Dynamic Analysis and Control of Two Phase Flow Instability in Boilnig Channel

The aim of this paper is to dynamically analyze the instability of two phase flow in a heated channel, in order to avoid its occurrence. Impact of the pump Is modeled by considering a pressure drop function in terms of mass velocity. The conditions of internal resistance characteristic and how it interacts with the pump characteristic curve, which will cause leadding instability; Has been Investigated. In presence of oscillation, the amplitude of oscillation in this phenomenon is limited. Also, It has been shown that the presence of a surge tank can cause instability of the pressure drop in the system. with considering condition that instability occurs if the slope of the external characteristic curve is smaller than the slope of the internal characteristic curve in the negative slope region of the internal resistance characteristic; Instability control methods have been investigated and analyzed by adding input resistance or by control the supply pressure. Lyapunov method is used in order to linear instability analysis and flow phase portrait is presented in singular points. Also, the solution show that the amplitude and frequency of oscillation depend on the oscillation damping coefficient and with decreasing it the frequency of the oscillation increases.