When lightning strikes
On average, every commercial aircraft is hit by lightning at least once a year. This may seem like a daunting prospect for those of us that regularly travel by air. However, thanks to the work of Cardiff University’s Morgan- Botti Lightning Laboratory (MBLL), aircraft are very rarely troubled.
The MBLL is the world’s only university-based lightning lab dedicated to aerospace research and only one of a handful worldwide, providing a research and test capability for understanding and enhancing the science of lightning protection.
One of the main areas of focus of the £2.4m facility is to study protection systems for aerospace structures and fuel systems. The facility can generate controlled lightning with currents up to 200,000 amps, more than five times that of an average lightning strike. The laboratory’s work is no longer limited to aircraft, with research activities expanding into preventing the death of trees from lightning strikes, the development of cleaner and safer insulation gases, and potentially investigating electricity discharges in outer space.
Challenge Cardiff sent Rhys Phillips (BSc 2008), a research engineer at Airbus and Cardiff University alumnus, to talk to Professor Manu Haddad, Director of the MBLL, about the high-impact research being conducted at the lab.
Rhys Phillips: Tell us a little bit about your work and what you do at the University.
Manu Haddad: My work is about high voltage systems. You can find high voltage systems in electric power networks, aerospace, vehicles, medical equipment and anything that is powered with more than 1000 volts. In your car you have a coil for ignition, an x-ray machine, electric pylons and electric substations - all of these are powered by high voltage systems.
Tell me about the group that you run here at the University. How big is it and what sort of facilities do you have to work in?
We have two labs: one specialises in high voltage sources and high voltage phenomena; and we have the lightning lab which specialises in high currents.
When it comes to the sorts of problems you solve, what is the difference? What sorts of problems would need to be done in a high voltage facility as opposed to a high current facility and vice versa?
If I put it in a simple way, in high voltage labs we look at insulation and how good the insulation between two conductors is. If one conductor is at high voltage level and the other is at ground level, we need to make sure that there is no sparking between them. In the high-current lab, it is the opposite. We want to know what the impact is of the current flowing through that test object. That is the case in the lightning lab where we are testing aerospace components when they are hit by lightning.
Are there key discoveries that have come out of your research?
In recent years we’ve been looking at insulation gases. Electrical systems need to be separated by large distances to avoid flashovers between conductors. If you use air, you need a lot of space. In order to reduce the size of these electrical systems, we use insulated systems that use a special insulating gas.
The gas that is used is sulphur hexafluoride, SF6, which is very bad for the environment – 24,000 times worse than carbon dioxide. When it escapes into the air, it can live for over 3,000 years, so the impact that it has on our planet is really bad. My current research is looking for an alternative gas to do the same job but without the damage to the environment and the global warming effect.
How important is collaboration with industry for your research?
I would say possibly 80% of my work is with industry, so it is very important. As engineers, we have specific knowledge in a particular area which is directly applicable to industry, whether it is in the power networks or in aerospace. That knowledge of high voltage of high electric field phenomena is important to industry.
If we think of the future of flight, in the more immediate future electric flight, and in the distant future flying cars, how does your work with lightning strike protection of aircraft translate to future technologies?
I think it will be of direct importance because if you solve the problem of lightning on aircraft, whatever you learn from that experience will help you to solve problems with flying cars or with drones. The work that we do is not only generated by lightning phenomena but by fault currents within the system and the impact of those high currents will be the same.
Read the full interview
This is a shortened version of the full interview that features in the summer 2017 issue of Challenge Cardiff, our research magazine.