Light Particles in Turbulent Flows (Twente Water Tunnel)
Dispersed bubbly flow has attracted much interest, both from a fundamental point of view and because of its widespread occurrence in industrial applications. In dispersed flows, the hydrodynamic interaction between the two-phases and the inertia of the small bubbles (which are called ‘light particles’) result in an inhomogeneous distribution of the particles. We characterize the properties of two-phase turbulent flows using the Twente Water Tunnel.
Twente Water Tunnel
The Twente Water Tunnel (see Figure 1) is an 8m high facility in which strong turbulence (up to a Taylor-Reynolds number of 400) can be created thanks to an active grid. The tunnel was designed for studying both single and two-phase turbulent flows. The downward average velocity is up to 90 cm/s in the measurement section. Nearly monodispersed bubbles with varying diameters (from 100µm to 5 mm) can be injected with a concentration up to 10%. The transparent measurement section with 2×0.45×0.45 m3 allows for optical techniques in the tunnel. The instrumentation includes 3D Particle Tracking Velocimetry (see Fig 2), 3D Particle Image Velocimetry, phase-sensitive hot-film anemometry, and Laser Doppler Anemometry.
Figure 1: Twente Water Tunnel
The questions we address are:
- The light particles distribution in the flow and in particular particle clustering;
- Effect of particles on spectra, and average rise/sink velocity of particles in turbulence;
- Statistics of velocities and accelerations of light particles in turbulent flow;
- Further Lagrangian aspects.
Figure 2: Instantaneous 3D bubble positions measured with 3D Particle Tracking Velocimetry.
Researchers: Ramon van den Berg, Daniel Chehata Gómez, Julián Martínez Mercado, Vivek Nagendra Prakash, Varghese Mathai, Jon Brons, Detlef Lohse, Chao Sun.
Collaborators: Hans Kuipers (FCRE-group U. Twente), J.-F. Pinton (l'École normale supérieure de Lyon), Federico Toschi (TU Eindhoven), ICTR International Collaboration for Turbulence Research.
Embedding: JMBC, European Research Network on Turbulence, ICTR International Collaboration for Turbulence Research, EuHIT
Sponsors: European Research Network on Turbulence, FOM, AkzoNobel, TataSteel, DSM, Shell