A Study on the Flowfield of an Innovative Z-Flowpath Gas Turbine Combustor
Reverse flow combustors were widely used in small and micro gas turbine engines. The wall area of this type of combustors was quite large. And there were two flow turning points in their flow-path. Thus the wall cooling and main flow dilution were two intrinsic problems for them. Apart from that, their high pressure losses and heavy weight were also two problems which seriously deteriorate the performance of the engines. Moreover, their primary hole jets on opposite walls were non-symmetrical, which would affect the stability and intensity of the recirculation flows. In order to improve the combustion performance, a new conceptual Z-flowpath combustor was proposed. The new combustor consisted of two 45 degree yawing instead of returning in the main flow-path. The flowfield of the new combustor was predicted by the commercial code FLUENT, after a validation for the flowfield in a model reverse flow combustor with previous experimental results. The prediction showed that the flowfield of the primary zone in the Z-flowpath combustor was highly symmetrical, the size and the intensity of the recirculation zone were about 10 and 2 times greater than the normal reverse flow combustor, respectively, while the pressure loss and the total area of the flame tube wall of the Z-flowpath combustor were decreased dramatically to be 69.4% and 51% of that in the reverse flow combustor, respectively.