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Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Volumes per year:

various

Year 2006

DOI: 10.1615/IHTC13.p15

HEAT TRANSFER IN MIXED CONVECTION OF SUPERHEATED STEAM FLOWING UPWARD IN TUBES

Yuzhou Chen
China Institute of Atomic Energy, Beijing, China

Yulong Mao
China Institute of Atomic Energy, Beijing, China

Chubsheng Yang
China Institute of Atomic Energy, Beijing, China

ABSTRACT

An experiment of heat transfer to superheated steam has been carried out in vertical tubes of D = 6, 12 and 20 mm with heated upward flow, covering the range of pressure of 0.2 to 6.2 MPa, Reynolds number of 3000 to 115000 and Grashof number of up to 1.2×10⁸. The mixed convection exhibits a substantial impairment in heat transfer due to the effect of buoyancy. The onset of impairment is strongly dependent on the pressure and diameter, and for higher pressure and/or larger diameter it could occur at rather high Reynolds number (>24000). Due to lack of appropriate prediction method, a modified correlation is attempted for calculation of the heat transfer in mixed convection.