Experimental study on the local interfacial characteristics of subcooled flow boiling under inclined condition

Subcooled flow boiling in inclined tube occurs widely in many industries and applications. An experimental study on the local interfacial characteristics of subcooled flow boiling was carried out under vertical and inclined conditions. The test section is a circular tube (i.d. 24 mm) of which axial heated length is 1 m. A double-sensor optical probe was used to investigate the radial distribution of interfacial parameters including local void fraction, bubble frequency, interfacial velocity, Sauter bubble diameter and Interfacial Area Concentration (IAC). The range of heat flux and mass flux are 140-900 kW/m² and 200-800 kg/m²s, respectively. The inclination angles are 5deg, 10deg, 20deg, 30deg, and the polar angle between measurement direction and inclination direction in the probe measurement cross-section are 0deg, 45deg, 90deg. From the test, the local interfacial parameters were measured at 15 radial locations at probe elevation. Based on these data obtained in the previous test loop, the influence of flow condition and inclination angle on the profiles of local interfacial parameters was discussed. (author)