Ekman Layer Scrubbing and Shroud Heat Transfer in Centrifugal Buoyancy-Driven Convection
Ekman Layer Scrubbing and Shroud Heat Transfer in Centrifugal Buoyancy-Driven Convection
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DOI：
10.1115/1.4050366
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发表时间：
2020-09
期刊：
影响因子：
--
通讯作者：
F. Gao;J. Chew
中科院分区：
文献类型：
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作者：
F. Gao;J. Chew
本文介绍了大涡和直接数值模拟的浮力驱动的对流在密封和开放的快速旋转腔的瑞利数在107-109的范围内，和轴向通流雷诺数2000和5600。粘性加热由于Ekman层擦洗效果，这是以前发现负责之间的可压缩N-S求解器和不可压缩的对应使用Boussinesq近似的密封腔罩努塞尔数预测的差异，进行了讨论，并按比例放大到发动机条件。对于有轴向通流的开口空腔，本文证实了平均流统计的层流埃克曼层行为达到最高条件。发现浮力数Bo可用于指示轴向通流的影响。对于所研究的条件，平均速度受Ra的影响，而速度波动受Bo的影响。在所考虑的Ra′范围内，用封闭和开放的空腔围带传热解得到的关联式Nu′=0.169（Ra′）0.318与水平板间自由重力对流的关联式在16%以内一致。
This paper presents large-eddy and direct numerical simulations of buoyancy-driven convection in sealed and open rapidly rotating cavities for Rayleigh numbers in the range 107–109, and axial throughflow Reynolds numbers 2000 and 5600. Viscous heating due to the Ekman layer scrubbing effect, which has previously been found responsible for the difference in sealed cavity shroud Nusselt number predictions between a compressible N–S solver and an incompressible counterpart using the Boussinesq approximation, is discussed and scaled up to engine conditions. For the open cavity with an axial throughflow, laminar Ekman layer behavior of the mean flow statistics is confirmed up to the highest condition in this paper. The Buoyancy number Bo is found useful to indicate the influence of an axial throughflow. For the conditions studied the mean velocities are subject to Ra, while the velocity fluctuations are affected by Bo. A correlation, Nu′=0.169(Ra′)0.318, obtained with both the sealed and open cavity shroud heat transfer solutions, agrees with that for free gravitational convection between horizontal plates within 16% for the range of Ra′ considered.