Mathematical modeling of two-phase flow instabilities in parallel channels

The objective of this subject is to study the two phase flow instabilities in parallel channel's upflow system. For the past several years, a group at the University of Miami has conducted experimental studies and theoretical analysis on two phase flow instabilities. This paper represents a mathematical model to compare the experimental results of NSF project MEA-8214867. It simulates the steady state characteristics and pressure drop instabilities in two parallel channels. The model is based on assumptions of homogeneous two-phase flow and thermodynamic equilibrium of the phases. Compressibility effects in the two-phase region and the thermal capacity of the heater wall have been included. Finite difference method has been used to prepare a computer code for the solution of the governing equations. This model can be used to predict the effects of system geometry, heat inputs, inlet subcooling, mass flow rate, quality, inlet and exit restrictions, as well as effects of property variations, amplitudes and period of sustained oscillations. Experimental results of two parallel channels electrically heated, forced convection upflow systems have been used to compare the model predictions