Calculation of pressure variation in a pressure vessel on delivery of saturated vapor

The method for calculation of pressure variation in a hermetic volume filled with stoking on delivery of saturated vapor is proposed. The method regards for time nonuniformity of stoking heating. Compared are the calculation and experimental data for the case of nonstationary flow of underheated and saturated water out of a pressure vessel into the 3.4 m3 hermetic volume having ceramic rings. The water regimes in the vessel at an initial temperature of 300 deg C and branch pipe diameters of 6, 10 and 15 mm are studied. It is shown that the best coincidence of the experimental curve with the calculation data (with regard for time delay, which did not affect the calculation data due to the following assumptions: the stoking heating regime is regular, vapor delivered into the drum is immediately mixed with air) is observed at different heat transfer coefficients (K). For the 6 mm diameter branch pipe the correlation is observed at K=100 W/m2xdeg C, and for the 15 mm branch pipe at K=400 W/m2xdeg C. It is explained by the fact that at greater diameters the vapour flow rate and its partial pressure increase, that leads to the increase of the heat transfer coefficient. Such magnitudes of K2 correlate with the experimental ones