LIQUID HYDROGEN TESTING OF AN ULTRA-LIGHT FLEXIBLE TEMPERATURE AND LIQUID LEVEL SENSING PROBE

摘要

The ultra-light, patent pending, flexible sensing probe technology for measuring fluid temperature gradients and liquid level inside flight vehicle cryogenic propellant tanks has been successfully tested in a liquid hydrogen environment. The novel one-piece mechanically flexible sensing probe called the Cryo-Tracker (C-T) consists of multiple dual-use silicon diode sensing elements encapsulated in layers of polyimide that can measure either temperature or liquid level. The sensing probe performed flawlessly in its first exposure to liquid hydrogen. The C-T flex probe was submerged in liquid hydrogen for a total of 33 days and was subjected to three cold shocks. The probe accurately measured liquid hydrogen temperature to within 0.5 K of a control standard without special calibration. The sensing probe measured liquid level under flowing conditions to an accuracy of ± 0.19 inches (± 4.8 mm) or approximately 0.3% of total liquid mass. The probe was used to calculate tank fill and drain liquid flow rates. These tests show the feasibility of the sensing probe for use in cryogenic propellant mass gauging systems for transportation vehicles and ground support equipment.