Development of technologies on innovative-simplified nuclear power plant using high-efficiency steam injectors. (9) Turbulence structure of two-phase flow in central steam jet injector

Experimental studies on turbulence structure in annular two-phase flow were carried out concerned with the central steam jet injector for a next-generation nuclear reactor. In the central steam jet injector, steam/water annular two-phase flow is formed at the mixing nozzle. To make an appropriate design for high-performance steam injector system, it is very important to accumulate the fundamental data of the thermo-hydro dynamic characteristics of annular flow in the steam injector system. Especially, the turbulence modification in multiphase flow due to the interactions between two-phases is one of the most important scientific issue and has attracted research attention. In this study, the behavior of the liquid film moving with wavy interface and the resultant gas-phase turbulence modification due to the phase interaction were investigated. The behavior of the interfacial waves in the liquid film flow such as the ripple or disturbance waves were observed by using high-speed video camera system and digital camera and made clear the interfacial velocity, the special structure of the interfacial waves. The measurements for gas-phase turbulence were precisely performed by using the constant temperature hot-wire anemometer, and made clear the velocity profiles, fluctuation velocity profiles in gas-phase turbulence flow passing through the throat section. The measurements for liquid film thickness by the electrode needle method were also performed. (author)