Inlet steam quality of a top break hole on horizontal pipe

The inlet steam quality of the top break on horizontal pipe was investigated on the high pressure steam-water two-phase loop of Xi'an Jiaotong University using the γ-ray attenuation technique. The mass attenuation coefficient of the γ-ray penetrating high pressure saturated water was measured, and it is shown that such a coefficient nearly keeps constant. The correlation of the inlet steam quality to the dimensionless number h/hb was obtained. The experimental results also indicate that the break inlet pressure was reduced due to the Bernoulli effect induced by the two-phase mixture advancing into the break. Such a pressure loss was verified to be an important and sensitive parameter to determine the critical discharge mass flow rate.