Method of calculation of unsteady formation of the liquid phase in rapidly expanding flows of supercooled steam in the stages of wet steam turbines

• Main Authors: Шубенко, Александр Леонидович, Голощапов, В. Н., Бабак, Н. Ю., Решитько, И. В.
• Format: Article
• Language: Russian
• Published: Journal of Mechanical Engineering 2015
• Subjects: moisture; stage; mathematical model; method; supercooled steam; condensation; влажность; ступень; математическая модель; метод; переохлажденный пар; конденсация; УДК 621.165; вологість; ступінь; математична модель; переохолоджений пар; конденсація
• Online Access: https://journals.uran.ua/jme/article/view/57516

The problem of the unsteady nucleation of the liquid phase in rapidly expanding flows of supercooled steam in the turbomachinery flow path was raised and solved. In order to solve it, the Zel’dovich–Frenkel classical theory of condensation for the case of time-dependent external conditions was elaborated. To characterize the level of unsteadiness, an unsteadiness factor was introduced linking the relaxation time with the steady-state distribution and rate of change of the nucleation barrier. A numerical and analytical method of calculating the condensation was developed, which is implemented in the form of the application program package. The method accommodates consistently the unsteadiness of the condensation process. It is based on a universal system of equations, which enables calculating the steady-state and unsteady flows with condensation under an arbitrary value of the coefficient of condensation. This system is a generalization for the case of the unsteady nucleation of the known system of “moment equations”. The numerical model studies were conducted which showed high efficiency and accuracy of the method over a wide range of expansion rates. A comparison to the existing “steady-state” methods and reference numerical solution was performed. The agreement of the results can be said to be satisfactory.