Abstract
In the design of industrial fluid machinery, obstacles structures in fluid channels are frequently encountered, such as the accelerator (or called liquid distributor) in the centrifuge. Traditional Standard Particle Image Velocimetry (PIV) uses a sheet laser to slice a field to form the image plane, requiring strong light transmittance for the measuring objects, which failed in the aspect of poor light conditions. The authors developed a novel PIV which was applicable for the impinging liquid film surrounded by mist and successfully applied it to a semi-enclosed flow field. This PIV system includes newly synthesized fluorescent tracer particles and a set of ultraviolet lights, and the emission intensity satisfied the exposure time of 150μs. Then the PIV was implemented in a full-scale rotating platform to study the flow characteristics of the impinging liquid film in centrifuge accelerator disk. Results show that the velocity of accelerated fluids could be divided into impinging and pushing velocity, and the dominant role of the two velocity components will exchange as the conditions vary. At the flow rate of 12 m3/h, only when the rotating speed was larger than 1650 r/min, the speed-up effect is striking, and at the rotating speed of 2310 r/min, the acceleration effect φ reached 0.52. At the rotating speed of 1650 r/min, the acceleration effect φ reached 0.51 when the flow rate equaled 9 m3/h.
Large Field of View Particle-Image Velocimetry (LF-PIV): Design and Performance