Abstract
Boiling heat transfer and enhancement of critical heat flux (CHF) of high-liquid-subcooling and high velocity water flow in a shorter and circular tube were investigated experimentally. The experiments were conducted in a range of velocity of water flow of 0.95m/s to 9.7 m/s and liquid subcooling of 20K to 50K. A test heater was made of thick copper block with 5mm internal diameter and 120 mm external diameter. The length of heater was 20mm : L/D was 4. The present experimental results showed that heat transfer coefficient and CHF increased as mass flux increased. The enhancement was caused by effect on shorter L/D, i.e., thermal entrance region effect. The enhancement of critical heat flux up to 10MW/m^2 was achieved in the present experiments. The boiling heat transfer characteristic was compared with Chen's correlation for conventional channel.
