Wetness and Efficiency Measurements in L.P. Turbines With an Optical Probe As an Aid to Improving Performance

Abstract

An absolute value for the wetness fraction in a partially condensed steam flow may be calculated from measurements of light transmission using the results of fundamental electromagnetic scattering theory. A probe is described that uses this principle for measuring radial wetness profiles in the final stages of L.P. turbines. Results are presented to show that the probe will provide reliable values for overall L.P. turbine efficiency and valuable diagnostic data on the performance of individual stages operating with wet or condensing flows.