Runsheng Zhang , Zhen Xiang , Shaohua Han , Xin Huang , Leping Zhou , Li Li , Hui Zhang , Xiaoze Du
{"title":"受鲨鱼皮启发的复合结构的薄膜冷却效果和流动损失的数值研究","authors":"Runsheng Zhang , Zhen Xiang , Shaohua Han , Xin Huang , Leping Zhou , Li Li , Hui Zhang , Xiaoze Du","doi":"10.1016/j.ijthermalsci.2024.109248","DOIUrl":null,"url":null,"abstract":"<div><p>In film cooling for thermal protection of turbine airfoils, the interaction of the cooling jet with the mainstream creates a counter-rotating vortex pair, causing the coolant to detach from the wall, particularly at high blowing ratios (BRs). Eight bionic composite cooling structures inspired by the shark skin structure are proposed to improve the film cooling effectiveness (FCE). The flow characteristics, adiabatic FCE and flow loss are numerically analyzed in detail by using RANS method and Realizable <em>k-ε</em> model, emphasizing the flow loss in the BRs range of 0.5–1.5. Because the cooling jets are separated towards both sides, the coolant near the centerline of the sine-wave and V-shaped trenches is relatively reduced, but the CRVP formed on both sides pushes the cooling fluid back to the cooled wall surface. The mechanism of improved FCE is revealed by the gas convergence to the centerline of the V-shaped, fan-shaped, and wave-shaped surface structures. The variation of blow ratio has a slight influence on the FCE of different cooling configurations. At 25 < X/D < 30, the spanwise-averaged FCE of the VT-WaveS increases significantly, (11.66 %–12.20 % when the BR is 1.0 and by 10.74 %–12.42 % when the BR is 1.5) compared to the sine-wave trench with V-shaped surface. The blade-shaped surface forms more uniform temperature distribution on the flat plate. The discharge coefficient of the VT-BladeS performs best at the BRs of 1.0 and 1.5. The total pressure loss coefficients of the cases are very close. This study revealed the mechanism of the composite structure to improve the FCE of the blade, and the proposed surface structure laid a foundation for the application of shark-skin-inspired surfaces in blade cooling.</p></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":4.9000,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Numerical study of the film cooling effectiveness and flow loss of a shark-skin-inspired composite structure\",\"authors\":\"Runsheng Zhang , Zhen Xiang , Shaohua Han , Xin Huang , Leping Zhou , Li Li , Hui Zhang , Xiaoze Du\",\"doi\":\"10.1016/j.ijthermalsci.2024.109248\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>In film cooling for thermal protection of turbine airfoils, the interaction of the cooling jet with the mainstream creates a counter-rotating vortex pair, causing the coolant to detach from the wall, particularly at high blowing ratios (BRs). Eight bionic composite cooling structures inspired by the shark skin structure are proposed to improve the film cooling effectiveness (FCE). The flow characteristics, adiabatic FCE and flow loss are numerically analyzed in detail by using RANS method and Realizable <em>k-ε</em> model, emphasizing the flow loss in the BRs range of 0.5–1.5. Because the cooling jets are separated towards both sides, the coolant near the centerline of the sine-wave and V-shaped trenches is relatively reduced, but the CRVP formed on both sides pushes the cooling fluid back to the cooled wall surface. The mechanism of improved FCE is revealed by the gas convergence to the centerline of the V-shaped, fan-shaped, and wave-shaped surface structures. The variation of blow ratio has a slight influence on the FCE of different cooling configurations. At 25 < X/D < 30, the spanwise-averaged FCE of the VT-WaveS increases significantly, (11.66 %–12.20 % when the BR is 1.0 and by 10.74 %–12.42 % when the BR is 1.5) compared to the sine-wave trench with V-shaped surface. The blade-shaped surface forms more uniform temperature distribution on the flat plate. The discharge coefficient of the VT-BladeS performs best at the BRs of 1.0 and 1.5. The total pressure loss coefficients of the cases are very close. This study revealed the mechanism of the composite structure to improve the FCE of the blade, and the proposed surface structure laid a foundation for the application of shark-skin-inspired surfaces in blade cooling.</p></div>\",\"PeriodicalId\":341,\"journal\":{\"name\":\"International Journal of Thermal Sciences\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":4.9000,\"publicationDate\":\"2024-07-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"International Journal of Thermal Sciences\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1290072924003703\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, MECHANICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Thermal Sciences","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1290072924003703","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
Numerical study of the film cooling effectiveness and flow loss of a shark-skin-inspired composite structure
In film cooling for thermal protection of turbine airfoils, the interaction of the cooling jet with the mainstream creates a counter-rotating vortex pair, causing the coolant to detach from the wall, particularly at high blowing ratios (BRs). Eight bionic composite cooling structures inspired by the shark skin structure are proposed to improve the film cooling effectiveness (FCE). The flow characteristics, adiabatic FCE and flow loss are numerically analyzed in detail by using RANS method and Realizable k-ε model, emphasizing the flow loss in the BRs range of 0.5–1.5. Because the cooling jets are separated towards both sides, the coolant near the centerline of the sine-wave and V-shaped trenches is relatively reduced, but the CRVP formed on both sides pushes the cooling fluid back to the cooled wall surface. The mechanism of improved FCE is revealed by the gas convergence to the centerline of the V-shaped, fan-shaped, and wave-shaped surface structures. The variation of blow ratio has a slight influence on the FCE of different cooling configurations. At 25 < X/D < 30, the spanwise-averaged FCE of the VT-WaveS increases significantly, (11.66 %–12.20 % when the BR is 1.0 and by 10.74 %–12.42 % when the BR is 1.5) compared to the sine-wave trench with V-shaped surface. The blade-shaped surface forms more uniform temperature distribution on the flat plate. The discharge coefficient of the VT-BladeS performs best at the BRs of 1.0 and 1.5. The total pressure loss coefficients of the cases are very close. This study revealed the mechanism of the composite structure to improve the FCE of the blade, and the proposed surface structure laid a foundation for the application of shark-skin-inspired surfaces in blade cooling.
期刊介绍:
The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review.
The fundamental subjects considered within the scope of the journal are:
* Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow
* Forced, natural or mixed convection in reactive or non-reactive media
* Single or multi–phase fluid flow with or without phase change
* Near–and far–field radiative heat transfer
* Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...)
* Multiscale modelling
The applied research topics include:
* Heat exchangers, heat pipes, cooling processes
* Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries)
* Nano–and micro–technology for energy, space, biosystems and devices
* Heat transport analysis in advanced systems
* Impact of energy–related processes on environment, and emerging energy systems
The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.