The assessment of the effect of binary homogeneous nucleation on wet steam energy loss in a low pressure steam turbine

Abstract

The objective of the paper was to recognize the possible effect of a low concentration of chemical impurity (NaCl) present in the inlet steam (2.27 ppb) in the assessment of the wet steam energy loss occurring in a 1000 MW nuclear low pressure steam turbine. The presented analysis suggests that the used binary nucleation model, accounting for the electrolytic nature of the droplets, predicts a reduced wet steam energy loss of order –9 %, in comparison with the unary pure steam droplet nucleation model. This minor difference, considering the uncertainties of the existing measurements and the incomplete knowledge of the real droplet nucleation conditions in the steam of the turbine (primarily in relation to the necessary input data of chemical impurities), suggests that unary pure steam droplet nucleation (Becker–Döring) is an acceptable approximation at the current state of knowledge.