湖库选择性取水泄出层厚度理论计算扩展分析

发布时间：2019-05-29 16:18

【摘要】：泄出层厚度是湖库水源选择性取水技术及应用的重要参数之一。在湖库纵向密度线性分布下，选择性取水的泄出层厚度理论分析和试验结论可用一表达式表示，差异存在于系数C。本文针泄出层厚度理论对密度条件要求严格及应用范围较窄问题，简化实际纵向密度分布为双线型密度分布，通过建立以取水口为中心球坐标体系和伯努利方程，理论推导了在实际上更为普遍的双线型密度分布下选择性出流泄出层厚度计算表达式，两者在形式上相同，但系数C由确定值变为变量C*，其由表征密度分布的参数k1, k2和θ决定，在双线形密度相同的情况下，可获得变量值与系数C相同。按照泄出层厚度的变化，可将选择性取水区分为两个区域，靠近取水口的部分泄出层随着距离取水口的距离快速增加，称其为非稳定区，远离取水口的部分泄出层厚度不变，，称其为稳定区。温度分层强度对泄出层厚度影响大，在取水流量和取水口位置不变时，水库由夏季-冬季的过程中，温度分层弱化，泄出层厚度会增加，在冬季-夏季的过程中，温度分层增强，泄出层厚度减小；取水口位置对泄出层厚度有影响，在案例研究中水库取水口自上而下变化过程中泄出层厚度减小。利用两夏季实测的纵向水温分布，基于CFD模拟了西安金盆水库不同深度取水口出流时的泄出层厚度，与双线型密度分布下计算公式计算结果比较，结果表明两者有较好的一致性，平均误差仅为1.2%。表明双线型密度分布下的泄出层厚度计算表达式有良好的适用性，与单线型下的泄出层厚度表达式相比，双线型密度分布下的泄出层厚度表达式具有更为广泛的应用范围。
[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.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV697.21

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