Development of a four-nozzle flapper servovalve driven by a giant magnetostrictive actuator

A novel configuration of a four-nozzle flapper servovalve driven by a giant magnetostrictive actuator is described, and giant magnetostrictive actuator displacement model and four-nozzle flapper valve pressure–flow equation are built, which can quantificationally describe the physical process from input current to control pressure in the giant magnetostrictive material–based four-nozzle flapper servovalve. Then, by a computational fluid dynamics method, control pressure under different zero-clearance configurations is determined by the numerical method and compared with the control pressure determined by a theoretical calculation method, which verifies the availability of the above-mentioned numerical method and the accuracy of the implemented numerical model. Subsequently, to elucidate the interaction rule between the control pressure and the orifice flow with the main structural parameters of a four-nozzle flapper servovalve, the parameters and the configurations of a single nozzle, four nozzles and a fixed orifice are investigated, which provides a theoretical basis for the design and optimisation of a giant magnetostrictive material–based four-nozzle flapper servovalve. A test system of a giant magnetostrictive material–based four-nozzle flapper servovalve is established, and the test results of static control pressure and hysteretic control pressure are obtained, which enables the determination of the maximum output control pressure.