Comparison of simulation and experimental results for functional verification of a propellant mass-flow regulation device

摘要

A development program for the Ariane 6 is currently underway. The need for a reliable flow regulator for tank pressurisation is required. The regulation device should demonstrate robust behaviour under a wide range of inlet conditions for the fluids, oxygen, hydrogen, helium and nitrogen. A two stage electro-magnetically (solenoid) driven design was selected. The two stage design combines the advantages of an electro-magnet valve (EV) with the ability to open a large seat at high pressures. Due to the design, a strong influence of fluid parameters was expected. A numerical model developed to support the early design phase was implemented and used to identify the influence on functional behaviour for the requirement domain. Tests on initial designs have been conducted to verify simulation results and to mitigate risks before qualification commences. The numerical model was able to qualitatively predict the influence of medium on opening times where a significant increase in opening time for the fluids nitrogen, and oxygen was identified. The influence of cryogenic temperatures for the medium oxygen was found to dramatically increase opening times, to the point where the valve may not open for specific inlet conditions. Test results could not verify this due to the strong secondary influence of small inlet reservoir size used for the test and the complex functional behaviour of the two stage valve. Effective, on-going use, of the model depends on model validation and the models ability to reproduce the complex functional behaviour observed in test. The first approach for correlating test and simulation through optimisation of flow coefficients with a cost function had limited success. A flaw in methodology was identified, specifically, the use of total opening time as the matching criteria which is influenced by other parameters not only the flow parameters used in the cost function. Future investigations will use the manoeuvre time to correlate simulation which is di