(AIAA, 2023-01)
Clark, Robert; Tai, Jimmy C. M.; Mavris, Dimitri N.
The development of a parametric variable cycle engine (VCE) model is investigated. The model is developed using the multiple design point (MDP) approach, which allows for the sizing of an engine that meets design criteria across multiple flight conditions. The proposed architecture, a three-stream double-bypass architecture, is modeled in the Numerical Propulsion System Simulation (NPSS) tool. A double bypass architecture is selected due to the need to maintain continuous third-stream flow to be used as a heat sink for cooled-cooling and aircraft cooling heat exchangers. Results show that a VCE utilizing an aft variable area bypass injector (VABI), variable compressor inlet guide vanes (IGVs), and variable nozzle throats can be modulated to provide higher sea-level static (SLS) thrust and lower cruise specific fuel consumption (SFC) than a standard mixed-flow turbofan engine. Furthermore, engine pressure ratio (EPR) is shown to be a convenient thermodynamic parameter, such that variable geometry schedules can be developed as a function of EPR only, without respect to flight altitude or Mach number.