【作者】 张明辉；

【导师】 张彬乾；

【作者基本信息】 西北工业大学 ， 流体力学， 2020， 博士

【摘要】 翼身融合布局(BWB)作为一种新型飞机外形,具有满足“绿色航空”民机要求的安全性、经济性、环保性、舒适性等综合性能优势,已经成为下一代民机的重点发展方向,具有广阔的应用前景。然而,随着研究工作的深入,BWB低速性能较差的问题日益突出,已成为制约BWB布局工程应用的主要技术瓶颈之一。论文工作以我国下一代大型宽体客机发展需求为目标,以300座级民机概念方案为研究对象,在保持BWB布局高速气动性能优势的前提下,以提高低速性能为重点,开展BWB布局高低速综合性能协调匹配设计研究,为BWB民机工程应用提供理论与技术储备。本文主要工作和结论如下:(1)BWB民机概念方案研究方法构建。BWB布局机体与操纵舵面高度融为一体的外形特点,使得研究工作面临诸多学科专业的挑战,为此,本文首先构建了基于BWB布局特点的概念方案多学科设计研究平台,包括多学科综合设计平台、流场数值模拟方法以及风洞试验与验证技术。多学科综合设计平台包括设计优化模块与设计评估模块两大部分,由总体、几何模型、气动、重量、推进系统、操稳等设计与分析模块组成。算例与后续研究工作表明,该平台很好地满足本文及项目团队BWB民机概念方案设计阶段的研究工作需要。(2)BWB民机高低速协调设计研究。针对BWB布局自身高速性能优异、低速性能较差的特点,在分析国内外研究现状的基础上,提出并研究BWB民机的高低速综合协调设计问题。为了充分挖掘BWB布局综合性能潜力,研究工作以300座级民机无尾布局概念方案为研究对象。首先,采用多学科综合设计平台,分析了总体参数、增升与配平对高低速性能的影响,指出实现高低速性能协调设计,需要以翼载作为核心参数,并采用小低头力矩增升装置和高纵向配平措施等设计技术。针对当前BWB民机研究中高速性能优越优异、低速性能较差导致的高速巡航与低速起降性能不匹配,机体长度较短带来的增升与配平矛盾突出、客舱舒适性与应急疏散难以兼容等三个核心技术难题,提出了BWB民机的“后体加长翼身混合布局”及其高低速性能综合协调设计思想和设计方法。设计思想可表述为“高速向低速适当妥协的总体参数协调,升致阻力与零升阻力匹配的高速性能补偿,后体加长与翼身快速融合过渡的布局优化设计,以综合提升高低速气动性能及解决客舱舒适性与应急疏散矛盾”。而设计方法则是“以翼载作为核心参数协调高低速设计矛盾,加长后体提升低速高升力构型配平和操稳性能,并解决客舱舒适性与应急疏散矛盾;优化巡航状态设计参数,翼身快速融合过渡优化布局方案,减小干扰阻力和升力损失,实现零升阻力与升致阻力的协调匹配及“三点归一”巡航自配平设计,补偿高速性能损失,全面实现高低速综合性能协调设计目标”。最后,采用本文构建的设计方法和设计平台,完成了概念方案的高低速综合性能协调设计,数值模拟、风洞试验及总体评估分析表明,所完成的概念方案在保持优异高速性能的同时,显著改善了低速性能,实现了高低速协调设计目标,并为后续增升与操纵舵面设计、总体布置等研究工作奠定了良好基础。(3)BWB布局增升装置设计。BWB布局机身相对宽短的布局形式,应用传统增升装置存在配平困难。本文针对性地提出BWB民机增升装置及其设计方法,以增强增升效率、降低配平压力。建立了开缝克鲁格Krueger襟翼二维参数化方法,通过参数影响规律和增升机理研究,给出二维开缝Krueger襟翼的设计原则。在保证基本翼型、运动机构及工程可行性等设计约束下,开展开缝Krueger襟翼几何外形与缝道参数的优化设计研究,优化设计结果满足基本翼型、运动机构等设计约束,并通过与典型前缘缝翼比较,验证了开缝Krueger襟翼良好的增升能力。以二维开缝Krueger襟翼优化设计方法为基础,拓展应用于BWB民机三维开缝Krueger襟翼设计,偏角匹配结果表明,从二维拓展到三维的开缝Krueger襟翼设计方法是可行的。进而,完成了开缝Krueger襟翼与后缘简单襟翼组合的BWB概念方案增升装置设计,概念方案的最大升力系数由干净构型的0.6提升至增升构型的1.3,失速迎角提高10°以上,低头力矩较小;增升装置收放前后全机焦点移动小,进一步验证了高低速协调设计方法的有效性和合理性。(4)BWB无尾布局的操纵舵面研究。BWB无尾布局具有诱人的气动性能,但稳定性和操纵性一直为人们所关注。本文首先分析无尾布局纵横航三轴的操稳问题,明确了纵向和航向操纵是BWB无尾布局舵面设计的关键问题,提出了无尾布局气动舵面设计方法,完成了BWB无尾复合操纵舵面方案设计。通过高低速风洞试验,系统研究了舵面的气动特性、操纵机理及其操纵能力。研究结果表明,舵面设计方案基本满足带通气短舱构型的高低速操纵需要,高低速协调的后体加长设计有助于提高尾舵的俯仰操纵效率;襟副翼与阻力舵协同偏转的航向耦合舵面设计,具有很强的航向操纵能力,且耦合滚转力矩很小,是BWB布局理想的航向操纵方式;采用副翼差动可满足滚转操纵需要。然而,面对背撑发动机最大推力状态产生的较大低头力矩、单发失效等边界飞行状态的操纵问题,无尾布局的舵面操纵能力仍显不足,仍需寻求新的辅助操纵措施,以保证飞行安全性。(5)V尾对BWB民机气动和操稳性能影响研究。针对BWB无尾布局纵向和航向操纵舵面不能完全满足民机安全性要求的问题,基于本文无尾布局研究结果,在无尾布局上增加V尾,探索彻底解决无尾布局纵向与航向操纵能力不足的技术途径。首先,分析了BWB民机纵向与航向配平需求,采用低阶气动分析方法实现了V尾快速设计,V尾由固定段和活动舵面组成,具备全动及后缘舵面同向和差动偏转功能。经数值模拟与风洞试验验证,V尾使概念方案纵向零升力矩增加,静稳定性增加,横侧全飞行姿态下具有良好的静稳定性;高速巡航升阻比略有降低,但仍基本保持了巡航自配平设计,阻力发散特性良好。V尾全动状态VA用于纵向控制,操纵能力与尾舵相当(约提供0.045);后缘活动舵面VE用于航向控制,满足单发失效等航向边界飞行状态操纵需要。增加V尾可使BWB布局的稳定性和操纵性显著增强,不仅满足纵向与航向操纵需求,也是BWB布局三轴力矩解耦的有效措施,使机翼舵面操纵任务简化,具有更多功能裕度,可参与增升、滚转等其它操纵任务。(6)BWB-300概念方案及其综合性能分析。综合高低速协调设计和V尾影响研究结果,形成了BWB-300概念方案。采用数值模拟及高低速风洞系列试验验证方法,对BWB-300概念方案气动性能和操稳特性进行了全面评估,结果表明,概念方案在保持优异高速性能的同时,也具有良好的低速性能,可用巡航升阻比达到24,巡航效率因子大于20;起降构型配平后最大升力系数达到1.1,失速迎角大于18°;概念方案具有良好的三轴静稳定性,舵面设计方案满足飞机操纵需要。项目团队的总体布置、性能分析、应急疏散仿真等结果表明,方案的舒适性和安全性提升。因此,BWB-300概念方案的综合性能全面提高。本文开展的高低速综合协调设计研究工作,为解决BWB民机高速巡航与低速起降性能协调匹配、增升与配平能力匹配、客舱舒适性与应急疏散兼容三个核心技术难题提供了坚实的理论与技术基础。更多还原

【Abstract】 The blended-wing-body(BWB)configuration,as an innovative transport aircraft concept,shows integrative benefits and serves as a most promising candidate for safe,economical,comfortable,and environmentally friendly transport of “green aviation”,which has comprehensive performance advantages and broad application prospects.However,the shortage low speed performance is becoming a serious issue for the development of a practical BWB.Aiming at the development demand of China’s next generation large wide-body passenger aircraft,this paper chooses the conceptual design of a 300-passenger BWB civil transports as the research object and conducts