|M.Sc Thesis||Department of Mechanical Engineering|
|Supervisor:||Prof. Emeritus Hetsroni Gad|
The recent surge of microfluidic devices has created a need for diagnostic tools, with resolutions of several microns that have the ability to explore those devices.
The flow field inside micro channels was investigated using Micro Particle Image Velocimetry (PIV) system. This non-intrusive method provides instantaneous two-dimensional velocity fields. The flow field inside the channels was presented as function of Reynolds number. The flow field was described by means of the stream wise velocity field inside the center of the channel, comparison between normalized velocity profiles of different flow rates, along with calculated and measured profiles inside the same channels. It was found that there is similarity between the normalized profiles independent of the Reynolds number. Moreover, there was similarity between the normalized velocities profiles measured in different channels with the same aspect ratio. A linear relation between the friction factors and the flow rates was found. Good correlation was found between the calculated friction factors based on laminar theory, and the friction factors obtained from the measured velocities and pressure drops. The pressure measurements did not show any change in the friction factor inside the microchannels in comparison to that of macro scales. A method for a pressure drop calculation inside a micro-channel using PIV measurements was proposed. The pressure drop was calculated by measuring the velocity in a known coordinate inside the channel. In order to characterize the micro-channels in three dimensions, a new technique was proposed based on the 2D PIV capabilities. A 3D re-constructed velocity profile was obtained.