A Review of Holography Applications in Multiphase Flow Visualization Study

Holographic techniques are used in many fields of science and engineering including flow observation. The purpose of this paper is to review applications of holography to multiphase flow study with emphasis on gas-solid and gas-liquid two-phase flows. The application of holography to multiphase flow has been actively explored in the areas of particle sizing in particulate flows and nuclei population measurements in cavitation study. It is also recognized that holography holds great potential as a means of visualizing dynamic situations inherent in multiphase flows. This potential has been demonstrated by holographic flow visualization studies of coal combustion processes in gas-solid flows, gas-liquid two-phase critical flow measurements, and flashing flows in a nozzle. More effective and refined holographic techniques as well as efficient image processing methods are very much in need to facilitate and enhance the understanding of complex physical phenomena occurring in multiphase flows.