レーザーフォーカス変位計による環状流液膜界面構造の計測 : 第1報,測定精度と液膜発達特性(流体工学,流体機械)

概要

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Accurate measurements of interfacial wave-structure of upward annular two-phase flow in a vertical pipe were performed using a laser focus displacement meter (LFD). The purpose of this study was to clarify the effectiveness of the LFD for obtaining detailed information concerning the interfacial structure of a liquid film in annular two-phase flow and to investigate the effect of axial length on the phenomena. We made simultaneous measurements of the liquid film interface in an acrylic rectangular pipe with 3-mm width using LFD and high-speed video camera to check the measuring accuracy of the LFD. These showed that the LFD could measure the interface of liquid film with high spatial and temporal resolution in various flow conditions. Adiabatic upward annular air-water flow experiments were conducted using a 3m-long, 11mm-ID pipe. Measurements of interfacial wave were conducted at 21 axial locations. The axial distances from the inlet (L) normalized by the pipe diameter (D) varied L/D=50-250. The results revealed that the maximum film thickness decreased gradually with some oscillations as flow developed. The flow development, i.e. decreasing of film thickness, existed till the pipe exit which means that the flow might never reach a fully developed condition.
2005-05-25