垂直矩形流路の対向二相流下における落下水制限に関する研究 : 第1報,流路断面形状・流路長の影響およびCCFL相関式の導出

概要

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Counter-current flow limitation (CCFL) experiments were carried out for both vertical rectangular channels and vertical circular tubes varying in size and in the configuration of their cross sections, to clarify CCFL characteristics in the vertical rectangular channels. Quantitative understanding of critical heat flux (CHF) in a narrow vertical rectangular channel is required for the thermohydraulic design and safety analysis of reasearch nuclear reactors in which flat-plate-type fuel is employed. Critical heat flux under downward low velocity is closely related to the falling water limitation under a counter-current flow. Results showed that the equivalent hydraulic diameter de, i. e., the width, and water gap of the channel play an important role in determining the CCFL characteristics of a rectangular channel. But a significant influence of channel length on CCFL characteristics was not observed in the ranges investigated. Using new dimensionless parameters, the authors propose a correlation for predicting the relationship between upward air velocity and downward water velocity based on the present experimental results.
社団法人日本機械学会の論文
1989-09-25