METHODS OF OPERATING A TURBOMACHINE COMBUSTOR ON HYDROGEN

A method of operating a combustor (17) of a turbomachine (10) on a total fuel input that contains a concentration of hydrogen that is greater than about 80% is provided. The method includes injecting a first mixture of air (15) and a first fuel (158) containing a first amount of hydrogen into the primary combustion zone (72) of the combustor (17) to generate a first flow of combustion gases (164) having a first temperature. The method further includes injecting, with one or more premix injectors (100), a second mixture of air (15) and a second fuel (160) containing a second amount of hydrogen into a secondary combustion zone (74) of the combustor (17) to generate a second flow of combustion gases (166) having a second temperature. The method further includes separately injecting a third fuel (162) into the secondary combustion zone (74) to generate a third flow of combustion gases (168) having a third temperature.