National Composites Centre in Bristol, U.K., has launched a new composite cryogenic storage tank testing program, which will be used to validate and accelerate design, manufacture, and testing capabilities.
The initial testing will involve a linerless carbon fiber tank that is designed for storing liquid hydrogen (LH2). Cryogenic storage tanks are an essential component of hydrogen-powered aircraft set to launch in the mid-2030s. While most designs for storing LH2 have been based on metallic tanks, they tend to be heavy. Composite tanks developed in the space industry tend to be suitable for only single-use applications. Commercial hydrogen aircraft will require fuel tanks that are lightweight, can be filled and emptied numerous times, and last for several decades.
To support the transition to a low-carbon economy, the NCC is developing the necessary knowledge for composite cryogenic storage tanks and testing by developing product demonstrators of increasing complexity. The NCC team of specialist engineers has also developed a range of cryogenic concepting and design tools to help UK organizations overcome known engineering challenges that are critical to accelerating hydrogen development.
Since there are no existing industry standards for aerospace cryogenic tanks, the ability to analyze a range of designs is essential. This has led to the development of a range of concepting tools that cover tank design space exploration, permeability, microcracking, thermal and mechanical stresses. These tools form a baseline toolset that can be used by industry for cryogenic tank projects, enabling detailed design and manufacturing risk identification and analysis. The NCC’s understanding of cryogenics at this fundamental level will enable them to support a wide range of industries and applications, each facing separate but overlapping challenges.
Testing is a crucial part of the cryogenic tank development program, which currently requires access to specialist testing facilities. LH2 requires well-insulated cryogenic storage vessels to maintain it at a temperature of -253°C, and handling requires specialist knowledge and equipment. To develop a U.K.-based testing capability for its customers, the NCC has partnered with Filton Systems Engineering (FSE), a Bristol-based SME specializing in fluid system engineering. FSE owns and operates a hydrogen test facility that is capable of both gaseous and liquid hydrogen testing.
Working in partnership with FSE, the NCC has developed a tank-testing program that uses an LH2 vacuum test chamber and cryo-rated testing instrumentation. As a world-leading composites research and development center, the NCC has designed and manufactured five linerless carbon fiber demonstrator tanks, using a mix of automated fiber placement (AFP), tape winding, and hand lay-up composite processes. The tanks will be used for the liquid hydrogen testing program, starting at the end of April 2023, with results expected summer 2023.
According to Daniel Galpin, an advanced research engineer at the NCC, the cross-sector capability that they have developed will enable the U.K. industry to accelerate and advance engineering expertise in composite cryogenic storage, and secure future commercial competitiveness. The comprehensive program will enable the NCC to support customers on their journey to design, validate, manufacture, and test high-cycle composite cryogenic tanks.
The NCC Hydrogen team is collaborating with partners and the supply chain to advance engineering expertise in composite cryogenic storage systems that will help the U.K. achieve its net-zero ambitions. This builds on the NCC’s investment in capability development for hydrogen pressure vessels and hydrogen smart pipes: two other areas that will help establish a strong H2 supply chain as the Government implements its U.K. Hydrogen Strategy to kick-start a vibrant hydrogen economy by 2030. The expertise and knowledge developed through the focus on cryogenics have enormous potential for numerous cross-sector applications and will guide technology development.