【作者】 董振兴；

【导师】 高亚东；

【作者基本信息】 南京航空航天大学 ， 航空宇航科学与技术， 2010， 硕士

【摘要】 无尾桨概念(NOTAR)改变了传统的尾桨设计概念,利用环量控制尾梁产生平衡旋翼反扭矩所需的力,从而取消尾桨,从根本上消除尾桨给直升机带来的各种不利影响。环量控制尾梁结构简单,安全性好,改善了可靠性和维护性,减少了直升机的振动和噪声,使操纵性能提高,特别适用于轻型直升机的飞行要求。本文对用壁面射流控制圆柱绕流的环量控制参数进行了研究,利用FLUENT软件计算并分析了缝隙位置、几何尺寸和数目等参数对环量控制尾梁气动特性的影响。其中,动量系数和缝隙几何参数对圆柱尾梁上气动力的影响是研究重点。本文具体工作包括:1.利用CATIA软件建立尾梁模型,采用了适用于尾梁流场计算的网格生成方法和网格生成软件GAMBIT进行对网格进行了划分;2.采用动量源方法模拟旋翼下洗流,编制动量源程序并导入FLUENT软件进行环量控制尾梁的气动特性研究,分别对风洞和旋翼下洗流的流场进行仿真分析,根据所得数据分析缝隙位置、尺寸和数目等参数对尾梁气动特性的影响,获得了圆柱体尾梁气动力随环量控制参数变化的规律,确定最优参数的选取。3.通过仿真数据与实验数据的对比分析,修正了环量控制尾梁理论模型,得到具有工程实用价值的分析模型,为后续实验研究工作提供理论指导。研究结果表明,缝隙位置和动量系数对圆柱体尾梁的气动性能影响明显;采用双缝喷气和合适的动量系数可提高圆柱体尾梁的最大升力系数,也可降低喷气能量消耗。更多还原

【Abstract】 NOTAR changed the conventional concept of helicopter tail rotor. This technology adopts a tail boom with circulation control to balance the rotor anti-torque for cancelling the tail rotor, which eliminates adverse effects of tail rotor on helicopters. The circulation control tail boom has a simple structure and good safety, which improves the reliability and maintainability and reduces vibrations and noises of helicopter. What’s more, it improves the manipulation of helicopter, so it is especially suitable for light helicopters.This paper studied the parameters of circulation control cylinder, which was controlled by the wall jet flowing around it. The influence of the slots’geometric parameters such as position, size and number on aerodynamic characteristics of a circulation control tail boom was analyzed by using the FLUENT software, which focused on effects of momentum coefficient’s and slots’geometric parameters on aerodynamic characteristics of the tail boom. The detailed work in this paper includes:First, a model of circulation control tail boom was established by using CATIA, and pre-treatment software of FLUENT, GAMBIT, was employed for meshing. A method for grid generation of flow field around the tail boom was presented.Second, the momentum source model was used to analyze the rotor downwash and its code was programmed in FLUENT. Aerodynamic characteristic of the circulation control tail boom was studied. Wind tunnel and rotor downwash flow field were simulated and analyzed respectively. Influence of the slots’geometric parameters such as position, size and number on aerodynamic characteristics of the tail boom was analyzed according to the flow field data. The law that aerodynamic characteristics of the tail boom changing with the momentum coefficient and the slots’geometric parameters was obtained and the best parameters were chosen.Third, the above CFD analysis results were compared with experimental data and the theoretical model of circulation control tail boom was revised. In the end, an analysis model for engineering practice was established to provide theoretical guidance for a following experimental study.The results show that the slots position and momentum coefficient have marked influences on aerodynamic performance of the tail boom. Using double-slit jets and a proper momentum coefficient can help to increases the maximum lift coefficient of circulation control tail boom, and also can reduce the jet energy consumption.更多还原