A multidisciplinary design method for generating hypersonic transport (HST) configurations using waveriders is presented. Waveriders generated from osculating cone flowfields are used as the initial platform for the vehicle, and various modifications required for the mission are implemented. The propulsion system assumes the use of ramjets and lowbypass turbofans with hydrocarbon fuel. Empirical estimates of the structure weight of the configuration are combined with a method for calculating the total mission fuel requirements. Design optimization is performed using both evolutionary and hill-climbing techniques to allow a thorough search of the design space; optimization variables include freestream, geometric, engine design, and mission parameters. A baseline 250 seat configuration was generated, and demonstrated the ability of the model to create optimized designs that meet mission requirements. Trades were conducted to investigate mission assumption and modeling sensitivities, and it was found that the total HST mass saw only small changes due to payload size, cruise range, and ramjet combustion efficiency assumptions. However, applying additional margin to the mass sizing technique resulted in a more than 40% increase in total mass, which indicates a relatively high sensitivity to mass estimating errors. Finally, a top level comparison with a modern subsonic transport indicated that, although HSTs can cut travel time by one-fifth, they will have to overcome economic challenges associated with higher total mass and lower overall fuel efficiency.
Nomenclature
ܣ= area ܣ ௫ = max cross-sectional area a, b, c, d, e, f, g = objective function weighting constantsat constant pressure ݂ = fuel/air ratio ܦ = drag ܦ = hydraulic diameter ܧ ௐ = wave drag efficiency factor ℎ = height (i.e. thickness); enthalpy ܫ ௦ = specific impulse ݈ = length ܮ = lift 1 AIAA Member 2 Professor, Department of Advanced Energy, 5-1-5 Kashiwanoha; Senior AIAA Member Downloaded by CORNELL UNIVERSITY on July 30, 2015 | http://arc.aiaa.org | ݉ = mass; slope used in cubic spline interpolation (if selected) ܯ = Mach number ݉ሶ = mass flow rate ݉ ௨ = fuel mass ݉ ௬ௗ = calculated payload mass ݉ ௬ௗ ᇱ = desired payload mass ݉ ௦௧௨௧௨ = structure mass ݉ ௧௧ = total mass at take-off ݊ = population size for genetic algorithm optimization ܰ = number of variables in optimization = pressure ݍ = dynamic pressure ܴ݁ = Reynolds number ܶ = thrust; temperature ܥܨܵܶ = thrust-specific fuel consumption ݓ = width ݔ = streamwise direction coordinate ݕ = vertical direction coordinate ݖ = spanwise direction coordinate ∆ℎ = heat of reaction ߚ = shock wave angle ߟ = combustion efficiency ߛ = ratio of specific heats ߶ = equivalence ratio ߠ = rational function parameter; angle ߠ ̅ = boundary layer momentum thickness parameter Subscipts 0 = stagnation conditions 0-10 = station numbers in engine analysis ܽ = air ݂ = fuel ݐݏ = stoichiometric conditions ܧܶ = trailing edge location (i.e. baseplane) ∞ = freestream conditions