Flow, Instabilities in a Natural Circulation Boiling Channel : 4th Report, Effect of Each Pressure Loss

Abstract

The frequency responses of the transfer function with respect to each pressure loss are studied to clarify the cause of the density-wave oscillation in a natural circulation boiling channel. In this work, the various parameters in the transfer function are classified into two groups : the common variable and the coefficient of the transfer function. The effects of each pressure loss on the stability are shown in the modified Nyquist diagrams with regard to those parameters. As a result, it was made clear that the inertia loss and the friction loss become the cause of the unstable flow as the parameter Y. becomes large, while the potential head loss does not cause the unstable flow. The acceleration loss always cause the unstable flow regardless of Y_e.