A REVIEW OF THE DEVELOPMENT AND CHARACTERISTICS OF PLANAR PHASE-DOPPLER ANEMOMETRY

Phase-Doppler anemometry is now a well-established measuring technique for simultaneous measurements of particle velocity, size, flux and co ncentration and its usefulness has been demonstrated in a wide range o f applications to multiphase Rows. Since its introduction in 1975, it took until 1980 to re-discover the measuring technique for particle si zing. Moreover, the increased understanding of the influence of the Ga ussian intensity distribution in the probe volume of a phase-Doppler a nemometer (PDA) revealed an important feature of PDA in a planar confi guration, namely the temporal separation of the contributions of two s cattering mechanisms, reflection and refraction, to the light received by the photodetectors. This implies the possibility of suppressing me asurement errors caused by the mixing of the two modes of scattered li ght and even makes it possible to perform refractive-index measurement s by comparison of the reflective and the refractive phases. In the mo st recent development of the so-called dual-mode PDA, the planar set-u p is one essential part of the system which ensures that an accurate m easurement of the particle size and, therefore, of the particulate vol ume flux is obtained. The present paper reviews the historical develop ment of planar PDA and its capabilities and present applications.