Development of a Low-Emission Combustor for a 100-kW Automotive Ceramic Gas Turbine (IV)

A low emission combustor, which uses a prevaporization-premixing lean combustion system for the 100-kW automotive ceramic gas turbine (CGT), has been subjected to performance tests. A second combustor prototype (PPL-2). which incorporates improvements intended to overcome a flashback problem observed in an initiel combustor prototype (PPL-1), had been tested. Now combustors with further improvements accomplished to the PPL-2 prototype, is tested. Test results of the PPL-2 combustor showed that, increasing the air distribution ratio in the lean combustion region to aviod flashback, and by providing a uniform flow layer at the entrance of the combustion region so as to supress flashback, were effective in expanding the stable combustion range by substantially improving the flashback characteristics. To improve the flashback characteristics further more, we have redesinged the bluffbody and the swirl chamber so as to obtain uniform flow of the mixture, in the prevaporization premixing zone. Test results shows that the flashback characteristics has been greatly improved, and a wide stable combustion range, needed to operate the 100-kW CGT engine, was obtained.