Numerical experience with the two-fluid model, RISQUE

Work with the one-dimensional two-fluid model can be described as an exploration of the feasibility of performing practical calculations with the model. The two-fluid model offers the most detailed description of two-phase flow. It is based on six conservation equations, i.e., mass, momentum and energy for each phase, and thus requires three constitutive equations for the interfacial transfers. The consequences of including the virtual mass effect in a one-dimensional two-fluid model were examined. It was found that the virtual mass has a profound effect upon the dynamics of two-phase flow. The propagation velocity for compressibility waves (sound speed) is strongly influenced by the virtual mass. Also, the behavior of the ''Helmholtz'' waves can be altered drastically: their speed of propagation is modified and the waves become stable under some conditions. The report summarizes some of the theoretical conclusions. In addition, numerical results obtained with RISQUE are presented and compared critically to both theoretical predictions and results obtained from the CANON blowdown experiment