Design of fast acting actuators for cryogenic valve applications in the ARIANE5-program (abstract)

Presently valve developments are being carried out for the new European space launcher ARIANE5. In the case of the tank pressurization and helium supply system valve actuation times in the order of 20–50 ms, liquid hydrogen and liquid helium temperatures, pressures of up to 210 bar, and the need of a very compact volume lead to a requirement profile of the valve actuation unit which is met by directly controlled solenoid actuators with an additional permanent magnet. The modeling of the magnetic circuit comprises the elements of permanent magnets, solenoids, ferromagnetic materials, and several airgaps. The solutions of the model are gained by means of FE program the which is capable of taking into account not only the time transients of the developing current in the solenoid but also moving parts in the magnetic field, which themselves contribute to the magnetic flux change. The results of major interest being calculated are the force versus stroke curves and the current versus time curves. The mechanical and magnetic properties of the employed materials are taken either from available data sources or from critically reviewed measurement data. Additionally, subsequently needed material characterizations were performed at ambient down to T=4 K. The simulation results are compared to static and dynamic test results and show good agreement. Finally the simulation proves to be very helpful to predict and explain the behavior of the complete valve unit consisting of actuator and flow part. Even effects due to cryogenic operation, which occur in the integrated valve, may be analyzed.