A solid-state concentration sensor for wind tunnel dispersion measurement

Studying how air pollution moves around between buildings is a very complicated problem: the flow of wind between buildings can be chaotic and unpredictable; the weather conditions are always changing, and there are many different possible sources of pollution. Wind tunnel measurements are still a valuable, trusted and efficient way to study how pollution spreads under these conditions.

To simulate pollution, a tracer gas that can be detected by specialised sensors is used. These sensors are accurate and fast, but very, very expensive. On the other hand, you can get inexpensive microchip-based sensors now that can detect specific gases very accurately. The purpose of our project is to adapt these inexpensive sensors to the specialised application of measuring tracer gases in wind tunnels. The challenges here are getting the slow microchip sensors to work much more quickly, and to build a probe around the sensor that can quickly suck up small amounts of gas and get that gas to the sensors.

If successful, we would be able to use large numbers of tracer gas probes at the same time: this means that (a) we could compare what was happening over large areas in the wind tunnel, despite how chaotic the flow can be- and (b) we could measure many points at once, drastically reducing the amount of time that the wind tunnel would need to run. We may even be able to get probes to respond to more than one type of tracer gas at the same time: this is something that hasn't been done before, so it would open up new avenues of research.