Design And Simulate The Vortex Hydraulic Well Of Switching The Intercepting And Abandon Flow

In recent years, the state invested a lot of manpower and resources to Dian Chi Lake water pollution. Although the Water Environment has improved, there are still many problems. So far, during the construction of the "95" 、 "fifth" and "Eleventh Five-Year" pollution interception system has achieved initial success, ranging from the source pollution control system to the end of the drain grating system. In order to prevent intrusion and large area of overflow produced by main canal and reduce the organic particles in intercepting rainfall and sediment deposition on the main canal before the rain from the early rainwater main access to the main canal, it is crucial to sand processing and select the e appropriate control mode to refuse the flow before the rain from rainwater main access to the main canal.Design and develop the vortex hydraulic well of switching the intercepting and abandon flow of this subject in order to prevent overflow and siltation on main canal. The well control the switch of intercepting and abandon flow according to the amount of water in main canal. Three-dimensional design software SOLIDWORKS and simulation software FLUENT used to build switch well model and simulate the solid-liquid two-phase flow, from which obtaining the best basic pool type. Then further optimize the basic pool type under the valve closed condition,studying the relationship between particle diameter、water inlet rates、the overflow pipe height、average particle residence time、 the overflow tube angle、 the ratio of diameter and deep of the pool body and the particle removal efficiency, which finally come to the optimization of pool-type structure and the switch well optimum operating condition parameters of the corresponding condition. At the same time we survey the actual on-site and choose the suitable sampling points of the main canal to detect quality and quantity of the rainwater, selecting part of the measured results for switch well simulation parameters settings.The following main conclusions drew from the simulation of basic pool type :①In the simulated water flow velocity,there is overflow situation of pool type one at the influent flow rate of 1m/s、2m/s、4m/s、5m/s. There is overflow situation of pool type two at the influent flow rate of 2m/s、4m/s、5m/s. There is overflow situation of pool type three at the influent flow rate of 4m/s、5m/s.②Particle trajectories are spiral swirl shape of basic pool-type, more regular and swirl better. There are more particles thrown to the wall surface of the pool body with the increase of the particle diameter. The particles of the wall surface have short residence time, and the residence time of the inside pool swirl particles are longer. When the water velocity is large, the particles sink poorly, mostly at the state of suspension in the sand bucket.③For particles besides 1um, removal rates of pool type three are relatively high, while removal rates of the pool type one are relatively low, but overall there is little difference between them. Pool-type one’s overflow rates are highest(excluding no overflow situation) under the same inlet flow rate situation. The overflow rates increase with the inlet flow rate under the same pool type. Based on the above analysis, basic pool-type two is used as the optimal basic pool.The main conclusions drew from the simulation of basic pool type two under the valve closed condition:①The particles trajectories of the basic pool type two in different inlet and overflow tube angles are all spiral and swirl shape under the valve closed condition. When the inlet flow rate is less than or equal to 2m/s, the particles entering from the pool body first downward swirl and then upward swirl and eventually most of the particles flow out from the overflow pipe. When the inlet flow rates are greater than 2m/s, the particles are divided into upper and lower swirl cyclone and upward swirl will continue topspin, but finally most of the particles flow out from the overflow pipe. In 90-degree angle switch well, particles swirl best, and particle trajectories are uniform, while residence times of the particles in the sand bucket are significantly higher than valves closed condition and particles also sink better. Particles swirl better and trajectories are uniform of 60 degrees and 150 degrees switch wells, while particles of 120 degree switch well trajectories are erratic and uneven. Particles trajectories of sand bucket are more rules and move oval spirally along the sand hopper, but 250 um particles sink badly in the sand bucket, which mostly remain in the upper part of the sand hopper.② For basic pool type two at the overflow angle of 90 degree(formerly basic pool type overflow angle), particle removal rates of besides 1um at different velocity of inlet under valve closed condition are higher than without valve closed.③Particle removal rate of pool two under the valve closed condition in the order from big to small is 90 degrees、150 degrees、60 degrees and 120 degrees according to the different overflow angles and beside very few cases. Particle removal rate in the order from big to small according to the different ratio of the diameter and deep:1.2、0.9、0.6.④Average particle residence times have the relationships with the particle diameter and velocity of inlet, while the particle removal rate and particle residence time have no specific law correlation, and particle residence time is not the main factors.For any working conditions, mainly in the following conclusions:①Under any operating conditions, 1um particle removal rate is very low, basically at about 10%.②Particle removal rate between a few dozen percent to four percent under different conditions and flow the following trends: particle removal rates increase with particle diameters growth in the case of the same velocity of inlet. For particles besides 1um, the particle removal rates present the tendency of first increasing and then decreasing along with the growth of the velocity inlet in the same particle diameter. Particle removal rate achieve better in a range of inlet velocity and the optimal particle removal rate is at the inlet velocity of 2m/s.③Particle diameter、water flow rates、the overflow pipe height、inlet and overflow tube angle and the ratio of diameter and deep of the pool body can affect the removal of particles to some extent, where the height of the overflow tube on the influence of removal rate relate to the overflow conditions and velocity of inlet, and the height of the overflow pipe has little effect on particle removal rate.Optimum operating condition parameters can refer to a variety of conditions in specific data sheet. Based on the above analysis the basic pool two is optimized, for 50um、250um which particle removal rate achieve better at the overflow angles of 90 degrees and 150 degrees, the ratio of diameter and deep of 1.2 or 0.9 under the condition of valve closed at the inlet velocity of 2m/s.