the high and low-speed performance coordinated design,which focus on the improvement of the low-speed characteristics while maintain high-speed cruise efficiency and accumulates theoretical and technical engineering experience for BWB civil transports.The main work and conclusions of this paper are as follows:(1)Foundation of the BWB civil transport conceptual design platform.The study faces design challenges form multiple disciplines and subjects,due to the tightly coupled feature of BWB layout and control surfaces.Therefore,based on the characteristics of BWB configuration,this paper firstly constructs a multidisciplinary conceptual design platform which includes a multidisciplinary design platform,simulation and the wind-tunnel experiment verification method.The multidisciplinary conceptual design platform consists of optimization and evaluation parts,which consist of parameterization,aerodynamic,weight,propulsion system,stability and control analysis modules.The module validations and subsequent studies approve that the conceptual design platform fulfill the BWB civil transport conceptual design needs of this paper and further studies of research team.(2)Investigation on the high and low-speed performance coordinated design of BWB configuration.Based on the analysis the BWB research status at home and abroad,current BWB designs suffers from a major design issue that the poor low-speed characteristics do not match the excellent high-speed performance.This paper puts forward the coordinated design problem of BWB civil transport,and tries to solve the problem.In order to fully explore the comprehensive performance potential of BWB configuration,this paper sets the tailless configuration as the research object for the 300-passenger BWB civil transports conceptual design.Firstly,the influence of the primary design parameters and the high-lift systems towards the high and low-speed performance are studied by applying the multi-disciplinary design method.It is find out that the wing loading is the key primary parameters to realize a coordinated design,while the high-lift systems with low nose-down pitching moment are preferred,and the longitude control ability of elevator should be enhanced.Current BWB designs suffer from three major technical problems: the poor low-speed characteristics do not match the excellent high-speed performance;the shorter blended body brings difficulties in the coordination of high-lift and balancing,cabin comfort and emergency evacuation.To solve these problems,the design idea of “aft-body lengthen hybrid wing-body configuration” is proposed.The primary parameter coordination strategy is adopted,that the high-speed performance is compromised to improve the required low-speed characteristic;while the matching of induced drag and zero-lift drag,lengthening the aft-body and the rapid transition of center-body and outer-wing help to realize a comprehensive performance for both high and low-speed condition and the cabin comfort and emergency evacuation.The BWB coordination design methodology is also provided that the wing loading is the core primary design parameters to coordinate the high and low-speed performance,while lengthening the aft-body is a suitable measure to improve the low-speed high-lift and longitude control and stability characteristics,and improve the cabin comfort and emergency evacuation.The cruise condition parameters are optimized to obtain better cruise efficiency,while the rapid transition of wing and body helps reduce the lift loss and interference drag,and realize a naturally trimmed design at the cruise design lift coefficient