STTR Phase I: 3D Printed Vapor Cooled Liquid Hydrogen Storage Tank for Use in Enterprise Level Unmanned Aerial Vehicles

该STR第一阶段项目将为无人机开发3D打印液氢燃料箱。无人机目前的动力是长寿命、低可靠性的汽油发动机，或短寿命、高可靠性的电力推进。如果使用适当的储氢方法，氢燃料电池有可能实现长寿命、高可靠性的推进。通过该项目开发的创新储氢系统，燃料电池电动汽车可以通过减少排放，促进地面和空中的能源独立，促进国民健康和福利。该项目将为电动无人机开发一种新型的液氢储存罐，这将提高军队中监视平台的可靠性和性能，降低美国军人的风险，同时确保我们国家的国防安全。同样的电动平台将通过对关键能源和交通基础设施的检查来促进国家福利，并在自然灾害期间作为第一反应人员的情报和通信平台。此外，该项目开发的关键技术将通过展示工程塑料在低温(-238°F)环境中的能力和性能来扩大添加剂制造的用途。这种低温3D打印聚合物部件具有广泛的影响，包括降低成本，涉及从医疗设备和航天器到药品和食品加工等依赖低温的技术领域。到目前为止，添加制造的聚合物从未用于低温应用。聚合物混合物的正确选择、轻质不透膜的测试和选择以及新型绝缘材料的热特性是项目成功的关键。自20世纪60年代以来，大多数低温研究，如氢通过聚合物的-423°F渗透，都没有被研究过，因此需要丰富的低温工程和测试经验，才能将现代材料和制造方法应用到该项目中。该项目的目标将通过测试金属化聚合物薄膜的氢渗透性以及将其经济高效地应用于保温板或罐壁的制造方法来填补知识空白。虽然先前的研究已经确定了一种耐低温热循环的聚合物混合物，但微破裂的可能性尚未得到彻底解决，将在本项目中进行评估。在商业低温应用中从未使用过的新型绝缘材料将进行热学表征并集成到原型储罐中。该项目将通过完成液氢燃料填充和测量质量沸腾速率来测试计算流体动力学模拟性能来结束。

This STTR Phase I project will develop 3D printed liquid hydrogen fuel tanks for unmanned aerial vehicles (UAVs). UAVs are currently powered by long endurance low reliability gasoline engines, or short endurance highly reliable electric propulsion. Hydrogen fuel cells offer the potential for long endurance highly reliable propulsion if the proper hydrogen storage method is used. Through the innovative hydrogen storage system developed by this project, fuel cell electric vehicles can advance national health and welfare through reduction of emissions, and promotion of energy independence both on the ground and in the air. This project will develop a new class of liquid hydrogen storage tanks for electric UAVs that will increase the reliability and performance of surveillance platforms in the armed forces, reducing risk to American service personnel while they secure the defense of our nation. The same electric platforms will promote the national welfare by enabling the inspection of key energy and transportation infrastructure and serving as intelligence and communications platforms for first responders during natural disasters. In addition, the key technology developed in this project will expand the utility of additive manufacturing by demonstrating the capabilities and performance of engineered plastics in cryogenic ( -238°F) environments. Such cryogenic rated 3D printed polymer parts have wide ranging impacts, including cost reduction, across cryogenic dependent technology areas from medical devices and spacecraft to drug and food processing.Additively manufactured polymers have never been used in cryogenic applications until now. The correct selection of polymer blend, testing and selection of a lightweight impermeable membrane, and thermal characterization of novel insulation materials are critical to project success. Since most cryogenic research, such as -423°F permeation of hydrogen through polymers, has not been studied since the 1960s, extensive cryogenic engineering and testing experience is required to apply modern materials and manufacturing methods to the project. The objectives of this project will fill knowledge gaps by testing metallized polymer films for hydrogen permeability, as well as manufacturing methods to cost effectively apply it to insulation panels or tank walls. While prior research has identified a polymer blend that is robust to cryogenic thermal cycling, the possibility of microcracking has not yet been thoroughly addressed and will be evaluated in this project. Novel insulation materials never before used in commercial cryogenic applications will be thermally characterized and integrated into the prototype tank. This project will conclude by completing a liquid hydrogen fuel fill and measuring the mass boil-off rate to test computational fluid dynamic modeled performance.