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混流式水輪機尾水管近壁湍流特性和流場結(jié)構(gòu)研究
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國家自然科學(xué)基金資助項目(51309128、51279071)和教育部高等學(xué)校博士學(xué)科點專項科研基金資助項目(20135314130002)


Numerical Study of Swirling Flow Fields in Francis Turbine under Small Opening Condition
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    摘要:

    采用滑移網(wǎng)格技術(shù)以及基于Vreman亞格子模型的全局動態(tài)大渦模擬方法,得到了HLA551-LJ-43型水輪機小開度工況下全流道內(nèi)速度、壓力以及渦量的分布,同時捕捉到尾水區(qū)域高強度的近壁湍流特性以及獨特的分離流動現(xiàn)象。計算結(jié)果表明,當(dāng)高轉(zhuǎn)速、小開度工況時,流道內(nèi)流體的圓周速度占有絕對優(yōu)勢,流體進入尾水管后“被甩出”呈旋轉(zhuǎn)下泄趨勢,在錐管段和彎管段內(nèi)產(chǎn)生了明顯的分流,同時在尾水管中心區(qū)域形成一個較大的空腔渦帶。該渦帶的流動形式與常規(guī)工況差異較大,反映出小開度工況偏離最優(yōu)工況最遠(yuǎn),流道中流體的漩渦、脫流、分離間斷和回流等各種水力不穩(wěn)定現(xiàn)象更為劇烈和復(fù)雜,具有獨特的流動形式,容易導(dǎo)致機組異常振動的發(fā)生。

    Abstract:

    The phenomenon that strong vibration of units occurred when the Francis turbine is operating under the small opening conditions, such as Gongzu, Shiquan, Liujia Gorges, Lijia Gorges and Three Gorges project. It was used the large eddy simulation (LES) method based on Vreman SubGrid Scale model to analysis the generation and evolution process of turbulence flow, captured the details of the flow structures and the dissipation of the turbulent kinetic energy. The SIMPIEC algorithm was applied to solve the coupled equation of velocity and pressure. The result shows that the small guide opening conditions deviated from the optimal conditions mostly. The unstable flow phenomenon including the swirl, flow separation, interruption and reflux was strong and complicated, which led to the abnormal vibration of the units.

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郭 濤,張立翔.混流式水輪機尾水管近壁湍流特性和流場結(jié)構(gòu)研究[J].農(nóng)業(yè)機械學(xué)報,2014,45(9):112-118. Guo Tao, Zhang Lixiang. Numerical Study of Swirling Flow Fields in Francis Turbine under Small Opening Condition[J]. Transactions of the Chinese Society for Agricultural Machinery,2014,45(9):112-118.

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  • 收稿日期:2014-03-03
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  • 在線發(fā)布日期: 2014-09-10
  • 出版日期: 2014-09-10