally the development of thermal flow for Pr > 1 in a triangular cavity under top-cooling conditions. The formation and development of the boundary layer un...

The stability of CO2 fluid in the Earth’s mantle is restricted by the carbonation of rock-forming minerals. Among those, the reaction with garnet is of particular interest because it constrains the stability of CO2 fluid in eclogites, whose minerals have been found in the CO2-bearing diamonds. In this work, we determined the equilibrium boundary fo...

In the context of racing to carbon neutrality, the pipe-embedded building system makes the opaque envelopes gradually regarded as the multi-functional element, which also provides an opportunity for thermal insulation solutions to transform from high to zero-carbon attributes. Based on the re-examination of the heat transfer process of conventional...

Thermomagnetic convection is a controlling phenomenon for heat-transfer in ferrofluids. It depends upon the magnetic field gradients, variation in magnetic susceptibility, particle concentration and temperature gradients. This article presents the effect of these parameters on cooling of a current carrying micro-wire in ferrofluid with a focus on m...

A PID controller is introduced into a latent heat thermal energy storage unit to compose a coupling system in order to control the discharging performance. Outlet temperature of the working fluid can be precisely regulated by means of its inlet velocity variation based on the PID controller. The theoretical model is built through combining heat tra...

The solar air heater has a low heat transfer coefficient due to the development of a laminar sublayer inside the channel of the solar collector. Adding artificial roughness or ribs to the surface of the wall of the absorber plate is an effective and promising method to increase heat transfer by interrupting the laminar sublayer. In this study, a tr...

A new approach that utilizes Thermoelastic Stress Analysis (TSA) is proposed to investigate fatigue-induced material degradation in laminated fiber-reinforced polymer composites (FRP). The proposed model accounts for non-adiabatic conditions, the effects of the material temperature on the material properties, and the effects of stiffness material d...

Abstract Many researchers have studied active and passive methods to improve thermal performance and increase heat transfer in internal flows. Various geometries and configurations of turbulators have been proposed to achieve optimal performance in heat exchangers, and these analyses are ongoing. However, limited studies have been conducted on turb...

The current study experimentally examines the impact of coil pitch on heat transfer behavior and friction factor through helical coils for α-Al 2 O 3 /Distilled water nanofluid turbulent flow. These tests were conducted on coils with coil pitches of 20, 35, and 50 mm. The nanoparticle volume fraction was 0.1%. The nanoparticles in a 0.1% volume con...

Metallic monolith structures are often used in compact reactor applications due to their superior heat transfer properties and lower pressure drop when compared to ceramic monoliths. Endothermic reactions like steam reforming depend heavily on externally supplied heat, making highly conductive supports especially useful. Simulations are invaluable...

In this expository note, we prove a localized bubbling result for solutions of the energy critical nonlinear heat equation with bounded $$\dot{H} ^1$$ H ˙ 1 norm. The proof uses a combination of Gérard’s profile decomposition (ESAIM Control Optim. Calc. Var. 3 : 213–233, 1998), concentration compactness techniques in the spirit of Duyckaerts, Kenig...

Recently, Nano-encapsulated phase change materials (NEPCM) have attracted the attention of researchers due to their promising application in thermal management. This research investigates magnetohydrodynamic mixed convection of NEPCM contained within a lid-driven trapezoidal prism enclosure containing a hot-centered elliptical obstacle. The upper c...

Molten chloride salts are stable at higher temperatures than many other salts, including nitrate salts, and are thus promising for heat transfer and/or thermal energy storage in concentrating solar power, nuclear power, and other thermal energy storage applications. However, corrosion in molten chloride salts remains a significant problem. While ma...

This study investigates the heat transfer performance and thermo-hydraulic characteristics of nanofluids containing graphene nanoparticles in a water and ethylene glycol mixture. Results show that both nanofluid samples, with concentrations of 0.15% and 0.10% by volume, experience increased heat transfer coefficients compared to the base fluid unde...

The current work focuses attention on discussing the peristaltic flow of Rabinowitsch nanofluid through ciliated tube. This technical study analyzes heat and mass transfer effects on the flow of a peristaltic flow, incompressible, nanofluid via a ciliated tube. The governing non-linear partial differential equations representing the flow model are...

Surface porosity is an important means of enhancing boiling heat transfer. In this paper, two kinds of composite porous structures of surface micropore + square channel and framework micropore + square channel were prepared by selective laser melting technology using AlSi10Mg as the powder material. The effect of composites with different pore form...

Every day, smaller, faster, and more potent modern technologies and systems are being created and put into use, which necessitates the advancement of the thermal fluids that are used in operation to increase the capacity for heat removal. Pool boiling is effectively used in many industrial applications such as refrigeration systems, power plants et...

