Gas dynamics of vacuum-pulsed drying food products

The purpose of the study is to form a mathematical model of gas-dynamic processes occurring during vacuum-impulse drying and analyze their dependence on the determining parameters. As an object of study, the operation of a water-ring vacuum pump of domestic production VVN1-1.5 is considered. The influence of leaks on the dependences of the pressure in the receiver and the mass flow rate of gas on time for a given volume of the receiver is studied. With an increase in the intensity of leakage (leaks) from 0.08 to 0.2, the pressure decreases from 20 to 9 kPa. This indicates a noticeable effect of leaks on the process of pumping air. It can be seen how the level of vacuum that can be achieved decreases with an increase in the leakage intensity. This reduces the time to reach it. Similarly, the mass flow rate decreases with increasing leakage intensity. With an increase in the volume of the vacuum chamber, the time to reach a given pressure increases, and with an increase in the diameter of the pipeline, this time decreases. In the time interval from 20 to 180 s, the pressure and mass flow drop by about 5 times. An increase in the leakage intensity by a factor of 2.5 leads to a decrease in pressure and mass flow at the final stage by about a factor of 2. It was established that the nature of the dependence "pressure, mass flow - time" at the initial moment of time from 20 to 40 s is steep, with increasing time it becomes flat. It seems appropriate in the future to improve the proposed model to take into account the effect of temperature and air humidity on the performance of liquid ring vacuum pumps, as well as the evaporation rate of various food products.