Purpose

Convective heat transfer features of a turbulent slot jet impingement are comprehensively studied using two different computational approaches, namely, URANS (unsteady Reynolds-averaged Navier–Stokes equations) and SAS (scale-adaptive simulation). Turbulent slot jet impingement heat transfer is used where a considerable heat transfer enhancement is required, and computationally, it is a quite challenging flow configuration.

Design/methodology/approach

Customized OpenFOAM 4.1, an open-access computational fluid dynamics (CFD) code, is used for SAS (SST-SAS k-ω) and URANS (standard k-ε and SST k-ω) computations. A low-Re version of the standard k-ε model is used, and other models are formulated for good wall-refined calculations. Three turbulence models are formulated in OpenFOAM 4.1 with second-order accurate discretization schemes.

Findings

It is observed that the profiles of the streamwise turbulence are under-predicted at all the streamwise locations by SST k-ω and SST SAS k-ω models, but follow similar trends as in the reported results. The standard k-ε model shows improvements in the predictions of the streamwise turbulence and mean streamwise velocity profiles in the zone of outer wall jet. Computed profiles of Nusselt number by SST k-ω and SST-SAS k-ω models are nearly identical and match well with the reported experimental results. However, the standard k-ε model does not provide a reasonable profile or quantification of the local Nusselt number.

Originality/value

Hybrid turbulence model is suitable for efficient CFD computations for the complex flow problems. This paper deals with a detailed comparison of the SAS model with URANS and LES for the first time in the literature. A thorough assessment of the computations is performed against the results reported using experimental and large eddy simulations techniques followed by a detailed discussion on flow physics. The present results are beneficial for scientists working with hybrid turbulence models and in industries working with high-efficiency cooling/heating system computations.

中文翻译：

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湍流狭缝射流冲击对流换热特性的计算分析

目的

使用两种不同的计算方法，即 URANS（非定常雷诺平均 Navier-Stokes 方程）和 SAS（尺度自适应模拟），对湍流狭缝射流冲击的对流换热特性进行了综合研究。湍流槽射流冲击传热用于需要显着增强传热的地方，并且在计算上，这是一种非常具有挑战性的流动配置。

设计/方法/方法

定制的 OpenFOAM 4.1 是一种开放式计算流体动力学 (CFD) 代码，用于 SAS (SST-SAS k-ω) 和 URANS（标准 k-ε 和 SST k-ω）计算。使用标准 k-ε 模型的低 Re 版本，并制定其他模型以进行良好的壁面细化计算。三个湍流模型在 OpenFOAM 4.1 中使用二阶精确离散化方案制定。

发现

据观察，SST k - ω和 SST SAS k - ω模型在所有流向位置处都低估了流向湍流的轮廓，但遵循与报告结果相似的趋势。标准的k - ε模型显示了外壁射流区域中流向湍流和平均流向速度剖面的预测的改进。通过 SST k - ω和 SST-SAS k - ω模型计算的努塞尔特数分布几乎相同，并且与报告的实验结果匹配良好。然而，标准k-ε 模型没有提供本地努塞尔数的合理轮廓或量化。

原创性/价值

混合湍流模型适用于复杂流动问题的高效 CFD 计算。本文在文献中首次详细比较了 SAS 模型与 URANS 和 LES。根据使用实验和大涡模拟技术报告的结果对计算进行彻底评估，然后详细讨论流动物理学。目前的结果对于研究混合湍流模型的科学家和从事高效冷却/加热系统计算的行业都是有益的。