本文關(guān)鍵詞：拍動翼海流能采集系統(tǒng)水動力學(xué)性能研究　出處：《浙江大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 有限體積法 流固耦合 拍動翼 海流能采集 Floquet穩(wěn)定性分析

【摘要】：海洋中蘊(yùn)藏著巨大能量的可再生清潔能源,包括海流能、波浪能、風(fēng)能、海水鹽度差能、海洋熱能等等。拍動翼海流能采集系統(tǒng)是受水生動物運(yùn)動能力啟發(fā)而提出的一種新的海流能采集方法。與傳統(tǒng)的用于采集海流能的葉輪機(jī)相比,拍動翼海流能采集系統(tǒng)具有易于在潛水中布置、能充分利用空間、對水生動物更加友好、對通航影響較小等特點(diǎn)。根據(jù)目前拍動翼能量采集系統(tǒng)的研究現(xiàn)狀,本文考慮翼與周圍流體之間的流固耦合,對拍動翼海流能采集系統(tǒng)進(jìn)行了系統(tǒng)研究。首先,本文確定了系統(tǒng)最優(yōu)的(f*,θ0)參數(shù)空間,其中f*為拍動頻率,θ0為轉(zhuǎn)角幅值;評估了非正弦轉(zhuǎn)動提高拍動翼海流能采集系統(tǒng)能量采集性能的效果;研究了慣性和阻尼對非正弦拍動翼海流能采集系統(tǒng)的影響;另外,本文還研究了由翼尖效應(yīng)和三維不穩(wěn)定性引起的三維效應(yīng)。最后本文基于全主動運(yùn)動模型研究了自由面對拍動翼海流能采集系統(tǒng)的影響。首先,在關(guān)于非正弦轉(zhuǎn)動對拍動翼海流能采集系統(tǒng)影響的研究中,本文確定了正弦轉(zhuǎn)動下使系統(tǒng)取得最高能量采集效率的參數(shù)組合為θ0 = 75°,f*= 0.16,取得的最高能量采集效率為32%。然后,本文通過增加控制翼轉(zhuǎn)動軌跡的參數(shù)β的值使翼的轉(zhuǎn)動軌跡由正弦轉(zhuǎn)動轉(zhuǎn)變?yōu)榉讲ㄐ娃D(zhuǎn)動,研究了非正弦轉(zhuǎn)動的影響。本文研究發(fā)現(xiàn),當(dāng)系統(tǒng)以最優(yōu)參數(shù)組合運(yùn)行時,非正弦轉(zhuǎn)動提高其能量采集性能的作用非常有限,系統(tǒng)能量采集效率的上限并沒有提高。對于小轉(zhuǎn)角幅值的工況,本文得到了與前人一致的結(jié)論,采用非正弦轉(zhuǎn)動確實(shí)可以提高系統(tǒng)的能量采集效率。但當(dāng)轉(zhuǎn)角幅值及拍動頻率都取最優(yōu)值的時候,非正弦轉(zhuǎn)動對系統(tǒng)能量采集效率的影響是負(fù)面的。根據(jù)本文的研究結(jié)果,采用簡單的方波型非正弦轉(zhuǎn)動方式不能提高半主動拍動翼海流能采集系統(tǒng)的能量采集效率上限。第二,在關(guān)于慣性和阻尼對半主動拍動翼海流能采集系統(tǒng)影響的研究中,本文首先在質(zhì)量比r = 1時進(jìn)行了參數(shù)化研究,確定了系統(tǒng)運(yùn)行的最佳運(yùn)動參數(shù),取得的最高能量采集效率為η=34%。然后在最優(yōu)運(yùn)動參數(shù)下進(jìn)行了r = 0.125到r = 100的計(jì)算。本文發(fā)現(xiàn),半主動系統(tǒng)的能量采集效率隨著水翼與其排開的流體的質(zhì)量之比r的增加而單調(diào)下降。對于r10的工況,系統(tǒng)的輸出功率隨質(zhì)量比的變化較小,一直保持在較高的水平,因此,從輸出功率的角度來講,此時慣性的影響可以忽略不計(jì)。半主動拍動翼海流能采集系統(tǒng)的轉(zhuǎn)動與平動之間的相位差具有自適應(yīng)性,在該部分的研究中取得的轉(zhuǎn)動與平動最優(yōu)相位差為Φ≈82°。此時,水翼運(yùn)動與周圍渦的發(fā)展具有良好的同步性。本文關(guān)于阻尼對拍動翼海流能采集系統(tǒng)影響的研究發(fā)現(xiàn),系統(tǒng)的能量采集效率隨著阻尼的增加先上升后下降,存在使系統(tǒng)的能量采集效率最高的最優(yōu)阻尼c*≈0.5—0.7。該結(jié)論與線性理論分析的結(jié)果有差別。這是因?yàn)榫�性理論僅適用于雷諾數(shù)無限大的情況,并且沒有考慮前緣渦的影響。第三,在三維效應(yīng)對系統(tǒng)能量采集性能影響的研究中,本文選取有限展長的水翼及展向設(shè)為周期性邊界條件的工況進(jìn)行研究。根據(jù)本文的計(jì)算,對于有限翼展的工況,系統(tǒng)的能量采集效率隨展弦比的減小而降低。不同拍動頻率的工況對翼展的敏感程度不同,大。因此,系統(tǒng)的最優(yōu)拍動頻率隨展弦比增大而增大。另外,本文發(fā)現(xiàn),三維效應(yīng)包含兩方面因素:翼尖效應(yīng)和流場的三維不穩(wěn)定性。本文基于全主動模型,運(yùn)用Floquet穩(wěn)定性分析,研究了雷諾數(shù)對三維不穩(wěn)定性的影響,確定了尾流轉(zhuǎn)捩的臨界雷諾數(shù)。三維直接數(shù)值模擬取得了與Floquet穩(wěn)定性分析一致的結(jié)果。最后,關(guān)于自由面對拍動翼海流能采集系統(tǒng)影響的研究,本文首先根據(jù)系統(tǒng)的實(shí)際工作狀況選取三個傅汝德數(shù)研究了浸沒深度的影響。研究發(fā)現(xiàn),當(dāng)水翼浸沒深度與弦長之比較小的時候(d/c8),自由面對系統(tǒng)能量采集效率的影響比較顯著,此時系統(tǒng)的能量采集效率隨著浸沒深度的減小而迅速升高。本文還對傅汝德數(shù)的影響進(jìn)行了研究。當(dāng)Fr1.2時可以不考慮傅汝德數(shù)的影響,在此傅汝德數(shù)范圍內(nèi)系統(tǒng)的能量采集效率表現(xiàn)出很好的穩(wěn)定性。但是,當(dāng)傅汝德數(shù)進(jìn)一步增大的時候,極端傅汝德數(shù)會使系統(tǒng)的能量采集效率降低。
[Abstract]:In the ocean, there are renewable and clean energy with great energy, including current energy, wave energy, wind energy, sea salinity difference energy, marine heat energy and so on. The current flapping wing energy acquisition system is a new kind of current aquatic animal movement inspired by the collection method. Compared with the traditional turbine for collecting ocean current energy, ocean current energy acquisition system of flapping wing is easily in diving arrangement, can make full use of space, more friendly, the characteristics of aquatic animal navigation has little impact. According to the current research status of flapping wing energy acquisition system at present, considering the coupling between the wing and the surrounding fluid flow, the flapping wing current energy acquisition system were studied. First of all, this paper determined the optimal system (f*. 