侧式分层取水下泄水温研究

发布时间：2018-07-27 15:42

【摘要】：水库修建后,由于水体水动力学特性和水体蓄热交换结构发生了改变,水库垂向水温将呈现出明显的分层现象。水温分层将使水库下层的水体水温常年维持在较稳定的低温状态,下泄低温水对农业灌溉和水生生态系统产生不利影响。为控制下泄水温,工程中常采用叠梁门取水口、侧式分层取水口及浮式管型取水口等分层取水措施。准确模拟和预测水库的下泄水温,对分层取水方案的调度运行具有指导意义。本文以某水库水温分布为背景,通过试验直接模拟水库水温分布,对侧式分层取水口下泄水温进行试验研究。通过FLUENT数值模拟软件,对下泄水温进行数值模拟,研究取水口附近的水体流动规律。本文的主要研究内容及成果包括以下几个方面:(1)介绍了水库水温分层的形成机理、低温下泄水的危害、减免下泄低温水影响的相应措施以及常见的分层取水形式。对水库下泄水温的研究方法进行归类总结。(2)以某水库水温分布为背景,给定取水口流量不变,依次改变取水口淹没深度,对比不同淹没深度工况的下泄水温。试验研究结果表明,取水口淹没深度越小,下泄水温越高;水库的表层与底层水温温差越大,则下泄水温提高幅度也越大。给定取水口淹没深度不变,依次改变取水流量,对比不同取水流量工况的下泄水温。试验研究结果表明,取水流量越小,下泄水温越低。(3)基于FLUENT建立了下泄水温的数值模拟方法。对相同流量不同淹没深度的下泄水温进行数值模拟,并与试验结果进行对比,结果表明利用FLUENT进行下泄水温模拟效果较好,该方法可以运用于下泄水温预测。(4)针对侧式分层取水口,利用FLUENT对温度分层条件下取水口附近的流场进行了初步研究。结果表明,取水口流场与水温分布密切相关。表层水体抽取量随淹没深度增大有所减小,但各工况下均未能抽取较深处水体。同一工况下,取水口抽取表层水体较底层水体多。
[Abstract]:After the construction of the reservoir, the vertical water temperature of the reservoir will show obvious stratification because of the change of the hydrodynamic characteristics of the water body and the structure of the heat storage exchange of the water body. Water temperature stratification will keep the water temperature of the lower layer of the reservoir in a stable low temperature state all year round, and the release of low temperature water will have adverse effects on agricultural irrigation and aquatic ecosystem. In order to control the temperature of water discharge, the measures of stratified water intake such as laminated girder gate, lateral layered intake and floating pipe intake are often used in engineering. The accurate simulation and prediction of the drainage temperature of the reservoir is of guiding significance for the operation of the stratified water intake scheme. Based on the water temperature distribution of a certain reservoir, the temperature distribution of the reservoir is simulated directly by experiments, and the water temperature of the lateral stratified intake outlet is studied experimentally. The flow law of water near the intake is studied by using the FLUENT software to simulate the temperature of the drainage water. The main research contents and achievements in this paper include the following aspects: (1) the formation mechanism of reservoir water temperature stratification, the harm of low-temperature water discharge, the corresponding measures to reduce the influence of low-temperature drain water and the common layering water intake form are introduced. The research methods of reservoir drainage temperature are classified and summarized. (2) based on the water temperature distribution of a reservoir, given the constant intake discharge, the submerged depth of the intake is changed in turn, and the water temperature under different conditions is compared. The experimental results show that the lower the submerged depth of the intake, the higher the water temperature, and the greater the temperature difference between the surface and bottom of the reservoir is, the greater the temperature of the outlet is. Given the inundation depth of the intake, the discharge rate is changed in turn, and the discharge temperature is compared under different conditions of the intake flow. The experimental results show that the lower the flow rate, the lower the water temperature. (3) based on FLUENT, a numerical simulation method is established. The numerical simulation of drainage temperature with the same discharge and different submergence depth is carried out, and the results are compared with the experimental results. The results show that the simulation effect of FLUENT is good. This method can be used to predict the temperature of the outlet. (4) the flow field near the outlet under the condition of temperature stratification is studied by FLUENT. The results show that the inlet flow field is closely related to the water temperature distribution. The amount of surface water extraction decreases with the increase of submergence depth, but it fails to extract the deeper water body under each working condition. Under the same working condition, the surface water extracted from the intake is more than the bottom water.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV697.21

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