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1

Unsteady MHD 2- liquid heat transmission plasma flow in a rotating system with Hall Currents via permeable conducting plates

Raju T. Linga, Rao Bonu Venkata

International Journal of Applied Mechanics and Engineering

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2026

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Vol. 31, no. 1

137--164

EN

A theoretical study is conducted on an unstable magneto hydrodynamic two-phase heat transfer plasma flow within a horizontal channel, which is bounded by conducting and permeable plates. The analysis takes place in a rotating frame of reference and includes the effect of Hall current. The regular perturbation approach determines the governing differential equations under the adopted conditions. The velocity and thermal distribution are visually resolved, and a parametric study is executed. Two fluid flow and heat transmission factors are affected by governing characteristics like as the porosity parameter, Hall parameter, Hartmann number, Taylor’s number, height, electrical, viscosity, and thermal conductivity ratios.

2

Analysis of fractional natural convection heat transfer of G0-MOS2 engine oil in an oscillating vertical cylinder

Elkott I., Abdel Latif M. S., El-Kalla I. L., Abdel Kader A. H.

International Journal of Applied Mechanics and Engineering

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2026

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Vol. 31, no. 1

16--26

EN

In this paper, We show using Laplace and finite Hankel transforms, how to derive exact solutions for the velocity and temperature profiles of a system of fractional differential equations which describe heat transfer by natural convection of a specific engine oil with molybdenum disulphide and graphene oxide (MoS2 + GO) hybrid nano-composites in oscillating vertical cylinder. A few figures are used to illustrate how the temperature profile and the Nusselt number are affected by the Prandtl number and the order of the fractional derivative.

3

Numerical modeling of the solidification process in a mold-casting system with a gaseous gap

Węgrzyn-Skrzypczak Ewa, Skrzypczak Tomasz, Sowa Leszek

Journal of Applied Mathematics and Computational Mechanics

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2025

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Vol. 24, nr 1

69--77

EN

The paper focuses on the numerical modeling of the solidification process, with particular emphasis on the key physical phenomenon of heat transfer within the mold-casting system. This process is influenced by the presence of a gaseous gap, which introduces thermal resistance at the interface and affects the solidification rate. The numerical model is developed using the Finite Element Method (FEM), with separate spatial discretizations for both the casting and the mold. Additionally, the thermal expansion of these regions, caused by temperature-dependent volume changes, is accounted for. The model utilizes two distinct meshes to compute the evolving temperature fields. Heat exchange between the cast- ing and the mold is governed by boundary conditions linking the two regions. The solution is computed incrementally, with each region being solved independently at each time step. This paper describes the main assumptions of the mathematical and numerical models and presents the comparison of results of three simulation variants carried out using a custom- -built program.

4

Effects of a magnetic field on circulation in an advanced inclined isothermal sectional surface with mass and heat transfer

Raj M. Sundar, Nagarajan G., Rajaraman R., Saravanan B., Muthucumaraswamy R.

International Journal of Applied Mechanics and Engineering

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2025

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Vol. 30, no. 2

161--176

EN

The purpose of this study is to investigate the influence of an external magnetic field on heat and mass distribution across a moving isothermal sectional surface. The temperature is elevated to ( ) of the plate. The proximity intensity is increased to the concentration of the plate ( ). The study addresses a range of physical factors, including time, velocity profile, temperature, and intensity, as well as thermal Grashof number (Tg), mass Grashof number (Tm), Schmidt number (Sc), and Prandtl number (Pr). The dimensionless equations are addressed using both the Laplace-transform technique and the finite difference method, which is used to analyze the energy, momentum, and concentration equations. The results are illustrated through graphical representations, and the tabular manner to showcase various flow parameters. The results indicate that the velocity increases proportionally with changes in (Tg) and (Tm). As the angle (α) rises, the velocity shows a clear incremental pattern when the magnetic field strength decreases. Local skin friction correlates positively with the angle (α), Sc, and Pr, and negatively with Gr, Gc, and time. The study includes a Nusselt number table for various parameters corresponding to an increase in the Prandtl number, as well as the Sherwood number for different components as the Schmidt number escalates. This work helps us learn more about the complicated interactions between magnetic fields and fluid movement, which is useful for many engineering and science projects.

