水源地取水泵站預(yù)沉曝氣池及前池流態(tài)改善CFD研究
發(fā)布時間：2019-06-20 06:09
【摘要】：水源地取水泵站包括預(yù)沉池、曝氣池、前池3個主要部分,取水泵站內(nèi)流速小,水位變幅大,內(nèi)部流態(tài)紊亂。當(dāng)取水泵站內(nèi)無水力優(yōu)化措施時,預(yù)沉池內(nèi)水流流態(tài)紊亂,曝氣池及前池內(nèi)存在回流區(qū)、死水區(qū)以及漩渦,取水泵站內(nèi)的不良流態(tài)會導(dǎo)致曝氣池及前池局部泥沙沉淀和入泵水流流速分布不均勻。本文通過CFD技術(shù),對水源地取水泵站工程整流措施展開研究,重點研究了預(yù)沉池前穿孔花墻配水均勻性,預(yù)沉曝氣池與前池聯(lián)合運行時整體水力優(yōu)化措施,以及多泵運行模式下前池內(nèi)流動特性和水泵吸水均勻性的差異。研究成果對進(jìn)一步改善取水泵站內(nèi)水流流態(tài),防止泥沙淤積,提高水泵運行的安全性、高效性有一定的指導(dǎo)意義,為多泵運行條件下開泵方式的選擇提供參考。(1)運用商用軟件ANSYS 14.5,紊流模型選取標(biāo)準(zhǔn)k-ε紊流模型。通過網(wǎng)格無關(guān)性分析,確定取水泵站整體網(wǎng)格總數(shù)為175.6萬。(2)預(yù)沉池穿孔花墻水力優(yōu)化研究。不同水位條件下,不同形式(矩形、圓形、菱形)的穿孔花墻配水均勻性存在較大差異;采用菱形穿孔花墻進(jìn)行配水,水流在預(yù)沉池內(nèi)流速分布更加均勻,流態(tài)相對平順,有利于泥沙等固體顆粒懸浮物的沉降。(3)取水泵站內(nèi)流動特性研究。對于斜坡閘孔入流取水泵站、斜坡擴(kuò)散自由入流取水泵站,在無措施條件下,其內(nèi)部流態(tài)較為紊亂,在曝氣池廊道轉(zhuǎn)角處、斜坡段均存在明顯脫流、漩渦以及回流區(qū),且水流進(jìn)入前池后存在嚴(yán)重偏流問題。斜坡閘孔入流取水泵站在斜坡段存在大面積回旋區(qū),水流以射流形式進(jìn)入前池很難擴(kuò)散均勻;斜坡擴(kuò)散自由入流取水泵站則在斜坡段和前池內(nèi)易形成大面積回流區(qū)。(4)取水泵站曝氣池流態(tài)改善研究。曝氣池廊道轉(zhuǎn)角處倒圓角、廊道轉(zhuǎn)角內(nèi)設(shè)U形導(dǎo)流墻和1/4弧形導(dǎo)流墻,有效地消除了廊道內(nèi)存在的脫流、死水區(qū);在斜坡段設(shè)雙U形導(dǎo)流墻和等分雙隔墩有效地改善了斜坡段明顯的偏流問題,削弱了斜坡段回流漩渦的發(fā)生,使得水流相對平順地進(jìn)入前池。(5)斜坡閘孔入流取水泵站前池流態(tài)改善研究。前池?zé)o整流措施時,水流通過閘孔射流形式直接撞擊后壁,在兩側(cè)形成大面積回流,且各泵機(jī)組吸水均勻性差異較大,各泵喇叭管入口斷面流速均勻度呈現(xiàn)倒V字分布,中間3#機(jī)組吸水均勻性較高,兩側(cè)機(jī)組吸水均勻性較差。通過在前池內(nèi)兩閘孔中線處設(shè)置八字形導(dǎo)流墩、泵機(jī)組間設(shè)置隔墩、改變前池兩側(cè)直角翼墻等組合措施,明顯改善了前池內(nèi)流態(tài)及流速分布,特別是底層水流擴(kuò)散均勻,基本無明顯漩渦存在,且面層大面積回旋區(qū)得到較好地控制,各泵機(jī)組吸水均勻性均得到提高,各泵吸水均勻性差異明顯減小。(6)斜坡擴(kuò)散自由入流取水泵站前池流態(tài)改善研究。前池?zé)o整流措施時,水流通過擴(kuò)散段進(jìn)入前池,在前池的兩側(cè)形成回流區(qū),同時在靠近前池后壁處有局部漩渦發(fā)生;此時,各泵機(jī)組吸水均勻性呈現(xiàn)兩側(cè)機(jī)組高,中間機(jī)組低。通過在泵機(jī)組間設(shè)置隔墩、在前池內(nèi)設(shè)置八字形導(dǎo)流墩、設(shè)置45°傾斜擋板等組合措施,明顯改善了前池內(nèi)流態(tài)及流速分布,提高了各泵機(jī)組吸水均勻性均。其中,隔墩高度的增加有利于改善前池面層流態(tài),且減弱了底層各泵機(jī)組喇叭管口吸水時水流間的相互干擾。八字形導(dǎo)流墩位置宜設(shè)置在擴(kuò)散段處,過分靠近后壁或偏向兩側(cè),在前池中層和面層兩側(cè)翼墻處漩渦回流現(xiàn)象越嚴(yán)重,且各泵機(jī)組吸水均勻性提升相對最大;八字形導(dǎo)流墩擴(kuò)散角宜取18°左右,擴(kuò)散角過小,兩側(cè)泵機(jī)組吸水均勻性有明顯下降,擴(kuò)散角過大,前池局部漩渦增多;采用45°傾斜擋板對于斜坡擴(kuò)散入流方案的取水泵站前池流態(tài)改善效果顯著,隨著傾斜擋板位置遠(yuǎn)離后壁方向移動,前池底層流速分布更加均勻,各泵機(jī)組吸水均勻性越好。(7)不同開泵方式下,斜坡閘孔入流取水泵站前池水力特性研究。取水泵站內(nèi)無措施條件下,不同的開泵方式對前池內(nèi)流態(tài)的影響較小;同時運行1#、2#、3#、4#泵機(jī)組,各泵機(jī)組吸水均勻性較好,且差異較小,為無措施條件下較優(yōu)運行方案。取水泵站采用優(yōu)化措施后,在不同的開泵方式下,各運行方案前池底層的流線分布均較為均勻,無明顯回流產(chǎn)生;在前池的中層存在不同程度的局部回流漩渦;在前池的面層流線分布較為均勻,且差異不明顯,有局部漩渦發(fā)生在兩側(cè)傾斜壁面處;在運行方案4和運行方案3開泵方式下,各運行的泵機(jī)組吸水均勻性較高,其中運行方案4運行泵機(jī)組喇叭管入口斷面流速均勻度均在72%以上,采用改善措施后的取水泵站宜采用運行方案4的開泵方式運行。
[Abstract]:The water intake and pumping station of the water source area includes the pre-settling tank, the aeration tank, the three main parts of the front tank, the flow velocity in the water taking pump station is small, the water level is large, and the internal flow pattern is disordered. When there are no hydraulic optimization measures in the water intake pump station, the flow pattern of the water in the pre-settling tank is disturbed, and the backflow area, the dead water area and the vortex are present in the aeration tank and the front pool, and the bad flow pattern in the water intake pump station can cause the local sediment deposition of the aeration tank and the front pool and the distribution of the flow velocity of the inlet pump water flow to be uneven. In this paper, by means of the CFD technology, the rectification measures of the water intake pump station in the water source field are studied, the water distribution uniformity of the front perforated flower wall of the pre-sinking pool, the overall hydraulic optimization of the pre-sinking aeration tank and the forebay are studied. And the difference of the flow characteristics of the front tank and the water absorption uniformity of the water