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An analytical study on the moisture separation performance in dryers

Book ·
OSTI ID:234270
; ;  [1]
  1. Toshiba Corp., Kawasaki (Japan). Nuclear Engineering Lab.
A boiling water reactor, BWR, could be regarded as a boiler to supply steam flow to its turbine-generator system. Steam is generated in a reactor core, then flows upward into separators as two-phase flow with high void fraction, where steam-flow is separated from the two-phase mixture by centrifugal force. As steam flow from separator outlets includes a small fraction of liquid droplets, known as carryover, which might damage the blades in the turbine if there were no way to sufficiently remove the droplets. A steam dryer is installed above and downstream of the separators to remove moisture and to supply dry steam to the turbine generator through the main steam line. Air-water tests were carried out to investigate dryer performance. The dispersed flow in the dryer test apparatuses was also simulated using a numerical code, which solves the Navier-Stokes equation for continuous gas phase and the Lagrangian equation of droplet motion for dispersed phase, to predict droplet removal efficiency. The numerical results were compared with the test data pertaining to the removal efficiency at each vane stage and overall pressure drop along dryer-vanes. Good agreement was obtained as for the efficiency, while relatively poor agreement was obtained for the pressure drop. The results also showed that the efficiency depended strongly on the droplet size distribution at the dryer inlet, which indicated the importance of estimating the droplets size. Effects of some design parameters on both removal efficiency and breakthrough onset condition are discussed.
OSTI ID:
234270
Report Number(s):
CONF-960306--; ISBN 0-7918-1226-X
Country of Publication:
United States
Language:
English