Investigation of fluctuation characteristics of heat transfer in liquid-vapor two-phase flow

The time-spatial distribution and the fluctuation behavior of void fraction wave and pressure wave are very important for understanding the mechanism of heat transfer of liquid-vapor two-phase flow. Based on the study of fluctuation behavior of pressure wave in liquid-gas two-phase flow in this paper the nonlinear and chaotic behavior of two-phase boiling system have been investigated by both theoretical and experimental method. According to the principles of deterministic chaotic dynamics and time series analysis theory an integrated chaos time series analysis software (WLCHAOS) was implemented. The experimental investigation has been made in R113 boiling liquid-vapor two-phase system to examine above new method. The results show following conclusions: The Chaos Time Series Analysis method (CTSA method) as a new and useful qualitative tools can be applied to study the nonlinear dynamic instability of heat transfer of boiling two-phase system. The investigation of R113 boiling two-phase experiments shows when the void fraction increased in slug flow, the flow has propagated more violent fluctuation and the slugs have broken disorderly, the flow regime is thrown into churn flow. Using our data treatment software (WLCHAOS) the time series, the power spectra and the phase-space trajectories obtained from experimental data of this flow pattern transmit have shown the churn flow came into chaotic state.