翼身融合（BWB）布局是"绿色航空"发展目标的下一代大型民用飞机的理想布局。由于高度融合的外形特点，BWB布局难以通过应用传统增升装置实现低速增升与配平的协调设计。本文采用开缝钝头克鲁格襟翼提高BWB布局低速失速特性。首先，构建了克鲁格襟翼二维参数化方法，该方法符合克鲁格襟翼运动机构特点，可准确描述几何外形与缝道配置。其次，开展克鲁格襟翼几何参数与偏转角度的影响规律研究，分析流动形态与增升机理，提出设计原则。综合考虑外形、运动机构与遮蔽效应等设计约束，以提高增升能力为目标，开展前缘开缝克鲁格襟翼优化设计。优化设计结果满足设计约束，数值分析表明其增升能力比初始外形与经典缝翼均有明显提高。最终，采用前缘开缝克鲁格襟翼与后缘简单襟翼构建BWB增升构型，数值模拟与风洞试验结果表明，增升方案能够实现升力系数要求，降低了对配平能力的需求，减小了增升装置和高升力配平设计压力。提出的克鲁格襟翼设计方法不仅适用于BWB布局，也为传统布局民机增升装置设计提供了技术支持。
The Blended-Wing-Body (BWB) is the most promising candidate for the next generation transport to achieve "green aviation". Due to its unique blended geometric characteristics, the low speed characteristics of BWB can hardly gain enough lift under trimmed condition by applying the traditional high-lift device. The slotted bull-nose Krueger flap is applied to improve the low speed stall characteristics of the BWB configuration. Firstly, a two-dimensional parameterized method for the slotted bull-nose Krueger flap is established to accurately describe the geometry and deployed settings, which accord with the characteristic of actuating mechanism. Then, the effects of Krueger geometry parameters and the deflecting angle are investigated, during which the features of the flow phenomena and high-lift mechanism are studied, and several design principles are proposed. After that, with considerations of geometry, mechanism, and shielding effect constraints, an optimization is conducted to enhance the lift improvement towards a more practical Krueger design. The optimization results for leading edge device satisfy the design constraints and show promising aerodynamic features compared with the initial design and a classic slat design. Finally, a BWB high-lift configuration consisting of leading edge slotted bull-nose Krueger flap and trailing edge simple-hinged flap is established. The aerodynamic characteristics of leading edge device are obtained by numerical simulation and the entire high-lift configuration is studied through wind tunnel experiments. The result shows that this kind of high-lift device is suitable to relieve the pressure of trim and realize sufficient lift gain. The study proves that the Krueger design methodology is suitable for further research and could be applied as a high-lift device for both conventional and innovative configurations.
[1] GREEN J E. Greener by design:The technology challenge[J]. Aeronautical Journal, 2002, 106(1056):57-113.
[2] OKONKWO P, SMITH H. Review of evolving trends in blended wing body aircraft design[J]. Progress in Aerospace Sciences, 2016, 82:1-23.
[3] 王元元. 波音考虑恢复X-48的试验研究[EB/OL]. (2016-02-03)[2018-11-03].http://www.aeroinfo.com.cn/Item/8431.aspx. WANG Y Y. Boeing ponders reviving X-48 for new tests[EB/OL]. (2016-02-03)[2018-11-03].http://www.aeroinfo.com.cn/Item/8431.aspx (in Chinese).
[4] 王元元. 波音持续深化BWB布局研究[EB/OL]. (2018-03-28)[2018-11-03].http://www.aeroinfo.com.cn/Item/22455.aspx. WANG Y Y. Boeing continues to refine the BWB layout[EB/OL]. (2018-03-28)[2018-11-03].http://www.aeroinfo.com.cn/Item/22455.aspx (in Chinese).
[5] SMITH A M O. High-lift aerodynamics[J]. Journal of Aircraft, 1975, 12(6):501-530.
[6] VAN DAM C P. The aerodynamic design of multi-element high-lift systems for transport airplanes[J]. Progress in Aerospace Sciences, 2002, 38(2):101-144.
[7] THIEDE P. EUROLIFT-Advanced high lift aerodynamics for transport aircraft[J]. Air & Space Europe, 2001, 3(3-4):105-108.
[8] WILD J. Recent research topics in high-lift aerodynamics[J]. CEAS Aeronautical Journal, 2016, 7(3):345-355.
