Turbine vane endwall film cooling with barchan-dune shaped ramp in a single-passage transonic wind tunnel

2020 ◽  
Vol 162 ◽  
pp. 120350
Author(s):  
Wenwu Zhou ◽  
Mohamed Qenawy ◽  
Hongyi Shao ◽  
Di Peng ◽  
Xin Wen ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Film Cooling ◽  
Single Passage ◽  
Barchan Dune ◽  
Turbine Vane ◽  
Endwall Film Cooling ◽  
Transonic Wind Tunnel

A Novel Single-Passage Transonic Wind Tunnel for Turbine-Vane Film Cooling

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Mohamed Qenawy ◽  
Lin Yuan ◽  
Yingzheng Liu ◽  
Di Peng ◽  
Xin Wen ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Film Cooling ◽  
Three Dimensional ◽  
Fast Response ◽  
Low Flow ◽  
Wind Tunnels ◽  
Single Passage ◽  
Turbine Vane ◽  
Response Pressure ◽  
Transonic Wind Tunnel

Abstract Wind-tunnel testing of turbines cascade is an important technique for quantifying the realistic conditions of turbine-vane film cooling. However, the complex and expensive facilities needed for the multipassage design of such wind tunnels have prompted the introduction of the single-passage design strategy. In this contribution, detailed procedures for building a novel single-passage transonic wind-tunnel using additive manufacturing are presented. In addition, the detailed flow structure caused by the passage was investigated. The proposed design was evaluated step-by-step using an integrated model that successively comprised two-dimensional (2D) periodic passage simulation, 2D single-passage simulation, three-dimensional (3D) single-passage simulation, construction, and testing. The proposed design was found to achieve flow periodicity at transonic flow conditions with relatively low-flow consumption. The results were validated by comparison to the available literature data. In addition, an endwall-cooling configuration was successfully deployed using fast-response pressure-sensitive paint (fast-PSP). This study, combined with the help of commercial software and 3D printing, shed light upon strategies for time- and cost-reduction in linear cascade design, which could benefit the turbomachinery community.

Turbine vane endwall film cooling from mid-chord or downstream rows and upstream coolant injection

2019 ◽  
Vol 133 ◽  
pp. 247-255 ◽  
Author(s):  
Nian Wang ◽  
Chao-Cheng Shiau ◽  
Je-Chin Han ◽  
Hongzhou Xu ◽  
Michael Fox
Keyword(s):  
Film Cooling ◽  
Coolant Injection ◽  
Turbine Vane ◽  
Endwall Film Cooling

Application of a CFD-Based Film Cooling Model to a Gas Turbine Vane Cascade With Cylindrical and Shaped Hole Endwall Film Cooling

2011 ◽  
Author(s):  
Tilman auf dem Kampe ◽  
Stefan Vo¨lker
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Cooling Flows ◽  
Turbine Vane ◽  
Mesh Resolution ◽  
Shaped Hole ◽  
Node Count ◽  
Endwall Film Cooling ◽  
Cooling Model ◽  
Near Wall

This paper presents the application of a CFD-based film cooling model to a gas turbine vane cascade test rig. The experimental investigations feature aerodynamic and endwall film cooling measurements on a first stage gas turbine vane in a linear cascade. An extended version of a previously developed cylindrical hole film cooling model has been employed, which now includes modeling of shaped hole cooling flows. The computational domain extends approximately one axial chord length upstream of the leading edge and downstream of the trailing edge of the vane. Adjacent solid parts are included by means of a conjugate heat transfer analysis to account for conduction effects. A hybrid mesh with resolved boundary layers and high spatial mesh resolution in the near-wall region is being used. This meshing approach ensures that the near-wall mesh resolution requirements of the film cooling model are satisfied, while maintaining a manageable total node count. Results obtained using the film cooling model are compared to surface distributions of film cooling effectiveness from the experimental cascade. Due to the moderate node count (≈ 3.5 × 106), CFD calculations including film cooling flows can be performed at comparatively low computational cost. The film cooling model, which previously had been validated against flat plate measurement data and applied to single cooling hole configurations only, is therefore shown to be a viable tool for the thermal design of gas turbine components with film cooling.

