Purpose

The performance of a bladeless Tesla turbine is closely tied to momentum diffusion, kinetic energy transfer and wall shear stress generation on its rotating disks. The surface roughness adds complexity of flow analysis in such a domain. This paper aims to assess the effect of roughness on flow structures and the application of roughness models in flow cross sections with submillimeter height, including both stationary and rotating walls.

Design/methodology/approach

This research starts with the examination of flow over a rough flat plate, and then proceeds to study flow within minichannels, evaluating the effect of roughness on flow characteristics. An in-house test stand validates the numerical solutions of minichannel. Finally, flow through the minichannel with corotating walls was analyzed. The k-ω SST turbulent model and Aupoix's roughness method are used for numerical simulations.

Findings

The findings emphasize the necessity of considering the constricted dimensions of the flow cross section, thereby improving the alignment of derived results with theoretical estimations. Moreover, this study explores the effects of roughness on flow characteristics within the minichannel with stationary and rotating walls, offering valuable insights into this intricate phenomenon, and depicts the appropriate performance of chosen roughness model in studied cases.

Originality/value

The originality of this investigation is the assessment and validation of flow characteristics inside minichannel with stationary and corotating walls when the roughness is implemented. This phenomenon, along with the effect of roughness on the transportation of kinetic energy to the rough surface of a minichannel in an in-house test setup, is assessed.

中文翻译：

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粗糙度模型在静止和旋转微通道流中的应用

 目的

无叶片特斯拉涡轮机的性能与其旋转盘上的动量扩散、动能传递和壁面剪切应力的产生密切相关。表面粗糙度增加了此类域中流动分析的复杂性。本文旨在评估粗糙度对流动结构的影响以及粗糙度模型在亚毫米高度流动横截面（包括静止壁和旋转壁）中的应用。

设计/方法论/途径

这项研究首先检查粗糙平板上的流动，然后继续研究微通道内的流动，评估粗糙度对流动特性的影响。内部测试台验证了迷你通道的数值解决方案。最后，分析了通过具有同步旋转壁的微通道的流动。采用k - ω SST湍流模型和Aupoix粗糙度法进行数值模拟。

 发现

研究结果强调了考虑流动横截面的收缩尺寸的必要性，从而提高了导出结果与理论估计的一致性。此外，本研究探讨了粗糙度对具有固定壁和旋转壁的微通道内流动特性的影响，为这种复杂现象提供了有价值的见解，并描述了所研究案例中所选粗糙度模型的适当性能。

 原创性/价值

这项研究的独创性是在实施粗糙度时评估和验证具有固定壁和同步旋转壁的微通道内的流动特性。在内部测试装置中评估了这种现象以及粗糙度对动能传输到微型通道粗糙表面的影响。