Experimental investigation on the density-wave oscillation of high-pressure steam-water two-phase flow in vertical parallel pipes

The influences of pressure, mass velocity, inlet subcooled temperature, inlet throttle, compressible volume, heat flux and non-symmetric heat flux on the threshold, period and amplitude of density wave oscillation (DWO) in the vertical parallel pipes of a nuclear power plant were studied under the conditions of system pressure within 3-18MPa, mass flow rate within 700-1400kg/(m2&middots), inlet subcooled temperature Tsub=30-120°C, heat flux within 0-600kW/m2, and pipe diameter d=13mm. Based on the experimental investigation and dimensional analysis, the measures for preventing the DWO and a dimensionless empirical correlation for predicting the DWO's threshold were proposed for the design and operation of integrated reactor steam generator and the once-through boiler etc.