EXPERIMENTAL STUDY OF THE INFLUENCE OF FOULING ON THE HEAT TRANSFER OF A SINGLE-ROW HEAT-EXCHANGE BUNDLE OF ROUND-FINNED TUBES UNDER THE CONDITIONS OF ENHANCED FREE CONVECTION

Experimental studies and generalization of the data on heat transfer of a single-row bundle of bimetal tubes with spiral knurled aluminum fi ns and uniform annular interfi n pollution in the regime of free convection to vertical air fl ows created by an exhaust shaft of height H = 0.52–2.24 m with an adjustable fl ow area fh = 0.0087–0.1185 m² have been presented. The bundle was made of six tubes with a fi nned-surface factor φ = 21.0 and intertube pitch S₁ = 64 mm. From the measurement data, the average reduced coeffi cients of heat transfer of the bundle have been calculated; they were values of 1.26 to 5.84 W/(m₂ · ^o C) at the Reynolds numbers of (20–163)∙10³ . It has been found that pollution may lead to a substantial reduction in the transfer (up to 41%). The optimum area of the outlet hole of the exhaust shaft increases as the exhaust-shaft height grows, but decreases with pollution of the bundle.
Experimental studies and generalization of the data on heat transfer of a single-row bundle of bimetal tubes with spiral knurled aluminum fi ns and uniform annular interfi n pollution in the regime of free convection to vertical air fl ows created by an exhaust shaft of height H = 0.52–2.24 m with an adjustable fl ow area fh = 0.0087–0.1185 m² have been presented. The bundle was made of six tubes with a fi nned-surface factor φ = 21.0 and intertube pitch S₁ = 64 mm. From the measurement data, the average reduced coeffi cients of heat transfer of the bundle have been calculated; they were values of 1.26 to 5.84 W/(m₂ · ^o C) at the Reynolds numbers of (20–163)∙10³ . It has been found that pollution may lead to a substantial reduction in the transfer (up to 41%). The optimum area of the outlet hole of the exhaust shaft increases as the exhaust-shaft height grows, but decreases with pollution of the bundle.
Author:  G. S. Marshalova, A. B. Sukhotskii, D. V. Ostrovskaya, E. S. Danil′chik
Keywords:  air-cooled apparatus, pollution, enhanced free convection, exhaust shaft
Page:  46