Sustainability is an important topic in the aviation industry. The vast amount of people and products that fly across the globe daily, produce enormous pollution. How can we correct this? Various large-scale researches, similar to the ASuMED project, deal with this question. Over the past few years, Demaco was actively involved with the design of a sustainable superconductive cryogenic engine for aircrafts.
Sustainability in the aviation industry
Aviation imposes a heavy burden on the environment. Most aircraft consume several kilograms of fuel per minute, resulting in toxic exhaust gases containing CO2, nitrogen oxides, and fine particulate matter.
ACARE Flightpath 2050 has set some challenging sustainability targets for the aviation industry to reduce these toxic exhaust gases. The program aims to pursue the following targets for 2050 as compared to the 2020 targets:
- Reduce CO2 emissions by 75%.
- Reduce emissions of nitrogen oxides and fine particulate matter by 90%.
- Reduce the noise level caused by aviation by 60%.
By nature, improvements to aircraft design are not likely to provide the desired results. This imposes the need to research new and alternative techniques.
One way to make an aircraft lighter and enhance a more sustainable operation is by developing a compact, light, and superconductive engine. The purpose of the 2017 ASuMED project has precisely this goal.
The ASuMED project was funded by the European Union, being an element of the Horizon 2020 Research and Innovation Program. The program is executed by an experienced consortium existing of: Air Liquide, Hochschule Aschaffenburg, Institute of Electrical Engineering, Karlsruher Institut für Technologie, K&S GmbH Projektmanagement, Oswald, Rolls-Royce, SuperOx, University of Cambridge, and Demaco, while Airbus took an advisory role in the project.
The project’s ultimate goal was to develop a cryogenic engine for the aviation industry that reduces fuel consumption and the exhaust of toxic gases.
Why a superconductive engine?
Super conduction is the phenomena under which specific materials lose their electrical resistance once they become extremely cooled. Electric currents are then no longer hindered by any resistance; this offers options to build compact yet very powerful and effective electrical applications.
Electric motors operate according to the same principle. The more conductive the material, the more energy can be converted while the electric motor can be built more compact and lighter.
The ASuMED cryogenic engine
The light and compact ASuMED engine uses superconductivity to obtain the necessary power density and efficiency to acquire the power needed for a hybrid-electric distributed thrust (HEDP) engine, which will propel future large commercial aircraft. The use of cryogenic gas combined with advanced cooling systems (auxiliary equipment) will cool the ASuMED engine to extremely low temperatures to allow superconductive aircraft engines.
How does this work? A cryogenic engine is based upon the double cryostat concept. It comprises two separated cryostats and two separate cooling systems. One system is used for the rotor the other for the stator. The rotor is cooled with helium gas of 25 K (-248.15 °C) and the stator with liquid nitrogen of 20 K (-253.15 °C).
Cooling a moving object
Cooling a moving object, like the rotor in the ASuMED project, comes with considerable challenges. Fixed objects can be cooled through conduction; with moving objects, this is hardly feasible. Alternatively, the best possible option that arose after thorough comparison and analysis is cooling by forced convection.
This is achieved by circulating gaseous helium in a closed system around the rotor (closed-loop cooling); this cools the rotor with a constant flow of cold gas.
Helium with a temperature of 25 K (-248.15 °C) is guided past the rotor. While the rotor is cooled, the gas warms up to approximately 30 K (-243.15 °C). After passing the rotor, the slightly warmed up gas is automatically collected in the cooling system and cooled again to 25 K to pass the rotor again. The process is continually repeated.
Where do we go from here?
The first steps are taken. The FEM analyses (based on the finite element method) is concluded, and the system’s design is completed. The goal of the ASuMED project is achieved. Together with the consortium, we have demonstrated a compact superconductive cryogenic engine’s ability to deliver enough thrust to be used in aviation.
Before the aviation industry can use this type of engine in aviation, further research, tests, and experiments are mandatory. These extensive in-depth experiments and tests will give new insights into how the system behaves under various conditions (for instance, in cold and hot environments), allowing further tweaking and optimizing the cryogenic cooling system.
Demaco a consultant for complex cryogenic issues
Demaco’s working methods are vastly diverse. We employ teams that deal with short-term standard projects, like supplying vacuum isolated transfer pipes or cryopreservation systems.
However, an essential part of our mission is the in-depth studies of complex cryogenic challenges. Being a prominent player in cryogenics, we are regularly consulted to determine the best solution for a variety of cryogenic challenges. Offering a solution for the rotor of the ASuMED project is a clear example of our expertise.
Our involvement in projects of this kind is usually stooled on much more than supplying cryogenic products. We offer the full package consisting of project management, cryogenic engineering, and the supply of the right cryogenic systems.
In many cases, our projects lead to brilliant new inventions. Demaco has already patented the new technique for the highly advanced ASuMED rotor; we anticipate that our invention will contribute to a sustainable aviation industry.
Do you want to know more?
Would you like to read more about liquid hydrogen? Take a look at our liquid hydrogen page for more about this promising cryogenic liquid.