Optimization of Twin-Aisle-Class Blended-Wing-Body Aircraft Incorporating Critical Requirements and High-Fidelity Aerodynamic Modelling

This study presents a performance and design assessment of the Blended-Wing-Body (BWB) aircraft in the twin-aisle class using aerodynamic optimization based on Reynolds-averaged Navier-Stokes equations employed within a mixed-fidelity multidisciplinary design environment. The formulation models critical design and performance requirements as constraints across the flight envelope and makes use of high design freedom to efficiently meet them. A baseline BWB configuration is first sized to match the specifications of a state-of-the-art reference tube-and-wing aircraft, the Airbus A350-900, and present-day technology levels are assumed in order to isolate the effect of the configuration. The investigation considers variations in cabin geometry and evaluates narrower centerbody concepts previously shown to be favorable for regional-class BWB aircraft. Results demonstrate that the optimized BWB aircraft, constrained to a -4% MAC low-speed static margin, achieves an estimated 30% reduction in block fuel burn over a 7,100 nmi mission relative to the reference aircraft, attaining a cruise lift-to-drag ratio of 28.4 at Mach 0.85 and 36,000 ft. A passenger cabin with 24 seats per row, separated by 4 aisles, outperforms wider and narrower variants. Optimizing for a higher cruise altitude of 44,000 ft markedly improves fuel efficiency by 3% while an increase in low-speed static margin to neutral increases fuel burn by 3.6%. The optimized aircraft perform adequately at stall to achieve the required field performance, and cruise aerodynamic performance is robust to changes in flight conditions. The results provide an accurate estimate of the BWB aircraft's fuel efficiency potential in the twin-aisle class, showing excellent fuel efficiency even with the inclusion of critical design requirements, encouraging further commercial exploration.