Different Temperature Stratification Environment Heavy Sediment Model And Its Distribution Rule

With the rapid development of China's economic and social,most of the cities in our country,especially in the northern city of rely mainly on seen by the region of water supply of reservoir water supply.But,in recent years,increasingly serious environmental pollution,especially in the reservoir water pollution caused by water shortage,poor quality seriously has affected the urban water supply and hindered social and economic construction.Therefore solve the problem of water quality of water supply,water treatment to reduce costs,improve the urban water security is more and more important.Among them,for some large deep water reservoir,because the vertical temperature is different,in the summer,the reservoir is easy to form a positive high surface temperature lower water temperature stratification,when inflow of water carrying a lot of high pollution,high sediment concentration of water into the reservoir,as a result of the existence of temperature stratification,pollution load will form different flow,in local areas of the reservoir forming high turbidity water.In order to understand the temperature stratification in the reservoir density change rules and characteristics of stream sediment concentration,the design method of the indoor model of reservoir,Through reservoir at the bottom of the refrigeration system design model successfully simulates the reservoir are layered environment temperature,According to the set of different temperature under the condition of stratified density flow observation in inflow sediment particle size of 0.01 mm and 0.01 mm,and the sediment concentration is 1.25,2.5,3.75,5,7.5 g/L,inflow velocity of0.00125,0.0025,0.005,0.0075,0.01,the variation of sediment concentration in m/s,and the motion law is studied under different conditions,quantitatively detected respectivelyin different operating conditions and under the condition of different heavy flow of laminar flow between the change of the different phases when the sediment concentration,focus on monitoring the laminar flow in the bottom slope separation between velocity and the internal active effect on the density flow sediment concentration;According to the experimental phenomena and laws,for solid liquid two phase flow and the momentum balance equation based on the principle of dimensional analysis is deduced under the environment of thermal stratification of density flow sediment concentration expressions,and related parameters of the expression is drawn through the design model test,the calculated values and measured values using the model test their income error within 15%,demonstrate the push practical usability.Different inflow conditions can affect the density flow in the water in the reservoir sediment distribution and rational selection of intake.The design of stratified water tank model,respectively by inflow velocity,inflow and sediment concentration and sediment particle size as a starting point,focus on the density flow in the bottom of the suspended load and bed load these two forms ability to carry sand rule and carry sand movement characteristics;When the sediment concentration is less than 2.5 g/L or inflow velocity between 0.00125 m/s ~ 0.00125 m/s,the density flow in the form of surface suspended load flow in horizontal fuzzy diffusion movement,now carry sand amount accounts for82.54%~89.63% of the whole section,desilting strongest ability;When the sediment concentration between 2.5 g/L ~ 5 g/L or inflow velocity between 0.005 m/s ~ 0.005m/s,the density flow in the form of a layer of suspended between qualitative horizontally clear wedge movement,now carry sand amount accounts for60.84%~80.79% of the whole section,desilting ability strong;When the sediment concentration is greater than 5 g/L or inflow velocity is greater than 0.01 m/s,the density flow in the form of a passage at the bottom of the qualitative horizontally scrolling pulse movement,carry sand amount at this time was only about53.05%~62.84% of the whole section,desilting ability is poor;Under the same conditions in sediment particle density flows more difficult with the surrounding water mixing,carry sand amount into smaller particle size of 60.13% ~ 85.86%,and this conclusion for reservoir water quality management,scheduling,and provide reference to access reservoir raw water of water production.