Research On The Multidisciplinary Design Optimization Technique Of The Airbreathing Wide-speed-range Cruising Vehicle

The air-breathing wide-speed-range cruising vehicle is expected to promote the air transportation efficiency,reduce the space round trip cost and enhance the weaponry deterrence.This kind of vehicle covers numerous disciplines,most of which are coupled with each other.In order to reduce the re-design situation that caused by objective conflicts among different disciplines,a multi-disciplinary design optimization approach is needed to carry out the overall design process.However,it is a huge challenge to deal with this process because this specific kind of vehicle needs a new concept of configuration,an efficient propulsion system that works in wide-speed-range,an advanced control system,a high strength structure,heat-resistant materials and so on,each of which needs novel design theories and approaches.This paper aims to carry out a conceptual design process of a new wide-speed-range cruising vehicle based on the multi-disciplinary design optimization approach.Firstly,the numerical approach,the engineering estimation approach,the design of experiment approach and the surrogate modeling approach are realized and validated for the reason that they can simplify the discipline analysis process or improve the optimization efficiency.Following that,four discipline models are established and analyzed.To be more specific,a suitable parametric approach in terms of aircraft geometry design is chosen based on comparisons and applications;a propulsion performance estimation program of the rocket-based combined cycle engine at full speed range is designed based on the thermodynamic analysis process;trajectory design and optimization methods of the ascent and re-entry sections of the aircraft are studied based on two-dimensional ballistic equations;novel design approaches of the wide-speed-range gliding vehicle and the air-breathing cruising aircraft configuration are developed based on the cone-derived waverider theory.Finally,based on analysis models and surrogate models of above disciplines,a discipline relationship matrix of the wide-speed-range cruising aircraft is established,and the parameter coupling relationships among the disciplines of geometry,aerodynamics,propulsion,mass and ballistics are sorted out.The bi-level system integrated optimization strategy is proposed,and the multidisciplinary design analysis and multidisciplinary design optimization process with the minimum climbing time as the optimization objective are realized.Through the construction and analysis process of various discipline models and the realization process of multidisciplinary design optimization,this paper has obtained the following new discoveries and research results:1.By comparing the performances of different parametrization methods in the field of airfoil fitting,it is found that any parametrization method cannot guarantee the best fitting ability for every type of airfoil.2.Based on the reliable RBCC performance thermodynamic analysis program,the influences of factors such as take-off weight,engine size and ballistic dynamic pressure on the equal dynamic pressure climbing ballistic performance of the RBCC powered aircraft are obtained.3.Based on the cone-derived waverider theory,a novel design method for the widespeed range gliding aircraft and airframe-waveriding air-breathing cruising aircraft is proposed.4.The BLSIO MDO strategy is developed based on actual design objects and applied to the design of a new air-breathing wide-speed range cruising aircraft with RBCC as its propulsion system.