【摘要】：選擇性取水廣泛地應(yīng)用于實(shí)際水庫中，理論和試驗(yàn)研究結(jié)果表明泄出層厚度均可用一般的數(shù)學(xué)表達(dá)式表示，只是系數(shù)C3存在差異，并且通過理論分析和試驗(yàn)數(shù)據(jù)各自得到泄出層內(nèi)速度分布表達(dá)式。本文利用FLUENT定制浮力傳熱湍流模型，確定模擬方法，模擬美國陸軍工程師團(tuán)水道試驗(yàn)，模擬與理論誤差僅為0.78%。 將模型擴(kuò)大為實(shí)際水庫，模擬結(jié)果表明：在進(jìn)行選擇性取水時(shí)，水體流動(dòng)可以分為三個(gè)區(qū)域，抽吸區(qū)域、慣性—浮力區(qū)域和粘性—對流區(qū)域，理論和試驗(yàn)所得到的泄出層厚度及速度無量綱分布公式只適用于慣性—浮力區(qū)域，并且在穩(wěn)定出流的情況下，泄出層厚度為23.80m，建議C3=1.58；通過分析溫度分布不同線性化后，，選擇性取水流動(dòng)特性會(huì)存在著差異；而孔口大小的變化（在模擬的孔口大小范圍內(nèi)）對選擇性取水則沒有實(shí)質(zhì)性的影響。 選擇性取水的理論研究只局限于水體密度單線型分布，并未對其他密度分布進(jìn)行研究，通過借鑒Wood分析方法，得出雙線性密度分布下的泄出層厚度及系數(shù)C3表達(dá)式；利用CFD計(jì)算軟件FLUENT，獲到模擬雙線性密度下選擇性取水的縱向范圍、系數(shù)C3以及相應(yīng)速度分布，結(jié)果表明泄出層厚度與相應(yīng)的理論值接近，在分析的距離范圍內(nèi)，誤差值在0.3%~13.4%之間，建議系數(shù)C3=1.656，速度分布也符合美國陸軍工程師團(tuán)水道試驗(yàn)站的試驗(yàn)結(jié)果。 高度固定的取水口一定程度上限制了選擇性取水技術(shù)的應(yīng)用，本文提出在取水口安裝擋板和增強(qiáng)型擋板，通過上、下檔板的旋轉(zhuǎn)達(dá)到規(guī)避不良水層技術(shù)思路。通過建立取水口上側(cè)安裝檔板和增強(qiáng)型擋板的CFD模型，表明孔口上方擋板能有效減少孔口中心上側(cè)的泄出層厚度和流量，間接增加下側(cè)的取水流量，8m上擋板向下傾斜-30°時(shí)，上、下流量分配比達(dá)到最大值，為1：4.3，不過4m擋板最為經(jīng)濟(jì)適宜，上、下流量分配比為1:3.93；4m增強(qiáng)型上擋板，上、下流量分配比最大值為1：4.78，對于4m增強(qiáng)型下?lián)醢�，上、下流量分配比最大值則為3.97:1；無論是擋板還是增強(qiáng)型擋板，傾斜角是這兩種技術(shù)影響泄出層厚度和流量分配的重要因素。通過數(shù)據(jù)比較，表明增強(qiáng)型擋板在減小泄出層厚度這方面要優(yōu)于擋板，而在流量方面，上、下流量分配比得到進(jìn)一步提高。因此取水口安裝擋板和增強(qiáng)型擋板可經(jīng)濟(jì)地增強(qiáng)選擇性取水的調(diào)節(jié)范圍
[Abstract]:Selective water intake is widely used in practical reservoirs. The theoretical and experimental results show that the thickness of the discharge layer can be expressed by general mathematical expressions, but the coefficient C _ 3 is different. The expression of velocity distribution in the discharge layer is obtained by theoretical analysis and experimental data. In this paper, fluent is used to customize the buoyancy heat transfer turbulence model, and the simulation method is determined to simulate the US Army Corps of Engineers watercourse test. The error between simulation and theory is only 0.78. The simulation results show that the water flow can be divided into three regions, the suction region, the inertial buoyancy region and the viscous convection region. The dimensionless distribution formulas of the thickness and velocity of the discharge layer obtained in theory and experiment are only applicable to the inertial buoyancy region, and the thickness of the discharge layer is 23.80 m under the condition of steady outflow. It is suggested that C _ 3N _ (1.58). After analyzing the linearization of the temperature distribution, The characteristics of selective water intake flow are different, but the change of pore size (in the range of simulated orifice size) has no substantial effect on selective water intake. The theoretical study of selective water intake is limited to the single-line distribution of water density, but not to other density distributions. By using Wood analysis method, the expressions of discharge layer thickness and coefficient C _ 3 under bilinear density distribution are obtained. By using CFD software fluent, the longitudinal range, coefficient C 3 and corresponding velocity distribution of selective water intake under bilinear density are obtained. The results show that the thickness of the discharge layer is close to the corresponding theoretical value, and within the range of analysis distance, The error value is between 0.34% and 13.4%, and the suggested coefficient is C _ 3N _ (1.656), and the velocity distribution is in accordance with the test results of the U. S. Army Corps of Engineers' watercourse test station. The application of selective water intake technology is limited to a certain extent by high fixed intake nozzle. In this paper, the installation of baffles and enhanced baffles at the intake points is proposed, and the technical ideas of avoiding the bad water layer can be reached through the rotation of the upper and lower gear plates. The CFD model of the upper side of the intake port and the enhanced baffle are established. The results show that the upper baffle of the orifice can effectively reduce the thickness and flow rate of the discharge layer on the upper side of the orifice, and indirectly increase the flow rate of the lower side when the upper baffle is inclined downwards to -30 擄. The lower flow distribution ratio reaches the maximum value of 1: 4.3, but the 4m baffle is the most economical and appropriate. The upper, lower flow distribution ratio is 1: 3.93 / 4m enhanced upper baffle. The upper and lower flow distribution ratio is 1: 4.78. For the 4m enhanced lower baffle, the upper, the lower flow distribution ratio is 1: 4.78. The maximum flow distribution ratio is 3.97: 1. The slope angle is an important factor affecting the discharge layer thickness and flow distribution of both the baffle and the enhanced baffle. The comparison of the data shows that the enhanced baffle is better than the baffle in reducing the thickness of the discharge layer, and in the flow rate, the lower flow distribution ratio is further improved. Therefore, the installation of baffles and the enhanced baffles at intake ports can economically enhance the range of adjustment for selective intake of water.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU991.1;TV697.41

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