It was decided to make the test rig out of six 0.5m x 0.5m Perspex sheets, with holes drilled in them to allow the attachment of modifications. Beneath this was a heating chamber containing a hot plate, which served the purpose of heating smoke to the required temperature. Smoke, containing large easily visualised particles, could then be sprayed into the heating chamber, which would then enter the main test rig as required.
The extraction of smoke was achieved through 8 computer fans mounted at the top of the rig, four of which blew air in, and four of which blew smoke out.
The smoke was visualised using a sheet of high-powered laser light which was shone through the test rig, illuminating a ≈1mm thick plane.
Test Rig Design
Particle Image Velocimetry (PIV) uses images of marker particles in a fluid flow to measure instantaneous velocity fields in experimental fluid mechanics. PIV is being utilized in the experimental rig so that the path of the smoke can be traced in order to gauge the effectiveness of the control system. This information can be used to draw comparisons with the Computational Fluid Dynamics simulations that are being run alongside the experiments.
Typical PIV setup
The PIV setup produces a laser sheet, which, in the case of the smoke control experiments, is then directed through the experimental test rig. The smoke is then allowed into the rig and the particles pass through the laser sheet. As this is occurring, a high-speed camera is used to take large quantities of photographs of the particles in the laser sheet. The particle movement can then be traced and analysis conducted upon the data to fully understand what is being visualised. The particle position data can then be used to produce PIV vector plots and both axial and radial velocity plots.
From left to right, PIV vector plot, axial velocity plot, radial velocity plot