本文關(guān)鍵詞：DBD等離子體誘導(dǎo)渦結(jié)構(gòu)控制附面層流動研究　出處：《哈爾濱工業(yè)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： DBD等離子體 流動控制 渦流發(fā)生器 等離子體簡化模型 壁面射流 氣膜冷卻 分離控制

【摘要】：隨著主動流動控制技術(shù)的快速發(fā)展,介質(zhì)阻擋放電(DBD)等離子體流動控制技術(shù)作為一種新型的主動流動控制技術(shù),已在全球范圍內(nèi)引起了研究者們的關(guān)注。DBD等離子體激勵器作為一種主動流動控制設(shè)備,具有輸入能量少、結(jié)構(gòu)簡單(無需移動部件)、控制靈活、反應(yīng)快速等優(yōu)點。隨著研究的開展,等離子體激勵器被逐步地應(yīng)用在流動分離、轉(zhuǎn)捩流動、湍流流動以及氣膜冷卻等流動控制領(lǐng)域,并實現(xiàn)了較好地控制效果。本文首先利用PIV實驗測試技術(shù)開展了等離子體對平板壁面附近流動特性影響的研究。實驗結(jié)果表明,等離子體激勵器對流場的誘導(dǎo)作用能夠顯著增加近壁區(qū)內(nèi)的流動速度,速度增幅?U最大可達來流速度的8.8%,而最大影響范圍?δ約為附面層厚度的60%,二者均出現(xiàn)在激勵器正極中心附近處;等離子體對流場的影響幅度與來流速度、激勵電壓的大小有關(guān),來流速度相同時,近壁區(qū)附近等離子體的影響范圍隨激勵電壓的增加而增加;激勵電壓相同時,影響范圍隨來流速度的增加而下降。其次,基于公開的凸包實驗數(shù)據(jù)對比討論了不同亞格子模型的特點,并利用PIV實驗結(jié)果修正了Shyy等人提出的電場線性化簡化模型中的模型參數(shù),從而建立了平板近壁區(qū)流場等離子體流動控制的大渦模擬方法。通過對DBD等離子體激勵器作用下的平板流場進行模擬發(fā)現(xiàn),等離子體對近壁區(qū)流動的影響主要體現(xiàn)在:一方面是通過其對激勵器附近局部區(qū)域低能流體的直接“加能”作用而實現(xiàn)的,另一方面則是利用生成的“誘導(dǎo)渦”增強了主流區(qū)與近壁區(qū)流體之間的能量交換所導(dǎo)致。隨后采用大渦模擬方法將DBD等離子體激勵器簡化模型和流動控制方程耦合聯(lián)立求解,探討了DBD等離子體作用下的平板、凸包流動的流場結(jié)構(gòu)特點。通過對流場的分析表明,在DBD等離子體激勵器作用下,流場壁面附近區(qū)域形成了一系列的正負(fù)“渦對”結(jié)構(gòu),“渦對”的產(chǎn)生促進了壁面附近區(qū)域內(nèi)流體與主流流體之間的能量交換。在平板流動中,誘導(dǎo)“渦對”有效地提高了附面層內(nèi)的流體速度,但其在向下游遷移的過程中不斷地遠(yuǎn)離壁面,對流動的控制作用不斷減弱。在凸包流動中,誘導(dǎo)“渦對”的遷移可以促使分離區(qū)內(nèi)低能流體向下游的移動,從而減小了分離區(qū)的大小,甚至消除分離。最后開展了利用DBD等離子體激勵器誘導(dǎo)“流向渦”,進行氣膜冷卻流場流動結(jié)構(gòu)控制的研究�；谇拔牡姆抡婺Ｐ吞接懥藛渭钇饕约岸嗉钇髯饔孟碌牧鲌觥傲飨驕u”的分布,分析了“流向渦”的發(fā)展同激勵器的激勵強度、激勵器極板間距以及激勵器極板長度之間的關(guān)系。研究結(jié)果表明,DBD等離子體激勵器誘導(dǎo)出的壁面射流流經(jīng)壁面后與來流發(fā)生作用,從而誘導(dǎo)卷曲形成“流向渦”,該“流向渦”在向下游遷移的過程中不斷膨脹并遠(yuǎn)離壁面。而相向布置的等離子體激勵器誘導(dǎo)流動發(fā)生卷曲從而形成相向運動的“流向渦”�！傲飨驕u”之間的互相作用,促進了其在法向方向的遷移。通過Q準(zhǔn)則的等值面分布識別出吹風(fēng)比M=1.0的條件下,冷卻孔出口附近以及下游區(qū)域的大渦擬序結(jié)構(gòu)。渦結(jié)構(gòu)中主要以發(fā)卡渦的分布為主,流向截面內(nèi)表現(xiàn)為旋向相反的渦對結(jié)構(gòu)(CVP)。發(fā)卡渦在向下游遷移的過程中,其明顯存在向著法向以及展向方向發(fā)展的速度。這也從側(cè)面反映出冷卻射流的核心區(qū)向周圍擴散,逐步遠(yuǎn)離壁面的趨勢。這種趨勢不利于冷卻氣體對高溫部件的表面進行冷卻。此外,研究過程中深入分析了不同等離子體激勵器布置形式對氣膜冷卻效果的改善作用。在對計算結(jié)果的分析中建立了不同等離子體激勵器布置形式下,冷卻孔附近大渦擬序結(jié)構(gòu)的發(fā)展演化規(guī)律,通過探討流場參數(shù)的分布規(guī)律獲得了“誘導(dǎo)渦”對冷卻流場渦結(jié)構(gòu)的控制機制。常規(guī)的等離子體激勵器通過誘導(dǎo)壁面射流,有效地減弱了冷卻孔出口下游近壁區(qū)的渦強度,導(dǎo)致渦破碎現(xiàn)象提前發(fā)生。但壁面射流在流場下游逐漸遠(yuǎn)離壁面的特性卻不可避免的增強冷卻氣體沿法向遷移的能力,使得其對壁面的冷卻效果有所下降。誘導(dǎo)流向渦結(jié)構(gòu)的布置形式,能夠誘導(dǎo)冷卻氣體產(chǎn)生三維的渦結(jié)構(gòu),該渦結(jié)構(gòu)與氣膜孔下游的大渦結(jié)構(gòu)相互抑制,能夠有效地減弱冷卻氣膜在法向方向的運動能力,促進冷卻氣流的核心區(qū)向壁面偏移,有效地改善了冷卻氣體對高溫部件表面的冷卻性能。
[Abstract]:With the rapid development of active flow control technology, dielectric barrier discharge (DBD) plasma flow control as a new type of active flow control technology, has attracted attention in the global scope of.DBD plasma actuator researchers as a kind of active flow control equipment, with less input energy and simple structure (without moving parts), flexible control, fast response and other advantages. With the development of the studies, the plasma actuator is gradually used in flow separation, transition flow, turbulent flow and gas film cooling control field, and achieve a better control effect. This paper uses PIV test technology to carry out research on the influence of flow characteristics near the plasma flat wall. Experimental results show that the flow field induced by the plasma actuator can significantly increase the flow velocity in the near wall region, speed Increase? U maximum flow rate of 8.8%, while the maximum range of influence? Delta is about the thickness of boundary layer 60%, two are in the vicinity of the center of positive influence amplitude exciter; plasma on the flow field and the flow velocity, the excitation voltage on the size of the flow at the same speed, the influence range of the near wall near the plasma increases with excitation voltage; voltage phase at the same time, influence range with the flow velocity increased. Secondly, comparing the convex hull of public experiment data is discussed based on the characteristics of different sub grid model, and use the PIV test results of the correction of the electric field of linear Shyy et al proposed simplified model parameter model in, so as to establish a flat near wall region flow plasma flow control method of large eddy simulation. Simulation found by plate flow of DBD plasma actuator under the action of plasma in recent The effect of wall flow is mainly reflected in: