ボイド率分布計測

Measurement of void fraction distribution

呉田 昌俊   

Kureta, Masatoshi

日本機械学会が流体計測法をまとめた技術資料の改定版を刊行する。本稿は、その応用編の一部であり、進展が著しい先進的な熱流体計測技術を用いた応用事例の紹介が主な内容となっている。「ボイド率分布計測」の章では、機器の内部を流れる気液二相流を対象として、ボイド率分布を中性子線で可視化や計測する技術について解説した。前半は、ボイド率の定義、中性子透過法による計測やCT撮像技術の基本原理について解説した。後半は、様々な混相流の2次元、2次元の時間変化、3次元、3次元の時間変化の順に、可視化・計測結果を示した。

The Japan Society of Mechanical Engineers publishes a revised version of the technical document summarizing fluid measurement techniques. This article is part of the application section, and the main content is an introduction of application examples using advanced thermal-fluid measurement technology that is progressing remarkably. In the chapter "Void Fraction Distribution Measurement", the technology for visualizing and measuring the void fraction distribution with neutron beams for the two-phase flow of gas-liquid flowing inside the instrument is summarized. In the first half, the definition of void fraction, measurement by neutron transmission method, and basic principles of CT imaging technology were explained. In the second half, visualization and measurement results were shown in the order of two-dimensional and two-dimensional time changes of various multiphase flows, and three-dimensional and three-dimensional time changes.