Supersonic Transport Engine Analysis

This project considered the inlet and engine of a supersonic transport aircraft. After defining an initial concept for the aircraft based on existing large-scale supersonic aircraft capabilities, requirements were defined for the inlet and engine. Design was focused on the target operating point of supersonic cruise. A flight profile was designed using standard departures and arrivals from JFK and LHR airports along the standard routes above the subsonic northern Atlantic tracks formerly used by the BAC Concorde aircraft.

An inlet was defined to operate the turbine aircraft safely in the supersonic regime. An Oswatitsch external compression supersonic inlet was designed to produce 4 equal strength shocks to optimally decelerate the flow. Boundary layer conditions, and off-design conditions were not evaluated here. Optimisation was performed with a custom developed program to evaluate the required ramp angles for all 3 ramps of the inlet, with a pressure recovery ratio of 0.9339 calculated.

Among engine concepts considered for supersonic aircraft of this type, a mixed-flow afterburning turbofan engine was selected. Engine analysis was performed in the target regime, used a 1-D steady analysis using the modified specific heat gas model, and neglected certain power drains such as bleed air and turbine cooling flow. Common values were attained for most internal engine parameters. Two main control parameters were reserved to vary the engine design, the bypass ratio and the compression ratio. Carpet plots were generated of thrust specific fuel consumption vs specific thrust, varying these design parameters to allow selection of a balanced design considering both performance and efficiency with and without afterburners.

Analysis was also performed on an existing engine, using limited information available about the F135-PW-100. This was undertaken to evaluate which would be a more practical selection for an SST program, ultimately selecting the existing engine.