フローノズル流量計流出係数に対する要因評価:　数値解析による予測

摘要

In nuclear plant, as water feeding into reactor have much effect on thermal power of plant, it is important to measure accurately the flow rate of water. Flow nozzle is on of typical differential pressure type flow meters and the discharge coefficient is used to calculate the flow rate. This coefficient is given by actual experiment and theory. We studied the theoretical assumption of the discharge coefficient curve using numerical simulation and evaluated the effect of flow nozzle configuration on the coefficient numerically and experimentally. As the result, numerical simulation can predict the discharge coefficient of theoretical curve within 0.3%. And we found that the throat length and throat tapping location of flow nozzle have much effect on the coefficient.%原子力発電プラントにおいて，炉心への給水流量はrn直接熱出力に影響するため，給水流量を高精度に評価rnすることが非常に重要である．給水流量計としては分rn解点検の必要性などからオリフィス，フローノズル等rnの差圧式流量計が一般的に用いられている．