Hydrodynamic considerations of venting with high viscosity non-reacting fluids

Visualization of emergency viscous two-phase venting behaviors

“…In this study, partial vapor/ liquid disengagement with a churn-turbulent or bubbly flow was selected for comparison. Both of the flow regimes are based on drift-flux model (Oster et al, 1990;Skouloudis & Kottowski, 1991). The temperature of the reactant was assumed to be constant during the blow-down period.…”

“…Results of the viscosity showed the deviation from the measured data (Fisher, 1993;Shaw & Levin, 1995). Other studies concerning the void fraction, mass flow rate, and hydrodynamic model for viscous flow relieved at the venting nozzle were proposed in the literature (Bell, Morris, & Oster, 1993;Frundt, Steiff, & Weinspach, 1997;Oster, Bell, & Kottowski, 1990;Oster, Kottoski, & Schroer, 1989;Skouloudis & Kottowski, 1991). Microscopic visualization of twophase flow at the instant of blow-down provides another approach to investigate the transient behaviors of viscous fluid in reactor (Bell & Morris, 1992;Chang & Shey, 1999;Duh, Hu, Lee, Kao, & Chang, 1999).…”

Hydrodynamic aspects of venting for vessels containing viscous fluids

“…There is a whole range of such relationships which are either of pure empirical origin or other more sophisticated relationships which are based on the detailed phenomenology of the flow, The numerical code used here employs a rather simple empirical model which has been calibrated against the DIERS depres-surisation data [q. This model relates the void fraction to the relative velocity between the two phases according to: (2) where the empirical factor Ad is referred to as the interface slip coefficient and has dimensions of m5 K g -' s ' . This coefficient has been tested against experimental data from the MPMC test facility of the JRC lspra [3] for simplenon-reacting fluids and the following values were proposed:…”