5

Improving heat transfer of air-cooled cylinders with fins with slits

Nakashima Kohei, Yoshida Masao, Nishii Kento, Yoshida Ayanari, Okura Nobuyuki

Combustion Engines

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2025

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R. 64, nr 3

141--146

EN

In finned cylinders with slits around the cooling fin circumference, thermocouples were attached at three positions in the radial direction on the surface of the fin, and fin surface temperatures were measured by rotating the cylinders relative to the flow direction in a wind tunnel to change the angular position of the attached thermocouples. The temperature distribution around the fin circumference and the average heat transfer coefficient were then investigated at air velocities from 20 km/h (5.6 m/s) to 60 km/h (16.7 m/s). Results indicated that, compared with fins without slits, fins with slits, either aligned or offset, decreased fin surface temperatures and increased the heat transfer coefficient. The fins with slits also resulted in a more uniform circumferential temperature at the fin root at a lower air velocity, but not at a higher air velocity, compared to fins without slits.

6

Effects of chemical reactions in the presence of temperature variations and isothermal mass diffusion over an inclined plate

Nagarajan G., Raj M. Sundar, Venkatesan J., Jeyanthi L., Muthucumaraswamy R.

International Journal of Applied Mechanics and Engineering

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2024

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Vol. 29, no. 2

104--117

EN

A detailed study of the erratic circulation around an unbounded inclined plate under fluctuating temperature and isothermal mass dispersion was carried out with a chemical reaction. This work concentrated on the harmonic inclination of the plate in its plane, and the accurate solution of the non-dimensional governing formulations was made possible by the Laplace transform technique. To evaluate their impact on different profiles, the investigation examined a variety of physical factors, including phase inclination, chemical response variable, Schmidt number, thermal Grashof number, mass Grashof number, and duration. Notably, the speed per second increased with decreasing phase angle. Furthermore, a decrease in either the thermal radiation variable or the chemical response variable induced an increase in velocity.

7

A practical alternative model to approximate a fully two dimensional thermally non-symmetric annular fin efficiency

Benallel Hadjira, Bouaziz Mohamed Najib

International Journal of Applied Mechanics and Engineering

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2024

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Vol. 29, no. 4

61--77

EN

A new practical and approximate two-dimensional is developed to take into account the thermally non-symmetric annular tick fin model and to avoid the laborious solution involving additional calculation of infinite eigenvalues. Using the perturbation method, a representative with satisfactory accuracy model is produced. For convenience, the developed analytical model is used here, in its numerical version, to show its validity and for an investigation of the effects of significant parameters on the efficiency of the annular fin. The same outcomes are obtained when the 1-D and present model are compared using the corresponding values. Then, different and easier calculations are carried out to illustrate the impact of the three primary parameters- the thickness, the asymmetry ratio, and the end Biot number- that define the annular fins. It is shown that, for thick or thin fins, the unequal convection heat coefficients of the the two surfaces have a significant impact on the distribution temperature and fin efficiency. With high thermal conductivity thick fins can increase cooling efficiency. For thicker fins, a significant impact of the end Biot on fin efficiency is observed.

8

Energy and economic analysis of material and construction solutions for multi-family building external partitions – a case study

Jura Jakub, Pawlik Piotr

Archives of Engineering Knowledge

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2024

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T. 10, Nr 1

1--5

EN

The article provides an overview of energy consumption in buildings, particularly residential ones. Key aspects of building design are discussed, such as the selection of construction technologies and materials, which impact the building’s energy efficiency and operational costs. The thermal insulation requirements, regulated by legal provisions, are presented, setting the maximum allowable values for thermal transmittance and the consumption of non-renewable primary energy by the building. The research section includes analyses for a multi-family building designed to be located in Czestochowa, highlighting different variants for external walls, flat roofs, ceilings over unheated basements, as well as window and door joinery, all aimed at achieving optimal energy performance. The conducted analyses considered thermal, moisture, and economic para-meters. For each building partition analysed, three variants were examined, all of which complied with the current Technical Requirements. When selecting materials for the building partitions, factors such as low costs, material availability, and ease of installation were prioritized to minimize errors. Risks related to water vapor condensation were also analysed. The chosen variants, through the selection of materials and construction techniques, allow for achieving high energy efficiency in the building while optimizing construction and operational costs, thereby improving occupant comfort and reducing CO2 emissions.

