The Effect of Compound Angle on Nozzle Pressure Side Film Cooling

2009 ◽  
Author(s):  
Luzeng Zhang ◽  
Juan Yin ◽  
Hee Koo Moon
Keyword(s):  
Film Cooling ◽  
Operating Conditions ◽  
The Other ◽  
Hole Injection ◽  
Pressure Side ◽  
Blowing Ratio ◽  
Test Models ◽  
Nozzle Pressure ◽  
Shaped Hole ◽  
Compound Angle

The effect of film cooling hole compound angle on nozzle pressure side film cooling effectiveness was experimentally investigated using a single row of shaped hole injection. The engine operating conditions were simulated in a scaled warm cascade, which was built based on industrial gas turbine nozzle vanes. Local film effectiveness measurements were made using a computerized pressure sensitive paint (PSP) technique. Nitrogen gas was used to simulate cooling flow as well as a tracer gas to indicate oxygen concentration such that film effectiveness by the mass transfer analogy. Three separate nozzle test models were fabricated, which have same cooling supply plenum configurations. One of them has a row of shaped hole on the pressure surface without a compound angle. The other two test models have same size film holes at the same location, but one with a 30-degree compound angle in co-flow and the other in counter-flow direction to the cooling supply. Four cooling mass flow ratios (MFR, blowing ratio) were studied for each of the nozzle test models and two-dimensional film effectiveness distributions were measured. Then the film effectiveness distributions were spanwise averaged for comparison. For all three cases, the overall film effectiveness increased with the MFR (or the blowing ratio), but not significantly. Film effectiveness by a compound angle injection is higher compared to those without a compound angle near the injection, further downstream the difference is insignificant.

The Effect of Compound Angle on Nozzle Suction Side Film Cooling

2012 ◽  
Author(s):  
Luzeng Zhang ◽  
Juan Yin ◽  
Hee Koo Moon
Keyword(s):  
Film Cooling ◽  
Flow Direction ◽  
Suction Side ◽  
Operating Conditions ◽  
The Other ◽  
Counter Flow ◽  
Film Cooling Effectiveness ◽  
Test Models ◽  
Angle Effect ◽  
Compound Angle

The film cooling hole compound angle effect on nozzle suction side film cooling effectiveness was experimentally investigated using a single row of shaped holes. Engine operating conditions were simulated in a scaled warm cascade, which was built based on industrial gas turbine nozzle vanes. Local film effectiveness measurements were made using a computerized pressure sensitive paint (PSP) technique. Nitrogen gas was used to simulate cooling flow as well as a tracer gas to indicate oxygen concentration such that film effectiveness can be obtained by the mass transfer analogy. Three separate nozzle test models were fabricated, which have the same cooling supply plenum configurations. The baseline configuration has a row of shaped holes on the suction surface without a compound angle. The other two test models have same size film holes at the same location, but one with a compound angle in co-flow and the other in counter-flow direction to the cooling supply. Four cooling mass flow ratios (MFR) were studied for each of the nozzle test models and two-dimensional film effectiveness distributions were measured. Then the film effectiveness distributions were spanwise averaged for comparison. The compound angle injections prevent jets lift-off for higher MFR cases, but for a lower MFR, the baseline configuration results in higher film effectiveness. The co-flow or counter-flow compound angle results in film shifting to upper or lower endwall, but the effect of the direction of the compound angle is less significant compared to the compound angle effect.

Film cooling characteristics on a grooved surface with different injection orientation angles

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Peng Yang ◽  
Guangchao Li ◽  
Jianyong Zhu
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
Orientation Angle ◽  
Hole Injection ◽  
Blowing Ratio ◽  
Reverse Trend ◽  
Grooved Surface ◽  
Shaped Hole

Abstract The film effectiveness was investigated on a grooved surface with the injection orientation angles of 30°, 90°, and 150° at the blowing ratios of 0.5, 0.8, 1.1, and 1.4. The injection orientation angle and the groove on the surface caused the effect of the various and irregular shaped hole injection due to the different orientation injection. The results showed that the new phenomenon of film effectiveness distributions was found on the grooved surface compared with the flat plate case. Film effectiveness distributions for the β = 30° were found to be the discontinuous strips. The surface averaged film effectiveness with the orientation angle of 30° was found to decrease with the increase of the blowing ratio. Additionally, the reverse trend was observed with the orientation angle of 150°. The film effectiveness with the orientation angle of 90° only slightly changed with the increase of the blowing ratio.

