How cool is that?

AMJune21Features - afrc1
AMJune21Features - afrc1

Dr Jill Miscandlon, senior manufacturing engineer at the University of Strathclyde's Advanced Forming Research Centre (AFRC) and Professor Yuan from the University’s department of Electronic and Electrical Engineering, examine the cool ways to research fully-electric long-haul flights – combining low temperatures and manufacturing expertise.

In the 1990s, Boeing began considering a replacement aircraft for the 767 and 747-400, but it was 2003 before it announced its new 7E7 – a new super-efficient, midsized aeroplane. Later the 7E7 would be known as the 787 Dreamliner, taking flight in 2009 using 20% less fuel than other similarly sized aeroplanes. By no means, was the design and manufacture of the aircraft an easy feat with years of research in the making.

Dr Jill Miscandlon, senior manufacturing engineer at the AFRC

Now we find ourselves at the beginning of a similarly enormous task to find a fully electric solution for a long-haul flight in the race to cut carbon emissions. While we are beginning to hear about hybrid solutions for short haul flights with progress being made on a global scale, international flights, which are fully electric, are a whole other ball game. Realistically we are still many years away from this.

At the University of Strathclyde’s Advanced Forming Research Centre (AFRC) and department of Electronic and Electrical Engineering (EEE) we are already looking at how we transform traditional electrical machines for high integrity applications, one of which is propulsion systems for aircraft. As part of the Future Electrical Machines Manufacturing (FEMM) hub, from the Engineering and Physical Sciences Research Council, we aim to revolutionise the design of these machines by bringing manufacturing to the start of the design process.

Working with the EEE departments of the universities of Sheffield and Newcastle, the FEMM hub combines world-leading expertise in electrical machine design with manufacturing and aims to overhaul the design of electrical machines.

The standard manufacturing route follows a design, model, validate, manufacture trajectory, and when manufacture at the prototype stage doesn’t work, the part will be reverted back to the design phase. So to alter our approach, and plug gaps with external expertise, giving equal weighting to design and manufacture from the get-go, we can reduce the time spent making modifications along the way and work together to design and manufacture a part that is structurally sound.

Collaboration is key

Now, the AFRC and EEE have collaborated once again, this time combining our manufacturing and design expertise with extensive research into applied superconductivity in energy storage, power transmission cables and electric propulsion for aircraft.

The University of Strathclyde's AFRC is a specialist technology centre within the National Manufacturing Institute Scotland

With existing electrical machines, the materials resist the flow of the current with energy lost making the system less efficient. In order to power an aeroplane the size of the 787 Dreamliner, for instance, the electrical motors would need an energy per unit mass of at least 40kW/kg. At present the most conventional motors on the market could manage is around 5kW/kg.

It is not currently feasible to use conventional electrical motors to power a large passenger aircraft – they are too bulky and lack sufficient power density. Hence, the primary challenge for us is how to make electric motors small yet powerful enough to allow a plane-load of passengers and their luggage to leave the ground and travel any distance at all before running out of fuel.

In order to get more power from electric motors we need to increase the amount of electricity that a motor is able to carry. Superconductors are materials, which are well placed to let electrical currents run through them with little or no resistance. They could hold the key to the fully electric long-haul flight and so we have combined our approach to consider how we could work together to start the vital research. Just like the development of the 787 Dreamliner, we are a long way away from take-off and research must start now.

Professor Yuan of the University’s department of Electronic and Electrical Engineering

Professor Yuan and Dr Zhang had been focused on low temperature conductors – cooling materials to -200°C to eradicate their electrical resistance. Superconductors, for example, chilled to -200°C, can carry 1,000 times the current of copper at room temperature. The colder a material gets, the more conductive it becomes until it reaches a critical temperature where all electrical resistance suddenly disappears and it becomes superconductive – increasing the amount of energy available.

Part of Professor Yuan’s research now is to improve the efficiency of electric motors by minimising the cooling required onboard the aircraft using his low temperature expertise, and the AFRC will bring manufacturing and design expertise to the table for a combined approach - a unique research team, as far as we are aware, across the world.

Going the distance

An electric aircraft that can fly intercontinental is going to be extremely challenging to design. It is likely that we will need a combination of both traditional and superconductive machines. Through collaboration, within the FEMM hub and our research into superconductors, we are able to see where things cross over with similarities and where the differences are. If we can understand what information applies to both approaches, we can establish where things translate. We might find that the components, for example, are similar in shape, however with the temperatures in which a traditional machine and a superconductor machine operate are vastly different so we need to establish the boundaries of what is applicable. It’s accepted that things will need to change but first we must determine the scope of that.

Collaboration on this is key. What we find is that when those designing the active components and those manufacturing them join up efforts, the conversation is shaped in a completely different way with enough expertise on both ends to understand what can be achieved.

We will be using our expertise in forming and forging along the way, but the new capability for the AFRC is designing components and selecting appropriate materials for use in cryogenic environments. Typically, we need to worry about hotter environments for combustion engines – up to 1,500/1,600°C – however now we are looking at the possibilities for parts within a cool -200°C. This research into low temperature testing for metallics and composite materials will give us the ability to work with new applications across various sectors, for example Scotland’s space sector where we see real traction. The lighter we can make the non-active components in the small satellites that are going into space, the more technology drive parts they can fit in and the larger amount of data that can be extracted. Additionally, within the energy sector, we could bring work back to the UK using the low temperature testing capabilities within projects looking at superconductor wires for clean energy.

First and foremost, we need to establish reliable cryogenic materials testing and determine if the materials we are already using stand up to the environment or if we need to devise new ones. This testing is going to underpin everything else. The Lightweight Manufacturing Centre (LMC), the AFRC’s sister centre within National Manufacturing Institute Scotland (NMIS), is also part of these conversations and we are currently scoping out what testing we need for both an electrical and mechanical point of view.

It may be well into the 2040s before we find ourselves onboard an electric aircraft taking us from the UK to the US, but the research must start now. We need to combine efforts, collaborate and share our learnings.

As well as working with our current collaborators, we are speaking with supply chains and manufacturers, big and small, to address this enormous challenge. The future is electric and it starts here.

https://electricalmachineshub.ac.uk

Company

AFRC

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