Study On The Effect Of Adjusting Pool On Curve Flow State Improvement

Whether in natural or artificial channels,curved sections are common.People called the curved section of the water flow as a curved flow,and the curved flow showed a three-dimensional spiral turbulent flow.When the water flows through the curved section,there are problems such as deterioration of the flow state,ultra-high water surface,sediment deposition on the convex bank,and erosion damage of the concave bank.Researchers sought engineering measures that could reduce the horizontal aspect ratio and improve the flow patterns of the curves.The proposed curved flow adjustment pool provides a new idea,this article as a research direction.This paper summarizes the current research status of the hydraulic characteristics of the curve flow from the aspect of the horizontal drop of the water surface,the circulation of the curve,and the vertical velocity distribution of the curve.The application and principles of engineering measures proposed by some researchers to improve the flow pattern of the curved water flow are introduced.In this paper,the combination of physical model test and numerical simulation is used to study the effect of setting adjustment tanks on the flow state of bends and the effect of improvement.In the model test,four kinds of slopes(i=0,0.017,0.052,and 0.070)and three adjustment tanks with different lengths(L=12cm,20 cm,and 30cm)were selected,and a total of seven working conditions.During the process of analysis and analysis of the test data,the curve of the water level along both sides of the curve flow under each working condition is obtained,and the two parameters,the decreasing rate of the lateral water surface difference and the water surface uniformity,are introduced as the evaluation of the effect of improving the flow state of the curve water flow.Indicators,to determine the effect of setting adjustment tanks under various operating conditions to improve the flow state of the curve.Through the model test,the following problems were analyzed:(1)Under the same working conditions,the horizontal cross ratio drop and the water surface evenness change of the curve after setting the adjustment tank;(2)The same flow and different slope conditions Next,set the flow conditions of the corners of the same specification after adjustment tanks;(3)Under the same flow,under the same ground conditions,set the flow status of the bends after adjusting the pool with different length parameters.The ICEM software was used to establish the model and mesh,and then the feasibility of the selected mathematical model was analyzed by comparing the velocity data of the flow field obtained from the model test with the data of the surface line along the two sides of the concave and convex along with the numerical calculation.Finally,the mathematical model used the RNG double equation model provided by ANSYS/FLUENT software,combined with VOF to deal with the free surface,the discrete equation was used finite volume method,and the PISO algorithm was used to calculate the pressure and velocity.There are four total calculation models,namely the 90° curve model with and without adjustment tanks,and the 180° curve model with and without adjustment tanks.Through simulation calculations,the following issues were analyzed:(1)Hydraulic characteristics and flow conditions of the bends;(2)Changes in the shape of the water flow after the adjustment of the pool;(3)Curve flow after setting the adjustment pool The vertical flow velocity varies along the course;(4)The turbulence intensity of the curved section of the curve is adjusted after the adjustment of the pool;(5)The effect of the adjustment tank on the flow state of the curve is improved under different bending degrees.