with maximum lift to drag ratio to obtain better overall performance.Then,applying the BWB multidisciplinary optimization design platform constructed in this paper,a coordinated conceptual design of the high and low speed comprehensive performance is completed.The numerical simulation,wind tunnel test and overall evaluation show that the completed conceptual design not only maintains excellent high-speed performance,but also significantly improves low-speed performance,achieves the goal of high and low-speed coordinated design,and lays a good foundation for subsequent design and overall layout of high-lift and control surface design.(3)Investigation on the high-lift system design.Due to its shorter control arm for longitudinal control surface,it is difficult to achieve a balanced BWB design with the traditional high-lift devices,so it is necessary to explore new high-lift devices that have better lift-enhancing capabilities and lower nose-down pitching moments.The combination of slotted leading-edge Krueger flaps and the trailing-edge simple flaps is proposed and applied on the BWB layout.The two-dimensional parameterization method of slotted Krueger flaps was established,and the design principles of slotted Krueger flaps are given through the parameter influence study and the flow mechanism analysis.Under constraints such as the basic foil profile,mechanical mechanism and engineering feasibility,an optimization design of the slotted Krueger flap is carried out,which takes the influence of geometrical and slot parameters into consideration.The optimized result meets the design constraints,and the aerodynamic characteristic comparison with typical leading edge slats proves that the optimized slotted Krueger flap has good lift-enhancing characteristic.The 2D optimization design method is further extended and applied to the 3D high-lift configuration design of BWB layout,while influence study on Krueger deflection angle indicates that the results of 2D and 3D design show good consistency.Furthermore,the BWB concept high-lift device design of the combination of the slotting Krueger flap and the trailing-edge simple flap is completed.The maximum lift coefficient is increased from 0.6 of the clean configuration to1.3 of high-lift configuration,and the stall angle of attack is enlarged by more than 10° with less nose-down pitch moment.The movement of the neutral point due to the high-lift device extension is smaller.The aerodynamic characteristics of high-lift configuration further verify the effectiveness and rationality of the high and low-speed coordinated design methodology.(4)Investigation on the control surface design of tailless BWB configuration.The BWB tailless layout has attractive aerodynamic performance,but stability and control is always a serious issue.by analyzing the longitudinal and lateral stability and control of the BWB tailless layout,this paper point out that the longitudinal and directional control are the key issues,illustrate the design method and completes the design of the BWB tailless composite control surface.Through high and low-speed wind tunnel test,the aerodynamic characteristics,control mechanism and ability of the control faces are studied.The results show that the control surface design almost fulfills the needs of high and low-speed maneuvering of the tailless BWB design,and lengthening the rear body helps to improve the elevator control efficiency;The combined deflection of flaperon and the drag rudder has strong directional control capability and the coupled rolling moment is rather small,which is the ideal directional control mode for BWB layout;the aileron differential defection can meet the needs of rolling control.