闸后跌坎对水流影响特性研究

发布时间：2018-01-01 02:17

本文关键词：闸后跌坎对水流影响特性研究　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：闸门后存在跌坎情况下的水流出流流态问题在实际工程中得到了广泛的应用。分析研究出闸门后存在跌坎情况下的淹没出流判别条件、淹没出流流态特点和淹没系数合理的确定方法,对工程实际应用和学术理论研究都有很大的作用和价值。但目前还没有完善的能确定由跌坎产生的淹没修正系数的系统取值。本论文首先列举出目前的对闸后存在跌坎情况下的闸孔淹没出流问题的处理方法,认为目前存在的淹没出流的判别方法和淹没系数的计算方式,将水平底板上的闸孔淹没出流的判别和淹没系数的确定方式直接应用到闸后存在跌坎情况是不正确的。提出了引入淹没修正系数β=h'/hc"的方式,给出了针对平底坎闸孔出流淹没判别的精确方法和修正后的淹没系数确定方法。然后采用数值模拟的方法进行计算,运用标准k-ε湍流数学模型,用VOF法追踪液体自由表面,并采用气液两相流的计算模型,建立了二维的闸后存在跌坎情况下的数值模型。分别以d/e、l/e为变量,根据工程中常用的闸后跌坎尺寸,选取d/e分别等于0.2、0.4、0.6、0.8、1、2六种情况,选取l/e分别等于1、2、3、4、5、6、7、8、9、10十种情况,共60种情况建立数值模型,对闸后存在跌坎情况下的淹没出流进行数值计算,得出的流场流态、流速分布随跌坎相对高度d/e、相对长度l/e的变化规律与理论分析规律基本一致。即通过对实际工程可能出现的各种尺寸的闸底坎的闸孔淹没出流进行了有序的系统的模拟计算研究,给出了有底坎的闸孔淹没出流淹没修正系数的β值与d/e、l/e的对应关系,为实际工程应用提供了依据。最后将数值模拟计算结果分别与经典的实验数据和本校实验室的实验数据进行了对比,数值模拟计算结果与这两组实验数据吻合度都较高。充分说明数值模拟方法可以应用于计算实际工程中明渠闸后存在跌坎情况下的湍流流场流态和流速分布等。本论文的研究结果可以直接应用于闸后存在跌坎情况下的淹没出流水力计算,为工程实际应用提供了依据,并为完善闸后存在跌坎情况下的闸孔淹没出流判别方式做出了重要贡献。
[Abstract]:The problem of water outflow flow behind the sluice is widely used in the practical engineering. The condition of the submergence and outflow is analyzed and studied in the case of the fall behind the sluice gate. The method of determining the characteristics of submerged outflow flow and the reasonable submergence coefficient. It has great effect and value to engineering practical application and academic theory research. But at present, there is no perfect system value that can determine the submergence correction coefficient produced by falling ridge. Firstly, this paper enumerates the current back storage of gate. The method to deal with the problem of sluice hole inundation and outflow under the condition of fall. It is considered that the existing method of distinguishing submergence discharge and calculating method of submergence coefficient. It is not correct to apply the judgment of the sluice hole on the horizontal bottom plate and the way of determining the submergence coefficient directly to the situation where the sluice falls after the sluice. The method of introducing the submergence correction coefficient 尾 / hc "is put forward. The accurate method and the modified method of determining the submergence coefficient of flat bottom sluice hole are given. Then the numerical simulation method is used to calculate and the standard k- 蔚 turbulence mathematical model is used. Using the VOF method to track the free surface of the liquid and using the gas-liquid two-phase flow calculation model, a two-dimensional numerical model with D / E / L / e as the variable is established. According to the commonly used size of the sluice, d / e = 0.2g / e = 0.2g / e = 0.6g / e = 0.6g / e = 0.8U / e = 0.2g / e = 0.2g / e = 1g / e = 1g / e = 1g / e = 1g / e = 1 / 2g / e respectively. A numerical model was established for 60 cases in 10 cases, and the flow pattern was obtained by numerical calculation of the submerged discharge flow in the case of a falling ridge behind the sluice. The velocity distribution varies with the relative height d / e of the ridge. The variation of the relative length of l / e is basically consistent with the theoretical analysis, that is, through the systematic simulation and calculation of the inundation and outflow of the sluice bottom sill of various sizes that may occur in the actual engineering. The corresponding relation between the correction coefficient of submergence and submergence coefficient of sluice hole with bottom ridge and D / E / 1 / e is given. Finally, the numerical simulation results are compared with the classical experimental data and the experimental data of our laboratory. The results of numerical simulation are in good agreement with these two groups of experimental data. It is fully demonstrated that the numerical simulation method can be used to calculate the turbulent flow field and velocity distribution in the case of open channel sluice in actual engineering. The results of this paper can be directly applied to the hydraulic calculation of submerged discharge under the condition that there is a dip in the back of the sluice. It provides a basis for practical application and makes an important contribution to the improvement of the way of judging the flood discharge of sluice hole under the condition of falling sluice after the sluice.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV135

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