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Effective Size of the Measuring Cross-Section of a Phase-Doppler Anemometry

  • T. Maeda
  • H. Morikita
  • K. Hishida
  • M. Maeda
Conference paper

Abstract

The paper presents a technique for measuring particle mass flux in dispersed two-phase flows with improved accuracy of mass flux measurements by a standard phase-Doppler anemometer (PDA) with an AID converter-based signal processor. The purpose was achieved by improved estimation of the effective area of the probe volume. The area of probe volume was calculated by a geometrical optics approximation after considering two major influences namely ‘trajectory ambiguity’ and ‘slit effect’. The calculation results showed that the effective measuring area in the present optical configuration can be determined as a simple function of the probe diameter, size of the spatial filter of the receiving optics and particle diameter by considering only refracted light when ‘phase validation’ is applied. In addition careful setting of the trigger level of the signal processor resulted in reducing number of rejected signals owing to low signal to noise ratio (SNR) within the defined effective measuring area and as a consequence the accuracy of mass flux measurement was improved by 15% compared with our earlier work. The flux measurement of a hollow-cone spray indicated that the error did not exceed 20%, at a volume fraction of 2 × 10−4%

Keywords

Phase Doppler anemometry Mass flux measurement Trajectory ambiguity Slit effect Geometrical optics approximation 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • T. Maeda
    • 1
  • H. Morikita
    • 1
  • K. Hishida
    • 1
  • M. Maeda
    • 1
  1. 1.Department of Mechanical EngineeringKeio UniversityKohoku-kuJapan

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