Advanced Experimental Techniques
The group possesses a state-of-the-art particle image velocimetry (PIV) setup, consisting of two high speed camera’s (1280 x 1024 px at 625 Hz) and a double pulsed Nd:YAG laser (2 x 50 mJ 50 Hz, 532 nm) equipped with beam expanding optics and optical filters. The PIV setup is used both with and without a laser. For measurements in liquids or gas-liquid systems we use the complete setup, whereas for PIV measurements of granular flows in optically accessible (i.e. pseudo 2D) systems we replace the laser by some strong halogen lamps. The PIV setup is situated in a special laser lab.
For measurements in true 3D fluidized beds optical techniques can not be used. For these systems we use electrical capacitance tomography (ECT) to obtain solids volume fraction distributions in two planes. By correlating the information from two planes additional information about the bubble velocity can be obtained.
For the study of bubbly flows at high gas fractions that are not optically accessible, we make use of optical probe measurements. We possess a four-point optical probe, that is used to measure bubble holdup, velocity and cord length.
For our research on novel reactors it is essential to determine the composition of the product gases. To this end we use three micro gas chromatographs with dedicated analysis software.
For kinetic measurements we make use of a thermo graphimetric analyzer (TGA). Currently we possess two different TGA’s, one for measurements at atmospheric conditions and one for pressurized conditions up to a pressure of 10 bars.
Apart from the aforementioned techniques, we make frequent use of thermocouples, pressure (difference) transducers, moisture sensors, several analyzers, etc.