on the one hand by the actuator near the local area of low-energy fluid directly "add" and realize the function, the other is using the "vortex" enhances the main flow region and near wall fluid between the exchange of energy caused by the later. Eddy simulation methods DBD plasma actuator flow control equations of the simplified model and the coupled simultaneous solution, discusses the tablet DBD under the action of plasma, the flow structure characteristics of convex hull flow. Through the analysis of the flow field in the DBD show that the plasma actuator under the action of regional flow field near the wall to form a series of positive and negative "vortex on the structure." on promoting the emergence of vortex "between the near wall region of fluid and mainstream fluid exchange of energy. In the plate flow, the vortex induced to effectively improve the flow of the boundary layer Speed, but in the process of migration to downstream continuously away from the wall, the weakening effect on the flow. In the convex hull "vortex flow, induced migration of" can promote the separation zone of low-energy fluid downward movement, thereby reducing the size of the separation zone, and even eliminate the separation. Finally we carry out the use of DBD plasma actuator induced "streamwise vortex", studied the film cooling flow control structure. The distribution of flow field simulation model of the above "single actuator and actuator under the action of streamwise vortex" based on the analysis of the development of streamwise vortex "incentive strength with the actuator, the relationship between the actuator and the plate spacing the actuator plate length. The results show that the wall jet DBD plasma actuator induced through the wall and flow effect, thereby inducing formation of streamwise vortex" curl "The" vortex "in the process of migration to downstream in the ever expanding and away from the wall. The opposite arrangement of the plasma actuator flow induced curling to form the opposite movement" vortex "." the interaction between the streamwise vortex ", the migration direction in law promoted by Q rules. The equivalent surface distribution to identify the blowing ratio M=1.0 under the conditions of large vortex cooling holes near the outlet and downstream regions of the coherent structures. The vortex structure is mainly in the distribution of Hairpin Vortex dominated flow section in the form of reverse rotating vortex on the structure (CVP). In the process of Hairpin Vortex downstream migration in the there was normal and spanwise direction toward the speed of development. This is also reflected from the side of the core area of cooling jet to spread around, step away from the wall surface trend. This trend is not conducive to the surface of the cooling gas of high temperature components Cooling. In addition, in the course of the study, in-depth analysis of the effects of different plasma actuator arrangement on film cooling effect. In the analysis of the calculation results of the established different plasma actuator arrangement, cooling holes near the large eddy coherent structure evolution law of development, through the distribution of flow field parameters obtained "control the mechanism of vortex induced vortex cooling structure. The plasma actuator induced by conventional wall jet, effectively reduced the intensity of vortex near wall region downstream of the cooling hole outlet, leading to vortex breakdown phenomena occur in advance. But the wall jet in the downstream flow gradually away from the wall surface properties are enhanced cooling gas inevitably along the normal direction the ability of migration, the decline of the cooling effect. The wall layout induced streamwise vortex structure, can induce the cooling gas to produce three-dimensional The vortex structure, mutual inhibition of large vortex structures downstream of the vortex structure and film hole, can effectively weaken the cooling gas film in the normal direction of the athletic ability, promote the core area of the wall offset of cooling airflow, and effectively improve the performance of cooling gas on surface of the high temperature parts.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：O53

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本文編號：1372562