Research On The Characteristics Of Stratified Water Intake For The Temperature-control Curtain Of Water Intake Tower

After the completion of the large reservoir,the physical and chemical properties of the natural river have changed,and it has also had some adverse effects on the surrounding environment.In order to achieve the purpose of improving the environment of the lower reaches of the river and reducing the adverse effects,layered water intake is one of the effective means.Compared with traditional stratified water intake measures,the Temperature-control Curtain stratified water intake has the advantages of small head loss,small engineering volume,convenient construction and operation and maintenance,and good effect of controlling the temperature of the discharge water.They can be applied to those without designed layered water intake measures.The water intake tower of Temperature-control Curtain proposed in this paper is a new type of Temperature-control Curtain.It is arranged near the water-receiving tower of the large reservoir.It has the advantages of smaller engineering volume,lower construction cost and more convenient operation.This paper takes a large reservoir as the background,establishes a three-dimensional water temperature model for temperature stratified reservoirs for numerical simulation,and carried out a numerical simulation study on the characteristics of the temperature of the discharge water before and after the implementation of the curtain.The main research contents and conclusions are as follows:1.Introduced the formation and characteristics of reservoir water temperature stratification,as well as the impact of low temperature water discharge on the environment,and lists 4 commonly used stratified water withdrawal types.This paper summarizes the research status of stratified water intake and water temperature stratified water intake,introduces the existing cases of water intake tower water screen,analyzes its advantages,and elaborates the significance of adopting control curtain stratified water intake.2.Based on the three-dimensional fluid calculation software Flow-3D,a large-scale reservoir is used as a background to carry out a generalized simulation of temperature stratified reservoirs,and a three-dimensional hydrodynamic water temperature numerical simulation model is established.The influencing factors of the reservoir discharge water temperature before the implementation of the water curtain of the water intake tower are studied.The flow field and the change of the discharge water temperature under different working conditions were calculated and analyzed,and the rules of the discharge water temperature were summarized.The discharge effect of the water intake port forms a lower main flow zone with a larger flow rate.The flow rate of the main flow zone increases with the increase of the downflow rate,and the elevation increases with the elevation of the intake port.The temperature characteristics of the discharge water are greatly affected by the distribution of the reservoir water temperature and the location of the water intake,and less affected by the discharge flow and the operating water level.3.Based on the three-dimensional hydrodynamic water temperature numerical simulation model,the influence of the water intake screen of the water tower on the flow field and the discharge water temperature under different working conditions is calculated,and the influencing factors of the discharge water temperature are obtained.The influence of the location on the flow field and the temperature of the discharge water,and a comparative analysis of the temperature of the discharge water before and after the installation of the water curtain is carried out,and the law of the temperature of the discharge water is summarized,and the expression of the relationship between the function of the discharge water temperature under the layered water intake screen of the water intake tower.The research shows that the Temperature-control Curtain of water intake tower can effectively improve the temperature stratification of water body in the reservoir area,which can effectively improve the low-temperature water discharge problem,and the higher the top elevation of the curtain,the higher the discharge water temperature.For the seasons with obvious vertical temperature stratification structure and large temperature gradient,the improvement effect of low-temperature water discharge is better;for the low-elevation water intake(such as bottom holes)condition,the improvement effect of low-temperature water discharge is better.