Begell House Inc.
Multiphase Science and Technology
MST
0276-1459
9
4
1997
UNDERSTANDING AND MODELLING DNB IN FORCED CONVECTIVE BOILING: MODELLING OF A MECHANISM BASED ON NUCLEATION SITE DRYOUT
329-379
10.1615/MultScienTechn.v9.i4.10
B.
Bricard
EDF/DER, Départment Transferts Thermiques et Aérodynamique, 6, quai Watier - 78401 Chatou Cedex, France
P.
Peturaud
EDF/DER, Départment Transferts Thermiques et Aérodynamique, 6, quai Watier - 78401 Chatou Cedex, France
Jean-Marc
Delhaye
Department of Mechanical Engineering, Clemson University, Clemson, SC, USA
Two existing mechanisms for DNB in forced convective boiling are unified into one which, based on nucleation site dryout, a priori covers the whole range of DNB, from bubbly to slug flow Two modelling approaches are explored. A first, simplified model, based on a global heat balance in the wall under a dry patch, enables the CHF to be calculated, distinguishing the case of thin and thick heating walls. From a comparison with CHF data, good results are obtained in a wide enough range. A second, detailed model, based on the two-dimensional unsteady thermal analysis of the wall in response to a nucleation cycle, is then developed in order to support the likeliness of the postulated mechanism in bubbly flow. A parametric study around a well-documented CHF data point, indicates some requirements for DNB to be reached.
STEAM-WATER SEPARATION
381-437
10.1615/MultScienTechn.v9.i4.20
Peter
Griffith
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 USA
A review is presented of the selection, design and operation of steam-water separation equipment. The criteria for choosing a separation system are first discussed and typical applications are described. Then, each of the major types of separator (gravity separators, drop inertia separators and cyclone separators) are reviewed in detail and the principal problems in design and operation for each respective type presented. Finally, procedures for testing separators are reviewed and overall conclusions drawn.