抄録
Vane type compressors pressurize a back-pressure chamber of the vane with discharge pressure to keep a contact between a vane tip and a stator wall in a steady-state operation. At a start-up operation, however, the discharge pressure has not increased yet and chattering phenomenon sometimes occurs. In this study, a mathematical model to analyze the vane behavior at the start-up operation is developed. The equation of motion is applied to each vane, and the back-pressure of each vane and pressure in a plate groove which is connected to the back-pressure chambers are calculated simultaneously. Then changes of suction and discharge pressure are calculated according to the flow rate through the compressor corresponding to the vane behavior. It is found that when the vane back-pressure becomes less than the suction pressure by a volume increase of the vane back-pressure chamber, the vane hardly comes out from the vane slot, because a negative force caused by the pressure difference is dominant to the vane behavior during the start-up operation. The size of plate groove, i.e. connection area between the back-pressure chamber and the plate groove and the existence of a pressure supply hole also influence the start-up characteristics. Although the start-up operation has irregular characteristics, the calculating results agree qualitatively with the experimental results.
