Mathematical modeling and experimental investigation of pressure characteristics inside the pilot stage of the deflector jet servo valve considering secondary jet velocity distribution

Existing mathematical models for deflector jet hydraulic amplifiers cannot accurately describe the influence of the deflector motion on the receiver jet, which results in calculation differences for the receiver pressure. To deeply investigate this problem, the momentum transfer model considering secondary jet velocity distribution was used to develop an improved model that is more aligned with the actual state of the flow field. In this model, the receiver jet velocity is calculated, for the first time, with a maximum error of 18% when compared with existing models. To verify the improved model, the recovery pressures in the receivers were verified by numerical simulations and experiments. The verification results show that the model can accurately predict the recovery pressures in the receivers within an 8.1% maximum error. This model fills the gaps in the theoretical research and lays a foundation for the structural design of deflector jet pressure servo valves.