NUMERICAL STUDY OF HOLE SHAPE EFFECT ON BLADE COOLING EFFECTIVENESS

2010 ◽  
Vol 24 (13) ◽  
pp. 1295-1298
Author(s):  
JUN YAO ◽  
SOHAN SIAN ◽  
YUFENG YAO ◽  
TONY W. DAVIS
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Numerical Data ◽  
Cylindrical Hole ◽  
Shape Effect ◽  
Cooling Effectiveness ◽  
Hole Shape ◽  
Blade Cooling ◽  
Adiabatic Cooling ◽  
Hole Model

Numerical study of hole shape effect on blade adiabatic cooling effectiveness has been carried out on four geometry models comprising a standard cylindrical hole, a cylindrical hole with an upstream ramp, a shaped diffuser, and a double console slot. In all the cases, the hole centerline has an inclination angle of 35 degree against the mainstream gas flow. Results of the cylindrical hole model are in good agreement with available experimental and other numerical data. For the other three hole geometry variants considered, it was found that the cooling effectiveness has been considerably enhanced by a max factor of 2, compared to that from the base model. The physical mechanism for this is mainly due to the weakening of coolant flow penetration in the vicinity of the hole exit, thus reducing the level of mixing and the entrainment with the surrounding hot gas flow.

Injection Angle Influence of Secondary Holes on the Enhancement of Film Cooling Effectiveness With Horn-Shaped or Cylindrical Primary Holes

2017 ◽  
Author(s):  
Rui Zhu ◽  
Gongnan Xie ◽  
Terrence W. Simon
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Cylindrical Hole ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Injection Angle ◽  
Inclination Angles ◽  
Cooling Hole ◽  
Cylindrical Holes

Secondary holes to a main film cooling hole are used to improve film cooling performance by creating anti-kidney vortices. The effects of injection angle of the secondary holes on both film cooling effectiveness and surrounding thermal and flow fields are investigated in this numerical study. Two kinds of primary hole shapes are adopted. One is a cylindrical hole, the other is a horn-shaped hole which is designed from a cylindrical hole by expanding the hole in the transverse direction to double the hole size at the exit. Two smaller cylindrical holes, the secondary holes, are located symmetrically about the centerline and downstream of the primary hole. Three compound injection angles (α = 30°, 45° and 60°, β = 30°) of the secondary holes are analyzed while the injection angle of the primary hole is kept at 45°. Cases with various blowing ratios are computed. It is shown from the simulation that cooling effectiveness of secondary holes with a horn-shaped primary hole is better than that with a cylindrical primary hole, especially at high blowing ratios. With a cylindrical primary hole, increasing inclination angle of the secondary holes provides better cooling effectiveness because the anti-kidney vortices created by shallow secondary holes cannot counteract the kidney vortex pairs adequately, enhancing mixing of main flow and coolant. For secondary holes with a horn-shaped primary hole, large secondary hole inclination angles provide better cooling performance at low blowing ratios; but, at high blowing ratios, secondary holes with small inclination angles are more effective, as the film coverage becomes wider in the downstream area.

A Novel Cooling Method for Turbine Rotor-Stator Rim Cavities Affected by Mainstream Ingress

2004 ◽  
Vol 127 (4) ◽  
pp. 798-806 ◽  
Author(s):  
Y. Okita ◽  
M. Nishiura ◽  
S. Yamawaki ◽  
Y. Hironaka
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Significant Advance ◽  
Axial Distribution ◽  
Cooling Effectiveness ◽  
Cooling Flow ◽  
Cooling Method ◽  
Flow Phenomena

A combined experimental and numerical study of interaction between cooling flow and mainstream gas flow in a turbine rotor-stator rim cavity is reported. Particular emphasis is put on the flow phenomena in a rim cavity downstream of rotor blades. The experiments are conducted on a rig simulating an engine HP-turbine in which cooling effectiveness distributions as well as velocities, turbulence quantities, pressure, and temperature profiles are measured. Numerical calculation, especially at a full 3D, unsteady solution level, can lead to satisfactory predictions in fluid and mass transfer inside the cavity. Both experimental and numerical results indicate that large turbulence stresses near the rotor disk intensify turbulent diffusion across the cavity and consequently axial distribution of the cooling effectiveness inside the cavity becomes uniform. In order to obtain an adequate distribution of cooling effectiveness across the rim cavity and to suppress the turbulence level near the rotor surface for more efficient cooling, a novel cooling method is developed using numerical simulation. The disk-front and -rear cavities are then redesigned according to the new cooling strategy and integrated in the test rig. Experimental results verify a significant advance in cooling performance with the new method.

Enhanced Film Cooling Effectiveness by Integration of Horn-Shaped and Cylindrical Holes

2017 ◽  
Author(s):  
Rui Zhu ◽  
Gongnan Xie ◽  
Terrence W. Simon
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Turbine Blades ◽  
Cylindrical Hole ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Transverse Tensile ◽  
First Case ◽  
Cylindrical Holes ◽  
Shaped Hole

In search of improved cooling of gas turbine blades, the thermal performances of two different film cooling hole geometries (horn-shaped and cylindrical) are investigated in this numerical study. The horn-shaped hole is designed from a cylindrical hole by expanding the hole in the transverse direction to double the hole size at the exit. The two hole shapes are evaluated singly and in tandem. The tandem geometry assumes three configurations made by locating the cylindrical hole at three different positions relative to the horn-shaped hole such that their two axes remain parallel to one another. One has the cylindrical hole downstream from the center of the horn-shaped hole, a second has the cylindrical hole to the left of (as seen by the flow emerging from the horn-shaped hole) and at the same streamwise location as the horn-shaped hole (θ = 90°) and the third has an intermediate geometry between those two geometries (downstream and to the left of the horn-shaped hole - θ = 45°). It is shown from the simulation results that the cooling effectiveness values for the θ = 45° and 90° cases are much better than that for θ = 0° (the first case), and the configuration with θ = 45° exhibits the best cooling performance of the three tandem arrangements. These improvements are attributed to the interaction of vortices from the two different holes, which weakens the counter-rotating vortex pairs inherent to film cooling jet to freestream interaction, counteracts with the lift forces, enhances transverse tensile forces and, thus, enlarges the film coverage zone by widening the flow attachment region. Overall, this research reveals that integration of horn-shaped and cylindrical holes provides much better film cooling effectiveness than cases where two cylindrical film cooling holes are applied with the same tandem configuration.

