THE UNSTEADY NONEQUILIBRIUM TWO-PHASE FLOWS IN PIPELINE SYSTEMS

摘要

The two-phase unsteady flows of nonequilibrium heterogeneous medium are considered. The new model of such flows based on hydraulic approach is considered. This model can generate the family of various models for special cases of streams. The boundary conditions represent the system of the algebraic or/and obvious differential equations. The stationary solution of a considered problem acts usually as the initial data. The relaxation method can be rather effective for solving of steady problem. The effect of change of scale under occurrence or disappearance of a phase produces significant computing difficulties. The notion of "trigonometric concentration" is offered for damping of this effect. The method of calculation for the two-phase flows based on the method of characteristics is considered. This method uses the two-scale joint grid: one for liquid phase and other for vapour phase. The examples of calculations are demonstrated. The results of calculation for the case of outflow of hyperthermal liquid under sudden pipe failure taking with appearance of vapour-liquid flow are demonstrated. The results of calculations of flows in the system of industrial pipelines of nuclear power plants are discussed.