Periodic Reporting for period 1 - COCOLIH2T (COmposite COnformal LIquid H2 Tank)
Reporting period: 2023-02-01 to 2024-07-31
Today, most H2 storage tanks are spherical or cylindrical. To better utilise the space available in aircraft, LH2 tanks will need to be conformal to the volume shape resulting in a greater occupancy of the available spaces within the fuselage or empennage. Conventionally, conformal storage solutions use metals which struggle to achieve net system weight savings. For commercial aviation, the light weight alternatives such as composites aim to achieve a higher Gravimetric Index (GI) for the whole storage system.
Beyond geometry and material optimisation, maintaining LH2 at -253°C on board aircraft presents different major challenges. Novel system architectures and protocols will be needed to manage pressures during operation, fuelling and de-fuelling. Lifecycle assurance to withstand 20+ years in service, mechanical and thermal fatigue, cryogenic cycling, etc. must be guaranteed. This will be achieved through secure design, combined with monitoring and detection systems. Structural Health Monitoring (SHM) systems will continuously assess tank integrity whilst Prognostic Health Monitoring (PHM) will scrutinise system integrity and remaining useful life.
Beyond geometry and material optimisation, maintaining LH2 at -253°C on board aircraft presents different major challenges. Novel system architectures and protocols will be needed to manage pressures during operation, fuelling and de-fuelling. Lifecycle assurance to withstand 20+ years in service, mechanical and thermal fatigue, cryogenic cycling, etc. must be guaranteed. This will be achieved through secure design, combined with monitoring and detection systems. Structural Health Monitoring (SHM) systems will continuously assess tank integrity whilst Prognostic Health Monitoring (PHM) will scrutinise system integrity and remaining useful life.
WP2 System Requirements and KPIs
Delivery of the D2.1 High Level Requirements and Objectives (HLRO) document. This document covers certification, safety and integration onto the aircraft, including the definition of the interfaces and the fuel cell requirements. Delivery of D2.2 General Requirements and Objectives (GRO), including comprehensive components and interface definitions. Flight load and tank interface analyses were also completed.
WP3 Integrated LH2 design
WP3 scope has grown tin include several additional actions identified after the start of the project - including extensive material testing, sub-element testing, processing trials, and the design of additional. The material test campaign was completed in M18, confirming the tank design & manufacturing plan. PDR was passed in M14, and CDR in M18.
WP4 Tank thermal and pressure management
In WP4, generalised thermomechanical, and computational fluid dynamics models were developed and used to analyse the COCOLIH2T tank. Completed work includes a sizing study to inform fuelling, refuelling and defueling strategies. Pressure management strategies and system architectures were developed. Using multi-dimensional modelling, the boil-off characteristics of LH2 were explored, and sloshing dynamics analysed. MLI testing has been used to validate and up-issue thermal models.
WP5 Subsystem development
Ancillary components and sub-systems are being developed within WP5. These include piping, valves, gauges and sensors required for safe operation of a liquid hydrogen tank.
System architectures and control system algorithms for fuel monitoring, including hydrogen level gauging, have been designed.
WP6 Tank health monitoring and inspection system
Investigation and down selection of the sensor technologies for structural health monitoring (SHM) and fuel system health monitoring (PHM), including algorithm development. Prototype development of an automated NDI system capable of inner tank inspection. Down-selected sensor technologies were validated through empirical testing and analysis both at room and cryogenic temperatures.
WP7 System integration and demonstration
As part of system integration preparation, test rigs, V&V plans and associated site infrastructure plans have been developed. Specifically, handling and test/assembly frames were designed, a test campaign for the first demonstrator was compiled to pre-test sensors. Additionally, WP7 contributed considerably to an assembly plan for both demonstrators in corporation with WP3-WP6, as well as the realisation of NLR's Energy to Propulsion Test Facility (EPTF).
WP8 Safety & Life Cycle Evaluation
A preliminary safety review of the liquid hydrogen storage system design was performed. A database categorising and evaluating 1000 incidents reported in the existing literature resulted in the derivation of 43 safety criteria. This database, along with an accompanying report, has been published in a public deliverable.
WP9 Communication, dissemination, exploitation and standardisation
A public website and LinkedIn page have been set up. Dissemination to date include press releases, conferences participation, CHJU/CAJU workshop attendance, and various informal events (e.g. trade shows, posters, etc.). The CAB (COCOLIH2T Advisory Board) has been established and interactions are ongoing.
Delivery of the D2.1 High Level Requirements and Objectives (HLRO) document. This document covers certification, safety and integration onto the aircraft, including the definition of the interfaces and the fuel cell requirements. Delivery of D2.2 General Requirements and Objectives (GRO), including comprehensive components and interface definitions. Flight load and tank interface analyses were also completed.
WP3 Integrated LH2 design
WP3 scope has grown tin include several additional actions identified after the start of the project - including extensive material testing, sub-element testing, processing trials, and the design of additional. The material test campaign was completed in M18, confirming the tank design & manufacturing plan. PDR was passed in M14, and CDR in M18.
WP4 Tank thermal and pressure management
In WP4, generalised thermomechanical, and computational fluid dynamics models were developed and used to analyse the COCOLIH2T tank. Completed work includes a sizing study to inform fuelling, refuelling and defueling strategies. Pressure management strategies and system architectures were developed. Using multi-dimensional modelling, the boil-off characteristics of LH2 were explored, and sloshing dynamics analysed. MLI testing has been used to validate and up-issue thermal models.
WP5 Subsystem development
Ancillary components and sub-systems are being developed within WP5. These include piping, valves, gauges and sensors required for safe operation of a liquid hydrogen tank.
System architectures and control system algorithms for fuel monitoring, including hydrogen level gauging, have been designed.
