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Number of results: 5
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Abstract

This paper analyses the experimental findings within heat transfer when heating up air, water and oil streams which are passed through a duct with internal structural packing elements in the form of metal foams. Three types of aluminum foams with different cell sizes, porosity specifications and thermal conductivities were used in the study. The test data were collected and they made it possible to establish the effect of the foam geometry, properties of fluids and flow hydrodynamic conditions on the convective heat transfer process from the heating surface to the fluid flowing by (wetting) that surface. The foam was found to be involved in heat transfer to a limited extent only. Heat is predominantly transferred directly from the duct wall to a fluid, and intensity of convective heat transfer is controlled by the wall effects. The influence of foam structural parameters, like cell size and/or porosity, becomes more clearly apparent under laminar flow conditions.
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Authors and Affiliations

Roman Dyga
Leon Troniewski
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Abstract

The inverse solution to the heat flux identification during the vertical plate cooling in air has been presented. The developed solution allowed to separate the energy absorbed by the chamber due to radiation from the convection heat losses to air. The uncertainty tests were carried out and the accuracy of the solution has been estimated at a level of 1%-5% depending on the boundary condition model. The inverse solution was obtained for the temperature measurements in the vertical plate. The stainless-steel plate was heated to 950°C and then cooled in the chamber in air only to about 30°C. The identified heat transfer coefficient was compared with the Churchill and Chu model. The solution has allowed to separate the radiation heat losses and to determine the Nusselt number values that stay in good agreement with the Churchill and Chu model for a nearly steady-state air flow for the plate temperature below 100°C.
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Authors and Affiliations

B. Hadała
1
ORCID: ORCID
Z. Malinowski
1
ORCID: ORCID
A. Gołdasz
2
ORCID: ORCID
A. Cebo-Rudnicka
1
ORCID: ORCID

  1. AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, Department of Heat Engineering and Environment Protection, al. Mickiewicza 30, 30-059 Kraków, Poland
  2. AGH University of Science and Technology, Faculty of Energy and Fuels, al. Mickiewicza 30, 30-059 Kraków, Poland
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Abstract

This study presents the behavior of a single wall carbon nanotube (SWCNT)/water nanofluid for convective laminar flow inside a straight circular pipe heated by a constant heat flux. Five volume fractions of SWCNT were used to investigate their effect on the heat transfer coefficient, Nusselt number, temperature distribution and velocity field in comparison with pure water flow. One model for each property was tested to calculate the effective thermal conductivity, effective dynamic viscosity, and effective specific heat of the SWCNT/water mixture. The models were extracted from experimental data of a previous work. The outcomes indicate that the rheological behavior of SWCNT introduces a special effect on the SWCNT/water properties, which vary with SWCNT volume fraction. The results show an improvement in the heat transfer coefficient with increasing volume fraction of nanoparticles. The velocity of SWCNT/water nanofluid increased by adding SWCNT nanoparticles, and the maximum increase was registered at 0.05% SWCNT volume fraction. The mixture temperature is increased with the axial distance of the pipe but a reduction in temperature distribution is observed with the increasing SWCNT volume fraction, which reflects the effect of thermophysical properties of the mixture.
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Authors and Affiliations

Farqad Rasheed Saeed
1
Marwah A. Jasim
2
Natheer B. Mahmood
3
Zahraa M. Jaffar
4

  1. Ministry of Science Technology, Directorate of Materials Research, 55509 Al-Jadriya, Iraq
  2. University of Baghdad, College of Engineering, Al-Jadriya,10074 Al-Jadriya, Iraq
  3. Ministry of Education, General Directorate of Baghdad Education, Karkh 2, 10072 Al-Jadriya, Iraq
  4. Al Nahrain University, College of Science, 10072 Al-Jadriya, Iraq
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Abstract

The paper is a thermodynamics analysis of the removal of any inert gas from the tank using the vapors of any liquefied petroleum gas cargo (called cargo tank gassing-up operation). For this purpose, a thermodynamic model was created which considers two boundary cases of this process. The first is a ‘piston pushing’ of inert gas using liquefied petroleum gas vapour. The second case is complete mixing of both gases and removal the mixture from the tank to the atmosphere until desired concentration or amount of liquefied petroleum gas cargo in the tank is reached. Calculations make it possible to determine the amount of a gas used to complete the operation and its loss incurred as a result of total mixing of both gases.
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Authors and Affiliations

Agnieszka Wieczorek
1

  1. Gdynia Maritime University, Morska 81–87, 81-225 Gdynia, Poland
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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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