Abstract
Knowing the value of energy which is accumulated with air and released from a pressure accumulator in a pneumatic pulsator is crucial for the determining of a pulsator performance. The pulsators are used for unclogging outlets of silos in which loose materials are stored. They also prevent from phenomena such as bridging, arching, clinging, ratholing which are specific for loose material.
Results of numerical simulations were used to determine values of energy which can be released from the pressure accumulator. Supersonic airflow during sudden vessel evacuation in which air is compressed up to 6 bar was simulated by using ideal gas model.
Very rapid changes of energy can by observed within time period of 25 ms. Outlet air velocity raises from 0 m/s up to almost 350 m/s during that time. Sudden temperature drop occurs from 300 K to 180 K at the same time.
Reported in literature analytical studies and research on the gaseous vessel evacuation utilize assumptions of gas and flow models which cannot be applied in the case being investigated in this study. Wide vessel outlet cross-section relative to the vessel dimensions makes that the gas inertia and influence of the vessel environment must be taken into account. Therefore the flow cannot be treated as one- dimensional.
As a result of the investigation, we obtain reference value of energy accumulated in the pressure accumulator, furthermore, we will be able to determine the efficiency of separate elements of the pneumatic pulsator system.
