本文關鍵詞： 淹沒射流 大渦模擬 流場結構 壓力演化 渦旋運動　出處：《工程科學與技術》2017年S1期 　論文類型：期刊論文

【摘要】：射流在工程領域具有非常廣泛的用途,為得到射流流場的演化過程,深入研究射流的運動機理,采用大渦模擬方法(LES)對淹沒射流紊動流場進行數(shù)值模擬,采用有限體積法(FVM)和PISO算法進行方程離散和數(shù)值計算,得到了淹沒射流的瞬態(tài)流場。分析壓力場的演化過程發(fā)現(xiàn),壓力場等值線呈一簇簇同心圓,沿射流軸線方向和垂直射流軸線方向圓心高壓和圓心低壓交錯分布;隨著射流的進行,同心圓隨射流下移并伴有變形、分裂、融合等現(xiàn)象。在淹沒射流區(qū)和沖擊射流區(qū)前部分,同心圓圓心的壓力上下波動并呈上升趨勢;在附壁射流區(qū),同心圓圓心的壓力較為平穩(wěn),進行較低頻率、小幅度的波動。分析速度場的演化過程發(fā)現(xiàn),在射流的進行中,射流主體左右擺動,軸線處存在高速流體團脫落現(xiàn)象。射流主體上固定點的速度和壓力大小有顯著的負相關關系。分析渦量場的演化過程發(fā)現(xiàn),兩個渦量束呈分段化中間大兩端小的"藕"形分布,并隨時間進行隨機擺動。通過渦量場與壓力場的對比看出,渦旋的擺動造成了射流主體的擺動,渦旋的存在導致了壓力場圓心低壓和圓心高壓交錯分布。淹沒射流流場具有很強的紊動性和隨機性,對射流流場演化過程和水力特性內在關系的研究得出了一些規(guī)律性的結論,但如射流擺動的定量分析等仍有許多內容有待研究。
[Abstract]:Jet is widely used in engineering field. In order to obtain the evolution process of jet flow field, the large eddy simulation method is used to simulate the turbulent flow field of submerged jet. The transient flow field of submerged jet is obtained by using finite volume method (FVM) and PISO algorithm. By analyzing the evolution process of pressure field, it is found that the contour of pressure field is a cluster of concentric circles. Along the axis of the jet and the direction of the axis of the vertical jet, the high pressure and the low pressure of the center of the circle are staggered; with the jet, the concentric circle moves down with the jet and is accompanied by the phenomena of deformation, splitting, fusion, etc. In the front part of the submerged jet zone and the impinging jet zone, The pressure of concentric circle center fluctuates up and down, and the pressure of concentric circle center fluctuates in a relatively low frequency and a small amplitude in the zone of wall jet. The evolution of velocity field shows that, in the process of jet flow, the pressure of concentric circle center is stable, and the pressure of concentric circle center fluctuates by small amplitude. The velocity and pressure of the fixed point on the jet body are inversely correlated with the velocity of the jet body, and the evolution process of the vorticity field is found by analyzing the evolution process of vorticity field. The two vortex beams are distributed in the shape of "lotus root" with small ends and large ends in the middle, and swing randomly with time. By comparing the vorticity field with the pressure field, it can be seen that the wobble of the vortex causes the wobble of the main body of the jet. The existence of vortices leads to the low pressure and interlaced distribution of high pressure in the center of the pressure field. The submerged jet flow field has strong turbulence and randomness. Some regular conclusions have been drawn on the inherent relationship between the evolution process of the jet flow field and the hydraulic characteristics. However, there are still many contents to be studied, such as quantitative analysis of jet wobble.
【作者單位】： 四川大學水力學與山區(qū)河流開發(fā)保護國家重點實驗室;四川大學水利水電學院;
【基金】：國家自然科學基金資助項目(51009102) 青年基金資助項目(51179133)
【分類號】：O358

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