Anomalous Heat Transfer Enhancement in Separated Flow over a Zigzag-Shaped Dense Package of Inclined Grooves in a Channel Wall at Different Temperature Boundary Conditions

IF 1 4区工程技术 Q4 MECHANICS Fluid Dynamics Pub Date : 2024-05-08 DOI:10.1134/s0015462823602875

S. A. Isaev, O. O. Mil’man, A. A. Klyus, D. V. Nikushchenko, D. S. Khmara, L. P. Yunakov

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Abstract

Rapid development of the anomalous enhancement of separated turbulent Re = 6000 air flow and heat transfer in an in-line single-row package of 31 inclined grooves, 0.2 in dimensionless depth, in a singled-out longitudinal region of the wall of a narrow channel is studied. It is due to the interference of vortex wakes behind the grooves and the acceleration in the channel flow core with the formation of a zone of ultrahigh longitudinal velocity. The wave-shaped parameter characteristics are stabilized in the region of approximately 15th groove, whereupon the oscillation amplitudes are moderately reduced. The return flows in the grooves are enhanced with distance from the entry section, the minimum negative friction diminishing from −2 to −4. The total relative heat removal from the structured region increases at q = const by a factor of approximately 2.75 and by the factor of two at T = const with increase in the relative hydraulic losses by the factor of 1.7, as compared with the case of a plane–parallel channel. The relative heat removal from the surface bounded by the contour of the 20th inclined groove amounts to 3.7 (q = const) with increase in the hydraulic losses by the factor of 2.2. An increase in the local maximum of the longitudinal velocity up to a factor of 1.5, as compared with the mean-mass velocity, can be observable.

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不同温度边界条件下通道壁上人字形斜槽密集包分离流的异常传热增强

摘要研究了在狭窄通道壁的单一纵向区域，由 31 个无量纲深度为 0.2 的倾斜凹槽组成的直列单排包中，分离湍流 Re = 6000 气流和传热的快速发展异常增强现象。这是由于沟槽后方的涡流漩涡的干扰和通道流心的加速，形成了一个超高纵向速度区。波形参数特征在大约第 15 个沟槽区域趋于稳定，振荡幅度适度减小。凹槽中的回流随着与入口部分距离的增加而增强，最小负摩擦力从-2 减小到-4。与平面平行通道相比，结构区的总相对散热量在 q = const 时增加了约 2.75 倍，在 T = const 时增加了 2 倍，相对水力损失增加了 1.7 倍。在水力损失增加 2.2 倍的情况下，第 20 个斜槽轮廓边界表面的相对散热量为 3.7（q = 常值）。与平均质量速度相比，纵向速度的局部最大值增加了 1.5 倍。

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来源期刊

Fluid Dynamics MECHANICS-PHYSICS, FLUIDS & PLASMAS

CiteScore

1.30

自引率

22.20%

发文量

审稿时长

6-12 weeks

期刊介绍： Fluid Dynamics is an international peer reviewed journal that publishes theoretical, computational, and experimental research on aeromechanics, hydrodynamics, plasma dynamics, underground hydrodynamics, and biomechanics of continuous media. Special attention is given to new trends developing at the leading edge of science, such as theory and application of multi-phase flows, chemically reactive flows, liquid and gas flows in electromagnetic fields, new hydrodynamical methods of increasing oil output, new approaches to the description of turbulent flows, etc.