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Number of results: 5
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Abstract

The paper presents analytical and numerical model calculation results of the temperature distribution along the thermal flow meter. Results show a very good conformity between numerical and analytical model. Apart from the calculation results the experimental investigations are presented. The author performed the test where a temperature of duct wall surface was measured. Therelation between mass flow rate in terms of the duct surface temperature difference was developed.
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Authors and Affiliations

Artur Cebula
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Abstract

The paper presents heat transfer calculation results concerning a control rod of Forsmark Nuclear Power Plant (NPP). The part of the control rod, which is the object of interest, is surrounded by a mixing region of hot and cold flows and, as a consequence, is subjected to thermal fluctuations. The paper describes a numerical test which validates the method based on the solution of the inverse heat conduction problem (IHCP). The comparison of the results achieved by two methods, computational fluid dynamics (CFD) simulations and IHCP, including a description of the IHCP method used in the calculation process, shows a very good agreement between the methods.
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Authors and Affiliations

Jan Taler
Artur Cebula
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Abstract

In this paper a mathematical model enabling the analysis of the heat-flow phenomena occurring in the waterwalls of the combustion chambers of the boilers for supercritical parameters is proposed. It is a one-dimensional model with distributed parameters based on the solution of equations describing the conservation laws of mass, momentum, and energy. The purpose of the numerical calculations is to determine the distributions of the fluid enthalpy and the temperature of the waterwall pipes. This temperature should not exceed the calculation temperature for particular category of steel. The derived differential equations are solved using two methods: with the use of the implicit difference scheme, in which the mesh with regular nodes was applied, and using the Runge-Kutta method. The temperature distribution of the waterwall pipes is determined using the CFD. All thermophysical properties of the fluid and waterwall pipes are computed in real-time. The time-spatial heat transfer coefficient distribution is also computed in the on-line mode. The heat calculations for the combustion chamber are carried out with the use of the zone method, thus the thermal load distribution of the waterwalls is known. The time needed for the computations is of great importance when taking into consideration calculations carried out in the on-line mode. A correctly solved one-dimensional model ensures the appropriately short computational time.

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Authors and Affiliations

Wiesław Zima
Sławomir Grądziel
Artur Cebula
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Abstract

This paper presents a method for determining the temperature distribution in the cross-section of waterwall tubes connected by fins using an in-house numerical algorithm prepared in the MATLAB environment, based on differential equations with separable variables. In order to verify the correctness of the algorithm operation, the temperature values obtained from it, determined for the frontal area of the tubes, are compared with the temperatures found in the Ansys Fluent environment and those measured on the test stand. A system corresponding to a fragment of the combustion chamber wall of a supercritical steam boiler was selected to perform the analysis. The system consists of three tubes connected by fins. The temperature distributions in the cross-sections of the tubes were compared for the case when each of the tubes was heated on one side with the same heat flux and when the heat flux falling on the central tube was by 50% higher than the heat flux incident on the neighbouring tubes. Experimental verification was carried out on a stand equipped with three vertical tubes connected by fins, heated on one side by infrared radiators.
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Authors and Affiliations

Marek Majdak
1
Sławomir Grądziel
2
Wiesław Zima
2
Artur Cebula
2
Monika Rerak
2
Ewa Kozak-Jagieła
2

  1. Majdak, Marek: Cracow University of Technology, Faculty of Environmental Engineeringand Energy, Warszawska 24, 31-155 Kraków, Poland
  2. Cracow University of Technology, Faculty of Environmental Engineeringand Energy, Warszawska 24, 31-155 Kraków, Poland
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Abstract

This paper presents a test stand for the capture of CO2 from flue gases arising due to firing pulverised hard coal. The stand, financed from the 2014–2021 Norway Grants, is installed at a Polish power plant. The innovation of the proposed CO2 capture method, developed by the Norwegian partner in the project (SINTEF Industry), lies in the use of activated carbon in the process of temperature swing adsorption in a moving bed. The paper also presents preliminary results of numerical simulations performed using the General PROcess Modelling System (gPROMS) software. The simulations concerned the operation of a supercritical power unit combined with a system for capturing CO2 from flue gases. Transient operation of the system was analysed, assuming rapid changes in the power unit load. Special attention was paid to the CO2 capture process energy consumption at an increase in load by 5% of the power unit nominal capacity in 30 s. It is found that the proposed CO2 capture method “keeps up” with such rapid load changes at the method energy consumption smaller than 2 MJ/kg CO2.
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Authors and Affiliations

Sławomir Grądziel
1
Wiesław Zima
1
Artur Cebula
1
Monika Rerak
1
Ewa Kozak-Jagieła
1
Adam Pawłowski
1
Richard Blom
2
Lars Olof Nord
3
Vidar Torarin Skjervold
3
Iorgia Mondino
2

  1. Cracow University of Technology, Faculty of Environmental Engineeringand Energy, Warszawska 24, 31-155 Kraków, Poland
  2. SINTEF Industry, P.O. Box 124 Blindern, N0314 Oslo, Norway
  3. Norwegian University of Science and Technology, Department of Energyand Process Engineering, P.O. Box 8900, NO-7491 Trondheim, Norway

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