title: Critical air/water blow-down in safety valves at low qualities.
abstract: Critical air/water blow-downs in safety valves for qualities from 0.01 to 0.113 and mass flow rates from 1.5 up to 4.3 kg/s have been observed in our test facility. These critical blow-downs are characterized by a large void fraction and by an intense mixing of the phases both in the valve body and in the outlet pipe. A qualitative estimation of the flow pattern in the outlet pipe using the map of Taitel and Dukler suggests that these air/water flows are intermittent flows--presumably slug flows--evolving to annular flows for qualities above 0.1. Intermittent flows are also predicted for critical air/water and air/glycerine flows taken from the literature for the same safety valve at slightly larger relieving pressures.
authors.affiliation: Technisches Büro, LESER GmbH & Co., KG, Wendenstrasse 133-135, 20537 Hamburg, Germany. moncalvo.davide@vdi.de
authors.forename: D
authors.initials: D
authors.lastname: Moncalvo
authors.forename: L
authors.initials: L
authors.lastname: Friedel
mesh_terms: D000388:Air; D000465:Algorithms; D004868:Equipment Failure / Q000706:statistics & numerical data*; D007221:Industry; D011312:Pressure; D012449:Safety; D014783:Viscosity; D014867:Water
chemical_list: D014867:Water