pump in the multi-pump operation mode. The research results can provide a reference for further improving the flow pattern of water flow in the water intake pump station, preventing sediment deposition, improving the safety and high efficiency of the operation of the water pump, and providing a reference for the selection of the pump mode under the condition of multi-pump operation. (1) Using the commercial software ANSYS 14.5, the turbulence model is used to select the standard k-turbulent flow model. Based on the grid-independent analysis, the total grid number of the water intake pumping station is determined to be 175.6 million. (2) The hydraulic optimization of the perforated flower wall of the primary sedimentation tank. in that condition of different water level, the water distribution uniformity of the perforated flower wall of different form (rectangle, round and diamond) is great difference; the diamond-shaped perforated flower wall is adopted for water distribution, the flow velocity distribution of the water flow in the pre-settling tank is more uniform, and the flow state is relatively smooth, And is beneficial to the settlement of suspended solids such as sand and the like. (3) Research on the flow characteristics of the water intake pump station. For the inlet water intake pump station of the slope gate and the free inflow water intake pump station of the slope, the internal state of the water intake pump station is more disordered under the condition of no measure, and there are obvious deflow, vortex and return area in the slope section at the corner of the gallery of the aeration tank, and there is a serious bias problem after the water flows into the forebay. The inlet water-taking pump station of the slope gate has a large-area swirl area in the slope section, and the water flow enters the front pool in the form of a jet to be difficult to spread evenly; the free-inflow water-taking pump station of the slope diffusion is easy to form a large-area return area in the slope section and the front pool. (4) The flow pattern of the aeration tank of the water intake pump station is improved. a U-shaped guide wall and a 1/4 arc-shaped guide wall are arranged in the corner of the gallery of the aeration tank, The generation of the back flow vortex of the slope section is weakened, so that the water flow enters the front pool relatively smoothly. (5) The flow pattern of the front pool of the inflow water intake pump station of the slope gate hole is improved. when there is no rectification measure in the front tank, the water flow directly impacts the rear wall through the form of a gate hole, a large area of reflux is formed on both sides, the water absorption uniformity of each pump unit is large, the flow rate uniformity of the inlet cross section of each pump is inverted V-shaped distribution, and the water absorption uniformity of the middle 3 # unit is high, And the water absorption uniformity of the two side units is poor. by arranging an eight-shaped guide pier at the middle line of the two gate holes in the front pool, a partition pier is arranged between the pump units, and the combination measures such as right-angle wing walls at the two sides of the front tank are changed, And the water absorption uniformity of each pump is obviously reduced. (6) The flow pattern of the front pool of the free-in-flow water-taking pump station for the slope diffusion is improved. When there is no rectification measure in the front tank, the water flow enters the front pool through the diffusion section, and the backflow area is formed on both sides of the front pool, and the local vortex occurs near the back wall of the front pool; at this time, the water