News Releases

December 2007

The Decawatt project – a step forward in microcombustion

A combustion micro-chamber measuring less than 1 cm³, where the air and the fuel are injected separately, has just been tested successfully. This marks a stage on the path towards creating a gas micro-turbine suitable for fitting to microdrones.

A combustion micro-chamber measuring less than 1 cm³ has just been tested successfully in the Onera Laerte laboratory in Palaiseau. This micro-chamber was designed to represent the core of a gas micro-turbine on a greatly reduced scale (2 cm in diameter and 2 cm high), intended to be fitted to micro-drones of 15-20 centimeters in size, for example. This system produces mechanical energy, which will then be converted into electricity. The power required is between 50 W and 100 W, with an autonomy in the range of 30 minutes for the micro-drone.

Initially, similar trials had been carried out using a chamber in which the fuel – hydrogen or propane – was premixed with air prior to injection (see previous article). In the present case, the geometry of the chamber is more realistic than that of the chamber tested previously. It actually corresponds to a gas micro-turbine architecture proposed by Onera (a 'volume' gas micro-turbine, as opposed to the MIT project, whose micro-turbine is flatter and is referred to as having a 'button' geometry). The fuel and air are injected separately into the micro-chamber (hydrogen and air: top photo; propane and air: opposite).

The following step is to study the rotation of a centripetal silicium turbine wheel 8 mm in diameter with paddles 400 µm in height. The test aims to investigate the ability of the micro-turbine to attain high rotation speeds – several hundred thousand rpm – and to confirm the technological choices made.

Last Update: December 17, 2007 - © ONERA 2009 - Terms of use