Numerical simulation and experimental study on pulse characteristics of self-excited oscillator cavity

Researches on the structure of large-sized self-excited pulse oscillating cavity are scarce, and the design lacks a solid reliable basis. By relying on the theory of computational fluid dynamics, a hydraulic oscillator model was constructed. Then, the impact of different cavity diameters, inner wall angles and cavity lengths on the pulse pressure discharge amplitude was analyzed, and the influence law of each structural parameter on the pulse variation was disclosed. The results indicate that when D1 = 22 mm, D2 = 28 mm, L1 = 26 mm, L2 = 28 mm, L = 57 mm, and D = 88 mm, the pulsation amplitude is relatively higher when the inner wall impact angle is 60°. The experimental findings demonstrate that the optimized structure can raise the pulsation amplitude of the hydraulic oscillator by 52% to 84% and stabilize the pressure loss within the range of 0.47 to 0.49 MPa. This research can offer a theoretical reference for the structural design of large-sized hydraulic oscillators.