The nucleate subcooled boiling is an efficient heat transfer form and plays an important role in many cooling applications. The size and distribution of bubbles in subcooled boiling have considerable influence on boiling heat transfer. In this paper, subcooled flow boiling experiment is carried out to investigate the nucleation point density and de...

The novel hybrid cold metal transfer (CMT)–pulsed gas metal arc welding (P-GMAW) process was used to perform the narrow gap welding of mild steel plates. A systematic approach was followed to select the working values of numerous process parameters using high-speed images of the welding arc in synchronization with the welding current and voltage. F...

The heat transfer characteristics of evaporative condensers in an R744 air conditioning system were evaluated using the numerical and the experimental methods. Two configurations of condensers were studied: Case 1 with five layers of tubes and Case 2 with eight layers of tubes. In order to evaluate the heat transfer characteristics, the temperature...

In the framework of Samara–Valencia model for heat transfer in dry surface grinding, analytical expressions for the time-dependent temperature field of the workpiece during the transient regime in which the wheel is engaged (cut-in) and disengaged (cut-out) from the workpiece are calculated. The main assumption we consider is a constant heat flux p...

The widespread use of single-base propellant may contribute to serious pollution of the environment. The study of single-base propellant pyrolysis could provide an in-depth understanding of the combustion mechanism, reveal the key steps and reaction kinetics of the combustion process, and reduce the damage when using single-base propellant to the e...

Triangles are an ever present feature in nature, which the building construction industry duly echoes. However, an exact expression intended to offer the radiant field due to any triangle in an upright or inclined position had not been identified by previous research. In this case, the author has been able to solve by direct integration, the canoni...

The micro-channel heat sink (MCHS) is an excellent choice due to its exceptional cooling capabilities, surpassing those of its competitors. In this research paper, a computational fluid dynamics analysis was performed to investigate the laminar flow and heat transfer characteristics of five different configurations of a variable geometry rectangula...

In this paper, a new multiscale concurrent topology optimization method for thermoelastic structures considering the iterative variation of temperature field is proposed for the first time, which breaks the limitation that previous multiscale concurrent topology optimization studies being compliable merely to uniform temperature field. In this meth...

The current work looks at a horizontally oriented double-pipe thermal energy storage system with PCM filled in the annular gap and heat transfer fluid (Water, MXene, and Al2O3 nanofluid) flowing in an inner tube from a physical standpoint. The discharging properties of a latent heat-based thermal energy storage system at various intake temperatures...

In past investigations of elastic instabilities and elastic turbulence, almost no attention has been devoted to the effects and influences of inertial phenomena. Within the present investigation, Nusselt number data are provided to illustrate the relative influences of inertia and polymeric viscoelastic phenomena within a rotating Couette flow (RCF...

The aerodynamics of a high-speed low-pressure turbine (LPT) cascade were investigated under steady and unsteady inlet flows. The tests were performed at outlet Mach (M) and Reynolds numbers (Re) of 0.90 and 70k, respectively. Unsteady wakes were simulated by means of a wake generator equipped with bars. A bar reduced frequency (f +) of ∼0.95 was us...

Previously, in small scale demonstrations, researchers have increased photovoltaic efficiency through cooling by enhancing heat transfer from panels to the air through wind speed. Here I show in the real-world operation of a larger scale photovoltaic generator that increases in wind speed can lead to small but notable energy losses, reflected in th...

In the present paper, the occurrence and development of the pseudo-desublimation process of AdBlue microdroplets in the microchannels and surfaces of catalytic reduction systems (SCR) are reported. In order to understand how the pseudo-desublimation process develops, the influence of heat flux values on the heat transfer of AdBlue injection was ana...

The novelty and motivation of this research can be emphasized by examining how the heat transfer mechanism of a non-Newtonian Powell-Eyring fluid, which flows because of a stretched sheet, is affected by factors like viscous dissipation, the slip velocity phenomenon, and Joule heating. In addition, the investigation delves into the heat transfer be...

Monolithic structures of catalytic reactors offer low flow resistance, but their drawback is weak heat and mass transport. For transport intensification, innovative streamlined structures were designed, the walls of which are shaped like an airplane wing. Extensive CFD (Computer Fluid Dynamics) studies were performed for the streamlined and—for com...

Boiler merupakan unit penting pada PLTU yang didalamnya terdapat superheater untuk memanaskan uap agar panas dan kekeringannya meningkat sehingga menjadi uap panas lanjut. Permasalahan terjadi pipa secondary superheater pecah karena mengalami panas berlebih akibat adanya deposit lapisan oksida didalamnya. Penelitian ini bertujuan untuk menyimulasik...