absorption uniformity of each pump unit is high, and the middle unit is low. An eight-shaped guide pier is arranged between the pump units, an eight-shaped guide pier is arranged in the front pool, and combined measures such as a 45-degree inclined baffle are arranged, so that the flow state and the flow velocity distribution in the front tank are obviously improved, and the water absorption uniformity of each pump unit is improved. In which, the increase of the height of the blocking pier is beneficial to the improvement of the laminar flow state of the front pool surface, and the mutual interference between the water flows in the water absorption of the horn mouth of each pump unit of the bottom layer is reduced. The position of the eight-shaped guide pier should be set at the diffusion section, which is too close to the rear wall or to the two sides. The more serious the swirling reflux phenomenon at the wing walls at the middle and the side of the front pool, and the water absorption uniformity of each pump unit is relatively maximum; the diffusion angle of the eight-shaped guide pier is preferably about 18 degrees, the diffusion angle is too small, the water absorption uniformity of the two-side pump units is obviously reduced, the diffusion angle is too large, and the local vortex of the front pool is increased; the 45-degree inclined baffle plate is adopted for improving the flow pattern of the front pool of the water taking pump station of the slope diffusion inflow scheme, The flow velocity distribution of the bottom layer of the front pool is more uniform, and the water absorption uniformity of each pump unit is better. (7) The hydraulic characteristics of the front pool of the inflow water intake pump station of the slope gate are studied in different open-pump modes. Under the condition of no measure in the water intake pump station, the effect of different open-pump methods on the flow pattern in the front pool is small; at the same time,1 #,2 #,3 # and 4 # pump units are operated, and the water absorption uniformity of each pump unit is good, and the difference is small, and the operation scheme is better under the condition of no measure. After the water intake pump station adopts the optimization measures, the flow line distribution of the bottom layer of the front pool of each operation scheme is uniform, no obvious backflow is generated under different open pump modes, the middle layer of the front pool is provided with a local reflux vortex at different degrees, and the surface layer streamline distribution of the front pool is more uniform, in that pump mode of the operation scheme 4 and the operation scheme 3, the water absorption uniformity of each operation pump unit is high, wherein the flow rate uniformity of the inlet section of the horn pipe of the operation scheme 4 is more than 72 percent, The water-taking pump station after the improvement measures should be operated in the open-pump mode of the operation scheme 4.
【學(xué)位授予單位】：揚州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TV675
，
本文編號：2502999
[Abstract]:The water intake and pumping station of the water source area includes the pre-settling tank, the aeration tank, the three main parts of the front tank, the flow velocity in the water taking pump station is small, the water level is large, and the internal flow pattern is disordered. When there are no hydraulic optimization measures in the water intake pump station, the flow pattern of the water in the pre-settling tank is disturbed, and the backflow area, the dead water area and the vortex are present in the aeration tank and the front pool, and the bad flow pattern in the water intake pump station can cause the local sediment