Comparative Study on Tip Clearance Flow Fields in Two Types of Transonic Centrifugal Compressor Impeller With Splitter Blades
Comparative Study on Tip Clearance Flow Fields in Two Types of Transonic Centrifugal Compressor Impeller With Splitter Blades
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DOI：
10.1115/gt2010-23345
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发表时间：
2010-12
期刊：
影响因子：
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通讯作者：
Kazutoyo Yamada;Y. Tamagawa;H. Fukushima;M. Furukawa;S. Ibaraki;Kenichiro Iwakiri
中科院分区：
文献类型：
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作者：
Kazutoyo Yamada;Y. Tamagawa;H. Fukushima;M. Furukawa;S. Ibaraki;Kenichiro Iwakiri
本文研究了两种不同叶片数的分流叶片跨音速离心压气机叶轮。为了研究两种压气机在气动性能和叶顶间隙流场方面的差异，对两种压气机在不同工况下的气动性能进行了RANS模拟。模拟结果表明，两种压气机中发生的流动事件基本相似。在低流速条件下，在叶尖附近产生低速区域，这是由于叶尖泄漏涡的膨胀造成的。低速区随着流量的减小而扩大，并与分流叶片前缘附近的压力面相互作用。这导致前缘尖端附近的叶片载荷下降，以及壳体吸力角附近的高熵流体积聚。此外，在近失速状态下，叶顶间隙流在分流叶片前缘前溢出，最终在失速状态下溢出发生在全叶。然而，实度的主要差异会影响叶尖间隙流/叶片相互作用，从而导致性能特性的变化。在低稠度叶轮中，由于叶尖处的高叶片载荷，叶尖泄漏涡破裂并具有较大的阻塞效应，从而降低了压比。高密实度叶轮易受溢流影响，导致叶轮早期大范围失速，降低效率。
Two types of transonic centrifugal compressor impeller with splitter blades, which are different in blade count, have been investigated in this study. RANS (Reynolds-Averaged Navier-Stokes) simulations were carried out for several operating conditions to clarify differences in aerodynamic performance characteristic and tip clearance flow field between the two compressors. The simulation shows that basically similar flow events happen in both compressors. A low velocity region is generated near the tip at low flow rate conditions, which results from an expansion of the tip leakage vortex. The low velocity region expands as the flow rate is decreased, and interacts with the pressure surface of the splitter blade near the leading edge. This causes a descent of the blade loading near the tip of the leading edge, and an accumulation of high entropy fluid near the casing-suction corner. Moreover, the tip clearance flow spills ahead of the leading edge of the splitter blade at near stall condition, and eventually the spillage happens at the full blade at stall condition. However, the major difference in solidity influences tip clearance flow/blade interaction, which leads to changes in the performance characteristics. In the impeller with low solidity, the tip leakage vortex breaks down with a large blockage effect because of high blade loading at the tip, which decreases the pressure ratio. The impeller with high solidity is subject to the spillage, which results in an early and large-scale stall that decreases the efficiency.