Gloyer-Taylor Laboratories (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 H₂ (LH₂) from a delivery or storage tank to another tank that they lose 50%−70% of the H₂ 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 H₂ boil-off. Now, first-of-its-kind results from NASA SBIR program show GTL’s composite tubing can reduce the chill-down time, H₂ boil-off and dry mass of cryogenic fluid transfer lines.

GTL first developed BHL technology for cryo-tank applications but it also works 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˚ Kelvin and beginning the flow of LH₂ 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 H₂ that is boiled off during fill operations, significantly reducing fuel costs and increasing operational safety.

Looking closer at the results, the SBIR effort tested a series of lightweight BHL composite tubes along the equivalent metal tubing. When the results are further examined, 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.