Physical Chemistry of Aqueous Systems: Meeting the Needs of Industry

ISBN Print: 978-1-56700-034-4

ISBN Online: 978-1-56700-445-8

LABORATORY AND FIELD MEASUREMENTS OF DROPLET NUCLEATION IN EXPANDING STEAM

DOI: 10.1615/ICPWS-1994.900
pages 703-710

Resumo

The aim of this paper is to give a survey of experimental and theoretical activities at CTU concerning droplet nucleation both in the convergent-divergent nozzle and in the LP part of a 200 MW fossil steam turbine. The size of droplets forming in expanding steam was determined by means of extinction measurements. In the nozzle experiments homogeneous nucleation was found to be the prevailing mechanism of the droplet formation for expansion rates P > 103 s-1. The heterogeneous condensation on the steam impurities might be of importance for P < 103 s-1. In the turbine experiments variation of the mean droplet radius past the last stage was found to be (0.1 + 0.2) 10-6m. It is concluded that direct application of the homogeneous nozzle results to the real turbine operating conditions is probably not possible, because of existing impurities in expanding steam, low expansion rates and unsteady and 3-D flow phenomena.