Experimental and numerical investigation on the film cooling performance of cylindrical hole and fan-shaped hole with vortex generator fed by crossflow

2022 ◽  
Vol 187 ◽  
pp. 122560
Author(s):  
Jie Wang ◽  
Chao Zhang ◽  
Xuebin Liu ◽  
Liming Song ◽  
Jun Li
Keyword(s):  
Numerical Investigation ◽  
Film Cooling ◽  
Vortex Generator ◽  
Cylindrical Hole ◽  
Cooling Performance ◽  
Shaped Hole

Experimental and Numerical Investigation on Film Cooling Performance and Flow Structure of Film Holes

2019 ◽  
Author(s):  
Nan Cao ◽  
Xue Li ◽  
Ze-yu Wu ◽  
Xiang Luo
Keyword(s):  
Flow Visualization ◽  
Numerical Investigation ◽  
Flow Structure ◽  
Film Cooling ◽  
Cylindrical Hole ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Blowing Ratio ◽  
Visualization Experiment ◽  
Shaped Hole

Abstract Discrete hole film cooling has been commonly used as an effective cooling technique to protect gas turbine blades from hot gas. There have been numerous investigations on the cylindrical hole and shaped hole, but few experimental investigations on the cooling mechanism of the novel film holes with side holes (anti-vortex hole and sister hole) are available. This paper presents an experimental and numerical investigation to study the film cooling performance and flow structure of four kinds of film holes (cylindrical hole, fan-shaped hole, anti-vortex hole and sister hole) on the flat plate. The film holes have the same main hole diameter of 4mm and the same inclination angle of 45°. The adiabatic film cooling effectiveness is obtained by the steady-state Thermochromic Liquid Crystal (TLC). The flow visualization experiment and numerical investigation are performed to investigate the flow structure and counter-rotating vortex pair (CRVP) intensity. The smoke is selected as the tracer particle in the flow visualization experiment. The mainstream Reynolds number is 2900, the blowing ratio ranges from 0.3 to 2.0, and the density ratio of coolant to mainstream is 1.065. Experimental results show that compared with the cylindrical hole, the film cooling performance of the anti-vortex hole and sister hole shows significant improvement at all blowing ratios. The sister hole can achieve the best cooling performance at blowing ratios of 0.3 to 1.5. The fan-shaped hole only performs well at high blowing ratios and it performs best at the blowing ratio of 2.0. Flow visualization experiment and numerical investigation reveal that the anti-vortex hole and sister hole can decrease the CRVP intensity of the main hole and suppress the coolant lift-off because of side holes, which increases the film coverage and cooling effectiveness. For the sister hole, the side holes are parallel to the main hole, but for the anti-vortex hole, there are lateral angles between them. The coolant interaction between the side holes and main hole of the sister hole is stronger than that of the anti-vortex hole. Therefore, the sister hole provides better film cooling performance than the anti-vortex hole.

Experimental Investigation on the Flat-Plate Film Cooling Enhancement Using the Vortex Generator Downstream for the Cylindrical Hole and Fan-Shaped Hole Configurations

2019 ◽  
Author(s):  
Chao Zhang ◽  
Jie Wang ◽  
Xin Luo ◽  
Liming Song ◽  
Jun Li ◽  
...  
Keyword(s):  
Film Cooling ◽  
Vortex Generator ◽  
Cylindrical Hole ◽  
Combined Model ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Shaped Hole ◽  
Hole Model

Abstract In our experiments, the film cooling performance of the configurations combined the different hole with the vortex generator was investigated experimentally, measured by the infrared camera. Four different configurations were studied at the blowing ratio varying at M = 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0. In all cases, the Reynold number of the mainstream based on the hole diameter remained at Re = 8000, and the density ratio kept at DR = 1.7. Experimental results show that for the two models combining the cylindrical hole and fan-shaped hole with the vortex generator respectively, the film cooling performance becomes better when the blowing ratio increases from M = 0.5 to M = 2.0, and then decreases when the blowing ratio increases from M = 2.0 to M = 3.0. The model combining the fan-shaped hole with the vortex generator performs the best among the four models at each blowing ratio. Its film attachment holds the most extensive lateral distribution and its overall film cooling effectiveness could keep at a high level at a wide range of blowing ratios from M = 1.0 to M = 3.0. The combined model of the fan-shaped hole could improve the area-averaged film effectiveness at most 25.5% than that of the single hole model at M = 2.0. Moreover, the combined model of the cylindrical hole could improve the area-averaged film cooling effectiveness at most 431% than that of the single cylindrical hole model at M = 3.0.

