Fuel Property Effects on Life Characteristics of Aircraft Turbine Engine Combustors

Results of a program to determine the effects of fuel properties on the life characteristics of two USAF/General Electric aircraft turbine engine combustors are presented. Thirteen test fuels were evaluated in an older technology cannular combustion system (J79) and in an advanced technology, virtually smokeless, compact, annular combustion system (F101) over wide ranges of simulated engine operating conditions. Fuel variables were hydrogen content, aromatic structure, volatility and distillation end point. Significant increases in combustor liner temperatures were observed as fuel hydrogen content was decreased. With fuel hydrogen contents of 14.5, 14.0, 13.0 and 12.0, the resulting relative combustor liner cyclic life predictions are 1.00, 0.78, 0.52, and 0.35 for the J79 combustor and 1.00, 0.72, 0.52 and 0.47 for the F101 combustor, respectively. Based on these findings, it is concluded that improved liner cooling design features will be needed in most current technology combustors to accommodate the projected lower hydrogen contents of future fuels.