Performance Study On Giant Magnetostrictive Actuated Water Hydraulic Servo Valve Based On CFD And FEM

Giant Magnetostrictive Material (GMM) is a new type of function material appearing in recent years with giant strain, fast response speed, high energy density and large output force and so on. Based upon giant magnetostrictive actuator (GMA), a water hydraulic servo valve driven by diphase oppositing giant magnetostrictive self-sensing actuator is put forward. In the thesis, the water hydraulic servo control valve is systematically, deep analyzed and researched by some technologies such as computational fluid dynamics(CFD), finite element method (FEM) and MATLAB dynamic simulation.Based on flow theories of pipe flow and flow in different kinds of typical orifices, theoritical analysis is conducted on hydraulic bridge of giant magnetostrictive water hydraulic servo valve. Simplified model of hydraulic bridge is established and relationship formula between pressure differential of spool ends and flapper displacement is obtained. The results obtained here are good validations for the following CFD simulation. By CFD steady flow technology, pressure distribution of the flapper and the fore face of nozzle is obtained. Relationship curve between pressure differential of spool ends and flapper displacement is also gotten.The dynamic calculation model of slide valve of the opening and closing process is established by CFD dynamic mesh technology. Variation of the opening can be defined by UDF function in FLUENT software. In the thesis, flow field of slide valve at different time is studyed when the opening decreases. Results show that the slide valve with annular groove has a much smaller steady-state flow force. By CFD steady flow analysis, radial unbalanced force of spool comes out very small when compared to hydrostatic bearing force. So, spool can suspend in sleeve well.Contact analysis is conducted on interference fit between nozzle and valve body by ABAQUS/Standard module in Abaqus software. Results show that contact stress between nozzle and valve body varies moderately when material expands owing to temperature variation. Thereby nozzle and valve body can keep good contact.Mechanical analysis is performed on feedback rod-spool components of the stable state of water hydraulic servo valve. Then, the finite element calculation model of the components is drawn. By FEM analysis, the displacement output of the water hydraulic servo valve with different feedback rod matched is obtained, which is useful for designing a suitable feedback rod.Equivalent dynamic model of diphase oppositing GMA is put forward and transfer function model of giant magnetostrictive water hydraulic servo valve is subsequently established. Simulation shows the response time is 0.016s, the amplitude frequency width is 60Hz and the phase frequency width is 50Hz, which implies that the designed servo valve has a good dynamic characteristic.