State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China.
Marine Energy and Intelligent Construction Research Institute, Tianjin University of Technology, Tianjin 300382, China.
Int J Environ Res Public Health. 2022 Aug 2;19(15):9472. doi: 10.3390/ijerph19159472.
The construction of reservoir dams has changed the environment and natural properties of the river course, and deep-water reservoirs present an obvious phenomenon of thermal stratification. Low-temperature outflow water in spring and summer will have a negative impact on the downstream ecological environment. Therefore, it is necessary to take selective withdrawal measures to regulate low-temperature outflow water. The temperature-control curtain project has the advantages of low cost, convenient construction and wide application. Based on the topographic data, a laboratory test model for regulating outflow temperature by a temperature-control curtain is established. A high-power electric heating system is adopted to form a nonlinear thermal stratification. The accuracy of the test data is verified by the prototype observed water temperature. The main parameters affecting the outflow temperature are investigated, including thermal stratification, flow height above the temperature-control curtain, water level, and discharge flow. The results show the following: firstly, the outflow temperature mainly depends on the thermal stratification, decreases with the increase of water level, and increases with the increase of discharge flow; secondly, the effect of a temperature-control curtain on improving the outflow temperature is directly related to the thermal stratification in different months, and the improvement effect is better in spring and summer; finally, the improvement effect increases with the decrease of flow height above the temperature-control curtain, increases with the increase of water level, and decreases with the increase of discharge flow.
水库大坝的建设改变了河道的环境和自然特性，深水库呈现出明显的热分层现象。春夏季低温出水会对下游生态环境产生负面影响，因此有必要采取选择性放水措施来调节低温出水。温度控制幕工程具有成本低、施工方便、应用广泛的优点。基于地形数据，建立了一种通过温度控制幕调节出水温度的实验室试验模型。采用大功率电加热系统形成非线性热分层，通过原型观测水温验证了试验数据的准确性。研究了影响出水温度的主要参数，包括热分层、温度控制幕上方的水流高度、水位和流量。结果表明：首先，出水温度主要取决于热分层，随水位升高而降低，随流量增加而升高；其次，温度控制幕对提高出水温度的效果与不同月份的热分层直接相关，春夏季效果更好；最后，改善效果随温度控制幕上方水流高度的降低而增加，随水位的升高而增加，随流量的增加而降低。
