Theoretical and experimental investigation of the gradual stop of a turbomachine

Unsteady processes and vibrations in hydraulic systems can often cause great damage. The fluid kinetic machine contained in a hydraulic system is often responsible for undesired peak values of the pressure and the occurrence of vibrations. The present investigation is concerned with a simple hydraulic system, taking into account the dynamic behavior of the fluid kinetic machine. A one-dimensional initial and boundary-value problem is formulated and its solution is compared with experimental results. Pressure, volume flow, and velocity relations as a function of time are calculated for a situation involving the sudden breakdown of the driving motor. Tests with a ventilator-pipeline system are conducted for an experimental verification of the theoretical results. The ventilator comes slowly to a stop, and volume flow rate, rotational speed, and pressure decrease monotonically.