The effect of gas-liquid properties on height of disturbance waves in a vertical annular two-phase flow

Gas–liquid two-phase flow, such as the flow near nuclear fuel rods in boiling water reactors (BWRs), is encountered in many industries. In such flows, the dryout of the water film occurs at the thin base film between two successive disturbance waves. Therefore, it is important to elucidate the detailed behavior of disturbance waves. In previous studies, many experiments on disturbance wave flow have been conducted under atmospheric conditions. However, the properties of liquids and gases under atmospheric pressure are quite different from those under BWR operating conditions (7 MPa, 285 °C). Therefore, in the present study, HFC134a gas and liquid ethanol, whose properties at a relatively low pressure and temperature (0.7 MPa, 40 °C) are similar to those of steam and water under BWR operating conditions, are used as working fluids. This paper reports the liquid film thickness characteristics in a two-phase HFC134a gas–liquid ethanol flow.