WP6 Tank health monitoring and inspection system
Investigation and down selection of the sensor technologies for structural health monitoring (SHM) and fuel system health monitoring (PHM), including algorithm development. Prototype development of an automated NDI system capable of inner tank inspection. Down-selected sensor technologies were validated through empirical testing and analysis both at room and cryogenic temperatures.
WP7 System integration and demonstration
As part of system integration preparation, test rigs, V&V plans and associated site infrastructure plans have been developed. Specifically, handling and test/assembly frames were designed, a test campaign for the first demonstrator was compiled to pre-test sensors. Additionally, WP7 contributed considerably to an assembly plan for both demonstrators in corporation with WP3-WP6, as well as the realisation of NLR's Energy to Propulsion Test Facility (EPTF).
WP8 Safety & Life Cycle Evaluation
A preliminary safety review of the liquid hydrogen storage system design was performed. A database categorising and evaluating 1000 incidents reported in the existing literature resulted in the derivation of 43 safety criteria. This database, along with an accompanying report, has been published in a public deliverable.
WP9 Communication, dissemination, exploitation and standardisation
A public website and LinkedIn page have been set up. Dissemination to date include press releases, conferences participation, CHJU/CAJU workshop attendance, and various informal events (e.g. trade shows, posters, etc.). The CAB (COCOLIH2T Advisory Board) has been established and interactions are ongoing.
WP2 System Requirements & KPIs
Key Performance Indicators (KPIs) have been established and will serve as a reference towards state-of-the-art values for liquid hydrogen tank system. Main results for the work package will include the Verification and Validation Plan (V&V), as well as a HLRO for aircraft level requirements and GRO for sub-system and component level requirements.
WP3 Integrated LH2 design
Reusable design learning towards the development of future double-walled cryogenic tanks or pressure vessels include: 1) Spacer design concept 2) Polar-boss design and lamination strategy 3) Collapsible mandrel methods for AFP manufacture of closed shell structures
WP4 Tank thermal and pressure management
Generalized thermal models allow for quick sizing studies on LH2 tank design. These validated models extend beyond tank design and will assist with modelling operations like refuelling, defuelling, and venting allows for better understanding and sizing of LH2 infrastructure at airports.
WP5 Subsystem development
New components such as Hydrogen fuel gauges and fly-away cryogenic valves (for fuelling & pressure relief) will be developed to TRL4. Commercial components such as hydrogen leak sensors, acoustic emission sensors (SHM), will be evaluated in a complex system. Control algorithms and hardware will be developed and tested using both liquid nitrogen (demo 1) and liquid hydrogen (demo 2).
WP6 Tank health monitoring and inspection system
The work for the period M1 – M18 had a number of important results including the development of key functional, safety and defect requirements for the new H2 tank concept, and the development of sensing and algorithmic capabilities that can enable structural and fuel system health monitoring in cryogenic temperatures.
WP7 System integration and demonstration
Test set-ups and a unique test facility are being designed and build to safely test 2 demonstrators with state-of-the-art sensors for measuring LH2 levels, pressures, temperatures and the structural health of the storage containers. Outputs of the test campaigns will be used to further develop composite liquid hydrogen containers in order to replace fossil fuels for hydrogen power and make aerospace more sustainable.
WP8 Safety & Life Cycle Evaluation
The preliminary safety analysis extends our understanding of the potential hazards associated with the use of liquid hydrogen in aviation and how they can be mitigated, which will help ensure the safety of hydrogen powered aircraft, despite the novelty of the technology. The safety analysis also provides valuable input for the development of new regulations to enable certification of hydrogen powered aircraft.
Key Performance Indicators (KPIs) have been established and will serve as a reference towards state-of-the-art values for liquid hydrogen tank system. Main results for the work package will include the Verification and Validation Plan (V&V), as well as a HLRO for aircraft level requirements and GRO for sub-system and component level requirements.
WP3 Integrated LH2 design
Reusable design learning towards the development of future double-walled cryogenic tanks or pressure vessels include: 1) Spacer design concept 2) Polar-boss design and lamination strategy 3) Collapsible mandrel methods for AFP manufacture of closed shell structures
WP4 Tank thermal and pressure management
Generalized thermal models allow for quick sizing studies on LH2 tank design. These validated models extend beyond tank design and will assist with modelling operations like refuelling, defuelling, and venting allows for better understanding and sizing of LH2 infrastructure at airports.
WP5 Subsystem development
New components such as Hydrogen fuel gauges and fly-away cryogenic valves (for fuelling & pressure relief) will be developed to TRL4. Commercial components such as hydrogen leak sensors, acoustic emission sensors (SHM), will be evaluated in a complex system. Control algorithms and hardware will be developed and tested using both liquid nitrogen (demo 1) and liquid hydrogen (demo 2).
WP6 Tank health monitoring and inspection system
The work for the period M1 – M18 had a number of important results including the development of key functional, safety and defect requirements for the new H2 tank concept, and the development of sensing and algorithmic capabilities that can enable structural and fuel system health monitoring in cryogenic temperatures.
WP7 System integration and demonstration
Test set-ups and a unique test facility are being designed and build to safely test 2 demonstrators with state-of-the-art sensors for measuring LH2 levels, pressures, temperatures and the structural health of the storage containers. Outputs of the test campaigns will be used to further develop composite liquid hydrogen containers in order to replace fossil fuels for hydrogen power and make aerospace more sustainable.
WP8 Safety & Life Cycle Evaluation
The preliminary safety analysis extends our understanding of the potential hazards associated with the use of liquid hydrogen in aviation and how they can be mitigated, which will help ensure the safety of hydrogen powered aircraft, despite the novelty of the technology. The safety analysis also provides valuable input for the development of new regulations to enable certification of hydrogen powered aircraft.