The Nathan Cummings Chair of Mechanics

Incumbent: Professor Dvora Barnea

My research interest is the area of Multiphase flow. Multiphase flow is a simultaneous flow of several phases such as gas-liquid, liquid-solid, or gas-liquid-solid. The area of multi-phase flow has direct applications to many disciplines such as energy production, petroleum industry, solar energy, safety of nuclear reactors and environmental engineering. Analytical, numerical and experimental methods are employed in the analysis of problems in this area.

The main topics of my research are:

Flow patterns: In multiphase flow, gas-liquid and/or solid can be distributed in the pipe in various ways, termed as flow patterns. Prediction of the flow patterns is an essential starting point for the calculation of the hydrodynamic parameters in multiphase flow. Models for the prediction of the flow patters were developed and verified by experiments.

Modeling flow hydrodynamics: Once the flow pattern is known, it is possible to predict the flow hydrodynamic parameters. Such models were developed, in particular for separated and slug flows.

Stability of separated flow: The stability of separated flow is an important problem and is a key point for modeling flow pattern transition.

Slug tracking modeling: Slug is a flow pattern where liquid slugs are separated by long gas bubbles. Numerical simulations were developed for the prediction of the behavior of the flow structure and velocities with time and space.

Slurry transportation: Theoretical and experimental studies for the developments of new models to predict the flow patterns, pressure drop, and transient phenomena in solid­liquid flows were carried out.

Statistical characteristics of slug flow: Due to the unsteady and developing character of slug flow the govern flow parameters can be described in statistical terms. Statistical analysis of slug flow that covered a wide range of gas and liquid flow rates and pipe inclinations was carried out.

Structure of bubbles' wake: Advanced experimental techniques such as PIV (particle image velocimetry), Image processing and optical probes for detecting instantaneous flow fields in the Taylor bubble wake were employed.

Stability of two phase flow in parallel pipes: When gas and liquid flow in parallel pipes the flow may be unstable and/or can be unevenly distributed among the pipes. This problem is closely related to DSG (direct steam generation) via solar energy.