Large-Scale Numerical Investigation of Coherent Structure Dynamics in Film Cooling

Abstract

A series of large-scale parallel simulations of flat-plate film cooling are performed to uncover the qualitative and quantitative relationship between coherent structure dynamics and heat-transfer features. The near-wall flow dynamics and heat-transfer features at five inclination angles of ${15}^{\circ },$ ${30}^{\circ },$ ${45}^{\circ },$ ${60}^{\circ }$ and ${90}^{\circ }$ are also analyzed in detail. Hybrid thermal lattice Boltzmann method and multiple graphic processing units are used to fulfill the simulation efficiently. The detailed coherent structure dynamics are captured by the high-resolution simulation. The results show that large vertical size of coherent structure and great intensity of negative spanwise vorticity indicate prominent coolant-jet detachment leading to bad cooling performance. Meanwhile, the value of area-averaged film cooling effectiveness is proportional to 4th power of area-averaged non-dimensional turbulent kinetic energy. This quantitative relationship is first proposed to make further understanding of film-cooing mixing mechanism. On the other hand, inclination angle has a complicated impact on flow dynamics and heat-transfer features. The vertical size of coherent structure becomes large and the strength of negative spanwise vorticity is strengthened in the case of large inclination angle, resulting in poor cooling performance. The influence of inclination angle is less remarkable in large-inclination-angle case than that of small inclination angle.

Additional information

Funding

The work is funded by the Fundamental Research Funds for the Central Universities of China (B210202131 and B210202128), Basic research program of Jiangsu Province (BK20200182), the fellowship of China Postdoctoral Science Foundation (2020M671314), Open Projects of State Key Laboratory for Strength and Vibration of Mechanical Structures in Xi’an Jiaotong University (SV-2020-KF-04) and Open Fund of Key Laboratory of Icing and Anti/De-icing (IADL20190302).

Notes on contributors

Yanqin Shangguan

Yanqin Shangguan received her Ph.D. degree in Aerospace Engineering in 2018 from Xi’an Jiaotong University in China with a major in flow and heat transfer. Then, she, as a lecturer, continued her academic research at Hohai University in China on high-performance investigation of flow and heat transfer. Since 2013, when she started her Ph.D. research, she has 21 publications in international journals, international and national conferences in the field of flow control and heat transfer. Among them, there are 4 papers that were published in international heat transfer top journal.