(5)Investigation on the aerodynamic influence of V-tails integrated on the BWB configuration.Investigation on the aerodynamic influence of V-tails integrated on the BWB configuration.The tailless BWB layouts always meet the problem that the longitudinal and lateral control capabilities of control surfaces can hardly guarantee the flight safety.Based on the tailless layout study of this paper,the technical approach of adding V-tail is applied to completely solve this problem.First,according to the longitudinal and lateral control requirements,a rapid design of V-tail is realized by adopting the low-order aerodynamic analysis method.The V-tail design consists of fixed parts and movable control surfaces,which can realize symmetrical and asymmetrical deflection for all-move and trailing-edge ruddervators.The CFD and wind tunnel experiment results indicate that the designed V-tail increases the longitudinal zero lift moment and the static stability,and the conceptual design achieve lateral and roll static stability during the flight;the high-speed lift-drag ratio is slightly decreased by 11%,but the design maintains naturally trimmed feature,and shows good divergence drag characteristics.The symmetry deflection of the V-tail’s all-move surfaces provide almost the same amount longitude moment as the center-body elevator;while the trailing-edge rudder VE is used to meet the lateral balancing requirement of extreme situations such as single engine failure.The integration of V-tail can significantly enhance the stability and control capability of the BWB layout,which not only meets the requirements of longitudinal and lateral control,but also is an effective measure to decouple the three-axis moment of the BWB layout.It simplifies the tasks of wing control surfaces,which can participate in high-lift,rolling control.(6)Investigation on the comprehensive performance BWB-300 conceptual scheme.The BWB-300 conceptual scheme is formed by combining the research results of high and low-speed coordinated design and the V-tail integration.The aerodynamic performance,stability characteristics and control capabilities of the BWB-300 concept scheme are evaluated comprehensively by numerical simulation and high-low speed wind tunnel tests.The results approves that the concept scheme has good low-speed performance while maintaining excellent high-speed performance,the maximum usable lift-drag ratio researches 24,while cruise efficiency is greater than 20,the balanced maximum lift coefficient reaches 1.1 for take-off and landing configuration,and the stall angle of attack is greater than 18.The conceptual scheme shows good static stability and the control surface could fulfill the needs of aircraft control.The overall layout,performance analysis,emergency evacuation simulation and other results of the project team show that the conceptual scheme of the high-speed and low-speed comprehensive coordinated design also has obvious advantages in comfort and safety,including cabin layout,emergency evacuation,and the performance is improved comprehensively.The research of the high and low-speed performance coordinated design in this paper solves three critical design issues of the BWB configuration,namely,the coordination of high-speed cruise performance and low-speed takeoff and landing performance,the matching of high-lift system lift increment and longitude balancing capacity,and the compatibility of cabin comfort and emergency evacuation,which provides a solid theoretical and technical foundation for BWB civil transports design.更多还原