Research On Temperature Distribution And Thermal Deformation Of Giant Magnetostrictive Electro-Hydrostatic Actuator

Compared with the traditional aircraft hydraulic system the pipeline and accessory located all over the whole machine, the giant magnetostrictive electro-hydrostatic actuator(GMEHA) has many advantages such as compact structure, high reliability. As the core component of the GMEHA, the performance of GMEHA is determined directly by the precision of the giant magnetostrictive actuator(GMA) output displacement. However, the temperature rising and thermal deformation of GMA are seriously impact on its output displacement because of its narrow inner space and poor heat transfer under high frequency current driving. Therefore, based on the application requirements of GMEHA, the research on the temperature distribution and thermal deformation of GMA is studied in this paper.Firstly, according to the GMA's structure characteristics and driving requirements in GMEHA, the GMA power loss models that include coil resistance loss, eddy current loss and hysteresis of giant magnetostrictive material(GMM) are built under high frequency and large current driven by long time. The GMA power loss models are solved and the mapping relationship between driving frequency and power loss is analyzed. The experiment platform of GMA power loss is built and the experimental result is in good agreement with the model. Then, two different cooling methods including pipe cooling and cavity cooling are designed due to GMA temperature rising seriously. FLUENT software is utilized to simulate the thermal coupling of pipe cooling GMA, and the steady state heat transfer results of GMA under different simulation conditions are analyzed. According to the theory of heat transfer laws, the cavity cooling GMA's steady-state equivalent thermal resistance model and heat-transfer mathematical model are built. The mathematical models of GMA heat-transfer are solved and the temperature distribution, the thermal deformation, and the heat transfer rate of GMA under free convection and forced convection are completely obtained, respectively. Finally, based on the above mentioned study, the experimental platform of GMA temperature control is built and the experimental results are in agreement with the simulation model and theoretical calculation. The effectiveness of pipe cooling and cavity cooling are compared. After the 1A current is sustained by the 80 min. The temperature rise of GMM rod can be controlled within 2? under pipe cooling and cavity cooling condition, respectively. And the thermal deformation control within 6?m and 1?m under pipe cooling and cavity cooling condition, respectively.