Hydrogen as a Fuel in Aviation

Question 1

5 properties of Hydrogen

Answer 1

1. Odorless, colorless and tasteless –> Human being cannot detect it
2. Energy density: In liquid state higher than in gaseous.
3. Volatility: High to detect leaks.
4. Diffusivity: It can diffuse through most materials.
5. Flammability: Flammable in a wide concentration range

Question 2

Hydrogen Storage Descriptors
Names, formulas and important influence factors

Answer 2

Formulas:
1. Gravimetrix index (eta_tank) = m(H2)/(m(H2) + m(tank))
2. Hydrogen-to-tank weight ratio (r_tank) = m(H2)/m(tank)

Important influence factors:
1. Type of storage
2. Shape
3. Capacity

Question 3

LH2 storage integration in fuselage: Types and drawbacks
Ideal surface-to-volume-ratio shape?

Answer 3

Types
1. Integral tank structure:
- Integrated within airframe
- Bear structural loads
- Tank diameter = fuselage diameter
2. non-Integral tank structure
- Extra structure for attaching to fuselage
- Cannot bear any additional loads
- Tank diameter < fuselage diameter

Drawbacks
1. Larger fuselage cross-section
2. Additional drag
3. Wing needs for structural support
4. Less cabin space

–> The ideal surface-to-volume-ratio is the sphere

Question 4

Define electrolysis

Answer 4

Process in which we can obtain Hydrogen (and Oxygen) from water and renewable electricity.

Question 5

Notable differences of introducing Liquid Hydrogen in airports

Answer 5

1. More time to refuel (4-times higher)
2. Introduce a lot of turbulence and friction, adding heat to LH2.
3. Need of more equipment and infrastructure.

Question 6

Effects of Emissions: CO2, NOx, Hydrogen, Contrails and soot/sulfures

Answer 6

Table EffectsOfEmissions