deposition of the aeration tank and the front pool and the distribution of the flow velocity of the inlet pump water flow to be uneven. In this paper, by means of the CFD technology, the rectification measures of the water intake pump station in the water source field are studied, the water distribution uniformity of the front perforated flower wall of the pre-sinking pool, the overall hydraulic optimization of the pre-sinking aeration tank and the forebay are studied. And the difference of the flow characteristics of the front tank and the water absorption uniformity of the water pump in the multi-pump operation mode. The research results can provide a reference for further improving the flow pattern of water flow in the water intake pump station, preventing sediment deposition, improving the safety and high efficiency of the operation of the water pump, and providing a reference for the selection of the pump mode under the condition of multi-pump operation. (1) Using the commercial software ANSYS 14.5, the turbulence model is used to select the standard k-turbulent flow model. Based on the grid-independent analysis, the total grid number of the water intake pumping station is determined to be 175.6 million. (2) The hydraulic optimization of the perforated flower wall of the primary sedimentation tank. in that condition of different water level, the water distribution uniformity of the perforated flower wall of different form (rectangle, round and diamond) is great difference; the diamond-shaped perforated flower wall is adopted for water distribution, the flow velocity distribution of the water flow in the pre-settling tank is more uniform, and the flow state is relatively smooth, And is beneficial to the settlement of suspended solids such as sand and the like. (3) Research on the flow characteristics of the water intake pump station. For the inlet water intake pump station of the slope gate and the free inflow water intake pump station of the slope, the internal state of the water intake pump station is more disordered under the condition of no measure, and there are obvious deflow, vortex and return area in the slope section at the corner of the gallery of the aeration tank, and there is a serious bias problem after the water flows into the forebay. The inlet water-taking pump station of the slope gate has a large-area swirl area in the slope section, and the water flow enters the front pool in the form of a jet to be difficult to spread evenly; the free-inflow water-taking pump station of the slope diffusion is easy to form a large-area return area in the slope section and the front pool. (4) The flow pattern of the aeration tank of the water intake pump station is improved. a U-shaped guide wall and a 1/4 arc-shaped guide wall are arranged in the corner of the gallery of the aeration tank, The generation of the back flow vortex of the slope section is weakened, so that the water flow enters the front pool relatively smoothly. (5) The flow pattern of the front pool of the inflow water intake pump station of the slope gate hole is improved. when there is no rectification measure in the front tank, the water flow directly impacts the rear wall through the form of a gate hole, a large area of reflux is formed on both sides, the water absorption uniformity of each pump unit is large, the flow rate uniformity of the inlet cross section of each pump is inverted V-shaped distribution, and the water absorption uniformity of the middle 3 # unit is high, And the water absorption uniformity of the two side units is poor. by arranging an eight-shaped guide pier at the middle line of the two gate holes in the front pool, a partition pier is arranged between the pump