Abstract
A new type fluidic oscillator had been developed and the fatigue testing machine to which this oscillator is applied is now used to study the mechanism of impact fatigue fracture of reed valves for compressors and engines. Since the output flow of this oscillator is used directly as working fluid of the machine, the oscillator must be operated under high supply pressure range above the critical one. The oscillator was realized with the construction that two outlets of a supersonic bistable device were bifurcated and the load capacitor was connected to each bifurcated channels. Thereby, the output jet can keep high power without losing energy through the load capacitor.
The fluidic circuit of the oscillator has been analyzed by a lumped parameter equivalent circuit model based on some parameters of a load capacitor, then the calculated values of oscillation frequencies have been compared with the experimental values. It was appeared that the inductive and thermal conductive effects in the load capacitor must be considered especially in the case of low aspect ratio of the load capacitor.
Switching condition was clarified that the pressure in the load capacitor rises up to 80% of the total pressure of the flow in the outlet. With this analytical model, the oscillation frequency can be estimated for various configurations of the load capacitor.
