Delft student team takes to the air on liquid hydrogen
AeroDelft, a team of students from TU Delft, is in the process of developing the very first manned aircraft driven by liquid hydrogen. On Wednesday, 24 April, the team unveiled the design of a prototype of this aircraft that only produces water vapour and causes no harmful emissions.
Over the last 120 years, the world of aviation has developed from a few daredevils who dreamt of flying into an industry that enables almost 38.1 million flights to reach their final destination every year. This growth has, however, also created an industry that accounts for 2% of all CO2 emissions, caused mainly by the gases emitted as a result of fuel consumption. Aviation therefore contributes significantly to global warming, which is caused by greenhouse gases, such as CO2. The use of hydrogen to fuel aircraft is still in its very early days and the team hopes to contribute to its development by demonstrating that it is possible to fly unmanned aircraft fuelled by hydrogen.
The team is hard at work designing the propulsion system that will need to convert hydrogen to power the Phoenix, as the AeroDelft aircraft is known. Hydrogen is a logical choice: it is the lightest element known and contains three times as much energy as petrol. In a recent interview, Guillaume Faury, CEO of Airbus, said: “The hydrogen cells offer outstanding efficiency and low noise. These advantages are prompting increasing numbers of transport companies to opt for hydrogen and there are already hydrogen-fuelled buses and cars on the roads”. Using hydrogen to drive vehicles is clearly possible.
It is carried in the aircraft in liquid form because it takes up much less space than the gas and enables more compact storage. This is quite a challenge, since hydrogen must be kept at -253 degrees in order to remain in liquid form. This will mean that the storage tank will need to have an insulating wall of at least 20 cm. The hydrogen is then mixed with oxygen in the cell, releasing energy and producing water vapour. It will actually be possible to take a glass of water from the exhaust of the Phoenix.
However, the use of hydrogen does not only have advantages. The fact that it is so rich in energy means that it can also be explosive. In order to meet the strict safety requirements associated with aviation and guarantee the safety of the people in the aircraft, the team intend to build in the possibility of discharging the hydrogen from the aircraft in order to prevent the danger of explosion in emergencies. Because the hydrogen charges a battery during flight, it will still be possible to land the aircraft safely after discharging the fuel.
The second major challenge involves making the production of hydrogen sustainable. Making liquid hydrogen currently requires too much energy to enable large-scale production. This is why AeroDelft hopes to use the presentation of the aircraft to emphasise hydrogen’s potential as a fuel and align itself with Henri Werij, Dean of the TU Delft Faculty of Aerospace Engineering, who recently said: “The aviation industry faces a major challenge – the need to make aviation more sustainable as soon as possible. This calls for collaboration and out-of-the-box thinking by a new generation of engineers with a belief and determination to change the world. This belief and determination is embodied by the students in AeroDelft”.
By showing the world that it is possible to fly on liquid hydrogen, the team hopes to inspire the rest of the world to invest more in the possibilities of liquid hydrogen and improve the efficiency of its production.
The engineers in the student team have calculated that the manned aircraft should be able to fly from Delft to Morocco on a single tank of fuel. To achieve this, the aircraft must fly as efficiently as possible. One of the revolutionary aspects of attempts to achieve this is the ‘laminar boundary layer suction’ system, which involves making 14 million minuscule holes in the wings. This technology ensures that the thin layer of air that sticks to the wing in normal aircraft, known as the boundary layer, is sucked away. This can lower air resistance by 15%, reducing the aircraft's fuel consumption.
On 7 September 2019, the team of 35 students of 23 different nationalities will test an initial downsized version of the aircraft and hopes the first test flights of the final version can take place at Rotterdam airfield in 2021.