Before V3V, the only methods of measuring the volumetric flow velocity utilised standard Particle Image Velocimetry (PIV) techniques. These include scanning a 2D laser sheet through a volumetric region of the flow (which is not an instantaneous measurement) or using a "thick light sheet" (which is not truly a volumetric measurement since the thickness of the sheet is limited to less than 1 cm). But now, with V3V, the full 3-Dimensional 3-Component (3D3C) velocity field can be measured instantaneously.
The V3V system measures the displacement of tracer particles in the flow over a known amount of time to determine the local velocity. The measurement volume is illuminated by a cone of laser light. The laser emits two very short duration pulses of laser light, separated by a known and t.Δ adjustable amount of time, As the flow passes through the measurement volume, laser light is scattered from the tracer particles during each laser pulse. The V3V Camera System captures separate images of the scattered laser light from each of the respective laser pulses within the entire measurement volume. Using a patented 3-aperture imaging technique, the 3-dimensional positions of the particles are determined at each laser pulse. The V3V System Computer features the TSI HyperStreaming image transfer system, allowing 17 minutes of continuous capture at the full camera frame rate of 15 Hz.
Once the images are transferred to the computer system, patented and proprietary algorithms in the INSIGHT V3V software are used to determine the complete 3D3C velocity field. First, the 3 dimensional particle positions are determined using information from all three camera apertures. The accuracy of the measured particle positions is less than 20 microns in the x-y plane and less than 100 microns in the z-direction. Unique particle tracking technology is implemented to determine displacement of the tracer t between the two laser pulses.Δ particles over the time Once the local velocities have been determined, advanced software tools allow interpolation onto a regular grid, as well as a full range of 3-dimensional graphics, plots, and movie generation. Higher order flow quantities, such as vorticity, can also be examined.
Features and benefits
- Single camera operation simplifies measurements and improves accuracy
- Automatic Calibration
- Rapid Processing
- Unique processing algorithms have been theoretically and experimentally validated
- Integrated 3D graphics and display
- Flow in mixing devices
- Propellor flows
- Flow through devices
- Flow in a model heart
- Internal flows
- Wave tanks