Film cooling characteristics on a grooved surface with different injection orientation angles

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Peng Yang ◽  
Guangchao Li ◽  
Jianyong Zhu
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
Orientation Angle ◽  
Hole Injection ◽  
Blowing Ratio ◽  
Reverse Trend ◽  
Grooved Surface ◽  
Shaped Hole

AbstractThe film effectiveness was investigated on a grooved surface with the injection orientation angles of 30°, 90°, and 150° at the blowing ratios of 0.5, 0.8, 1.1, and 1.4. The injection orientation angle and the groove on the surface caused the effect of the various and irregular shaped hole injection due to the different orientation injection. The results showed that the new phenomenon of film effectiveness distributions was found on the grooved surface compared with the flat plate case. Film effectiveness distributions for the β = 30° were found to be the discontinuous strips. The surface averaged film effectiveness with the orientation angle of 30° was found to decrease with the increase of the blowing ratio. Additionally, the reverse trend was observed with the orientation angle of 150°. The film effectiveness with the orientation angle of 90° only slightly changed with the increase of the blowing ratio.

Influence of Coolant Density on Turbine Blade Film-Cooling With Compound-Angle Shaped Holes

2012 ◽  
Author(s):  
Kevin Liu ◽  
Shang-Feng Yang ◽  
Je-Chin Han
Keyword(s):  
Film Cooling ◽  
Momentum Flux ◽  
Density Ratio ◽  
Flux Ratio ◽  
Suction Side ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Shaped Hole ◽  
Compound Angle

Adiabatic film-cooling effectiveness is examined systematically on a typical high pressure turbine blade by varying three critical flow parameters: coolant blowing ratio, coolant-to-mainstream density ratio, and freestream turbulence intensity. Three average coolant blowing ratios 1.0, 1.5, and 2.0; three coolant density ratios 1.0, 1.5, and 2.0; two turbulence intensities 4.2% and 10.5%, are chosen for this study. Conduction-free pressure sensitive paint (PSP) technique is used to measure film-cooling effectiveness. Three foreign gases — N2 for low density, CO2 for medium density, and a mixture of SF6 and Argon for high density are selected to study the effect of coolant density. The test blade features 45° compound-angle shaped holes on the suction side and pressure side, and 3 rows of 30° radial-angle cylindrical holes around the leading edge region. The inlet and the exit Mach number are 0.27 and 0.44, respectively. Reynolds number based on the exit velocity and blade axial chord length is 750,000. Results reveal that the PSP is a powerful technique capable of producing clear and detailed film effectiveness contours with diverse foreign gases. As blowing ratio exceeds the optimum value, it induces more mixing of coolant and mainstream. Thus film-cooling effectiveness reduces. Greater coolant-to-mainstream density ratio results in lower coolant-to-mainstream momentum and prevents coolant to lift-off; as a result, film-cooling increases. Higher freestream turbulence causes effectiveness to drop everywhere except in the region downstream of suction side. Results are also correlated with momentum flux ratio and compared with previous studies. It shows that compound shaped hole has the greatest optimum momentum flux ratio, and then followed by axial shaped hole, compound cylindrical hole, and axial cylindrical hole.

The Effects of Axisymmetric Convergent Contouring and Blowing Ratio On Endwall Film Cooling and Vane Pressure Side Surface Phantom Cooling Performance

2021 ◽  
Author(s):  
Bo Bai ◽  
Zhigang Li ◽  
Jun Li ◽  
Shuo Mao ◽  
Wing Ng
Keyword(s):  
Numerical Method ◽  
Film Cooling ◽  
Side Surface ◽  
Operating Conditions ◽  
Constant Density ◽  
Pressure Side ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Endwall Film Cooling

Abstract In this paper, a detailed numerical investigation on the endwall film cooling and vane pressure side surface phantom cooling was performed, at the simulated realistic gas turbine operating conditions (high inlet freestream turbulence level of 16 %, exit Mach number of 0.85 and exit Reynolds number of 1.7×106). Based on a double coolant temperature model, a novel numerical method for the predictions of adiabatic wall film cooling effectiveness was proposed. This numerical method was validated by comparing the predicted results with experimental data of endwall Nusselt number, endwall film cooling effectiveness and near endwall flow visualization. The results indicate that the present numerical method can accurately predict endwall thermal load distributions and endwall film cooling distributions, and vane surface phantom cooling distributions. The endwall heat transfer coefficient, endwall film cooling effectiveness, phantom cooling effectiveness of the vane pressure side surface and total pressure loss coefficients (TPLC) were predicted and compared for two endwall contouring shapes (flat endwall and axisymmetric convergent contoured endwall) at three different blowing ratios (low blowing ratio of BR=1.0, design blowing ratio of BR=2.5 and high blowing ratio of BR=3.5) with a constant density ratio of DR=1.2, based on the present novel numerical method.

