The ability to predict void formation, void fraction and critical heat flux —CHF— in flow boiling under oscillatory flow and vibration conditions is important to the safety technology of nuclear reactor during earthquake. In the present study, the onset of nucleate boiling —ONB— and CHF on saturated flow boiling under vibration conditions were investigated experimentally.
Steady state experiments were conducted using a copper thin-film and saturated and subcooled water at 0.1 MPa. The liquid velocity was 0.25, 1.38, 3.20 and 4.07 m/s, respectively; the liquid subcooling was 0 K and 20 K. A heater was made of a printed circuit board. A test section was a rectangular flow channel of 10 mm width and 10 mm height. The test heater was heated by Joule heating of d.c. current from a low-voltage high-current stabilizer. The heating rate of the heater was determined from supplied current and voltage. The temperature of the heater was obtained by referring to the measured electric resistance. The test section was arranged for horizontal position facing upward and for vertical position, respectively. For the vibration condition, the test section was set on a vibration table. The ONB was decided as an occurrence of the first boiling bubble. The critical heat flux was determined as that immediately before the heating surface physically burned-out.
The CHF on saturated flow boiling under vibration conditions were investigated experimentally.
