Hi, my name is Henk Jan van Gerner. I’m a mechanical engineer with a PhD in fluid dynamics and I work as a research engineer at Royal Netherlands Aerospace Centre NLR for 15 years.
What was your original motivation to become a researcher?
I always wanted to understand things, e.g. why is the sky blue, how machinery works, or how does the human body work. I also liked to build things. Since building biological things was not really possible when I started my studies, I decided to go for mechanical engineering. What I like about being an engineer and researcher is that we are trying to understand really complex phenomena and use that understanding to build things that (hopefully!) contribute to a better world. What I also like is working in teams; Together with colleagues from many companies, we are trying to make better solutions and products.
What is your (main) research area today?
My main research area is thermal control. We make cooling systems for spacecraft and aircraft, but also for terrestrial applications. For example, we made a cooling system that controls the temperature of a 5000 kg optical table (which is used to make high resolution screens for smartphones) within ±0.0002°C temperature stability. Such extreme temperature stability is required to reduce thermal expansion of the optical table to achieve nanometer accuracy. We also developed a cooling system for the Alpha Magnetic Spectrometer (AMS02). AMS02 is a particle detector that has been launched with the space shuttle in May 2011, after which it was mounted on the International Space Station. Since then, the thermal control system keeps the AMS02 particle detector at a very stable temperature in a strongly fluctuating thermal environment. We are now using this thermal expertise to develop cooling systems for aircraft.
What is the main objective of your team in BRAVA?
The main objective of our team is to built a demonstrator of a cooling system with 200 kW cooling capacity to remove the waste heat of fuel cells for aircraft propulsion. Current large fuel cell systems use liquid cooling (usually a water/eglycol mixture) to remove the waste heat from the fuel cells. This cooling method is relative simple and a proven robust technology for automotive products. However, the total amount of fuel cell waste heat of an aircraft is orders of magnitude larger than for an automotive applications and the mass of a conventional liquid cooling system can become prohibitively large. For this reason, we are developing a novel two-phase cooling system. In a two-phase cooling system, the evaporation of a liquid is used, and because you can remove a lot of heat with a relative small amount of evaporated liquid, this can potentially result in a large mass reduction of the cooling system and required pump power. However, a two-phase cooling system is more complex than a conventional liquid cooling system and these challenges are being addressed in the BRAVA project.
What expertise and facilities does your team have to meet those objectives?
We have built two-phase cooling systems for aircraft applications before, but these were on a much smaller, e.g. 2 kW to 5 kW systems for cooling DC/DC converters in aircraft. The BRAVA demonstrator will have a much larger cooling capacity (200 kW), but we can use the same simulation tools and building expertise. Also, we have well-equipped facilities where we can do the required testing and built the demonstrator. We can also do e.g. vibration tests to show that the system can handle the harsh conditions that can be encountered in aircraft.
Which aspects of your research at BRAVA do you believe are the most innovative and what unique opportunities offer BRAVA to yourself and/or your organisation?
Two-phase cooling systems have been built before, but never on this scale and never for fuel cells. This results in unique challenges. For example, in our first test, we are observing ‘liquid superheat’ which is the phenomena in which the liquid is above the boiling temperature but ‘refuses’ to boil. This results in too high temperatures and this issue must be solved, e.g. by adding nucleation sites that can initiate boiling of the liquid. In this project, we are learning a lot and gain more expertise in developing cooling systems.
How do you see the future use of the BRAVA-results and the impact of BRAVA-project in our daily lives?
I really like to travel, but flying is far from sustainable. I hope that someday we can fly sustainable with hydrogen powered aircraft and that our work and this project contributed to achieve this.
