Abstract
The two-phase flow state that originates with the transient self-evaporation of hot water on the upstream side of a water level regulating valve, decreases the flow rate capacity of the valve, and accordingly causes the water level in equipment to rise. The purposee of our research was to establish an advanced control technique to prevent an excessive rise in the water level in equipment. To do this, we proposed a feedforward water level control technique using dynamic analyses with a computer model and confirm the applicability of this technique in experiments with a model test apparatus. One feature of the new technique is that valve openings are decided according to feedforward signals that indicate the degree of self-evaporation that has occurred, and then, valve openings are corrected by feedback signals that indicate a deviation in the water level in equipment. Test results of the new feedforward control system showed that rises in the water level could be reduced to thirty percent of those seen when conventional feedback control systems are used.
