【摘要】：地面效應(yīng)對(duì)直升機(jī)的垂直起降及貼地飛行性能有顯著的影響。目前,對(duì)地面效應(yīng)的研究基本停留在單旋翼帶尾槳構(gòu)型,基于共軸雙旋翼直升機(jī)的優(yōu)勢(shì),其在未來(lái)將有很大的應(yīng)用領(lǐng)域,因此本文對(duì)共軸雙旋翼地面效應(yīng)氣動(dòng)特性進(jìn)行研究。論文基于時(shí)間步進(jìn)算法建立了適用于共軸雙旋翼氣動(dòng)特性研究的旋翼自由尾跡模型,并采用面元法模擬地面對(duì)周圍流場(chǎng)的影響。在建模過(guò)程中,建立槳葉剛性揮舞運(yùn)動(dòng)模型,采用Weissinger-L一階升力面模型考慮了槳葉的三維效應(yīng),并充分突出旋翼/旋翼和旋翼/地面之間的氣動(dòng)干擾,在穩(wěn)定狀態(tài)下對(duì)雙旋翼系統(tǒng)配平分析并將各模型耦合進(jìn)行數(shù)值迭代求解。本文發(fā)展的共軸雙旋翼地面效應(yīng)氣動(dòng)特性分析模型是在單旋翼自由尾跡模型的基礎(chǔ)上建立的,可分析單旋翼和共軸雙旋翼在地面效應(yīng)狀態(tài)的流場(chǎng)特性。通過(guò)已有的試驗(yàn)數(shù)據(jù)和本文試驗(yàn)研究得到的數(shù)據(jù)驗(yàn)證了本文數(shù)學(xué)模型的正確有效。最后論文利用經(jīng)驗(yàn)證過(guò)的數(shù)學(xué)模型,先計(jì)算分析了地面效應(yīng)下單旋翼懸停和前飛狀態(tài)的旋翼氣動(dòng)特性,然后著重研究了水平地面和存在一定角度的傾斜地面影響下共軸雙旋翼自由尾跡幾何形狀、流場(chǎng)特性和旋翼性能,地面的存在對(duì)旋翼周圍流場(chǎng)存在一定的擾動(dòng),地面滿足無(wú)穿透邊界條件,其影響使旋翼下洗流徑向擴(kuò)展且向上卷起,對(duì)共軸雙旋翼尤其是下旋翼的拉力產(chǎn)生明顯的影響。通過(guò)對(duì)共軸雙旋翼的氣動(dòng)干擾特性進(jìn)行了計(jì)算分析研究,得到了一些有意義的結(jié)論。
[Abstract]:The ground effect has a significant effect on the vertical take-off and landing performance of the helicopter. At present, the research on ground effect basically stays on the configuration of single rotor with tail propeller. Based on the superiority of coaxial double rotor helicopter, it will have a very large application field in the future. Therefore, the aerodynamic characteristics of ground effect of coaxial double rotor are studied in this paper. Based on the time stepping algorithm, a rotor free wake model for the study of the aerodynamic characteristics of a coaxial double rotor is established in this paper, and the surface element method is used to simulate the influence of the flow field around the rotor. In the process of modeling, the rigid motion model of blade is established, and the Weissinger-L first order lift surface model is used to consider the three-dimensional effect of the blade, and the aerodynamic interference between rotor / rotor and rotor / ground is fully highlighted. In the stable state, the double rotor system is equalized and each model coupled is solved by numerical iteration. The analytical model of ground effect of coaxial double rotor is established on the basis of the free wake model of single rotor, which can be used to analyze the flow field characteristics of single rotor and coaxial double rotor in ground effect state. The validity of the mathematical model is verified by the existing experimental data and the experimental data obtained in this paper. Finally, based on the verified mathematical model, the aerodynamic characteristics of the rotor with ground effect in hovering and forward flight states are calculated and analyzed. Then, the free wake geometry, flow field characteristics and rotor performance of the coaxial biaxial rotor under the influence of horizontal ground and inclined ground with certain angles are studied. The presence of the ground has some disturbance on the flow field around the rotor. The ground satisfies the condition of non-penetrating boundary, and its influence makes the downward wash flow of rotor expand radial and roll up, which has an obvious effect on the pull force of the coaxial double rotor, especially the lower rotor. The aerodynamic interference characteristics of coaxial double rotor are calculated and analyzed, and some meaningful conclusions are obtained.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：V211.52

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本文編號(hào)：2191429