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Abstract

The production of thin-walled castings with wall thickness in the range of 1.5 to 3 mm and below requires the development of insulation

moulding sands and/or core materials. The test has been taken to develop these kind of materials. The study included a description of their

thermophysical properties. Authors described problems related to the heat flow in the casting-mould system, i.e. mathematically described

the main dependence of heat give-up during crystallization of the casting. The influence of the content of polyglicol on the thermophysical

properties of the mould with gypsum and cement binder was examined. Using the ATD method determined were the increments ΔT1 and

ΔT2 describing the temperature changes in the mould during crystallization of hypoeutectic alloy of AlSi6 and the temperature difference

between casting material and mould during the crystallization. In the considered range of technological parameters a description of the

heat flow kinetics was given.

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Authors and Affiliations

M. Cholewa
Ł. Kozakiewicz
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Abstract

Transient heat transfer is studied and compared in two plane-parallel composite walls and one EPIDIAN 53 epoxy resin wall acting as a matrix for both composites. The first of the two walls is made of carbon-epoxy composite; the other wall is made of glass-epoxy composite, both with comparable thickness of about 1 mm and the same number of carbon and glass fabric layers (four layers). The study was conducted for temperatures in the range of 20-120 °C. The results of the study of thermal diffusivity which characterizes the material as a heat conductor under transient conditions have a preliminary character. Three series of tests were conducted for each wall. Each series took about 24 h. The results from the three series were approximated using linear functions and were found between (0.7-1.35) x 10-7m2/s. In the whole range of temperature variation, the thermal diffusivity values for carbon-epoxy composite are from 1.2 to 1.5 times higher than those for the other two materials with nearly the same thermal diffusivity characteristics.
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Authors and Affiliations

Janusz Terpiłowski
Joanna Piotrowska-Woroniak
Julita Romanowska
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Abstract

The work presents a numerical investigation for the convective heat transfer of nanofluids under a laminar flow inside a straight tube. Different models applied to investigate the improvement in convective heat transfer, and Nusselt number in comparison with the experimental data. The impact of temperature dependence, temperature independence, and Brownian motion, was studied through the used models. In addition, temperature distribution and velocity field discussed through the presented models. Various concentrations of nanoparticles are used to explore the results of each equation with more precision. It was shown that achieving the solution through specific models could provide better consistency between obtained results and experimental data than the others.
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Bibliography

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Authors and Affiliations

Farqad Rasheed Saeed
1
Marwah Abdulkareem Al-Dulaimi

  1. Ministry of Science and Technology, Directorate of Materials Research, 55509 Al-Jadriya, Iraq

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