Effect of heat flux on fluctuating pressure in steam-water two-phase flow

Experiments are carried out to study the feature of pressure fluctuating in helical coil for both adiabatic and boiling steam-water two-phase flows. And the effects of heat flux on the fluctuations are stressed study. It shows that heat flux has great influence on the fluctuation feature. The root mean square (RMS) of the fluctuation process under the condition of low heat flux is similar as that of adiabatic flow, while the RMS of great heat flux differs greatly for that of adiabatic flow. The fractal dimension is close to 1.50 under the condition of great heat flux, which means the pressure fluctuating is approaching stochastic process. The correlation dimension increases with increasing of heat flux. The Kolmogorov entropy on the condition of low heat flux is greater than that of adiabatic flow, while the contrary appears under the condition of great heat flux. It can be concluded that the flow pattern map and transition theories for flow patterns on basis of adiabatic flow just can be extrapolated to boiling flow with low heat flux