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.