Enhanced Transient Heat Transfer Caused by Partially Twisted Heater in Various Gases

抄録

Forced convection transient heat transfer coefficients due to exponentially increasing heat input were measured for helium gas and carbon dioxide gas flowing over a partially twisted heater. A partially twisted platinum plate with a thickness of 0.1 mm was heated by electric current and used as the test heater. The gas flow velocities ranged from 1 to 10 m/s, the gas temperatures ranged from 313 K to 353 K, and the periods of heat generation rate ranged from 46 ms to 17 s. The study showed a strong enhancement in the heat transfer coefficient for the twisted heater over that of a plate heater. Compared with those of a plate heater, the heat transfer coefficients of helium gas and carbon dioxide gas were enhanced 13 % and 28 %, respectively. Correlations for quasi-steady state heat transfer of the twisted heater in helium gas and carbon dioxide gas were obtained based on the experimental data.