Use of the Schlieren Method to the Convection Analysis in the Steel Charge of Mixed Porosity / Wykorzystanie Metody Schlierena Do Analizy Zjawiska Konwekcji W Przypadku Wsadu Stalowego O Porowatości Mieszanej
The paper presents experimental studies devoted to the convection phenomenon within the steel charge of mixed porosity. Such charges constitute bundles of hollow long elements such as pipes or rectangular sections which are heat treated. A significant portion of the gas phase in the volume of the charge makes that natural convection of the gas occurring within the individual elements may have an effect on the course of heating. To the tests the Schlieren method was used which is one of the optical visualization methods applied to the analysis of the flow phenomena in the transparent and non luminous media such as air or water. The tested samples have the form of porous charge beds made from pipes and rectangular profiles. During the experiments the samples were heating up for the constant heat flux rate. The direction of flux was vertical, from the bottom to the top.
 R. Wyczółkowski, Classification and characterization of porous charges found in the industrial heat treatment practice. Metallurgical Metallurgist-News 79, 877-879 (2012).
 R. Wyczółkowski, Analysis of the Rayleigh number in the area of steel rectangular sections in the conditions of steady and unsteady heat flow. Civil and Environmental Engineering Reports - CEER 14, 3, 107-118 (2014).
 P.K. Panigrahri, K. Muralidhar, Imaging Heat and Mass Transfer Processes Visualization and Analysis. Springer Science, New York 2013.
 G.S. Settles, Schlieren and Shadowgraph Imaging in the Great Outdoors; Proceedings of the 2nd Pacific Symposium on Flow Visualization and Image Processing, May 16-19, 1999, Honolulu, USA.
 T.R. Fodemskied, Thermal measurements, part II.WNT, Warszawa 2001 (in polish).
 W. Hauf, U. Grigull: Optical methods in heat transfer. In Advances in Heat Transfer vol. 6, J.P. Hartnett and T.F. Irvine eds. Academic Press, New York 1970.
 C.C. Ting, S.J. Wu, J.S. Huang, H.D. Lin, Y.B. Luo, The improvement of color Schlieren technique by using an LCD projector. AASRC/CCAS Joint Conference, Taichung, December, 2004.
 U.Girgull, W. Hauf: Natural Convection in Horizontal Cylindrical Annuli. Proceedings of 3rd International Heat Transfer Conference 2, 182-195 (1966).
 Y. Yaluria, Natural Convection - Heat and Mass Transfer. Pergamon Press, Oxford, New York 1980.
 T.H. Kuehn, R. J. Goldstein, An Experimental and Theoretical Study of Natural Convection in the Annulus between Horizontal Concentric Cylinder. Journal of Fluid Mechanics. 75, 695-719 (1976).
 J. Lis, Experimental Investigation of Natural Convection Heat Transfer in Simple and Obstructed Horizontal Annuli. Proceedings of the 3rd International Heat Transfer Conference. Paper 2, 61, 196-204 (1966).
 R.E. Powe, C.T. Carley, E .H. Bishhop, Free Convection Flow Patterns in Cylindrical Annuli. Transactions of the ASME. Journal of Heat Transfer 1969, August, pp. 310-314.
 B. Farouk, S.J. Güceri: Laminar and Turbulent Natural Convection in the Annulus between Horizolnat Concentric Cylinders. Transaction of ASME. Journal of Heat Transfer 104, 631-636 (1982).
 T.S. Lee, Numerical Experiments With Laminar Convection between Concentric and Eccentric Heated Rotating Cylinders. Numerical Heat Transfer 6, 4-A, 203-218 (1984).
 S. Wyczółkowski, Modeling of steady free convection in two-dimensional enclosed space. Seria Monografie 52, Czestochowa University of Technology, Czestochowa 1998 (in polish).