טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentArca Javier
SubjectDevelopment of a Digital Holography System for the
Investigation of Particle-Fluid Coupling in a
Turbulent Flow
DepartmentDepartment of Mechanical Engineering
Supervisor Dr. Rene Van Hout
Full Thesis textFull thesis text - English Version


Abstract

Particle - fluid coupling in turbulent flows is one of the important research topics in experimental fluid dynamics due to the large spectrum of important flow situations involving a dispersed liquid, gas or solid material in a continuous gas or liquid. Multiphase flows are of significant importance in industrial and natural processes. Typical examples are fuel injection in an automobile engine, power processing, bubbly flows, dust storms, rain, aerosol transport, aerosol synthesis of powders, three-phase flows with micro-bubbles and flocculate particles, and all sorts of atomizers for painting, cleaning and applying medication. In all of the above examples there exist important interactions between the continuous and dispersed phases that arise because of the drag experienced by the dispersed particles as they move through the continuous fluid.

"Holographic Particle Image velocimetry” (HPIV) is a non-intrusive method that measures the instantaneous three-dimensional (3D) velocity field of particles dispersed in fluid flows inside a volume using holography. The hologram records the 3D information of flow particles, seeded or inherent in the flow. The reconstructed hologram contains information about the particle's size, shape and (3D) position. By finding the 3D displacements of particles in the image volume between two exposures separated by a short time lapse, an instantaneous, volumetric 3D velocity field can be retrieved.

The objective of this research was to develop the holographic technique for multidimensional, spatially and temporally resolved measurements and implement it in the study of particle-fluid coupling in a turbulent flow. The holography setup was designed, assembled, calibrated, and tested in different configurations at the Environmental Multi Phase Laboratory. Specific programs were developed for digital hologram reconstruction, particle position detection, recognition and classification into the volume of interest (VOI), particle tracking and to calculate the particles 3D trajectories and dynamic characteristics such as 3D velocities, and accelerations.

Preliminary, "proof of concept" experiments were carried out at the Environmental Multi Phase Laboratory ("The closed loop water channel experiment") and the HPIV method was applied in order to calculate the dispersed particle characteristics.