The calculation of the view factor is an important consideration in radiative heat transfer analysis. Thermal engineering requires the view factor calculations between complex geometries containing parallel and inclined surfaces. There is currently no analytic formula available for this, so the summation rule (SR) must be used. However, when comple...

In this paper, we extracted values of geomagnetic anomaly sourced in the lithosphere from the total intensity of geomagnetic that is measured on the 750 points on an area (100x100 km2) around the Khulj hot springs. The two-dimensional map of the distribution of the anomaly geomagnetic corresponding to this area was made via these extracted values o...

Abstract This study investigates the 3D flow properties and heat transfer of copper, titanium/ water nanofluids across a bidirectional surface under the impact of MHD. The thermophysical features of nanofluid are employed using the Tiwari and Das model. Boundary layer theory has simplified the resulting physical principles. By using the proper tran...

Following our recent investigation \cite{Ke23a}, this paper centers on exploring the influence of shear on internally heated convection and its flow within a square cavity. The study delves into the behavior of both Newtonian and viscoplastic fluids within this setup. The cavity features two vertical side walls that consistently maintain low temper...

In recent years, heat transfer enhancement of heat exchange equipment has attracted more and more attention. In this paper, the heat transfer and pressure drop characteristics of sine wavy flying-wing fins are studied by numerical method. The objective is to improve the integrated heat transfer and pressure drop performance of sine wavy flying-wing...

Poplar fiber mass is a non-uniform medium that is composed of discrete microelements making it an imperative raw material in the production of ultra-thin high-density wood fiberboards. Preheating, therefore, becomes a crucial process in producing ultra-thin boards from poplar fiber masses. This study aims to investigate the thermal conductivity pro...

In this article, the effect of the rotation variable and other variables on the peristaltic flow of Powell-Eyring fluid in an inclined asymmetric channel with an inclining magnetic field through a porous medium with heat transfer is examined. Long wavelength and low Reynolds number are assumed, where the perturbation approach is used to solve the n...

Here in, heat transfer characteristics of a magnetized Casson sodium alginate-alumina/copper hybrid nanofluid flowing through the permeable moving plane are investigated considering the effects of thermal radiation and Joule heating with Tiwari and Das model. The primary objective of the present study is to investigate the influence of the velocity...

This special issue aims to present and discuss the latest advances in the development and application of machine learning and data-driven modeling techniques in the field of mass and thermal transport. Topics covered include, but are not limited to: 1. Artificial intelligence techniques for heat and mass transfer applications; 2. Development of mac...

Obtaining thermal parameters based in the analysis only on the amplitude or phase of the photoacoustic (PA) signal from photothermal measurements is useful and valid once classical theoretical expectations are that the same parameters are contained in the photoacoustic signal. This work studies the issue of disagreement between experimentally measu...

Statistics from large-eddy-simulation (LES) of cooling films with different cooling holes are used to evaluate budgets in the transport equation of turbulent heat flux. The capability of LES has been assessed by comparing simulated results with experimental data, while the correctness of the procedure generating turbulent heat flux budgets has been...

In this study, heat transfer is analyzed for an incompressible steady laminar micropolar fluid flow among two symmetrical stretchable disks. The associated Partial Differential Equations (PDEs) are converted into Ordinary Differential Equations (ODEs) through appropriate similarity transformations and then solved numerically through applying the qu...

A CALPHAD-coupled finite element model of dissimilar AZ31/ZK61 resistance spot welding was established in this work. The coupled effect of phase transformation and heat transfer was considered in this model, which presents the solid fraction contour evolution within the joint. During the cooling stage of AZ31/ZK61 resistance spot welding, a low-sol...

Nowadays PVT modules (Photovoltaic Thermal modules) consist of a standard PV module and a separated heat absorber. The aim of such devices is to generate heat and electricity simultaneously in a compact unit. Justified by the fact that standard PV panels are connected to a common heat exchanger, this investigation faces two major topics of a new PV...

We consider the problem of determination of a temperature field that does not cause thermal stresses in a finite hollow axisymmetric cylinder with characteristics of the material depending on two coordinates. Convective heat exchange takes place between the cylinder and the medium and the process of stationary heat transfer in the cylinder occurs a...

Numerical simulation of the thixoforming process of GH4037 nickel-based superalloy disc-shaped components is performed using DEFORM-3D software (Defrom V11). The complete numerical simulation process includes three stages in this work: heat transfer to air, heat transfer on the ejector rod, and the semi-solid thixoforming process. The effects of bi...

