b'SPRAY TRANSFER EFFICIENCIESexactly size and location of the PIVTwo test planes can be identified in Figure 6). methods were used Figure 3 demonstrates the PIVto evaluate setup overtop of the conveyor whichthe boundary included a diffused laser sheet and alayer and synchronised camera oriented normaltransfer to the PIV laser plane. The PIV systemefficiency consisted of a Solo PIV Nd:YAGof each double-pulse laser, a high-speedmitigation LaVision Imager Intense camera, anddevice.LaVision DaVis 8.0 image acquisition and processing software. The laser sheet is emitted with a nominally Gaussian intensity profile, of which the middle 20% was used, which Figure 2. 1/4J+SUE15A air illuminated the spray in the xz-plane. The laser sheet was approximately 5 mm thick in the measurement regions and will be considered sufficiently were selected to evaluation removalair flow that later influences the spraythin to represent a two-dimensional of the boundary layer flow, as well astrajectories and transfer efficiency. Twospray cross-section for this study. increased turbulence, respectively. image regions were acquired, focusingThe camera provided double-framed on i) the manipulation region andimages of 1376x1040 pixels, with a Two test methods were used toii) the spray region; the PIV regionsknown time delay between images. evaluate the boundary layer andare identified in Figures 1 and 3 (theImage calibration was conducted by transfer efficiency of each mitigation device. The first was Particle Image Velocimetry (PIV) which provides a planar vector field, oriented in the xz-plane. The second was physical collection of the spray from the conveyer surface to measure and compare exactly how much fluid is effectively transferred from the nozzle to the conveyer under each set of conditions.PARTICLE IMAGE VELOCIMETRY (PIV) SETUPParticle Image Velocimetry (PIV) was used to acquire 2D vector fields within the boundary layer allowing investigation of the air flow with andFigure 3. PIV setup with camera, laser, PIV image regions (red). The without boundary layer manipulation.atomising external-mix spray nozzle. vacuum setup is also shown, but was These results provide insight into thenot installed during PIV testsing.76 WORLD PULP&PAPER'