两相流场粒子成像测速技术(PTV-PIV)初探

PRELIMINARY INVESTIGATION OF PARTICLE IMAGE VELOCIMETRY (PTV-PIV) TECHNIQUE IN TWO-PHASE FLOW

在单相ＰＴＶ－ＰＩＶ研究基础上，研究液固两相流场粒子成像图像数字测速技术．首次用ＰＴＶ技术得到直槽道中液固两相流场二维瞬时全场两相流速分布．初步探讨了两相ＰＴＶ－ＰＩＶ技术中与单相ＰＴＶ－ＰＩＶ测速技术的关键不同之处，提出两相ＰＴＶ－ＰＩＶ测速采样的两相相容性准则．为深入研究两相流场粒子成像测速技术奠定了基础．

On the basis of the single phase PTV-PIV investigation, solid-liquid two phase flow field particle image velocimetry technique was studied in this paper. Specially processed Al 2 O 3 powder of 5 μ m was taken as liquid phase tracer, millet of 1.5mm in diameter and 1.265kg/m 3 of density was taken as particle tracer. They were scattered in the circulating water channel to form the experimental two phase flow field. Laser sheet was obtained by using a 45mW He-Ne laser source and a series of mirrors and lenses to illuminate the flow field,two external synchronization CCD cameras were used to get the flow field frames through optical lenses. The starting time interval between the two CCD cameras from the same flow domain were collected into a PC586 through a frame grabber board. The two phase frames were discriminated and relative data was processed by software, and the two phase flow velocity distribution near the boundary layer was obtained. This paper emphasizes the study of the difference between two phase PTV-PIV sampling technique and single phase PIV-PTV technique, and discusses the effect of density difference between tracer particles, the effect of optical property difference to measurement,and the compatible criterion of the two-phase velocities in velocity sampling. These studies pave the way for the further study of two phase particle image velocimetry technique.