scholarly journals Numerical investigation of flat-plate film cooling using Very-Large Eddy Simulation method

2022 ◽  
Vol 171 ◽  
pp. 107263
Author(s):  
Yi Jin ◽  
Lu Lu ◽  
Ziwei Huang ◽  
Xingsi Han
Author(s):  
Guozhan Li ◽  
Jianyang Yu ◽  
Fu Chen ◽  
Huaping Liu ◽  
Yanping Song ◽  
...  

This paper presents results on a saw tooth plasma actuator for the inducement of flow topology and the improvement of flat plate film cooling efficiency. A phenomenological plasma model is constructed to generate the three-dimensional plasma force vectors of the saw tooth plasma actuator. The dynamics of airflow induced by the saw tooth plasma actuator on a flat plate in quiescent air are numerically investigated. The results show that the saw tooth plasma actuator pushes the fluids in all three directions and induces a three-dimensional jet flow with counter rotating streamwise oriented vortices that propagate downstream. The flow field characteristics of both cylindrical hole with and without the saw tooth plasma actuator are studied by large eddy simulation, and a comparison is made. The saw tooth plasma actuator improves the cold jet adherent performance and promotes the spanwise spreading rate of the coolant. Meanwhile, the streamwise vortices induced by the saw tooth plasma actuator suppress the development of counter-rotating vortex pair, thus delaying the diffusion of coolant in the crossflow. Accordingly, the centerline cooling efficiency and the spanwise-averaged cooling efficiency are improved by 36% and 144% at x/ d = 15, compared with the baseline case without the saw tooth plasma actuator.


Author(s):  
Hitesh Sharma ◽  
Dushyant Singh ◽  
Ashutosh Kumar Singh

Abstract In the present work, Large Eddy Simulation (LES) was performed to access the film cooling performance in the supersonic flow over a flat plate with a perpendicular slot injection configuration. The study was carried out for three mainstream Mach No.; Mα = 1.2, 2.67, 3.3 and three coolant stream Mach No.; 0.05, 0.1, 0.15. In supersonic flow, temperature rise inside the boundary layer is a major issue considering it causes high rates of heat transfer to the coolant film. To select a suitable LES Sub-Grid Scale (SGS) model, LES results obtained from the present study using the LES Sub-Grid Scale (SGS) models such as Smagorinky- Lilly, Wale, and WMLES models were compared with DNS results available for flow and heat transfer. The parametric study showed that the higher mainstream Mach No. caused increased wall temperature and reduced effectiveness. The film cooling effectiveness appeared to reduce almost by 10% when the mainstream Mach No. is increased from 1.2 to 2.67, however, no apparent difference was observed in effectiveness between the mainstream Mach No. 2.67 and 3.3. It was found that doubling and tripling the coolant stream Mach No. from 0.05 to 0.1 and 0.15, the length of potential core region also doubled and tripled respectively from 4 X/S to 8 X/S and 13 X/S and hence significant improvement in the film cooling effectiveness was observed.


2012 ◽  
Vol 2012 (0) ◽  
pp. _J051021-1-_J051021-4
Author(s):  
Eiji SAKAI ◽  
Toshihiko TAKAHASHI ◽  
Hiroaki WATANABE

2021 ◽  
Vol 263 (6) ◽  
pp. 298-306
Author(s):  
Zhenan Song ◽  
Daoqing Chang ◽  
Hongling Sun

The influence of the multiple ultrasound transmitting units and the steady injecting water or suck-ing water on the shear layer oscillation and noise by flow-induced cavity is numerically investi-gated in this paper. The ultrasound transmitting units and the steady injecting water or sucking water are located upstream of the leading edge of the cavity. The flow field near the cavity is com-puted based on the large eddy simulation method (LES). The calculation and analysis results show that the peak amplitude of noise can be reduced by the steady injecting water at the leading edge of the opening. And within a specific range of flow rates, the greater the injecting rate is, the more obvious the peak amplitude of noise decreases


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