COMBUSTORS FOR MICRO-GAS TURBINE-ENGINES

The development of a hydrogen-air microcombustor is described. The com bustor is intended for use in a 1 mm(2) inlet area, micro-gas turbine engine. While the size of the device poses several difficulties, it al so provides new and unique opportunities. The combustion concept inves tigated is based upon introducing hydrogen and premixing it with air u pstream of the combustor. The wide flammability limits of hydrogen-air mixtures and the use of refractory ceramics enable combustion at lean conditions, obviating the need for both a combustor dilution zone and combustor wall cooling. The entire combustion process is carried out at temperatures below the limitations set by material properties, resu lting in a significant reduction of complexity when compared to larger -scale gas turbine combustors. A feasibility study with initial design analyses is presented followed by experimental results fi om 0.13 cm( 3) silicon carbide and steel microcombusters. The combustors were oper ated for tens of hours, and produced the requisite heat release for a microengine application over a range of fuel-air ratios, inlet tempera tures, and pressures up to four atmospheres. Issues of flame stability , hear transfer, ignition and mixing are addressed. A discussion of re quirements Soi-catalytic processes for hydrocarbon fuels is also prese nted.