Steam cooled rich-burn combustor liner

An object of the invention is to cool a rich burn combustor without extracting excessive amounts of heat and to use the extracted heat. In accordance with the invention, a combustor (10) having a primary combustor (12) and a secondary combustor (13) with a throat (20) between them is provided with a jacket including a wall (27) radially outwardly of a wall (14) of the primary combustor (12). Steam is injected into a manifold (33) at the throat end of combustor (12) and flows in a plurality of spiral paths through the space between walls (14) and (27) to an outlet manifold (32) at the other end of combustor (12) becoming superheated. The superheated steam is employed to drive a stream utilization device. The spiral steam flow paths are established by barriers (38) wound in spiral fashion on the outside of wall (14) of the combustor (12). Another object is to minimize stress on the wall (14) of the primary combustor (12). Thus, the steam pressure in inlet manifold (33), is approximately the same as the combustor discharge pressure at throat (20) and annular expansion tubes (30) and (31) minimize stresses in the jacket comprised of walls (27), (28), and (29). The second combustor (13) accomplishes lean burning of the gases discharged from primary combustor (12). The combination of the rich burning of heavy fuels followed by lean burning minimizes the NOx in the exhaust gas discharged from combustor (13).