Natural evaporation of sodium under the conditions of mist formation

The natural evaporation of liquid sodium from a horizontal isothermal plane is described. Experiments were carried out by changing the temperature of liquid sodium or the pressure of argon gas. Estimation of the amount of evaporation was also made by the critical supersaturation model (CSM). The experimental results were compared with the theoretical estimation. The rate of evaporation was 1 to 3 times as large as that estimated from the analogy of heat transfer and material transfer, and was almost same as the result of forced evaporation experiment. The estimated values of vapor pressure by the CSM were accurate enough for practical use. However, this agreement does not mean the adequacy of assumption of the CSM. For the further discussion, more information concerning the mist formation is required. (Kato, T.)