Experimentally investigation of the CCD binning option in particle imaging velocimetry measurements of laminar flows

Abstract

In this work we present an experimental investigation of the employment usage application of the vertical pixel binning (PB) option for PIV (particle image velocimetry) measurements. The PB option increases the speed of a CCD, at the cost of loosing spatial resolution. Consequently, it is expected that PB will positively impact the dynamic velocity range of the PIV measurements. In order to show the benefit of the CCD PB option in PIV measurements, we have carried out series of microPIV experiments on laminar flows, seeded with 1 μ m fluorescent polystyrene microparticles and passing through a 200 μ m × 200 μ m × 50000 μ m microchannel. The flow images were recorded at normal, 2 × 1, and 3 × 1 vertical PB modes of a monochrome CCD camera. The experimentally obtained velocity profiles were calculated using the ensemble-averaged cross-correlation method and Gaussian sup-pixel interpolation and then compared with theoretically calculated velocity profiles. We found that the error introduced by the PB option did not exceed the inherent uncertainty of the PIV system used. For a particular PIV system CCD camera, using the PB option allowed an increase in the dynamic velocity range of a PIV system by more than a factor of two, without extra investments.