This thesis examines two techniques for measuring two-phase flow parameters in an air/water system using intrusive conductivity probes. Specifically, the theoretical derivation for measuring void fraction and interfacial area using a two-sensor needle-type probe is derived, and a statistical analysis of the accuracy using the two-sensor probe for measuring interfacial...
The next generation of nuclear safety analysis computer codes will include detailed modeling of the interfacial area concentration. The interfacial area concentration is the essence of the two-fluid model. It is the most accurate of the two-phase models since it considers each phase independently and links the two phases together...
Two-phase flow in a fractal-like branching microchannel heat sink may have
enhanced heat transfer capabilities over single phase flow in the same branching
channel network. In order to exploit this potential, a complete understanding
of flow boiling in this geometry is required. The fractal-like geometry is similar
to that of...
Two-phase gas-liquid flows in microscale fractal-like branching channel flow networks were experimentally studied to assess the validity of existing void fraction correlations and flow regimes based on superficial gas and liquid velocities. Void fractions were assessed using two different methods. First, void fraction data were acquired using a High-Speed-High-Resolution (HSHR)...
This paper describes a study of two-phase gas-liquid vertical
annular climbing film flow. Using a high speed Fastax movie camera,
motion was slowed sufficiently to facilitate detailed analysis of the
climbing film structure, based on single frame projections. The
dynamic characteristics of the liquid film could likewise be obtained,
though...
Momentum transfer in climbing-film flow in an annular duct was
investigated. Air and various liquids, with a wide range of viscosities
and surface tensions, were investigated. The two phases flowed co-currently
upward, the liquid climbing as a thin film on the inner wail
while the outer wall remained dry.
The...
The next generation of nuclear safety analysis computer codes will require detailed
modeling of two-phase fluid flow. The most complete and fundamental model used for
these calculations is known as the two-fluid model. It is the most accurate of the two-phase
models since it considers each phase independently and links...
An improved version of the one-dimensional horizontal two-fluid flow model has been developed by incorporating physical terms for gravity and local void fraction profiles. Introduction of an interface mixing layer concept allows the one-dimensional two-fluid model to remain hyperbolic. This will overcomes a major obstacle in using the current one-dimensional...
A phase distribution parameter has been added to the one-dimensional two-phase horizontal flow conservation equations. The phase distribution parameter was incorporated into the conservation equations in an attempt to add stability and remove correlation switching by incorporating gravity. Determination of the phase distribution parameter requires an average void fraction profile...