Estimation of two-phase flow quality with acceleration oscillation

The oscillation of pipes containing two-phase flow is very important not only for the design of heat exchangers but also for the estimation of flow behavior by detecting the vibration or noise transferred from sounding rod with pressing components. The skilled engineers sometimes can estimate the two-phase behavior with vibration or noise from components such as heat exchangers or steam generators. To understand the oscillation behavior and possibility to estimate the flow behavior, the air-water two-phase flow experiments were conducted with small vertical tubes of 2 and 11.5 mm in inner diameter. The oscillation of differential pressure was (DP) measured at the long observation span more than fifty times diameter to avoid the static pressure oscillation due the fluctuation of void fraction. The acceleration oscillation (WV) was also measured at several location of pipes. The root mean square (RMS) value of WV and DP was well correlated with Lockhart-Martinelli parameter. It was also demonstrated that the two-phase quality could be estimated with the proposed correlation for RMS values when the liquid flow rate and RMS value were known. (author)