Experimental Investigation and Optimal Design on the Film Cooling Performance of Fan-Shaped Hole With Vortex Generator Fed by Crossflow

2021 ◽  
Author(s):  
Jie Wang ◽  
Chao Zhang ◽  
Xuebin Liu ◽  
Liming Song ◽  
Jun Li ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Film Cooling ◽  
Vortex Generator ◽  
Optimized Design ◽  
Combined Model ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Shaped Hole

Abstract Aiming at investigating the effects of crossflow and vortex generator on film cooling characteristics of fan-shaped hole, the film cooling performance was measured experimentally by infrared camera. The blowing ratio is fixed at 0.5 and 1.5. The Reynolds number of the mainstream based on the hole diameter remains at 7000 and the inlet Reynolds number of crossflow is 40000. The experimental results show that the film cooling performance becomes better when the blowing ratio increases from 0.5 to 1.5 for each model, and the film cooling performance becomes worse under the influence of crossflow. When the blowing ratio is 1.5, the area-averaged film cooling effectiveness of the fan-shaped hole model with vortex generator decreases by 16.6% because of the influence of crossflow. The combined model always performs better compared with the model without vortex generator under all working conditions. When the blowing ratio becomes 1.5, under the influence of crossflow, the area-averaged film cooling effectiveness of the combined model could increase by 14.8%, compared with the model without vortex generator. To further improve the film cooling performance, the global optimization algorithm based on the Kriging method and the CFD technology are coupled to optimize the combined model under crossflow condition at the high blowing ratio, and the optimized design is verified by experiments. The experimental results show that the area-averaged film cooling effectiveness of the optimized design increases by 17.8% compared with the reference model.

Experimental and Numerical Study on the Flat-Plate Film Cooling Enhancement Using the Vortex Generator Downstream for the Fan-Shaped Hole Configuration

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Chao Zhang ◽  
Jie Wang ◽  
Xuebin Liu ◽  
Liming Song ◽  
Jun Li ◽  
...  
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Infrared Camera ◽  
Vortex Generator ◽  
Cylindrical Hole ◽  
Film Cooling Effectiveness ◽  
Aerodynamic Loss ◽  
Blowing Ratio ◽  
Cooling Enhancement ◽  
Shaped Hole

Abstract The shaped hole is the significant advancement for improving film cooling that has been practically achieved. This present study puts forward a new design combining the vortex generator (VG) with the shaped hole (FV). To investigate the effect of the new design, experiments were carried out to measure the film cooling performance of the four different configurations including the baseline cylindrical hole (CH) model, the model combing the cylindrical hole with VG (CV), shaped hole model (FAN), and FV model, at the blowing ratio varying at M = 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 by the infrared camera. Experimental results show that the FV model performs the best among the four models at each blowing ratio. The FV model could improve the area-averaged film effectiveness at most 25.5% than that of the CH model at M = 2.0. Moreover, the FV model could improve the area-averaged film cooling effectiveness at most 431% than that of the CH model at M = 3.0. Besides, the aerodynamic analysis of the four models at different blowing ratios was carried out by the numerical study. The simulation results show that the introduction of VG causes slightly more aerodynamic loss while the fan-shaped hole improves it. The aerodynamic performance of the FV model is almost the same as the CH model when M < 2 and smaller than that of the CH model when M > 2.

Advanced Film Cooling Performance of a Y-Shaped Hole With Inner Crossflow

2018 ◽  
Author(s):  
Jianxia Luo ◽  
Cunliang Liu ◽  
Huiren Zhu
Keyword(s):  
Film Cooling ◽  
Flow Direction ◽  
Cylindrical Hole ◽  
Navier Stokes ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Lateral Film ◽  
Shaped Hole

