Choking Flow in Supercritical Fluids

点击翻译按钮获取中文摘要

A particular safety concern in Supercritical Water Reactors (SCWRs) is the estimation of cooling conditions during a postulated Loss-of-Coolant Accident (LOCA) under which choking flow may occur. Such a situation determines both the evolution of the reactor coolant inventory and reactor pressure rate changes. Most of choking flow predictions are based on models developed from subcritical data. To determine whether these models are appropriate or not for supercritical fluids, we present the continuation of a program intended to collect choking flow data using water at supercritical conditions. Thus, a supercritical loop is under construction at École Polytechnique; it consists of a high-pressure, high-temperature branch interconnected to a medium pressure steam-water loop. The high-pressure system is used to control supercritical water flow conditions at the inlet of a test section. The medium pressure loop serves as a pressure controlled reservoir required to achieve continuous steady-state discharge flow experiments with the downstream pressure controlled at will. Different test sections, instrumented with pressure transducers and temperature measurement devices, having different discharge geometries and diameters will be used to study their effects on supercritical choking flows. For different supercritical water inlet conditions, pressure distribution data will be collected by changing and controlling the downstream (discharge) pressure. The experimental information will then be used in model validations. If needed, these data will be used to develop a new model to estimate the choking flow rate at supercritical conditions.