TURBINE SECTION OF HIGH BYPASS TURBOFAN

摘要

A turbofan engine (20) comprises a fan (42) having fan blades (70). A compressor is in communication with the fan section. The fan (42) is configured to communicate a portion of air into a bypass path defining a bypass area outwardly of the compressor and a portion into the compressor. A bypass ratio is greater than 6.0. A combustor (48) is in fluid communication with the compressor. A turbine is in communication with the combustor (48). The turbine has a first turbine section (27) that includes two or more stages (200, 202, 204) and a second turbine section (26) that includes at least two stages. A ratio of airfoils in the first turbine section (27) to the bypass ratio is less than 170. The first turbine section (27) includes a maximum gas path radius. A ratio of the maximum gas path radius to a maximum radius of the fan blades (70) is less than 0.50. A speed reduction mechanism (46) is coupled to the fan (42) and rotatable by the turbine.