The design, manufacture and testing of energy-converting micro gas turbines that optimise the combustion of fuels is the specialism of German firm Euro-K, which has facilities in Berlin and Cottbus.
The company, which has been progressively increasing the effectiveness of its systems, concentrating on innovative burner geometry to raise combustion efficiency and reduce exhaust gas emissions, has been using metal additive-manufacturing (AM) technology from EOS (www.eos.info/en
) to help it achieve its development goals.
Whereas the formation of a combustible fuel/air mixture is relatively straightforward with gaseous fuels, liquid fuels present a challenge, because the surface area must be greatly increased.
This is generally done by projecting it in a very fine spray, using pneumatic, mechanical or pressure differential principles. Consequently, the availability of burners that support the use of liquid as well as gaseous fuels is limited.
Euro-K set out to produce a compact micro-burner that can handle both types of fuel efficiently. Its design freedom was greatly enhanced using AM, which avoids the constraints of conventional metal cutting and the uneven cooling of castings.
This technology can produce small batch sizes economically and allows burner assembly costs to be reduced by 20%.
One of the machines that Euro-K uses is an EOS M 290 metal AM system, with the CAD software used for the design work allowing data to be transferred quickly and easily to the EOS system following definition of the final shape and size of the burner.
To create the optimal burner for use in the micro gas turbines of one of its customers, the Euro-K project team chose EOS nickel-alloy IN718 — a heat- and corrosion-resistant material that has excellent tensile strength, resilience, and resistance to creep and fracture at temperatures up to 700°C.