0) parameter space, where f* is the flapping frequency, 0 angle theta amplitude; evaluation of the non sinusoidal currents can improve rotation of the flapping wing energy acquisition performance data acquisition system effect; inertia and damping can influence the acquisition system of non sinusoidal flapping wing flow on the sea; in addition, this paper also studies the 3D effect caused by the tip effect and three-dimensional instability. Finally, all active motion model is studied based on the free face of flapping wing ocean current energy acquisition system. First of all, in the study of non sinusoidal rotational energy acquisition system influence on flapping wing currents, we determined the parameters of combined sine rotation to achieve the maximum efficiency of energy acquisition system for 0 theta = 75 DEG, f*= 0.16, the highest energy collection efficiency is achieved 32%. Then, by increasing the parameter beta of the control wing's rotation trajectory, the rotation trajectory of the wing is changed from sinusoidal rotation to square wave rotation, and the influence of non sinusoidal rotation is studied. This paper finds that when the system runs in the best parameter combination, the effect of non sinusoidal rotation on improving the energy collection performance is very limited, and the upper limit of the energy collection efficiency of the system is not improved. For the condition of the small angle amplitude, this paper obtains the agreement with the predecessors. The non sinusoidal rotation can improve the energy acquisition efficiency of the system. But when the angle amplitude and flapping frequency are the optimal value, non sinusoidal rotation effect on the energy collection efficiency of the system is negative. According to the results of this study, using a simple square wave of non sinusoidal rotation cannot be improved semi-active flapping wing marine current energy collection efficiency limit acquisition system. Second, research on the inertia and damping semi-active flapping wing can affect the current acquisition system, firstly, when the weight ratio of R = 1 for the parametric study, the best motion parameters of the system were determined, the highest energy collection efficiency achieved for =34%. Then the calculation of R = 0.125 to r = 100 is carried out under the optimal motion parameters. It is found that the energy acquisition efficiency of a semi-active system decreases monotonically with the increase of the ratio of R to the mass of the hydrofoil and its discharged fluid. For the working condition of R10, the output power of the system changes little with the mass ratio. It keeps at a higher level. Therefore, from the point of view