Coal powder measurement by digital holography with expanded measurement area

Yingchun Wu; Xuecheng Wu; Zhihua Wang; Linghong Chen; Kefa Cen

doi:10.1364/AO.50.000H22

Coal powder measurement by digital holography with expanded measurement area

Appl Opt. 2011 Dec 1;50(34):H22-9. doi: 10.1364/AO.50.000H22.

Authors

Yingchun Wu¹, Xuecheng Wu, Zhihua Wang, Linghong Chen, Kefa Cen

Affiliation

¹ Department of Energy Engineering, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 2010, China.

PMID: 22193011
DOI: 10.1364/AO.50.000H22

Abstract

The field of view of digital in-line holography for flow field diagnostics is restricted to a small volume due to the finite size and the low spatial resolution of the available CCD. Expansion of the measurement cross section of digital holographic particle image velocimetry was investigated with a lens-based holography configuration. By sampling the chirp signal in the center lobe completely and undersampling the chirp signal in the second- and higher-order lobes by a magnified virtual recording plane produced by an imaging camera lens, the field of view is expanded. Simulation results show that the three-dimensional (3D) location and size of the relatively large particle can be reconstructed with good accuracy. A digital holographic particle image velocimetry system was established for coal particle flow field diagnostics. Compared with the lensless configuration, the field of view of the digital holography system was enlarged 1.9 times, up to 2.78 cm × 2.78 cm × 3 cm. The 3D location, size distribution, and the 3D vector field of coal powder were obtained. The results show that the application of digital in-line holography to measure large particle flow field is feasible.