湖庫選擇性取水泄出層厚度理論計算擴展分析
發(fā)布時間：2019-05-29 16:18
【摘要】：泄出層厚度是湖庫水源選擇性取水技術及應用的重要參數(shù)之一。在湖庫縱向密度線性分布下，選擇性取水的泄出層厚度理論分析和試驗結論可用一表達式表示，差異存在于系數(shù)C。本文針泄出層厚度理論對密度條件要求嚴格及應用范圍較窄問題，簡化實際縱向密度分布為雙線型密度分布，通過建立以取水口為中心球坐標體系和伯努利方程，理論推導了在實際上更為普遍的雙線型密度分布下選擇性出流泄出層厚度計算表達式，兩者在形式上相同，但系數(shù)C由確定值變?yōu)樽兞緾*，其由表征密度分布的參數(shù)k1, k2和θ決定，在雙線形密度相同的情況下，可獲得變量值與系數(shù)C相同。按照泄出層厚度的變化，可將選擇性取水區(qū)分為兩個區(qū)域，靠近取水口的部分泄出層隨著距離取水口的距離快速增加，稱其為非穩(wěn)定區(qū)，遠離取水口的部分泄出層厚度不變，，稱其為穩(wěn)定區(qū)。溫度分層強度對泄出層厚度影響大，在取水流量和取水口位置不變時，水庫由夏季-冬季的過程中，溫度分層弱化，泄出層厚度會增加，在冬季-夏季的過程中，溫度分層增強，泄出層厚度減小；取水口位置對泄出層厚度有影響，在案例研究中水庫取水口自上而下變化過程中泄出層厚度減小。利用兩夏季實測的縱向水溫分布，基于CFD模擬了西安金盆水庫不同深度取水口出流時的泄出層厚度，與雙線型密度分布下計算公式計算結果比較，結果表明兩者有較好的一致性，平均誤差僅為1.2%。表明雙線型密度分布下的泄出層厚度計算表達式有良好的適用性，與單線型下的泄出層厚度表達式相比，雙線型密度分布下的泄出層厚度表達式具有更為廣泛的應用范圍。
[Abstract]:The thickness of discharge layer is one of the important parameters for selective water intake technology and application of lake and reservoir water sources. Under the linear distribution of longitudinal density of lake and reservoir, the theoretical analysis and experimental conclusion of the thickness of discharge layer for selective water intake can be expressed by an expression, and the difference exists in the coefficient C. In this paper, the thickness theory of outlet layer requires strict density condition and narrow application range, simplifies the actual longitudinal density distribution to double linear density distribution, and establishes the spherical coordinate system with water intake as the center and Bernoulli equation. In this paper, the expressions for calculating the thickness of selective outlet layer under the more general bilinear density distribution are derived theoretically, which are the same in form, but the coefficient C changes from the definite value to the variable C, and the parameter K1, which represents the density distribution, is changed from the definite value to the variable C, and the coefficient C is changed from the definite value to the variable C, which represents the density distribution. K2 and theta determine that when the bilinear density is the same, the variable value is the same as the coefficient C. According to the change of the thickness of the discharge layer, the selective water intake area can be divided into two regions. The partial discharge layer near the water intake increases rapidly with the distance from the water intake port, which is called an unstable zone, and the thickness of the partial discharge layer far away from the water intake is unchanged. It is called a stable zone. The intensity of temperature stratification has a great influence on the thickness of the discharge layer. when the water intake flow and the position of the intake port remain unchanged, the temperature stratification of the reservoir is weakened from summer to winter, and the thickness of the discharge layer will increase. In the process of winter and summer, The temperature stratification increases and the thickness of the discharge layer decreases. The position of the intake port has an influence on the thickness of the discharge layer. In the case study, the thickness of the discharge layer decreases during the change of the reservoir intake port from top to bottom. Based on the longitudinal water temperature distribution measured in two summers, the thickness of discharge layer at different depths of water intake in Xi'an Jinpan Reservoir is simulated based on CFD, and the results are compared with those calculated by the formula under double linear density distribution. The results show that the two have good consistency, and the average error is only 1.2%. It is shown that the expression of the thickness of the discharge layer under the double line density distribution has a good applicability. Compared with the expression of the thickness of the discharge layer under the single line type, the expression of the thickness of the discharge layer under the double line density distribution has a more extensive application range.
【學位授予單位】：西安建筑科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV697.21
本文編號：2488052
[Abstract]:The thickness of discharge layer is one of the important parameters for selective water intake technology and application of lake and reservoir water sources. Under the linear distribution of longitudinal density of lake and reservoir, the theoretical analysis and experimental conclusion of the thickness of discharge layer for selective water intake can be expressed by an expression, and the difference exists in the coefficient C. In this paper, the thickness theory of outlet layer requires strict density condition and narrow application range, simplifies the actual longitudinal density distribution to double linear density distribution, and establishes the spherical coordinate system with water intake as the center and Bernoulli equation. In this paper, the expressions for calculating the thickness of selective outlet layer under the more general bilinear density distribution are derived theoretically, which are the same in form, but the coefficient C changes from the definite value to the variable C, and the parameter K1, which represents the density distribution, is changed from the definite value to the variable C, and the coefficient C is changed from the definite value to the variable C, which represents the density distribution. K2 and theta determine that when the bilinear density is the same, the variable value is the same as the coefficient C. According to the change of the thickness of the discharge layer, the selective water intake area can be divided into two regions. The partial discharge layer near the water intake increases rapidly with the distance from the water intake port, which is called an unstable zone, and the thickness of the partial discharge layer far away from the water intake is unchanged. It is called a stable zone. The intensity of temperature stratification has a great influence on the thickness of the discharge layer. when the water intake flow and the position of the intake port remain unchanged, the temperature stratification of the reservoir is weakened from summer to winter, and the thickness of the discharge layer will increase. In the process of winter and summer, The temperature stratification increases and the thickness of the discharge layer decreases. The position of the intake port has an influence on the thickness of the discharge layer. In the case study, the thickness of the discharge layer decreases during the change of the reservoir intake port from top to bottom. Based on the longitudinal water temperature distribution measured in two summers, the thickness of discharge layer at different depths of water intake in Xi'an Jinpan Reservoir is simulated based on CFD, and the results are compared with those calculated by the formula under double linear density distribution. The results show that the two have good consistency, and the average error is only 1.2%. It is shown that the expression of the thickness of the discharge layer under the double line density distribution has a good applicability. Compared with the expression of the thickness of the discharge layer under the single line type, the expression of the thickness of the discharge layer under the double line density distribution has a more extensive application range.
【學位授予單位】：西安建筑科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV697.21
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