Features of shock-wave and vortex processes simulation at depressurization of circuits with superheated water coolant

Simulating the boiling fluid outflow taking into account external condensation

“…Figure 3.d-f shows that there are pressure surges in the space relative to the pipe section and the outer wall. It may be noted that the structure of pressure surges is close to the quasi-stationary gas-dynamic outflow from the nozzle to the wall, experimentally fixed for superheated steam [8] and numerically calculated in [2]. The process of phase transition dramatically changes the pattern of gas-dynamic discontinuities.…”

“…The problem is solved using the computational complex LСPFCT [7]. A detailed description of the physical model is presented in [1,2,5]. Fig.…”

“…1. Scheme of the computational domain: c -axis of symmetry, a -boundary condition of the "wall" type, k -boundary condition of the "Cauchy-Lagrange" type [2], l -channel length, R -outer radius of the channel, r -inner radius of the channel. At a distance of 200 mm to the wall in a closed area a compression wave generates and moves to the wall (Figure 2f) causing a wave of condensation (Figure 2c).…”

“…When depressurizing tanks and pipelines of power plants filled with water under high pressure, superheated water is released with a sharp decrease in pressure in the rupture zone, with the formation of a compression wave in the surrounding space and further formation of the boiling coolant jet. In previous works [1,2] the outflow was simulated into the area with free inflow-outflow at the boundaries. As a result, there was no reflection of pressure waves and the pressure in the outer region did not rise above the local saturation pressure.…”