Analysis of the occurrence of natural convection in a bed of bars in vertical temperature gradient conditions

• Autorzy: Wyczółkowski R. , Musiał D.
• Języki publikacji: EN

Abstrakty

EN

The reason for undertaking this study was to determine the possible involvement of natural convection in the global heat transfer, that occurs in the heated steel rods bed. This problem is related to the setting of the effective thermal conductivity of the bars bed. This value is one of the boundary conditions for heating modeling of steel rods bundles during heat treatment. The aim of this study was to determine for which geometry of the bed bars, there will be no free convection. To analyze the problem the Rayleigh criterion was used. It was assumed that for the value of the number Ra < 1700 convection in the bed bars does not occur. For analysis, the results of measurements of the temperature distribution in the unidirectionally heated beds of bars were used. It has been shown, that for obtained, during the test, differences of temperature between the surfaces of adjacent rods, convection can occur only when the diameter of the rod exceeds 18 mm.

Słowa kluczowe

EN

natural convection; bed of bars; porous material

PL

konwekcja naturalna; złoża prętów; materiały porowate

• Wydawca: Wydawnictwo Instytutu Maszyn Przepływowych PAN ; Komitet Termodynamiki i Spalania PAN
• Czasopismo: Archives of Thermodynamics
• Rocznik: 2013
• Tom: Vol. 34, no. 1
• Strony: 71--83
• Opis fizyczny: Bibliogr. 9 poz., il.

Twórcy

autor

Wyczółkowski R.

• Czestochowa University of Technology, Faculty of Process and Materials Engineering and Applied Physics, Department of Industrial Furnaces and Environmental Protection al. Armii Krajowej 19, 42-200 Częstochowa, Poland

autor

Musiał D.

• Czestochowa University of Technology, Faculty of Process and Materials Engineering and Applied Physics, Department of Industrial Furnaces and Environmental Protection al. Armii Krajowej 19, 42-200 Częstochowa, Poland

Bibliografia

• 1. Dobrzański L.A.: Metallic Engineering Materials.WNT,Warsaw 2004 (in Polish).
• 2. Sahay S.S., Krishnan K.: Model based optimization of continuous annealing operation for bundle of packed rods. Ironmak. Steelmak., 34( 2007), 1, 89–94.
• 3. Kaviany M.: Principles of Heat Transfer in Porous Media. Springer-Verlag, New York 1991.
• 4. Pastucha L., Otwinowski W.: Basis of Heat Transfer. Wydawnictwo Politechniki Częstochowskiej, Częstochowa 1999 (in Polish).
• 5. Wiśniewski S.: Heat Transfer. PWN, Warsaw 1979 (in Polish).
• 6. Wyczółkowski S.: Modelling of Steady Free Convection in Two-dimensional Enclosed Space. Wydawnictwo Politechniki Częstochowskiej, Częstochowa 1998 (in Polish).
• 7. Kostowski E.: Heat Flow. Wydawnictwo Politechniki Śląskiej, Gliwice 2000 (in Polish).
• 8. Raźnjević K.: Thermal Table with Diagrams. WNT, Warsaw 1966 (in Polish).
• 9. Musiał D. Heat Transfer in Steel Rods Bundle During Heating. PhD thesis, Czestochowa University of Technology. Częstochowa 2007 (in Polish).