9

Innovative catalytic streamlined carriers with triangular channels

Sindera Katarzyna, Korpyś Mateusz, Iwaniszyn Marzena, Gancarczyk Anna, Suwak Mikołaj, Kołodziej Andrzej

Chemical and Process Engineering : New Frontiers

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2023

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Vol. 44, nr 3

art. no. e31

EN

The paper presents research on a novel catalytic carrier, called “streamlined structure”. The carrier is a short-channel monolith, whose walls are shaped like an airfoil profile (airplane wing). The intention is heat transfer intensification coupled with moderate flow resistance. Streamlined structures with triangular channel cross-section, 3mm, 6mm and 12 mm long, were designed and manufactured using the SLM (Selective Laser Melting) technique for the experimental verification. The structures were modelled using the CFD (Computational Fluid Dynamics) software to derive flow resistance, flow patterns and heat transfer coefficients. Compared to classic structures, CFD showed intensified heat transfer, combined with acceptable flow resistance increase. CFD proved the lack of an inlet vortex, which in classical structures seriously reduces the intensity of heat transfer. The CFD has been satisfactorily verified by experiments.

10

Effect of POCS geometry on fluid flow and heat transfer

Iwaniszyn Marzena

Chemical and Process Engineering : New Frontiers

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2023

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Vol. 44, nr 3

art. no. e30

EN

Hydraulic and transport properties of periodic open cellular structures (POCS) based on cubic cells were investigated numerically. Different cell and strut dimensions, as well as strut shapes, were examined. Numerical results of heat transfer and flow resistance, as well as modeled morphological parameters were verified experimentally. The most beneficial properties were obtained for the POCS with convex triangular, circular and hexagonal struts.

11

Enhancement of heat transfer in helical coil heat exchangers using nano-fluids

Parveez Malik, Hanief Mohammad

Chemical and Process Engineering

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2022

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Vol. 43, nr 2

279--283

EN

Investigation for heat transfer behaviour of Al2O3 and CuO nano-fluid in helical coil heat exchangers was carried out in this study. The thermo-physical properties of the fluids have temperature dependent nature. The main emphasis was to depict the influence of nano-particle concentration by volume on the characteristics of temperature, rate of heat transfer and heat transfer coefficients (convective). In order to enhance efficiency, density and thermal conductivity are considered to be the most important variables. In comparison to water and for equal flow rate, the rate of heat transfer of nano-fluid increases conspicuously. Efficiency of the helical coil heat exchanger increased by 38.80%.

12

Simulations of Heat Transfer through Multilayer Protective Clothing Exposed to Flame

Puszkarz Adam K., Machnowski Waldemar

Autex Research Journal

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2022

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Vol. 22, no. 3

298--304

EN

In this paper, the safety and thermal comfort of protective clothing used by firefighters was analyzed. Three-dimensional geometry and morphology models of real multilayer assemblies used in thermal protective clothing were mapped by selected Computer-Aided Design (CAD) software. In the designed assembly models, different scales of the resolution were used for the particular layers – a homogenization for nonwoven fabrics model and designing the geometry of the individual yarns in the model of woven fabrics. Then, the finite volume method to simulate heat transfer through the assemblies caused by their exposure to the flame was applied. Finally, the simulation results with experimental measurements conducted according to the EN ISO 9151 were compared. Based on both the experimental and simulation results, parameters describing the tested clothing protective features directly affecting the firefighter’s safety were determined. As a result of the experiment and simulations, comparable values of these parameters were determined, which could show that used methods are an efficient tool in studying the thermal properties of multilayer protective clothing.

