Estimation of the Possibility of Using the Classical Theory of Nucleation in the Calculation of the Limiting Superheat for a Metastable Liquid in the Region of Onset of Nucleate Boiling

Resumo

Experimental data obtained at VTI for the onset of nucleate boiling of water in a uniformly heated pipe with a diameter of 5.77 and 6.34 mm at a mass flow rate W_j = 1400–5000 kg/(m² s) and at a pressure of P = 9.81, 14.7, 19.62 MPa are presented in comparison with a theoretical calculation on the homogeneous nucleation mechanism in a metastable liquid for the liquid superheating limits obtained using the classical Gibbs formula [1]. It is assumed that the thermodynamic instability of the process in the area under the spinodal affects the breakage of metastable liquid films with the formation of holes through the entire thickness thereof, which ultimately leads to the formation of unwettable dry spots (spinodal dewetting) and causes a spontaneous transition to the film boiling mode.