跨声速风扇转子间隙流动结构分析

Analysis on tip flow structure in transonic fan rotor

为探索跨声速转子间隙流动结构,归纳间隙泄漏涡(TLV)和激波相互作用机理,以跨声速转子为研究对象,数值模拟不同间隙下流动特性.此外,着重探究TLV与激波的相互作用,斜激波受到间隙泄漏流的干扰,被削弱打断向上游凹曲;建立三维模型,加深对跨声速叶尖区域流动的全面认识.研究表明:随间隙增大,相同流量下,效率越小,压比也越小;TLV强度更大,偏离吸力面程度增大,沿周向和展向影响范围都越大.压力差提供泄漏流迁移动力,间隙提供泄漏流形成通道.选取h/c=1.0%间隙,随着间隙高度的增大,泄漏流周向运动趋势更明显且二次泄漏现象更剧烈;沿泄漏流方向无量纲流向涡量有少量减少,无量纲螺旋度较高,集中涡特性明显.

In order to analyze the tip flow structure and explore the intersection of shock and tip clearance vortex, a transonic fan rotor was studied using three dimensional numerical calculation and comparative analysis of flow field with various clearances. Further study of the intersection of tip leakage vortex and shock were obtained by establishing the 3-D flow model of the process, thus enhancing the comprehensive understanding of tip leakage flow. The research indicated that the performance was improved with the decrease of the clearance, including efficiency and pressure ratio. Moreover, with the increase of tip gap, the intensity of tip leakage vortex （TLV） was enhanced and the scope of high-entropy area was expanded along the circumferential direction and spanwise direction. The pressure difference between pressure surface and suction surface provided the impetus for the migration of the leakage flow, and lateral gap offered the migration channel. Under h/c=1.0%, the circumferential movement tended to be more notable and the secondary leakage turned more dramatic with the increase of tip height. Propagating of TLV led to the rapid reduction of the normalized streamwise vorticity, while the constant value of the normalized helicity showed that the concentrated vortex feature was maintained. What＇s more, the shock was distorted by the tip leakage vortex near suction, weakening the shock wave and pushing the shock upward.