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ISSN Online: 2377-424X

ISBN Print: 0-89116-909-1

International Heat Transfer Conference 9
August, 19-24, 1990 , Jerusalem, Israel

GRAETZ PROBLEM WITH MAXIMUM DENSITY EFFECTS IN CONVECTIVELY COOLED HORIZONTAL WATER PIPES - HEAT TRANSFER CHARACTERISTICS PRECEDING THE ONSET OF ICE FORMATION

Get access (open in a dialog) DOI: 10.1615/IHTC9.2610
pages 321-326

摘要

The maximum density effects on Graetz problem (thermal entrance region problem) in horizontal water pipes with convective boundary condition in the ice-free zone are studied theoretically to clarify the role of natural convection effects in ice formation problems in water pipes.
The developing secondary flow and temperature fields, bulk temperature, wall temperature, pipe center temperature, and local heat transfer results are presented for three cases with uniform entrance water temperature T0 = 6°C, ambient air temperature T = −2 and −10°C, Rayleigh number Ra = 0,5 × 104, 105 and 5 × 105, and Biot number Bi = 0.5 and 5 to study the inversion phenomenon before the onset of ice formation. The results of the present study suggest that the inversion process caused by the maximum density effect of water has significant implications for the subsequent ice formation in horizontal water pipes with laminar flow. The practical implications of the inversion process (natural convection and maximum density effects) on steady state ice formation in horizontal water pipes with laminar flow are pointed out.