Theoretical Film Cooling Performance of Multi Trench Configurations on Flat Plate

2013 ◽  
Author(s):  
Antar M. M. Abdala ◽  
Qun Zheng ◽  
Fifi N. M. Elwekeel
Keyword(s):  
Film Cooling ◽  
Additional Benefit ◽  
The Other ◽  
Low Flow ◽  
Computational Simulations ◽  
Cooling Performance ◽  
Blowing Ratio ◽  
Ansys Cfx ◽  
Shaped Hole ◽  
Adiabatic Effectiveness

In the present work, computational simulations was made using ANSYS CFX to predict the improvements in film cooling performance with multi trench. Multi-trench configuration consists of two trenches together, one wider trench and the other is narrow trench that extruded from the wider one. Several blowing ratios in the range (0.5:5) were investigated. By using the multi trench configuration, the coolant jet impacted the trench wall two times allowing increasing the spreading of coolant laterally in the trench, reducing jet velocity and jet completely covered on the surface. The results indicate that this configuration increased adiabatic effectiveness as blowing ratio increased. No observed film blow-off at all blowing ratios. The adiabatic film effectiveness of multi trench case outperformed the narrow trench case, laidback fan-shaped hole, fan-shaped hole and cylinder hole at different blowing ratios. An additional benefit is the low flow rate will provide the same cooling effect by using multi trench configuration.

The Effects of Vane Showerhead Injection Angle and Film Compound Angle on Nozzle Endwall Cooling (Phantom Cooling)

2014 ◽  
Author(s):  
Luzeng Zhang ◽  
Juan Yin ◽  
Hee Koo Moon
Keyword(s):  
Film Cooling ◽  
Suction Side ◽  
Pressure Side ◽  
Nitrogen Gas ◽  
Injection Angle ◽  
Test Models ◽  
Cooling Effects ◽  
Film Cooling Holes ◽  
Compound Angle ◽  
Endwall Cooling

The effects of airfoil showerhead injection angle and film cooling hole compound angle on nozzle endwall cooling (second order film cooling effects, also called “phantom cooling”) was experimentally investigated in a scaled linear cascade. The test cascade was built based on a typical industrial gas turbine nozzle vane. Endwall surface phantom cooling film effectiveness measurements were made using a computerized pressure sensitive paint (PSP) technique. Nitrogen gas was used to simulate cooling flow as well as a tracer gas to indicate oxygen concentration such that film effectiveness can be obtained by the mass transfer analogy. Two separate nozzle test models were fabricated, which have the same number and size of film cooling holes but different configurations. One had a showerhead angle of 45° and no compound angles on the pressure and suction side film holes. The other had a 30° showerhead angle and 30° compound angles on the pressure and suction side film cooling holes. Nitrogen gas (cooling air) was fed through nozzle vanes, and measurements were conducted on the endwall surface between the two airfoils where no direct film cooling was applied. Six cooling mass flow ratios (MFRs, blowing ratios) were studied, and local (phantom) film effectiveness distributions were measured. Film effectiveness distributions were pitchwise averaged for comparison. Phantom cooling on the endwall by the suction side film injections was found to be insignificant, but the pressure side airfoil film injections noticeably helped the endwall cooling (phantom cooling) and was a strong function of the MFR. It was concluded that reducing the showerhead angle and introducing a compound angle on the pressure side injections would enhance the endwall surface phantom cooling, particularly for a higher MFR.

Experimental Investigation of Adiabatic Film Cooling Effectiveness Over a Circular Fan and Laidback Fan Shaped Hole Flat Plate Test Models

2015 ◽  
Author(s):  
Giridhara Babu Yepuri ◽  
Felix Jesuraj ◽  
Suresh Batchu ◽  
Kesavan Venkataraman
Keyword(s):  
Experimental Investigation ◽  
Flat Plate ◽  
Film Cooling ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Test Models ◽  
Plate Models ◽  
Shaped Hole ◽  
Hole Model

The experimental investigation of adiabatic film cooling effectiveness is carried out on a flat plates with 4:1 scaled up hole geometries, similar to that of typical turbine nozzle guide vane film cooling holes. Under this study, three flat plate models are considered with the two rows of holes having circular, fan and laidback fan shapes arranged in a staggered manner. These flat plate models are generated using solid works design software and fabricated using low thermal conductivity nylon based material using RPT technique. The mass flow results indicated the average nominal coefficient of discharge for the cooling holes as 0.71, for all these three models based on the inlet hole area and length of the holes. The laterally averaged adiabatic film cooling effectiveness is found along the stream wise direction at a density ratio of 1.62 by varying the blowing ratio in the range of 0.5 to 2.5. The surface temperatures of the test models are captured using the infrared camera, to evaluate the film cooling effectiveness. The experimentally evaluated results shows that, there is no increase in cooling effectiveness for the blowing ratio of 2.0 to 2.5 in the stream wise direction up to the X/d of 25 and there is a marginal increase above the X/d of 25 in the cases of these type of two row circular and Fan shaped hole models. Where as in the Laidback fan shaped hole model, the increase in cooling effectiveness is found significant up to the blowing ratio of 2.5 in the considered range. From the comparative results of adiabatic film cooling effectiveness of these three models, the laidback fan shaped hole model shows the higher film cooling effectiveness than the circular and fan shaped holes model at all the considered blowing ratios.

