Purpose

The flow phenomenon of particle image velocimetry has revealed the transition process of the complex multi-scale vortex between the boundary layer and mainstream region. Nonetheless, present computational fluid dynamics methods inadequately distinguish the discernable flows in detail. A multi-physical field coupling model, which was applied in rotor-stator fluid machinery (Umavathi, 2015; Syawitri et al., 2020), was put forward to ensure the identification of multi-scale vortexes and the improvement of performance prediction in torque converter.

Design/methodology/approach

A newly-developed multi-physical field simulation framework that coupled the scale-resolving simulation method with a dynamic modified viscosity coefficient was proposed to comparatively investigate the influence of energy exchange on thermal and flow characteristics and the description of the flow field in detail.

Findings

Regardless of whether quantitative or qualitative, its description ability on turbulence statistics, pressure-streamline, vortex structure and eddy viscosity ratio were visually experimentally and numerically analyzed. The results revealed that the modification of transmission medium viscous can identify flows more exactly between the viscous sublayer and outer boundary layer. Compared with RANS and large eddy simulation, a stress-blended eddy simulation model with a dynamic modified viscosity coefficient, which was further used to achieve blending on the stress level, can effectively solve the calculating problem of the transition region between the near-wall boundary layer and mainstream region.

Research limitations/implications

This indeed provides an excellent description of the transient flow field and vortex structure in different physical flow states. Furthermore, the experimental data has proven that the maximum error of the external performance prediction was less than 4%.

Originality/value

An improved model was applied to simulate and analyze the flow mechanism through the evolution of vortex structures in a working chamber, to deepen the designer with a fundamental understanding on how to reduce flow losses and flow non-uniformity in manufacturing.

中文翻译：

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使用新开发的应力混合涡流模拟计算和分析液力变矩器中的热流场

目的

粒子图像测速的流动现象揭示了边界层与主流区域之间复杂的多尺度涡旋的过渡过程。尽管如此，目前的计算流体动力学方法不足以详细区分可辨别的流动。提出了一种应用于转子-定子流体机械的多物理场耦合模型（Umavathi, 2015; Syawitri et al. , 2020），以确保多尺度涡的识别和扭矩性能预测的改进转换器。

设计/方法/方法

提出了一种新开发的多物理场模拟框架，将尺度解析模拟方法与动态修正粘度系数相结合，以比较研究能量交换对热流特性的影响以及流场的详细描述。

发现

无论是定量还是定性，都对其湍流统计、压力流线、涡结构和涡粘比的描述能力进行了直观的实验和数值分析。结果表明，传输介质粘性的修正可以更准确地识别粘性子层和外边界层之间的流动。与RANS和大涡模拟相比，采用动态修正粘度系数的应力混合涡模拟模型，进一步实现应力水平的混合，可以有效解决近壁面边界之间过渡区的计算问题。层和主流区域。

研究限制/影响

这确实很好地描述了不同物理流动状态下的瞬态流场和涡流结构。此外，实验数据证明，外部性能预测的最大误差小于4%。

原创性/价值

应用改进的模型来模拟和分析工作腔内涡流结构演变的流动机制，加深设计人员对如何减少制造过程中的流动损失和流动不均匀性的基本认识。