Film cooling performances of three film holes have been numerical researched in this paper, including a lateral inclined cylindrical hole, a fan-shaped hole and a y-shaped hole. The simulation is computed by the commercial software Fluent based on Reynolds Averaged Navier-Stokes (RANS) equations and realizable k-ε turbulence model with enhanced wall treatment. The y-shaped hole is a novel film hole developed from the lateral inclined cylindrical hole. With inner crossflow, the jet of the lateral inclined cylindrical hole performs to be two streams as a result of the helical motion in the hole. Accordingly, the hole exit was optimized with two expansions: one is expanded along the lateral inclined direction and the other is expanded along the mainstream flow direction. The lateral inclined cylindrical hole with two expansions at the exit is named the y-shaped hole. Compared to the fundamental lateral inclined cylindrical hole, the y-shaped hole has different counter-rotating vortices and much better film coverage. Experiments have been conducted to test the film cooling performance of the y-shaped hole. Compared to the lateral inclined cylindrical hole, much higher film cooling effectiveness has been measured in the y-shaped hole as a result of the enhanced lateral film coverage and the weakened film dissipation in the streamwise direction. The film performance of the y-shaped hole rises with the increase of the blowing ratio. At M = 2.0, the film of the y-shaped hole keeps close to the wall while the film of the lateral inclined cylindrical hole is completely lifted up, resulting in the increase of the area average film cooling effectiveness up to 128.7%.

Numerical Investigation on the Effects of Vortex Generator Locations on Film Cooling Performance

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Daren Zheng ◽  
Xinjun Wang ◽  
Qi Yuan
Keyword(s):  
Adverse Effect ◽  
Numerical Investigation ◽  
Opposite Direction ◽  
Film Cooling ◽  
Vortex Generator ◽  
Cooling Performance ◽  
Blowing Ratio ◽  
Twisted Flow

Abstract Described in this paper is a numerical investigation on the concept for enhancing film cooling performance by placing vortex generator (VG) upstream the film hole. Six film cooling configurations with different VG locations are investigated, including the distances for VG upstream the film hole (Upstream Distances) of 20 mm, 25 mm, and 30 mm and the VG gaps of 0, 2 mm, 4 mm and 6 mm respectively. The effect of VG locations on film cooling performance were conducted. The film cooling performance is evaluated at the density of 0.97 with the blowing ratio of 1.0. Results obtained show that the twisted flow generated by upstream VG rotates in the opposite direction of kidney vortex, producing an adverse effect on kidney vortex. The enhanced adverse effect could dramatically improve the film cooling performance. Moreover, the intensity of twisted flow is greatly related to the VG locations. The film cooling performance improves with the increasing upstream distances. The film cooling performance improves first and then impairs with increasing VG gaps. In this case, the film cooling performance in the case with gap of 4 mm is superior to those in other cases.

Film Cooling From Novel Sister Shaped Single-Holes

2014 ◽  
Author(s):  
Siavash Khajehhasani ◽  
Bassam Jubran
Keyword(s):  
Film Cooling ◽  
Three Dimensional ◽  
Lateral Spreading ◽  
Navier Stokes ◽  
The Novel ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Shaped Hole ◽  
Lift Off

A numerical investigation of the film cooling performance from novel sister shaped single-holes (SSSH) is presented in this paper and the obtained results are compared with a single cylindrical hole, a forward diffused shaped hole, as well as discrete sister holes. Three types of the novel sister shaped single-hole schemes namely downstream, upstream and up/downstream SSSH, are designed based on merging the discrete sister holes to the primary hole in order to reduce the jet lift-off effect and increase the lateral spreading of the coolant on the blade surface as well as a reduction in the amount of coolant in comparison with discrete sister holes. The simulations are performed using three-dimensional Reynolds-Averaged Navier Stokes analysis with the realizable k–ε model combined with the standard wall function. The upstream SSSH demonstrates similar film cooling performance to that of the forward diffused shaped hole for the low blowing ratio of 0.5. While it performs more efficiently at M = 1, where the centerline and laterally averaged effectiveness results improved by 70% and 17%, respectively. On the other hand, the downstream and up/downstream SSSH schemes show a considerable improvement in film cooling performance in terms of obtaining higher film cooling effectiveness and less jet lift-off effect as compared with the single cylindrical and forward diffused shaped holes for both blowing ratios of M = 0.5 and 1. For example, the laterally averaged effectiveness for the downstream SSSH configuration shows an improvement of approximately 57% and 110% on average as compared to the forward diffused shaped hole for blowing ratios of 0.5 and 1, respectively.

Sign in / Sign up

Export Citation Format

Share Document