Film Cooling Effectiveness Downstream of Compound and Fan-Shaped Holes

2001 ◽  
Author(s):  
C. H. N. Yuen ◽  
R. F. Martinez-Botas ◽  
J. H. Whitelaw
Keyword(s):  
Film Cooling ◽  
Diameter Ratio ◽  
Co2 Injection ◽  
Cylindrical Shape ◽  
Cooling Effectiveness ◽  
Detailed Measurement ◽  
Blowing Ratio ◽  
Fluid Mass ◽  
Shaped Hole ◽  
Compound Angle

The steady-state wide band liquid crystal technique is used to study the film cooling performance downstream of a variety of geometries in a flat plate. This technique provides a detailed measurement of both cooling effectiveness and heat transfer coefficient. This paper presents the effects of compound and fan–shaped holes, the effect of streamwise angle variation has been presented at previous meetings. The following configurations are investigated: a single hole, a row of holes with a pitch-to-diameter ratio, p/D, of 3, two inline rows with p/D of 3 and two staggered rows with p/D of 6; all with a stream–wise angle of 30°. The spacing between two rows was chosen as 12.4D. Two lateral injection are investigated: 30° and 60° compound angle. The fan shaped hole used comprised of a lateral expansion of 14° from the original simple cylindrical shape with streamwise inclination of 30°; forward expansion was not incorporated. The length-to-diameter ratio, L/D, was maintained at a value of 4 for all the compound cases, the L/D for the fan shaped-hole was 6, larger due to its physical limitation. The tests were performed with a jet-to-freestream density ratio of 1.5; achieved by using a foreign gas (CO2) injection. The range of momentum flux ratios (M) covered was 0.33 to 1.67. The row of 30° compound angle holes gave a lower value of effectiveness when compared to the non-compound case at M<0.67, but greater values and coverage at M>1.0, consistent with previous experiments. The row of 60° compound angle gave greater effectiveness, coverage and uniformity than the row of 30° compound at a given blowing ratio; the jet-to-jet interaction was greater for the 60° row due to the added lateral momentum. The row of 60° compound gave an increase of order 100% relative to the non-compounded row for M>1. Two inline rows of fan-shape holes delivered less effectiveness than the corresponding single row at the same spanwise distance for a given jet fluid mass, or blowing ratio with twice the jet fluid mass. For equal blowing ratios and equal flow rates the fan-shaped hole gave a much higher effectiveness.

The Effects of Injection Angle and Hole Exit Shape on Turbine Nozzle Pressure Side Film Cooling

2000 ◽  
Author(s):  
Luzeng J. Zhang ◽  
Ram Pudupatty
Keyword(s):  
Oxygen Concentration ◽  
Film Cooling ◽  
Hole Injection ◽  
Pressure Side ◽  
Pressure Sensitive Paint ◽  
Airfoil Surface ◽  
Film Cooling Effectiveness ◽  
Injection Angle ◽  
Pressure Sensitive ◽  
Shaped Hole

Using the pressure sensitive paint (PSP) technique, film cooling effectiveness was measured on a turbine vane pressure surface, with a four-row showerhead cooling hole configuration and a single row of holes on the pressure side. Nitrogen gas was used to simulate film cooling flow providing an oxygen concentration map corresponding to an effectiveness map by the mass transfer analogy. Three showerhead coolant injection angles (45°, 90°, and 135°) were studied and two pressure side injection angles (20° and 40°) for cylindrical holes and a 40° angle for shaped hole were studied. In addition, studies were performed on three combinations of shower head and pressure side injections. Film effectiveness was measured for each of the cases at three blowing ratios. The pressure sensitive paint (PSP) was used to indicate oxygen concentration and was calibrated at various temperatures and pressures to obtain better accuracy before being applied to the airfoil surface. The results indicate that 45° spanwise angle injection provides best film coverage for the shower head injections. For pressure side injections, the 20° cylindrical hole injection results in the highest effectiveness values and the shaped hole improves film effectiveness immediately downstream from the injection point. The film effectiveness for three combined injections and the interaction between showerhead injection and the pressure side injection are also presented and discussed.

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