Investigation on Flow Characteristics and Its Effect on Heat Transfer Enhancement in a Wide Channel with Staggered Diamond-S Pin Fins

IF 1.9 3区工程技术 Q3 ENGINEERING, MECHANICAL

Journal of Turbomachinery-Transactions of the Asme Pub Date : 2023-05-05 DOI:10.1115/1.4062502

Jingtian Duan, Kecheng Zhang, Jin Xu, J. Lei, Junmei Wu

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Abstract

Flow statistic in the mid-plane of a rectangular channel with diamond-s pin fins was obtained by means of particle imaging velocimetry (PIV) at Re=10000. Large scale and small scale fluctuation was separated using proper orthogonal decomposition (POD). The flow characteristics were compared to Nusselt number distribution on the endwall acquired by thermochromic liquid crystal (TLC) to reveal flow mechanism driving heat transfer enhancement. Results indicate that local vorticity plays an important role on strengthening Nu on both sides of leading point (Zone 1). Downstream of the two sharp edges on both sides (Zone 2), small size disturbances from shear layer eddies drive local heat transfer. The flow characteristics and heat transfer distribution downstream of the 1st row (Zone 3) presents alternated feature along Y direction due to the interaction between shear layers of neighboring pin fins. Lateral velocity fluctuation induced by large vortex shedding drives the heat transfer augmentation in Zone 3 where there is violent large vortex shedding. While small size disturbances of the shear layer drive local heat transfer enhancement in Zone 3 downstream of pin fins where large vortex shedding is suppressed. For the 2nd and 3rd row, there is no difference in the flow characteristics downstream of neighboring pin fins. Small size fluctuations distributed uniformly downstream of large vortex shedding (Zone 4) resulting in a uniformly distributed Nu.

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交错菱形S形翅片宽通道内流动特性及其对强化传热作用的研究

利用粒子成像测速仪（PIV）在Re=10000时获得了带有菱形销鳍的矩形通道中平面内的流动统计数据。利用适当的正交分解（POD）将大尺度波动和小尺度波动分离开来。将流动特性与通过热致变色液晶（TLC）获得的端壁上的努塞尔数分布进行比较，以揭示驱动传热增强的流动机制。结果表明，局地涡度对引导点（1区）两侧Nu的增强起着重要作用。在两侧（2区）的两个尖锐边缘的下游，剪切层涡流产生的小尺寸扰动驱动局部传热。由于相邻针翅剪切层之间的相互作用，第一排（3区）下游的流动特性和传热分布沿Y方向呈现交替特征。大涡脱落引起的横向速度波动驱动了3区的传热增加，3区存在剧烈的大涡脱落。而剪切层的小尺寸扰动驱动了销翅片下游3区的局部传热增强，在那里大的涡流脱落被抑制。对于第二排和第三排，相邻的针形翅片下游的流动特性没有差异。在大旋涡脱落（4区）下游均匀分布的小尺寸波动导致均匀分布的Nu。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Turbomachinery-Transactions of the Asme 工程技术-工程：机械

CiteScore

4.70

自引率

11.80%

发文量

168

审稿时长

9 months

期刊介绍： The Journal of Turbomachinery publishes archival-quality, peer-reviewed technical papers that advance the state-of-the-art of turbomachinery technology related to gas turbine engines. The broad scope of the subject matter includes the fluid dynamics, heat transfer, and aeromechanics technology associated with the design, analysis, modeling, testing, and performance of turbomachinery. Emphasis is placed on gas-path technologies associated with axial compressors, centrifugal compressors, and turbines. Topics: Aerodynamic design, analysis, and test of compressor and turbine blading; Compressor stall, surge, and operability issues; Heat transfer phenomena and film cooling design, analysis, and testing in turbines; Aeromechanical instabilities; Computational fluid dynamics (CFD) applied to turbomachinery, boundary layer development, measurement techniques, and cavity and leaking flows.