Study of the film boiling heat transfer and two-phase flow interface behavior using image processing

In the current study, based on a small-scale quench test facility, the two-phase flow interface behavior during quench transients is visualized and analyzed utilizing an image processing framework. The high-fidelity experimental results obtained for two-phase flow in the current framework can support various studies both in the time domain and in the frequency domain. In particular, visualization of the data obtained from different heating surfaces under different test conditions are used to perform a fullscale transient 2-D vapor film reconstruction. The liquid-vapor interface variations in various heat transfer regimes as well as at the initial film breakup point can be directly obtained through the processed data. Moreover, the temporal variation of the interfacial wave frequency approaching quench is investigated in detail. Based on the high-resolution data obtained for the liquid-vapor interface, the detailed phase velocity and temperature profiles are obtained through theoretic analysis, based on which the film boiling heat transfer coefficient (HTC) can be determined. In addition, an improved film boiling HTC model is developed considering the effects of wall superheat, liquid subcooling temperature, vapor film thickness as well as fluid properties. The model is found to predict film boiling HTC well within 15% error. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this study, the behavior of two-phase flow interface during quench transients is visualized and analyzed using an image processing framework. The temporal variation of the interfacial wave frequency approaching quench is investigated in detail. Detailed phase velocity and temperature profiles are obtained through theoretical analysis based on high-resolution data for the liquid-vapor interface.