Design of Full-Scale Endwall Film Cooling of a Turbine Vane

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Jian Liu ◽  
Wei Du ◽  
Guohua Zhang ◽  
Safeer Hussain ◽  
Lei Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Film Cooling ◽  
Pressure Coefficient ◽  
Pressure Side ◽  
Junction Region ◽  
Film Cooling Effectiveness ◽  
Coefficient Distribution ◽  
Turbine Vane ◽  
Endwall Film Cooling ◽  
Film Cooling Holes

Abstract Endwall film cooling is a significant cooling method to protect the endwall region and the junction region of endwall and a turbine vane, where usually a relatively high temperature load exists. This work aims to find the optimized arrangement of film cooling holes on the endwall and improve the film cooling in some difficult regions on the endwall, such as pressure side-endwall junction region. Several ideas for film cooling hole arrangement design are proposed, based on the pressure coefficient distribution, the streamline distribution, and the heat transfer coefficient (HTC) distribution, respectively. Four specified designs are built and compared. The results are obtained by numerical calculations with a well-validated turbulence model, the k–ω shear stress transport (SST) model. From this work, the designs based on the pressure coefficient distribution (designs 1 and 2) force the flow from the pressure side to the suction side (SS), especially in design 2, which adopts compound angle holes. The designs based on pressure coefficients have benefit in the cooling of the SS but give worse coolant coverage on the pressure side. In addition, designs 1 and 2 have little influence on the original pressure field. The design based on the streamline distributions (design 3) has larger coolant coverage on the endwall and provides good coolant coverage on the endwall and pressure side junction region. The design based on the HTC distribution provides large overall film cooling effectiveness on both the pressure side and the SS. More film cooling holes are placed on the high temperature regions, which is more effective in practice.

Turbine Vane Endwall Film Cooling Effectiveness of Different Purge Slot Configurations in a Linear Cascade

2019 ◽  
Author(s):  
Gunther Müller ◽  
Christian Landfester ◽  
Martin Böhle ◽  
Robert Krewinkel
Keyword(s):  
Film Cooling ◽  
Density Ratio ◽  
Region Of Interest ◽  
Experimental Tests ◽  
Secondary Flows ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Turbine Vane ◽  
Density Ratios ◽  
Endwall Film Cooling

Abstract This study is concerned with the film cooling effectiveness of the flow issuing from the gap between the NGV and the transition duct on the NGV endwall, i.e. the purge slot. Different slot widths, positions and injection angles were examined in order to represent changes due to thermal expansion as well as design modifications. Apart from these geometric variations, different blowing ratios (BR) and density ratios (DR) were realized to investigate the effects of the interaction between secondary flow and film cooling effectiveness. The experimental tests were performed in a linear scale-1 cascade equipped with four highly loaded turbine vanes at the Institute of Fluid Mechanics and Fluid Machinery of the University of Kaiserslautern. The mainstream flow parameters were, with a Reynolds number of 300,000 and a Mach number (outlet) of 0.6, set to meet real engine conditions. By using various flow conditioners, periodic flow was obtained in the region of interest (ROI). The adiabatic film cooling effectiveness was determined by using the Pressure Sensitive Paint (PSP) technique. In this context, nitrogen and carbon dioxide were used as tracer gases realizing two different density ratios DR = 1.0 and 1.6. The investigation was conducted for a broad range of blowing ratios with 0.25 ≤ BR ≤ 1.50. In combination with 10 geometry variations and the aforementioned blowing and density ratio variations 100 single operating points were investigated. For a better understanding of the coolant distribution, the secondary flows on the endwall were visualized by oil dye. The measurement results will be discussed based on the areal distribution of film cooling effectiveness, its lateral spanwise as well as its area average. The results will provide a better insight into various parametric effects of gap variations on turbine vane endwall film cooling performance — notably under realistic engine conditions.

Transonic Turbine Vane Endwall Film Cooling Using PSP Measurement Technique

2019 ◽  
Author(s):  
Chao-Cheng Shiau ◽  
Izzet Sahin ◽  
Izhar Ullah ◽  
Je-Chin Han ◽  
Alexander V. Mirzamoghadam ◽  
...  
Keyword(s):  
Shock Wave ◽  
Film Cooling ◽  
Density Ratio ◽  
Cross Flow ◽  
Flow Conditions ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Cooling Flow ◽  
Turbine Vane ◽  
Endwall Film Cooling

