Research of Supercritical Water Flow Instability under Natural Circulation Based on Factorial Analysis

The supercritical water flow instability under natural circulation is important to the safety of the reactor. By the method of factorial analysis, the effects of different factors and the factor interaction on the natural circulation stability boundary are computed. The results show that, for the steady state mass flow, the inlet resistance coefficient has the biggest percentage contribution rate about 70.89%. The next is the interaction of heating zone length and inlet temperature, and its percentage contribution rate is about 13.26%. The third is the heating zone length, and its percentage contribution rate is about 12.32%. For the oscillation period, the heating zone length has the biggest percentage contribution rate about 68.47%, the next is the inlet resistance coefficient, and its percentage contribution rate is about 24.04%. The effect of other factors and factor interaction on the steady state flow and oscillation period are negligible.