Results of a computer simulation of a nonintrusive, optical steam quality monitor

In a steam plant, the liquid phase cannot be completely eliminated from steam produced in the steam generator. Wetness factor, or fraction of total mass in the liquid phase, serves as an indication of plant efficiency and normal operation. During start-up, accidents, or anomalous plant operation, the wetness factor may reach high levels, continually monitoring the wetness factor would allow real time adjustment of plant parameters, improving plant efficiency and reducing maintenance. A nonintrusive, continuous, optical steam quality monitor is proposed for the above problem. The authors examine the feasibility of the proposed monitor by simulating its operation with a computer program. In particular, the intensity of scattered light received by the detectors, and variations of the intensity with changes in wetness, are determined. Various implementations of the monitor are simulated at both high and low pressure. The ratio of steam qualities is found to be nearly linear for a given size-number density distribution