Abstract This work focuses on the parametric study of film cooling effectiveness on turbine vane endwall under various flow conditions. The experiments were performed in a five-vane annular sector cascade facility in a blowdown wind tunnel. The controlled exit isentropic Mach numbers were 0.7, 0.9, and 1.0, from high subsonic to transonic conditions. The freestream turbulence intensity is estimated to be 12%. Three coolant-to-mainstream mass flow ratios (MFR) in the range 0.75%, 1.0%, and 1.25% are studied. N2, CO2, and Argon/SF6 mixture were used to investigate the effects of density ratio (DR), ranging from 1.0, 1.5 to 2.0. There are 8 cylindrical holes on the endwall inside the passage. Pressure-sensitive paint (PSP) technique was used to capture the endwall pressure distribution for shock wave visualization and obtain the detailed film cooling effectiveness distributions. Both the high-fidelity effectiveness contour and the laterally (spanwise) averaged effectiveness were measured to quantify the parametric effect. This study will provide the gas turbine designer more insight on how the endwall film cooling effectiveness varies with different cooling flow conditions including shock wave through the endwall cross-flow passage.

Turbine Vane Endwall Film Cooling Effectiveness of Different Purge Slot Configurations in a Linear Cascade

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Gunther Müller ◽  
Christian Landfester ◽  
Martin Böhle ◽  
Robert Krewinkel
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Density Ratio ◽  
Experimental Tests ◽  
Secondary Flows ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Turbine Vane ◽  
Density Ratios ◽  
Endwall Film Cooling

Abstract This study is concerned with the film cooling effectiveness of the flow issuing from the gap between the nozzle guide vane (NGV) and the transition duct on the NGV endwall, i.e., the purge slot. Different slot widths, positions, and injection angles were examined in order to represent changes due to thermal expansion as well as design modifications. Apart from these geometric variations, different blowing ratios (BRs) and density ratios (DRs) were realized to investigate the effects of the interaction between secondary flow and film cooling effectiveness. The experimental tests were performed in a linear scale-1 cascade equipped with four highly loaded turbine vanes at the Institute of Fluid Mechanics and Fluid Machinery of the University of Kaiserslautern. The mainstream flow parameters were, with a Reynolds number of 300,000 and a Mach number (outlet) of 0.6, set to meet real engine conditions. By using various flow conditioners, periodic flow was obtained in the region of interest (ROI). The adiabatic film cooling effectiveness was determined using the pressure sensitive paint (PSP) technique. In this context, nitrogen and carbon dioxide were used as tracer gases realizing two different density ratios DR = 1.0 and 1.6. The investigation was conducted for a broad range of blowing ratios with 0.25 ≤ BR ≤ 1.50. In combination with 10 geometry variations and the aforementioned blowing and density ratio variations, 100 single operating points were investigated. For a better understanding of the coolant distribution, the secondary flows on the endwall were visualized by oil dye. The measurement results will be discussed based on the areal distribution of film cooling effectiveness, its lateral spanwise, as well as its area average. The results will provide a better insight into various parametric effects of gap variations on turbine vane endwall film cooling performance—notably under realistic engine conditions.

Effect of Midpassage Gap, Endwall Misalignment, and Roughness on Endwall Film-Cooling

2005 ◽  
Vol 128 (1) ◽  
pp. 62-70 ◽  
Author(s):  
N. D. Cardwell ◽  
N. Sundaram ◽  
K. A. Thole
Keyword(s):  
Film Cooling ◽  
Large Scale ◽  
Suction Side ◽  
Engine Operation ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Severe Reduction ◽  
Turbine Vane ◽  
Endwall Film Cooling ◽  
High Pressure Coolant

To maintain acceptable turbine airfoil temperatures, film cooling is typically used whereby coolant, extracted from the compressor, is injected through component surfaces. In manufacturing a turbine, the first stage vanes are cast in either single airfoils or double airfoils. As the engine is assembled, these singlets or doublets are placed in a turbine disk in which there are inherent gaps between the airfoils. The turbine is designed to allow outflow of high-pressure coolant rather than hot gas ingestion. Moreover, it is quite possible that the singlets or doublets become misaligned during engine operation. It has also become of interest to the turbine community as to the effect of corrosion and deposition of particles on component heat transfer. This study uses a large-scale turbine vane in which the following two effects are investigated: the effect of a midpassage gap on endwall film cooling and the effect of roughness on endwall film cooling. The results indicate that the midpassage gap was found to have a significant effect on the coolant exiting from the combustor-turbine interface slot. When the gap is misaligned, the results indicate a severe reduction in the film-cooling effectiveness in the case where the pressure side endwall is below the endwall associated with the suction side of the adjacent vane.

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