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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Transient Heat Transfer for a Twisted Plate in Forced Convection Flow of Helium Gas

Get access (open in a dialog) DOI: 10.1615/IHTC15.hte.008667
pages 4331-4341

Résumé

The knowledge of heat transfer enhancement using a heater with twisted configuration is important for the high performance design of high temperature thermal systems such as very high temperature reactors (VHTR). In this study, forced convection transient heat transfer for helium at various periods of exponential increase of heat input to a twisted plate was experimentally studied. The heat generation rate, Q, was raised with exponential function, Q = Q0 exp(t/?) (where, t is time, and ? is period of heat generation rate). The transient heat transfer experimental data were measured for the periods ranged from 43 ms to 17 s and at temperatures of 303 K and 313 K under 500 kPa. The flow velocities ranged from 4 m/s to 10 m/s. The pitches of the twisted plates were 20 mm, 25 mm, and 30 mm. The surface temperature and heat flux increased exponentially with the time. It was clarified that the heat transfer coefficient approaches the quasisteady-state one for the period longer than about 1 s, and it becomes higher for the period shorter than about 1 s. The heat transfer coefficients were compared with the values of flat plate which has the same width and thickness with the twisted one. The heat transfer coefficients of twisted plate with a pitch of 20 mm are about 15% higher than those of flat plate at the quasi-steady state. Therefore, an enhancement in the heat transfer coefficient for the twisted plate was clarified. Based on the experimental data, empirical correlation of heat transfer for twisted plate was obtained.