Tuesday, December 17, 2024

A 'safe' version of a hydrogen airship

Working with Gemini,  I postulated an airship with a double layer gasbag. The inner gasbag would contain hydrogen. This would provide lift and act as a store of fuel for fuel cells powering electrically driven propellers. The outer gasbag would contain helium which provides fire risk insulation from the hydrogen. I asked Gemini if such a design was feasible.

Gemini: You've proposed a very interesting and conceptually sound design for a safer hydrogen airship! The idea of a double-layered gasbag with hydrogen inside and helium outside offers a significant safety advantage. Let's analyze its feasibility and discuss a possible cross-section design.

Feasibility: The concept is definitely feasible from a technical standpoint. The main challenges would revolve around engineering and material science rather than fundamental physics.

Material Selection: Choosing appropriate materials for both the inner and outer gasbags is crucial. The inner bag needs to be highly impermeable to hydrogen, while the outer bag needs to be strong and relatively impermeable to both helium and air. Modern materials like multilayer laminates with specialized coatings could meet these requirements.

Weight: Adding a second gasbag increases the overall weight of the airship, which reduces its payload capacity. Set against this is the increased lifting ability of  hydrogen. This is a key trade-off. Careful material selection and design optimization are essential to minimize this weight penalty.

Complexity: Manufacturing and maintaining a double-layered gasbag system is more complex than a single-layered one. This would increase production and operational costs.

Pressure Management: Maintaining the correct pressure differential between the inner and outer gasbags is important to prevent stress on the materials and ensure optimal performance.

Cross-Section Design: Here's a simplified cross-section concept based on the 1930s British R105 airship. I've shown an Airbus 380 fuselage for size comparison:

     Structural Framework (e.g., lightweight beams)

Key Features of the Design:

Outer Envelope: Provides the primary aerodynamic shape and protection from the elements. It also contains the helium.

Helium Layer: Acts as a buffer zone, preventing any potential ignition source from reaching the hydrogen. It also contributes to overall lift, though less than the hydrogen.

Inner Envelope: Contains the hydrogen fuel. This layer must be exceptionally good at preventing hydrogen leakage.

Structural Framework: Provides structural support for the gasbags and connects them to the airship's gondola and other components. This would likely be a lightweight frame made of aluminum or composite materials.

Advantages:

Enhanced Safety: The helium layer significantly reduces the risk of hydrogen ignition.

Redundancy: If the outer gasbag is breached, the inner gasbag still contains the hydrogen.

Disadvantages:

Increased Weight and Complexity: The double-layered design adds weight and manufacturing complexity.

Cost: The use of specialized materials and more complex construction will increase costs.

Conclusion:

The double-layered gasbag concept is a very promising approach to improving the safety of hydrogen airships. While there are engineering challenges to overcome, it is technically feasible and offers a significant safety advantage over single-layer designs. The trade-offs between weight, complexity, and cost need to be carefully evaluated in any practical implementation.

OK industrialists, you have the concept. Feel free to develop and make use of it but remember - I proposed it and you owe me for that.

No comments: