Test Bench Design for Cryogenic Leak Testing of Hydrogen Distribution System Components under Vibrational Loads

Kurzfassung

In this thesis, a test bench concept was developed to measure the leak rate of hydrogen distribution system components intended for the propellant management of hydrogen-powered aircrafts. The challenge presented itself in achieving a high leak rate detection precision while simulating the conditions experienced by the test component in their normal operating environment. These conditions, namely, are the cryogenic component temperature and the vibrational loads experienced. Multiple concept options were considered, employing different strategies for achieving the required testing conditions. Based on the performance analysis of various concept options, a heat exchanger-based concept, in which the test component is cooled directly with a heat exchanger, was found to be the most suitable for the testing objective. The test concept is designed for a mass spectrometer-based leak detection system with a precision of up to 5 ⋅ 10-12 mbar ⋅ l/s [1]. This concept was further developed, addressing specific design challenges such as thermal insulation, isolation of unwanted potential test bench leaks from the test component leak detection and the thermal length contraction of components. The results of the test bench concept study show strong potential in achieving the required testing conditions with a high leak detection precision. The results, however, are based on a theoretical inspection and may not reflect the real performance of the test bench concept. The next step, therefore, is to perform tests to validate the performance of the test bench systems.