Gloyer-Taylor Laboratories, Inc. (GTL), an aerospace engineering research and development company, has announced breakthrough results for its Blended Hybrid Laminate (BHL) composite technology for cryogenic tubes, pipes and transfer lines.

NASA has found when transferring liquid hydrogen (LH2) from a delivery or storage tank to another tank that they lose 50-70 percent of the hydrogen to boil-off. A few of the biggest refueling challenges are the lengthy cool-down times needed to get LH2 to the fuel tank and wasted fuel due to hydrogen boiloff. Now, a first of its kind results from a NASA SBIR program show GTL’s composite tubing can reduce the chill-down time, hydrogen boil-off, as well as the dry mass of cryogenic fluid transfer lines.

GTL first developed BHL technology for cryo-tank applications but it also works exceptionally well for transfer lines, tubes and pipes, providing up to ten times lower thermal mass than metal tubing. In a recent series of tests, GTL demonstrated the feasibility of these pipes in quickly reaching 20 degrees Kelvin temperature and beginning the flow of liquid hydrogen within two seconds. This means that once integrated into operational systems, an aircraft could fill their LH2 tanks in minutes rather than hours and easily manage the small amount of hydrogen that is boiled off during fill operations, significantly reducing fuel costs and increasing operational safety.

“We are thrilled with our team’s efforts to test and validate our BHL technology and its demonstrated ability to outperform conventional metal transfer lines for both mass and boil-off characteristics,” said GTL President Paul Gloyer. “We first had strong results with our tank technology and now we have tubes that demonstrate fast fill and refill capabilities. The ultralight weight BHL technology being used/validated in this effort marks another key milestone in our efforts to advance hydrogen-powered innovation and vehicles.”

Looking closer at the results, the SBIR effort tested a series of lightweight BHL composite tubes along with equivalent metal tubing. And when looking closer at the results, the tests confirmed and validated the enhanced thermal properties of BHL tubes and demonstrated that GTL’s BHL composite tubes chilled down approximately ten times faster than equivalent stainless-steel tubing. The combination of a significant reduction in thermal mass and enhanced heat transfer properties achieved this improvement. With this technology, LH2 boil-off during transfer can be significantly reduced, opening the door to practical no-vent filling of LH2 tanks for aircraft, trucks and spacecraft.

The Phase II effort also verified the scalability of the BHL tubes and demonstrated the capability to build tubes with a range of diameters and lengths. The effort also demonstrated the capability to create tube bends and accommodate tube flexure. As part of the effort, GTL fabricated flight-capable BHL tubing at the main liquid oxygen and liquid methane propellant lines for GTL’s Disruptor suborbital rocket, which successfully used a cold-flow ground test of the vehicle.

GTL has multiple concurrent projects that leverage BHL technology. GTL is currently integrating BHL composite tubing into the flight prototype of GTL’s ultra-lightweight composite LH2 Dewar tank, scheduled for flight testing on a manned helicopter starting in Q4 2024. In the coming year, BHL tubes will be integrated into flight applications where their lightweight, high-performance capabilities will be further validated. GTL intends to integrate BHL tubes into future vehicle designs and cryogenic transfer line solutions. Its BHL technology applies to nearly any cryogenic system and thereby applicable to launch systems; Lunar, cislunar and Mars applications, and satellite systems.