Boiling incipience of liquid sodium flow in an annular channel based on wavelet analysis

Abstract

During hypothetical accidents of sodium-cooled fast reactors, such as unprotected loss of flow, transient power surge accidents, unprotected thermal trap accidents, etc., sodium boiling may occur. A series of boiling incipient phenomena for liquid sodium flow in an annular channel were investigated experimentally. The boiling incipience signal in different experimental conditions were analyzed through the Discrete Wavelet Transform (DWT). The various differential pressure signals in the process of boiling incipience were collected by a differential pressure transducer installed on the effective heating section. The experiment was performed in the heat flux range of 128–846 kW/m2, mass flow rate range of 7.2–122.0 kg/h, system pressure range of 0.85–28.79 kPa and inlet subcooling range of 63.1–287 °C. Since these correlations of predicting the boiling incipience for water in different channels are not suitable for the boiling incipience of liquid sodium, a semi-empirical correlation for the prediction of boiling incipience is obtained in the present study. The prediction error of the new semi-empirical correlation for experimental data is basically within ± 30% in this paper. This work provides a meaningful liquid sodium boiling incipience prediction method.