HYDRODYNAMIC FORCES, PRESSURE AND MASS FLUX IN TWO-PHASE AIR-WATER FLOW THROUGH TRANSPARENT SAFETY VALVE MODEL

Safety devices are of major importance in the nuclear and chemical industry. Examples of such systems are safety valves and rupture disks. The behavior of this type of valve in single-phase flow (gas or liquid) has been described in detail in the literature, while for two-phase flow there is a lack of relative models since the phenomena are much more complex. The design and sizing of this apparatus is an important issue which would prevent its wrong functionality that could cause a hazardous situation. In this paper, a transparent (made in Polymethyl methacrylate) model of a safety valve is studied (1 1/2 in G 3 in); this has allowed full optical access and therefore the identification of the structure of the flow and the observation of the different phenomena occurring. Instead of a spring, used in an actual safety valve, the disk is fixed and its position can vary from completely closed to fully opened position. Thus, the static flow behavior of the valve is examined.