13

Numerical Investigation of Heat Transfer in Garment Air Gap

Zhang Yijie, Jia Juhong

Autex Research Journal

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2022

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Vol. 22, no. 1

89--95

EN

This article aimed to study the characteristics and mechanisms of 3D heat transfer through clothing involving the air gap. A three-dimensional finite volume method is used to obtain the coupled conductive, convective, and radiative heat transfer in a body-air-cloth microclimate system. The flow contours and characteristics of temperature, heat flux, and velocity have been obtained. The reason for the high flux and temperature regions was analyzed. Computational results show that the coupled effect of the air gap and the airflow between the skin and garment strongly influences the temperature and heat flux distribution. There are several high-temperature regions on the clothing and high heat flux regions on the body skin because the conductive heat flux can cross through the narrow air gap and reach the cloth surface easily. The high-speed cooling airflow brings about high forced convective heat flux, which will result in the temperature increase on the upper cloth surface. The radiative heat flux has a strong correlation with the temperature gradient between the body and clothing. But its proportion in the total heat flux is relatively small.

14

Investigation of Heat Transfer in Seersucker Woven Fabrics using Thermographic Method

Zgórniak P., Matusiak M., Frącczak L.

Autex Research Journal

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2022

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Vol. 22, no. 3

282--289

EN

Seersucker woven fabrics are characterized by unconventional structure and surface topography. Their crucial feature is a three-dimensional puckered effect created by puckered and flat strips occurring in the warp direction. Such a structure influences the basic mechanical and utility properties of the fabrics. The aim of the presented work is to analyze the heat transfer in seersucker woven fabrics. Measurement of the heat transfer was done using an infrared camera. Thermograms created for different seersucker woven fabrics, as well as for flat and puckered areas of the seersucker woven fabrics, were analyzed from the aspect of heat exchange between a hot plate and the environment through the fabric. The results showed that the linear density of the weft yarn influences the heat transfer through seersucker woven fabrics. The results allowed the comparison of the heat transfer through the seersucker woven fabrics in both flat and puckered areas. The investigations performed confirmed that the thermographic method can be applied to complex analyses of the heat transfer through seersucker woven fabrics.

15

Conductive Heat Transfer Prediction of Plain Socks in Wet State

Mansoor Tariq, Hes Lubos, Khalil Amany, Militky Jiri, Tunak Maros, Bajzik Vladimir, Kyosev Yordan

Autex Research Journal

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2022

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Vol. 22, no. 4

391--403

EN

In this study, an algebraic model and its experimental verification was carried out to investigate the effect of moisture content on the heat loss that takes place due to conduction of sock fabrics. The results show that increasing moisture content in the studied socks caused a significant increase in their conductive heat loss. Plain knitted socks with different fiber composition were wetted to a saturated level, and then their moisture content was reduced stepwise. When achieving the required moisture content, the socks samples were characterized by the Alambeta testing instrument for heat transfer. Three different existing modified mathematical models for the thermal conductivity of wet fabrics were used for predicting thermal resistance of socks under wet conditions. The results from both ways are in very good agreement for all the socks at a 95% confidence level. In the above-mentioned models, the prediction of thermal resistance presents newly a combined effect of the real filling coefficient and thermal conductivity of the so-called “wet” polymers instead of dry polymers. With these modifications, the used models predicted the thermal resistance at different moisture levels. Predicted thermal resistance is converted into heat transfer (due to conduction) with a significantly high coefficient of correlation.

16

Dimethicone-assisted laser cutting of CFRP hole

Chen Xinghua, Li Wenyuan, Rong Youmin, Zhang Guojun, Chen Long, Huang Yu

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e182, 2022

EN

When cutting carbon fiber reinforced polymer (CFRP) plate with UV nanosecond laser, the surface heat-affected zone (HAZ) such as fiber exposure and carbonization will occur, which affects the surface morphology and properties of CFRP. In this paper, dimethicone-assisted laser cutting technology is proposed. Compared with laser direct cutting, we found that dimethicone-assisted cutting has obvious advantages in cutting CFRP. Due to the heat transfer inhibition of dimethicone, there is almost no burning phenomenon of matrix materials. The orthogonal test method was used to study the three key process parameters (laser scanning speed, repetition frequency and concentric circle spacing) of dimethicone-assisted laser cutting CFRP. It is concluded that the HAZ width can be controlled at 38.70–54.77 μm with dimethicone, compared with the traditional direct machining (HAZ width: 109.64–439.13 μm). Under the optimal cutting parameters of laser scanning speed of 500 mm/s, repetition rate of 50 kHz and concentric circle spacing of 0.04 mm, the minimum HAZ is 38.70 μm, which is reduced by 85.89% (the HAZ width of laser direct machining is 274.37 μm).