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.

Effect of Hole Shape on Blade Cooling Effectiveness

2010 ◽  
Author(s):  
Jun Yao ◽  
Sohan Sian ◽  
Jawaaz Khan ◽  
Yufeng Yao
Keyword(s):  
Cooling Effectiveness ◽  
Hole Shape ◽  
Blade Cooling

A Novel Cooling Method for Turbine Rotor-Stator Rim Cavities Affected by Mainstream Ingress

2004 ◽  
Author(s):  
Y. Okita ◽  
M. Nishiura ◽  
S. Yamawaki ◽  
Y. Hironaka
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Significant Advance ◽  
Axial Distribution ◽  
Cooling Effectiveness ◽  
Cooling Flow ◽  
Cooling Method ◽  
Flow Phenomena

A combined experimental and numerical study of interaction between cooling flow and mainstream gas flow in a turbine rotor-stator rim cavity is reported. Particular emphasis is put on the flow phenomena in a rim cavity downstream of rotor blades. The experiments are conducted on a rig simulating a engine HP-turbine in which cooling effectiveness distributions as well as velocities, turbulence quantities, pressure and temperature profiles are measured. Numerical calculation, especially at a full 3D, unsteady solution level, can lead to satisfactory predictions in fluid and mass transfer inside the cavity. Both experimental and numerical results indicate that large turbulence stresses near the rotor disk intensify turbulent diffusion across the cavity and consequently axial distribution of the cooling effectiveness inside the cavity becomes uniform. In order to obtain an adequate distribution of cooling effectiveness across the rim cavity and to suppress the turbulence level near the rotor surface for more efficient cooling, a novel cooling method is developed using numerical simulation. The disk-front and -rear cavities are then redesigned according to the new cooling strategy and integrated in the test rig. Experimental results verify a significant advance in cooling performance with the new method.

The effect of hole shape on blade cooling effectiveness

2010 ◽  
Vol 2 (4) ◽  
pp. 242
Author(s):  
Yufeng Yao ◽  
Jun Yao
Keyword(s):  
Cooling Effectiveness ◽  
Hole Shape ◽  
Blade Cooling

Experimental and Numerical Study on the Effect of Fan-Shaped Hole Configuration on Film Cooling Effectiveness

2019 ◽  
Author(s):  
Hyun Jae Seo ◽  
Sang Hyeon Park ◽  
Jae Su Kwak ◽  
Young Seok Kang
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Turbine Blades ◽  
Experimental Studies ◽  
Shape Parameters ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Hole Shape ◽  
Expansion Angle ◽  
Shaped Hole

Abstract Film cooling technique has been widely applied to protect gas turbine blades from high temperature combustion gases. In this study, to improve the cooling effectiveness of fan-shaped film cooling holes, the effect of the main shape parameters on the film cooling effectiveness was investigated through numerical and experimental studies. Commercial software based on Reynolds Averaged Navier-Stokes (RANS) analysis was used in the numerical study, and the PSP (Pressure Sensitive Paint) technique was used to experimentally measure the film cooling effectiveness. The design points for the optimization were derived by the Box-Behnken method, which is one of the design of experiments (DOE). Three shape parameters of a fan-shaped hole were selected as design variables: the forward expansion angle, the lateral expansion angle, and the length of cylindrical part of the hole. The area-averaged film cooling effectiveness was selected as an objective function and the optimal hole shape of each analysis was obtained using the response surface methodology (RSM). It was confirmed that the film cooling effectiveness was affected by all three variables in both numerical and experimental results. Both analyses showed similar trends of each variable on film cooling effectiveness, but the optimal hole shape obtained by each method was different. The difference is attributed to flow separation not captured by RANS based analysis and surface roughness caused by the manufacturing process and the PSP coating in experimental analysis. Notably, the experimentally optimized hole showed better film cooling effectiveness than that of the numerically optimized hole in the comparison experiments.

Numerical Performances Study of Curved Photovoltaic Panel Integrated with Phase Change Material

2020 ◽  
Vol 22 (4) ◽  
pp. 1439-1452
Author(s):  
Mohamed L. Benlekkam ◽  
Driss Nehari ◽  
Habib Y. Madani
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Numerical Study ◽  
Numerical Data ◽  
Navier Stokes ◽  
Photovoltaic Panel ◽  
Pv Panel ◽  
Energy Equations ◽  
Solid Liquid ◽  
Change Material

AbstractThe temperature rise of photovoltaic’s cells deteriorates its conversion efficiency. The use of a phase change material (PCM) layer linked to a curved photovoltaic PV panel so-called PV-mirror to control its temperature elevation has been numerically studied. This numerical study was carried out to explore the effect of inner fins length on the thermal and electrical improvement of curved PV panel. So a numerical model of heat transfer with solid-liquid phase change has been developed to solve the Navier–Stokes and energy equations. The predicted results are validated with an available experimental and numerical data. Results shows that the use of fins improve the thermal load distribution presented on the upper front of PV/PCM system and maintained it under 42°C compared with another without fins and enhance the PV cells efficiency by more than 2%.

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