units, and the combination measures such as right-angle wing walls at the two sides of the front tank are changed, And the water absorption uniformity of each pump is obviously reduced. (6) The flow pattern of the front pool of the free-in-flow water-taking pump station for the slope diffusion is improved. When there is no rectification measure in the front tank, the water flow enters the front pool through the diffusion section, and the backflow area is formed on both sides of the front pool, and the local vortex occurs near the back wall of the front pool; at this time, the water absorption uniformity of each pump unit is high, and the middle unit is low. An eight-shaped guide pier is arranged between the pump units, an eight-shaped guide pier is arranged in the front pool, and combined measures such as a 45-degree inclined baffle are arranged, so that the flow state and the flow velocity distribution in the front tank are obviously improved, and the water absorption uniformity of each pump unit is improved. In which, the increase of the height of the blocking pier is beneficial to the improvement of the laminar flow state of the front pool surface, and the mutual interference between the water flows in the water absorption of the horn mouth of each pump unit of the bottom layer is reduced. The position of the eight-shaped guide pier should be set at the diffusion section, which is too close to the rear wall or to the two sides. The more serious the swirling reflux phenomenon at the wing walls at the middle and the side of the front pool, and the water absorption uniformity of each pump unit is relatively maximum; the diffusion angle of the eight-shaped guide pier is preferably about 18 degrees, the diffusion angle is too small, the water absorption uniformity of the two-side pump units is obviously reduced, the diffusion angle is too large, and the local vortex of the front pool is increased; the 45-degree inclined baffle plate is adopted for improving the flow pattern of the front pool of the water taking pump station of the slope diffusion inflow scheme, The flow velocity distribution of the bottom layer of the front pool is more uniform, and the water absorption uniformity of each pump unit is better. (7) The hydraulic characteristics of the front pool of the inflow water intake pump station of the slope gate are studied in different open-pump modes. Under the condition of no measure in the water intake pump station, the effect of different open-pump methods on the flow pattern in the front pool is small; at the same time,1 #,2 #,3 # and 4 # pump units are operated, and the water absorption uniformity of each pump unit is good, and the difference is small, and the operation scheme is better under the condition of no measure. After the water intake pump station adopts the optimization measures, the flow line distribution of the bottom layer of the front pool of each operation scheme is uniform, no obvious backflow is generated under different open pump modes, the middle layer of the front pool is provided with a local reflux vortex at different degrees, and the surface layer streamline distribution of the front pool is more uniform, in that pump mode of the operation scheme 4 and the operation scheme 3, the water absorption uniformity of each operation pump unit is high, wherein the flow rate uniformity of the inlet section of the horn pipe of the operation scheme 4 is more than 72 percent, The water-taking pump station after the improvement measures should be operated in the open-pump mode of the operation scheme 4.
【學(xué)位授予單位】：揚州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TV675
，
本文編號：2502999
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