The selection of an axial turbine or a radial turbine is a key problem for advanced micro-turbine engine with larger mass flow rate and power.A comparative research was completed to determine the suitable turbine form.For a micro-turbine engine of 12 centimeters diameter

one-dimension estimative model of axial turbine was established

and the output characteristic of axial turbine was analyzed.A micro axial turbine was designed

and the differences of power

efficiency

size and mass between the axial turbine and radial turbine were compared.The results indicate that:axial turbine has more compact size and lighter mass

but radial turbine has larger power.For an advanced micro-turbine engine

when the total pressure ratio of the compressor exceeds 4

a two-stage scheme is required for the axial turbine to provide enough power output

rather than one-stage for radial turbine.The comparison between two-stage axial turbine and one-stage radial turbine indicates that

radial turbine-stage has smaller size and mass when the flow rate is less than 500g/s

and the total pressure ratio is 4~6

and the engine has a high thrust-mass ratio.So when a high pressure ratio is required but the power output of one-stage radial turbine isn't exceeded

the radial turbine has more advantages.