The Scaled Half Tank test bench

Kurzfassung

Hydrogen as an energy carrier is a promising solution for sustainable and CO2-neutral mobility. For aerospace applications, the storage of hydrogen in liquid form (LH2) is an interesting solution due to its higher gravimetric energy density compared to kerosene and its higher volumetric energy density compared to gaseous high pressure vessels. The development of LH2 tank systems made of carbon fiber reinforced polymers (CFRP) starts with characterizing thermal and mechanical material properties as well as the permeability of the material. Further, specific tests are carried out to test structural features as feedthroughs or joints. All these tests are carried out with sample geometries that are simplified compared to a real tank. Because realistic tanks are large and tests are expensive, a test for a scaled half tank test was developed as an efficient intermediate level. The objective is to demonstrate tank structure technologies at a representative material and geometry level, as well as to validate analysis predictions. The core of the test rig is the half-tank test specimen, which comprises a tank with an internal diameter of 400 mm that is cut perpendicular to the tank axis. The half-tank is pressed and sealed against the bench cover. The inside of the half-tank can therefore be filled with cryogenic medium (LN2 or LH2) or helium and can be pressurized to an internal pressure of up to 20 bar. The half tank and cover plate are placed on a recipient, allowing the surroundings of the half-tank to be evacuated and leakage measurements to be carried out. The tests focus on the thermomechanical behaviour and the leakage behaviour in the tank dome and its cylindrical area. Electrical sensors and fibre optic sensors enable the measurement of temperature and deformation on the inside and outside and windows in the recipient allow further optical inspection.