An Experimental Study of Tip Clearance Flow in a Radial Inflow Turbine
An Experimental Study of Tip Clearance Flow in a Radial Inflow Turbine
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DOI：
10.1115/98-gt-467
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发表时间：
1998-06
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影响因子：
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通讯作者：
R. Dambach;H. Hodson;I. Huntsman
中科院分区：
文献类型：
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作者：
R. Dambach;H. Hodson;I. Huntsman
本文描述了径流式涡轮机叶尖间隙流动的实验研究。进行了流量可视化和静压测量。这些与穿过尖端间隙的热线相结合。实验数据表明径流式涡轮叶顶间隙流动可分为三个区域。第一个区域位于转子入口处，其中相对壳体运动的影响主导着尖端上的流动。第二个区域位于中弦附近，相对套管运动的影响减弱。最后，引流器中存在第三个区域，相对壳体运动的影响变小，泄漏流类似于轴流式涡轮机中的叶尖流动行为。速度分布的积分表明，由于刮擦效应，转子第一部分的叶尖泄漏很少。研究发现，径流式涡轮机中的大部分叶尖泄漏流都流过导流管。在四个弦向位置测量的质量流量与标准轴向涡轮叶尖泄漏模型进行比较。结果表明需要一种适合径流式涡轮机的模型。热线测量还表明径流式涡轮机的导流器中的叶尖间隙损失较高。这解释了为什么径向流入式涡轮机的级效率更受增加径向间隙的影响而不是增加轴向间隙的影响。版权所有 © 1998 ASME
This paper describes an experimental investigation of tip clearance flow in a radial inflow turbine. Flow visualisation and static pressure measurements were performed. These were combined with hot-wire traverses into the tip gap. The experimental data indicates that the tip clearance flow in a radial turbine can be divided into three regions. The first region is located at the rotor inlet, where the influence of relative casing motion dominates the flow over the tip. The second region is located towards midchord, where the effect of relative casing motion is weakened. Finally a third region exists in the exducer, where the effect of relative casing motion becomes small and the leakage flow resembles the tip flow behaviour in an axial turbine.Integration of the velocity profiles showed that there is little tip leakage in the first part of the rotor because of the effect of scraping. It was found that the bulk of tip leakage flow in a radial turbine passes through the exducer. The mass flow rate, measured at four chordwise positions, was compared with a standard axial turbine tip leakage model. The result revealed the need for a model suited to radial turbines. The hot-wire measurements also indicated a higher tip gap loss in the exducer of the radial turbine. This explains why the stage efficiency of a radial inflow turbine is more affected by increasing the radial clearance than by increasing the axial clearance.Copyright © 1998 by ASME