双平板叶栅绕流的流动结构及其激励特性研究
发布时间：2018-12-08 10:32
【摘要】：绕流叶片的非稳态流动及其尾迹涡结构是诱发水力机械振动的主导因素。以横向布置的一对平板叶栅为研究对象,基于LES计算雷诺数在4.8×104下的三维绕流流场,分析绕流流场涡演化结构、升阻力及压力脉动等特性,以揭示尾迹干涉下平板绕流的流场结构及其激励机制。结果表明:该雷诺数下,单平板绕流平板表面存在错列布置的发卡涡结构,绕流尾迹呈现出高度的三维特性;双平板叶栅绕流状态下,上、下游平板间的间隙流动结构有明显抑制上游平板表面涡结构演化的作用;平板受力在模式H和模式L之间不断切换,且升力波动的幅值随阻力的增大而增大,尾迹干涉下下游平板受力的模式切换频率升高,升力波动幅值也增大;平板表面压力脉动的主要激励源为平板尾涡脱落。尾迹干涉下平板绕流及受力分析,可为水力机械叶片尾迹干涉下的流动主动控制提供参考。
[Abstract]:The unsteady flow around the blade and its wake vortex structure are the leading factors to induce the hydro-mechanical vibration. Taking a pair of transversely arranged flat cascade as the research object, the three-dimensional flow field around Reynolds number at 4.8 脳 10 ~ 4 is calculated based on LES, and the characteristics of vortex evolution structure, lift resistance and pressure pulsation around the flow field are analyzed. In order to reveal the flow field structure and excitation mechanism of the plate flow under wake interference. The results show that there is a staggered hairpin vortex structure on the surface of a single plate flow around the Reynolds number, and the wake of the flow around the plate presents a high three-dimensional characteristic. Under the condition of double plate cascade flow, the gap flow structure between upstream and downstream plates can obviously inhibit the evolution of vortex structure on the upstream plate surface. The amplitude of lift fluctuation increases with the increase of resistance, and the mode switching frequency of downstream plate forces increases under wake interference, and the amplitude of lift fluctuation increases. The main source of pressure pulsation on plate surface is plate wake shedding. The flow around the plate under wake interference and its force analysis can provide a reference for the active control of the flow under the wake interference of the blade of hydraulic machinery.
【作者单位】： 江苏大学能源与动力工程学院;
【基金】：国家自然科学基金项目(51576090) 江苏高校优势学科建设工程项目
【分类号】：TV136
，
本文编号：2368199
[Abstract]:The unsteady flow around the blade and its wake vortex structure are the leading factors to induce the hydro-mechanical vibration. Taking a pair of transversely arranged flat cascade as the research object, the three-dimensional flow field around Reynolds number at 4.8 脳 10 ~ 4 is calculated based on LES, and the characteristics of vortex evolution structure, lift resistance and pressure pulsation around the flow field are analyzed. In order to reveal the flow field structure and excitation mechanism of the plate flow under wake interference. The results show that there is a staggered hairpin vortex structure on the surface of a single plate flow around the Reynolds number, and the wake of the flow around the plate presents a high three-dimensional characteristic. Under the condition of double plate cascade flow, the gap flow structure between upstream and downstream plates can obviously inhibit the evolution of vortex structure on the upstream plate surface. The amplitude of lift fluctuation increases with the increase of resistance, and the mode switching frequency of downstream plate forces increases under wake interference, and the amplitude of lift fluctuation increases. The main source of pressure pulsation on plate surface is plate wake shedding. The flow around the plate under wake interference and its force analysis can provide a reference for the active control of the flow under the wake interference of the blade of hydraulic machinery.
【作者单位】： 江苏大学能源与动力工程学院;
【基金】：国家自然科学基金项目(51576090) 江苏高校优势学科建设工程项目
【分类号】：TV136
，
本文编号：2368199
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