of output power, the influence of inertia can be ignored. Phase rotation between the semi-active flapping wing current energy acquisition system and translational difference is adaptive, made in the study of this part of the rotation and translation of the optimal phase difference phi = 82 degrees. At this time, the movement of hydrofoil and the development of the surrounding vortices have good synchronism. This paper studies on the damping effect on the flapping wing current acquisition system found that the efficiency of energy acquisition system with the increase of damping increased after the first drop, the system energy collection efficiency highest optimal damping c* = 0.5 - 0.7. The result of this conclusion is different from the result of linear theory. This is because the linear theory is only applicable to the infinitely large Reynolds number and does not take into account the influence of the leading edge vortices. Third, in the study of the influence of three-dimensional effect on the energy harvesting performance of the system, we choose the finite extended length hydrofoil and the developing conditions as periodic boundary conditions. According to the calculation in this paper, the energy acquisition efficiency of the system decreases with the decrease of the aspect ratio for the limited wingspan. The sensitivity of different flapping frequency conditions on different span, large. Therefore, the optimal flapping frequency system with the aspect ratio increases. In addition, this paper found that the 3D effect consists of two factors: the three-dimensional instability tip effect and flow field. Based on the full active model and the Floquet stability analysis, the influence of Reynolds number on the three-dimensional instability is studied, and the critical Reynolds number of the wake transition is determined. The results of the three-dimensional direct numerical simulation are consistent with the stability analysis of Floquet. Finally, research on flapping wing current acquisition system can influence the effect of free face, according to the actual working condition of the system selects three number of Fu Rude immersion depth. The study found that, when the immersion depth and length of the hydrofoil is relatively small (d/c8), when the influence of free surface energy acquisition system efficiency significantly, the efficiency of energy acquisition system increases rapidly with the decrease of the immersion depth of the. The influence of Fu Rude number is also studied in this paper. When Fr1.2 does not consider the influence of the Fu Rude number, the energy acquisition efficiency of the system in the range of the Fu Rude number shows a good stability. However, when the Fu Rude number is further increased, the extreme Fu Rude number will reduce the efficiency of the system's energy acquisition.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：P743.1;O352

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相關(guān)期刊論文 前7條

1 李彥麗;王兆立;蘇玉民;秦再白;;非定常拍動翼的水動力性能研究[J];哈爾濱工程大學(xué)學(xué)報;2009年12期

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本文編號：1340185