缘线匹配对非定常流动影响初探

为深化缘线匹配对叶轮机非定常流动影响的认识,本文以关注尾迹撞击叶表展向轨迹为出发点,围绕缘线匹配对叶轮机非定常流动及性能影响进行了初步数值探索.研究表明:不同缘线匹配时叶片整体性能参数具有不同的脉动水平;给定缘线匹配下,整体性能参数脉动幅值随工况几乎不变或变化很缓;在设计点为达到降低某种脉动目的而实施的缘线匹配在非设计点同样有效;尽管微弱,数值模拟中还发现缘线匹配对上游尾迹随流掺混产生影响;缘线匹配严重影响时均相关项量值水平,尤其在叶尖、叶根和前缘附近.

EXPLORATION ON INFLUENCES OF EDGE MATCHING ON UNSTEADY FLOW OF TURBOMACHINERY

Numerical exploration is presented in order to better understand the influences of edge matching on unsteady flow and performance of turbomachinery. The intention is to improve turbo- machinery performance by changing the radial movement and accumulation and mixing of the blade boundary layers via edge matching. A wake model is adopted in setting the inlet boundary condition. Thus the downstream blade and the wake which represents the trailing edge of upstream blade con- struct one combination of edge matching. Different edge matching combinations in present paper are formed by modifying the wake shape in cross-flow section. Results show that edge matching can change the oscillation level of turbomachinery performance. And for a given edge matching combination, the amplitude of the performance parameter oscillation remains almost unchanged or changes very slowly. Therefore, the edge matching combination adopted for design point operation will remain effective for off-design operation. Though it is faint, it is also found that the edge matching could affect wake mixing. Edge matching makes severe influences on the magnitude of time average correlation of flow quantities especially in the near tip and the hub and the blade leading edge regions. The influence of edge matching should be further investigated.