洞内淹没射流与水平旋流梯级内消能泄洪洞的水力特性研究

发布时间：2018-11-26 19:04

【摘要】：高速水流问题历来是高坝泄洪消能的一大难题,在面对高水头泄洪消能的时候,无论采用哪种单一的内消能工形式,都将会碰到一些较难以克服的困难,并且在导流洞改建时,因受到深水闸门应用条件的限制,也无法改建为兼放空洞使用,而导流洞改建为泄洪洞同时兼放空洞是许多水利水电工程建设的需要。因此针对这种情况,提出了“洞内淹没射流与水平旋流梯级内消能工”这一种新型的复合式内消能工,可以解决上述问题。该梯级内消能工主要由第一级的淹没射流内消能工和第二级的水平旋流内消能工组成,本文对其基本的流态、流速、壁面压强、射流恢复长度、旋流洞通气孔的通风量、旋流空腔直径和旋流角等水力特性进行试验量测,然后对该消能工的水力特性与消能机理进行分析,主要成果有:1.该新型梯级内消能工,可以在保证竖井内水位高于射流段尾水洞顶部高程情况下,模型运行过程中各部分流态均较为稳定,可以适用于高水头的泄洪消能。2.泄洪洞内水流流速与壁面压强在上游射流段与下游旋流段的各部位,均表现出了分区变化特点,射流孔口段与旋流阻塞段变化剧烈。旋流段空腔旋流流速分布近似符合准自由涡的分布规律。3.通气量受下游水位变化影响明显,尾水洞为自由出流时通气量较大,当下游出口淹没后通气量明显减小,但淹没后随下游水位的升高,通风量减小不明显。4.通过射流段,消耗掉了一部分水流能量,从而降低了旋流段的作用水头,使得一个高水头消能问题变为一个多级的中低水头问题,使其可以应用于超过100m甚至更高水头下的泄洪消能。该体型整体消能率占总水头的75%～79%,其中第一级射流段占总水头的15%～22%,第二级旋流段占总水头的55%～62%。
[Abstract]:The problem of high speed flow has always been a difficult problem for high dam flood discharge and energy dissipation. In the face of high head flood discharge energy dissipation, no matter what kind of single internal energy dissipator is adopted, it will encounter some more difficult difficulties, and it will be difficult to overcome in the reconstruction of diversion tunnel. Because of the limitation of the application condition of the deep water gate, it is impossible to transform the diversion tunnel into a flood discharge tunnel and also to release the hole simultaneously, which is the need of many water conservancy and hydropower projects. Therefore, a new type of compound inner energy dissipator named "submerged jet and horizontal swirl cascade energy dissipator" is proposed, which can solve the above problems. The cascade inner energy dissipator is mainly composed of the first stage submerged jet energy dissipator and the second stage horizontal swirl energy dissipator. This paper deals with the basic flow pattern, velocity of flow, wall pressure, jet recovery length, ventilation rate of the ventilation hole in the swirl tunnel. The hydraulic characteristics of swirl cavity diameter and swirl angle are measured and the hydraulic characteristics and energy dissipation mechanism of the dissipator are analyzed. The main results are as follows: 1. The new cascade inner energy dissipator can ensure that the water level in the shaft is higher than the top elevation of the tail water tunnel in the jet section, and the flow pattern of each part of the model is relatively stable in the course of operation, which can be applied to flood discharge and energy dissipation at high water head. The flow velocity and wall pressure in the spillway tunnel show the characteristics of zonal variation in each part of the upstream jet section and downstream swirl section, and the jet orifice section and the swirl block section change sharply. The velocity distribution of cavity swirl in swirl section approximately accords with the distribution law of quasi-free vortex. 3. The aeration volume is obviously affected by the variation of the downstream water level, and the ventilation volume of the tail water tunnel is larger when the flow is free, and decreases obviously when the downstream outlet is submerged, but the ventilation volume does not decrease obviously with the increase of the downstream water level after the inundation. 4. Through the jet section, a part of the flow energy is consumed, which reduces the acting head of the swirl section, and makes a high head energy dissipation problem become a multistage low water head problem. It can be applied to flood discharge and energy dissipation over 100 m or higher head. The total energy dissipation rate of this type is 75% of the total water head, in which the first stage of jet accounts for 1510% of the total head of water, and the second stage of swirl accounts for 55% of the total head of water.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV135.2

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