Begell House Inc.
Multiphase Science and Technology
MST
0276-1459
5
1-4
1990
TWO-FLUID MODEL FOR TWO-PHASE FLOW
1-63
10.1615/MultScienTechn.v5.i1-4.10
Mamoru
Ishii
Therma-Hydraulics and Reactor Safety Laboratory, School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907, USA
The two-fluid model formulation is discussed in detail. The emphasis of the paper is on the three-dimensional formulation and the closure issues. The origin of the interfacial and turbulent transfer terms in the averaged formulation is explained and their original mathematical forms are examined. The interfacial transfer of mass, momentum, and energy is proportional to the interfacial area and driving force. This is not a postulate but a careful examination of the mathematical form of the exact interfacial terms. These two effects are considered separately. Since all the interfacial transfer terms involve the interfacial area concentration, the accurate modelling of the local interfacial is the first step to be taken for development of reliable two-fluid model closure relations. The interfacial momentum interaction has been studied in terms of the standard drag, lift, virtual mass, and Basset forces. Available analytical and semi-empirical correlations and closure relations are reviewed and existing shortcomings are pointed out. The other major area of importance is the modelling of turbulent transfer in two-phase flow. The two-phase turbulence cannot be understood without understanding the interfacial drag and lift forces accurately. There are some indications that the mixing length type model may not be sufficient to describe the three-dimensional turbulent and flow structures. Although it is a very difficult challenge, the two-phase flow turbulence should be investigated both experimentally and analytically with long time-scale research.
MULTIPHASE INSTRUMENTATION AND EXPERIMENTAL TECHNIQUES
65-84
10.1615/MultScienTechn.v5.i1-4.20
Jean-Marc
Delhaye
Clemson University, Department of Mechanical Engineering, USA
The state of the art of measuring techniques in gas-liquid two-phase flow is reviewed on and typical experiments for basic research are presented. Current needs in instrumentation for research and industrial applications are discussed.
COMPUTATIONAL METHODS FOR MULTIPHASE FLOW
85-238
10.1615/MultScienTechn.v5.i1-4.30
Wolfgang
Wulff
Nonproliferation and National Security Department, Brookhaven National Laboratory; Stony Brook University, P.O. Box 5000, Upton, NY 11973-5000
The balance equations of multiphase flows are classified and techniques are reviewed for rendering these partial differentials into partial or completely discretized equations. Numerical methods are presented for integrating the partially, and for solving the completely discretized equations. The issues of computing accuracy and economy are discussed. Numerical methods used in major computer codes for multiphase flow analyses are reviewed, and it is demonstrated that quantification of computing errors and improvement of computing economy should be the objectives of future research in numerical methods for multiphase flows.
INERTIAL COUPLING IN TWO-PHASE FLOW: MACROSCOPIC PROPERTIES OF SUSPENSIONS IN AN INVISCID FLUID
239-361
10.1615/MultScienTechn.v5.i1-4.40
Graham B.
Wallis
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755
Classical solutions for the motion of a single sphere in an inviscid fluid are reviewed and extensively investigated by self-consistent models. The Maxwell equations for electrical conductivity of a suspension of spheres can be used, as found, to derive the added mass of a sphere array as well as the added kinetic energy due to relative motion. Good agreements are shown between the current analysis and general equations suggested.