Presented by J.J. Schröder at the “Jahrestreffen der Verfahrens-Ingenieure”, Strasbourg, September 17 to 19, 1986.
Homogeneous non-equilibrium two-phase critical flow model†
Article first published online: 2 FEB 2004
Copyright © 1987 VCH Verlagsgesellschaft mbH
Chemical Engineering & Technology
Volume 10, Issue 1, pages 420–426, 1987
How to Cite
Schröder, J. J. and Vuxuan, N. (1987), Homogeneous non-equilibrium two-phase critical flow model. Chem. Eng. Technol., 10: 420–426. doi: 10.1002/ceat.270100152
- Issue published online: 2 FEB 2004
- Article first published online: 2 FEB 2004
- Manuscript Received: 18 DEC 1986
An important aspect of nuclear and chemical reactor safety is the ability to predict the maximum or critical mass flow rate from a break or leak in a pipe system. At the beginning of such a blowdown, if the stagnation condition of the fluid is subcooled or slightly saturated thermodynamic non-equilibrium exists in the downstream, e.g. the fluid becomes superheated to a degree determined by the liquid pressure. A simplified non-equilibrium model, explained in this report, is valid for rapidly decreasing pressure along the flow path. It presumes that fluid has to be superheated by an amount governed by physical principles before it starts to flash into steam. The flow is assumed to be homogeneous, i.e. the steam and liquid velocities are equal. An adiabatic flow calculation mode (Fanno lines) is employed to evaluate the critical flow rate for long pipes. The model is found to satisfactorily describe critical flow tests. Good agreement is obtained with the large scale Marviken tests as well as with small scale experiments.