17

Influence of the position of the electrical contact on the size of the temperature distribution

Medveď Dušan, Zbojovský Ján

Przegląd Elektrotechniczny

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2021

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R. 97, nr 12

230--233

EN

This paper deals with the investigation of temperature field distribution around the high-current electric contact. The analyses of temperature field were realised in simulation environment ANSYS and provide better understanding why the electrical contact position influences the heat dissipation. Material of electrical contact was copper, aluminium, brass and non-standard material for power devices, silver. Results were compared and the conclusion with the recommendation were stated in the end of this paper.

PL

Artykuł dotyczy badania rozkładu pola temperatury wokół wysokoprądowego styku elektrycznego. Analizy pola temperatury zostały przeprowadzone w środowisku symulacyjnym ANSYS i pozwalają lepiej zrozumieć, dlaczego położenie styku elektrycznego wpływa na rozpraszanie ciepła. Materiałem styku elektrycznego była miedź, aluminium, mosiądz oraz niestandardowy materiał do urządzeń zasilających, srebro.

18

Effects of pressure gradient on convective heat transfer in a boundary layer flow of a Maxwell fluid past a stretching sheet

Kashif A. N., Salah F., Sankar D. S., Izyan M. D. N., Viswanathan K. K.

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 3

104--118

EN

The pressure gradient term plays a vital role in convective heat transfer in the boundary layer flow of a Maxwell fluid over a stretching sheet. The importance of the effects of the term can be monitored by developing Maxwell’s equation of momentum and energy with the pressure gradient term. To achieve this goal, an approximation technique, i.e. Homotopy Perturbation Method (HPM) is employed with an application of algorithms of Adams Method (AM) and Gear Method (GM). With this approximation method we can study the effects of the pressure gradient [...], Deborah number [...], the ratio of the free stream velocity parameter to the stretching sheet parameter [...] and Prandtl number [...] on both the momentum and thermal boundary layer thicknesses. The results have been compared in the absence and presence of the pressure gradient term m. It has an impact of thinning of the momentum and boundary layer thickness for non-zero values of the pressure gradient. The convergence of the system has been taken into account for the stretching sheet parameter. The result of the system indicates the significant thinning of the momentum and thermal boundary layer thickness in velocity and temperature profiles.

19

Projektowanie drzwi przeciwpożarowych - propozycja metody

Kreft Dominik

Izolacje

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2020

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R. 25, nr 7/8

44--46, 48

PL

W artykule opisano propozycję projektowania jednoskrzydłowych drzwi przeciwpożarowych w oparciu o normy PN-EN 1363 oraz PN-EN 1634. Wykorzystano podstawowe równania przenikania ciepła, wynikające z prawa Pecleta, dotyczącego tego rodzaju przenoszenia ciepła. Zaprezentowano wyniki badań statystycznych zebranych na podstawie przeprowadzonych badań ogniowych w certyfikowanych laboratoriach.

EN

The paper presents the method of design of single leaf fire resistant doors according to PN-EN 1363 and PN-EN 1634 standards. Basic heat transfer equations derived from the Peclet formula have been used. Statistical data resulting from fire resistance tests conducted by certified laboratories have been presented.

20

Outcome of nanofluid flow containing arbitrary shape nanoparticles induced by a permeable stretching sheet

Sarkar A., Kundu P. K.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 2

142--156

EN

In this work we have discussed the impact of thermal radiation on heat transfer to nanofluid flow over an unsteady permeable stretching sheet using various types of arbitrary shape nanoparticles of Copper (Cu), Silver (Ag), Alumina [...], and Titania Oxide [...] in the base fluid. Suitable transformations have been employed to build ODEs from the partial differential equations. Numerical results are therefore obtained particularly for cylindrical shape and spherical shape nanoparticles. Our analysis substantiates that the velocity and temperature profiles increases with enhanced thermal radiation parameter. Further, Nusselt number is more advanced for the nanofluid that contains cylindrical shape nanoparticles as compared to spherical shape nanoparticles.