折坡扩散消力池水跃公式研究

发布时间：2018-11-17 16:01

【摘要】：折坡扩散消力池能较好的适应工程实际需要，扩散体型和折坡水跃使得此类消力池消能效果良好，并能适应下游水位变化。与常规的矩形消力池相比，具有消能效果良好、保护下游边坡、缩短消力池长度等优点。在实际工程中，折坡扩散消力池已有了较为广泛的应用，如布伦口水电站、喜河水电站等，而对折坡扩散消力池水跃公式的理论研究较少。因此，，根据工程实际需求进一步深入研究折坡扩散消力池水力特性，寻求更简便、精确的折坡消力池水跃公式，对闸坝下游消能防冲设计具有重要实践意义。针对折坡扩散消力池水跃公式尚无大量研究的问题，本文进行了以下研究工作：（1）通过对水跃模型试验数据拟合分析，得出佛汝德数与共轭水深经验关系式，即折坡扩散消力池水跃经验计算公式。在本文试验条件下，该计算式计算误差较小，分别为1.07%、1.14%、0.23%、2.64%、4.08%、0.00%，总体误差在5%以内，平均误差为1.53%。公式形式简单、结构合理、物理意义明确，能够为工程设计提供一定的参考，为折坡扩散消力池水跃的研究提供了一种新的思路。（2）折坡扩散消力池中水跃长度与跃前断面佛汝德数、共轭水深比存在相关关系，水跃长度与共轭水深比、跃前断面佛汝德数成正比关系。消力池水跃消能效率与跃前断面佛汝德数呈现出良好的相关关系。消能率的变化随佛汝德数的增大而增大，随着佛汝德数的增大，消能率的增加值逐渐减小。（3）通过动量方程与连续方程联立，采用积分方法解决了折坡扩散消力池斜坡水跃体重力的计算问题，推导折坡扩散消力池水跃理论公式。采用试验研究数据对现行多种计算方法，进行了分析计算，并将计算结果进行对比分析。计算方法分别为美国陆军工程兵团算法、周名德算法、李琼算法和本文推导的水跃理论公式。结果表明本文推导出来的折坡扩散消力池水跃共轭水深关系式比三种已有计算方法计算误差小，分别为2.73%、1.38%、0.28%、3.06%、3.55%，误差平均值为1.87%。说明此种计算方法具有一定可靠性，可为相关工程设计提供依据。（4）通过改变体型条件，结合工程实例，分析了理论公式在折坡水跃、平底矩形水跃中的应用。结果表明，理论公式同样适用于等宽折坡水跃；忽略扩散角与坡度时，理论公式与平底矩形水跃共轭水深计算公式一致。
[Abstract]:The slope diffusion stilling pool can better meet the practical needs of engineering. The diffusion type and sloping hydraulic jump make the energy dissipation effect of this kind of stilling pool good and can adapt to the change of downstream water level. Compared with the conventional rectangular stilling pool, it has the advantages of good energy dissipation effect, protecting the downstream slope and shortening the length of the stilling pool. In the practical engineering, the slope diffusion stilling pool has been widely used, such as Brancou Hydropower Station, Xihe Hydropower Station and so on, but the theoretical research on the hydraulic jump formula of the slope diffusion stilling pool is less. Therefore, it is of great practical significance for the downstream energy dissipation design of sluice dams to further study the hydraulic characteristics of the damped diffusion stilling pool according to the actual engineering requirements, and to seek a simpler and more accurate formula for the hydraulic jump of the sloping stilling pool. In order to solve the problem that there is no large amount of research on the hydraulic jump formula of the sloping diffusion stilling pool, the following research work has been done in this paper: (1) the empirical relationship between Froude number and conjugate water depth is obtained by fitting and analyzing the data of hydraulic jump model test. That is, the empirical formula of hydraulic jump in diffusive stilling pool with broken slope. Under the experimental conditions in this paper, the calculation error of this formula is smaller, which is 1.077.1.14 and 0.232.644.080.000. The overall error is less than 5%, and the average error is 1.53. The formula is simple in form, reasonable in structure and clear in physical meaning. It can provide a certain reference for engineering design, and provide a new way of thinking for the research of hydraulic jump in the dampening pool of slope diffusion. (2) there is a correlation between the hydraulic jump length and the Froude number and the conjugate water depth ratio in the slope-diffusive stilling pool. The hydraulic jump length is proportional to the conjugate water depth ratio, and the Froude number of the front section is proportional to the Froude number of the former section. There is a good correlation between the water energy dissipation efficiency of the stilling pool and the Froude number of the front section. The change of energy dissipation rate increases with the increase of Froude number, and decreases with the increase of Froude number. (3) through the combination of momentum equation and continuous equation, this paper solves the problem of calculating the hydraulic jump weight of the slope of the sloping diffusion stilling pool by using the integral method, and deduces the theoretical formula of the hydraulic jump of the slope diffusion stilling pool. This paper analyzes and calculates various calculation methods by using experimental research data, and compares and analyzes the calculated results. The calculation methods are the US Army Corps of Engineers algorithm, Zhou Mingde algorithm, Li Qiong algorithm and the theoretical formula of water jump derived in this paper. The results show that the formula derived in this paper is less than the calculation error of the three existing methods, which are 2.73 and 1.38 and 0.28 and 3.06, respectively. The average error is 1.87. It shows that this calculation method has certain reliability and can provide basis for related engineering design. (4) the application of theoretical formula in slope jump and rectangular jump with flat bottom is analyzed by changing the shape condition and combining with engineering examples. The results show that the theoretical formula is also applicable to the equal-width slope jump, and when the diffusion angle and slope are ignored, the theoretical formula is consistent with the conjugate water depth calculation formula of rectangular water jump with flat bottom.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV135.2

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