Flow and heat transfer measurements in a swirl chamber with different outlet geometries
Flow and heat transfer measurements in a swirl chamber with different outlet geometries
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DOI：
10.1007/s00348-015-1937-3
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发表时间：
2015-04
影响因子：
2.4
通讯作者：
Christoph Biegger;B. Weigand
中科院分区：
文献类型：
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作者：
Christoph Biegger;B. Weigand
在技术应用中，高效冷却对于高热负荷部件如涡轮机叶片是必要的。与轴向流相比，一种潜在的和有前途的技术是旋流管流。附加的周向速度和增强的湍流混合增加了传热。但其复杂的流场和传热机理尚处于研究阶段。此外，涡流室在不同出口条件下的可靠性对于稳健的冷却设计非常重要。因此，我们研究了直出口、切向出口和弯曲出口的影响。为了获得对流动现象的理解，我们通过立体PIV（粒子图像测速）测量了速度场。利用热致变色液晶测量传热系数的方法对制冷性能进行了实验研究。为了精确的冷却设计，我们使用局部绝热壁温作为计算传热系数的正确参考温度。我们将给出实际雷诺数从10，000到40，000以及旋流数在到之间时的速度场、压力损失和传热结果。与轴向管流相比，所获得的热传递高出四倍以上。我们的测量结果表明，这里研究的出口改向对流场和传热系数没有显着的影响。
In technical applications, an efficient cooling is necessary for high thermal load components such as turbine blades. One potential and promising technique is a swirling tube flow in comparison with an axial flow. The additional circumferential velocity and enhanced turbulent mixing increase the heat transfer. But the complex flow field and heat transfer mechanisms are still under research. Furthermore, the reliability of a swirl chamber regarding different outlet conditions is of great interest for a robust cooling design. Therefore, we investigated the influence of a straight, a tangential and abend outlet. To gain understanding of the flow phenomena, we measured the velocity field by means of stereo-PIV (particle image velocimetry). We experimentally studied the cooling capability measuring the heat transfer coefficients using thermochromic liquid crystals. For an accurate cooling design, we used the local adiabatic wall temperature as the correct reference temperature for calculating the heat transfer coefficients. We will show the velocity field, the pressure loss and the heat transfer results for realistic Reynolds numbers from 10,000 to 40,000 and for swirl numbers betweenand. The obtained heat transfer is more than four times higher compared to an axial tube flow. Our measurements indicate that the here investigated outlet redirection has no significant influence on the flow field and the heat transfer coefficients.