[9] THOMPSON T. Technology portfolio analysis for environmentally responsible aviation:AIAA-2014-2875[R]. Reston, VA:AIAA, 2014.
[10] BRADLEY M K, DRONEY C K. Subsonic ultra green aircraft research, Phase I final report:NASA/CR-2011-216847[R]. Washington, D.C.:NASA, 2011.
[11] KOZEK M, SCHIRRER A. Modeling and control for a blended wing body aircraft[M]. New York:Springer, 2014.
[12] TAMIGNIAUX T, STARK S, BRUNE G. An experimental investigation of the insect shielding effectiveness of a Krueger flap/wing airfoil configuration:AIAA-1987-2615[R]. Reston, VA:AIAA, 1987.
[13] WICKE K, LINKE F, GOLLNICK V, et al. Insect contamination impact on operational and economic effectiveness of natural-laminar-flow aircraft[J]. Journal of Aircraft, 2016, 53(1):158-167.
[14] KRUEGER W. Systematic wind-tunnel measurements on a laminar wing with nose flap[M]. Washington, D.C.:NACA, 1947.
[15] NIU C. Airframe structural design:Practical design information and data on aircraft structures[M]. Hong Kong:Conmilit Press Limited, 1999.
[16] RUDOLPH P K C. High-lift systems on commercial subsonic airliners:NASA CR 4746[R]. Washington, D.C.:NASA, 1996.
[17] Boeing Commercial Airplane Group. High Reynolds number hybrid laminar flow control (HLFC) flight experiment Ⅱ:NASA CR 209324[R]. Washington, D.C.:NASA, 1999.
[18] WILD J. Aerodynamic design of a high-lift system compatible with a natural laminar flow wing within the DeSiReH project[C]//29th Congress of the International Council of the Aeronautical Science. St. Petersburg:ICAS, 2014:1-8.
[19] IANNELLI P, WILD J, MINERVINO M, et al. Design of a high-lift system for a laminar wing[C]//Proceedings of the 5th European Conference for Aeronautics and Space Sciences, 2013.
[20] IANNELLI P, WILD J, MINERVINO M, et al. Analysis and application of suitable CFD-based optimization strategies for high-lift system design[C]//European Congress on Computational Methods in Applied Sciences and Engineering. Vienna:ECCOMAS, 2012.
[21] AKAYDIN H D, HOUSMAN J A, KIRIS C C, et al. Computational design of a Krueger flap targeting conventional slat aerodynamics:AIAA-2016-2958[R]. Reston, VA:AIAA, 2016.
[22] BAHR C J, HUTCHESON F V, THOMAS R H, et al. A comparison of the noise characteristics of a conventional slat and Krueger flap:AIAA-2016-2961[R]. Reston, VA:AIAA, 2016.
[23] VICROY D D, DICKEY E D, PRINCEN N, et al. Overview of low-speed aerodynamic tests on a 5.75% scale blended-wing-body twin jet configuration:AIAA-2016-0009[R]. Reston, VA:AIAA, 2016.
[24] KIM S, ALONSO J, JAMESON A. Design optimization of high-lift configurations using a viscous continuous adjoint method:AIAA-2002-0844[R]. Reston, VA:AIAA, 2002.
[25] AIAA.1st AIAA CFD high lift prediction workshop[EB/OL]. (2011-06-10)[2018-11-03].http://hiliftpw.larc.nasa.gov/.
[26] COJOCARU M G, NICULESCU M L, PEPELEA D. Leading edge device aerodynamic optimization[J]. INCAS Bulletin, 2015, 7(4):77-84.
[27] 张彬乾, 罗烈,陈真利, 等. 飞翼布局隐身翼型优化设计研究[J].航空学报, 2013, 35(4):957-967. ZHANG B Q, LUO L, CHEN Z L, et al. On stealth airfoil optimization design for flying wing configuration[J]. Acta Aeronautica et Astronautica Sinica, 2013, 35(4):957-967(in Chinese).
[28] JEONG S, MURAYAMA M, YAMAMOTO K. Efficient optimization design method using Kriging model[J]. Journal of Aircraft, 2005, 42(2):413-420.
[29] INANNELLI P, MOENS F, MINERVINO M, et al. Comparison of optimization strategies for high-lift design[J]. Journal of Aircraft, 2017, 54(2):642-658.
CJA