ICONE19-44166 Development of Prediction Technology of Two-Phase Flow Dynamics under Earthquake Acceleration (2) : Experimental Study on Flow Rate Fluctuation

Abstract

Nuclear reactors were contracted considering structural safety for a big earthquake. On the other hand, a thermal-fluid safety of the nuclear reactor is not fully confirmed under the earthquake. This study was done as one of a series study for a two-phase flow dynamics under earthquake acceleration. This study was in charge of effect of flow rate on behavior of two-phase flow. In the study, the behavior of the gas-liquid two-phase flow under the fluctuation of the liquid flow rate was studied experimentally. The flow was bubbly flow and/or plug flow in a horizontal pipe. In the experiment, the working fluids were water and nitrogen gas. The water was driven by a pump and the flow rate fluctuation was given by a reciprocating piston attached to the main flow loop. The gas was injected to the water at a mixer and the gas-liquid two-phase fluid flowed to the horizontal transparent pipe or a test section. At the test section, the flow behavior was observed by a high-speed video camera. Under the flow rate fluctuation, local deformation of a bubble was found. Clustering of bubbles was also observed but it was formed at the mixer.