The purpose of this study is to generate some experimental data associated with the thermal heat exchange between an oil jet flow and a rotating gear. To this end, a specific test bench was designed. The principle of this test bench is to inject oil heated to a temperature of about 80 °C onto a rotating test sample at ambient temperature. Temperatu...

Egypt suffering in the present time from increase of atmospheric temperatures by [4-5 degrees].If the humans can handle this by using air conditions and fans and stay in home or office, but the engines in [cars-industrials] can't leave their service position. Our technicians start to wash the radiator with water to increase cooling efficiency. Some...

For gas turbines, the energy of the fluid can be expressed in terms of the enthalpy change, which is almost directly related to the turbine temperature. The performance of the gas turbine can be improved by continuously improving the temperature and compression ratio. In this article, for the cooling of blades, making several radial holes has been...

This paper investigates MHD fluid flow and distribution of heat inside a filter chamber during a process of filtering particles from the fluid. A flow model of MHD viscous incompressible fluid inside a filter is studied to seek semi-analytical solutions which are analysed to find flow and heat dynamics that lead to optimal outflow (maximum filtrate...

Every simplification has the potential to add a systematic error to the measured value. Sometimes, the addition does not render the measurement useless. In the case of oil well flow measurements based on the thermal properties of the fluid in the well, the addition of a systematic error of up to 20% can occur if the variation in the internal energy...

This study aims to investigate the impact of body heat loss on the thermal and aerodynamic conditions in a whole-body cryotherapy chamber. The underlying hypothesis is that the heat generated by the human body alters the thermal and aerodynamic environment inside the cabin. A numerical study was conducted to test this hypothesis and analyze the the...

In view of the high specific removal energy, high heat generation rate, low heat transfer efficiency, and easy-to-produce local high-temperature and grinding burns, new macro-structured grinding wheel forms were proposed, namely, large spiral angle grooved grinding wheels (LSG-GW, β>85°) and large spiral angle flow disturbance grooved wheels (LSDG-...

The dynamic modeling of heat transfer in bio-based materials is a challenging endeavor due to the wide variety of factors that influence the thermal behavior of bio-based materials with Phase Change Materials (PCMs). There are a lot of factors related to heat transfer with phase change that are sometimes beyond our control. Since the phase change r...

Spectral methods for the solution of a boundary value problem of an ordinary differential equation are reviewed with particular emphasis laid on pseudo-spectral collocation method. The pseudo-collocation method is then used to solve the one dimensional bio-heat equation with metabolic heat generation in cylindrical coordinates applied to human tiss...

The thermal conductivity of graphene is in the range of 3000–5000 W m⁻¹ K⁻¹, showing great potential in high thermal conductivity devices. However, the thermal conductivity of graphene-reinforced polymer is typically lower than 10 W m⁻¹ K⁻¹, which is far from theoretical expectations. To understand the mechanisms of heat transfer in graphene-reinfo...

The lithosphere‐asthenosphere boundary and mid‐lithospheric discontinuities are primary attributes of the upper mantle. The Pannonian region is an extensional sedimentary basin enclosed by collisional orogens. Here, we estimate the negative phase depth of S‐to‐P receiver functions to image the lithospheric thickness and other discontinuities with h...

Bu çalışmada literatüründe hakkında oldukça sınırlı çalışma olan elektrosprey soğutmada, elektrik geriliminin, soğutucu akışkan debisinin ve nozul çapının ısı alıcı üzerindeki ısı transfer performansına etkileri araştırılmıştır. Deneyler 20 mm ısı alıcı-nozul arası mesafede ve 1,88-2,02-2,19-2,4-2,59-2,75-2,99-3,2 kW/m2 ısı akılarında gerçekleştiri...

Finite element method (FEM) is an efficient numerical tool for the solution of partial differential equations (PDEs). It is one of the most general methods when compared to other numerical techniques. PDEs posed in a variational form over a given space, say a Hilbert space, are better numerically handled with the FEM. The FEM algorithm is used in v...

Several primary mechanisms are less utilized in engineering and recent technologies due to unsustainable heating. The impact of viscous dissipation and Joule heating is very important to examine current density and heat rate across a magnetized cylinder. The key objective of this examination was to insulate excessive heat around the cylinder. The p...

In this paper, using a dynamic RC model for heat transfer in a room on the ground floor, the three-time constants of heat transfer that corresponds to the different parts of a weekend cottage on Kopaonik were determined. The model considered the heat accumulation and losses through the facade wall, floor and interior part of the room. The time cons...

Fluidized bed reactors are essential in a wide range of industrial applications, encompassing processes such as Fischer–Tropsch synthesis and catalytic cracking. The optimization of performance and reduction in energy consumption in these reactors necessitate the use of efficient heat transfer mechanisms. The present work examines the considerable...