Current status of miniature gas turbine generators (summary of achievements and problems)

This paper briefly reviews researches on miniature gas turbine generators performed to date in the world. Two major approaches ; MEMS-based and mechanical-machining-based approaches are described. The first approach was proposed by Massachusetts Institute of Technology (MIT) in 1997. A lot of outstanding outputs were produced by MIT, but the MEMS-based coin-sized engine has not been demonstrated to date. This paper discusses main three challenging issues of this type of engine. The second approach was taken by at least several groups. The main challenging issues are similar to those of MEMS-based engines. In 2007, Tohoku University and IHI with collaborators established the heat cycle of a juice-can-sized engine with a compressor impeller of 16 mm in diameter. This is the world's smallest operating gas turbine engine that has been reported in open literatures.