Host: The Japan Society of Mechanical Engineers
Name : The 30th International Conference on Nuclear Engineering (ICONE30)
Date : May 21, 2023 - May 26, 2023
In a space nuclear reactor with a heat pipe cooling core, the heat transfer limit of the heat pipe is an important factor affecting the reactor power. In heat pipes with wicks, the capillary limit is one of the most common limits. The capillary capacity of the wick is the key factor affecting the capillary limit of the heat pipe. The wettability of the working fluid and the wick material greatly affects the capillary capacity of the wick in the heat pipe. In this paper, the wettability of liquid sodium on 304 stainless steel was studied, and the change of contact angle of sodium on 304 stainless steel plate with temperature was measured. The experiment was carried out in a high-temperature vacuum contact angle measuring instrument. The vacuum degree of the experiment was 0.06 MPa. The experiment found that before 300 °C, the contact angle is maintained above 140 °, showing a non-wetting state. This is due to the stainless steel plate surface with a dense layer of Cr2O3 oxide film, which hinders the wetting between liquid sodium and stainless steel. After 300 °C as the temperature increases, the contact angle decreases. The overall change trend of contact angle shows a process of rapid decline first, then slow decline, and finally rapid decline. With the increase of temperature, Cr2O3 is gradually reduced by liquid sodium to form stable NaCrO2. The wettability between liquid sodium and a stainless steel plate was improved. At 420 °C, the contact angle has reached 50 °. When the temperature reaches 530 °C, the contact angle of sodium and stainless steel plate size changes to 0°, reaching a state of complete wetting.
