Jin Wu, Li Zhang, Lijian Cheng, R. Jiang, Zhong-yi Fu, Hui-ren Zhu
This paper researches on the effects of Reynolds number and mass flow ratio on the film cooling characteristics at high turbulence intensity (Tu = 15%). The experiment adopted an actual three-dimensional twisted vane and presents the film cooling characteristics on full-coverage film surface in a two-passage, linear cascade. The cooling effectiveness and heat transfer coefficient of the vane’s whole surface were obtained by using transient liquid crystal measurement technique. The transient liquid crystal is SPN/R35C1W, whose bandwidth is 2°C. There are fifteen rows of film cooling holes which have different diameter, injection angle and yaw angle. The secondary flow was supplied by two cavities. The front cavity supplied the secondary flow to thirteen rows of film cooling holes that were arranged in the suction surface, the leading edge and the front half of the pressure surface. The rear cavity supplied the secondary flow to the rear half of pressure surface which included two rows of film cooling holes. The investigated parameters are Reynolds number of 1 × 105, 1.3 × 105 and 1.6 × 105 and the mass flow ratio of MFR = 5.5%∼12.5% (6 cases). The data recorded in the experiment was analyzed with MATLAB. Results show that the combined effects of mass flow ratio and channel vortex are the maintain reasons that influence the distribution of cooling effectiveness in the contour. Increasing the mass flow ratio can improve the film cooling effectiveness on leading edge and pressure surface, while that presents complex rule on suction surface. Increasing the Reynolds number can improve the heat transfer coefficient at the same mass flow ratio. When increasing the mass flow ratio, the heat transfer coefficient increases on leading edge and pressure surface at Re = 1.6 × 105. However, the decreases at film hole outlet region on the suction side, and not obviously changes at the film hole downstream region.
{"title":"An Experimental Investigation of Full-Coverage Film Cooling Characteristics of a Turbine Guide Vane","authors":"Jin Wu, Li Zhang, Lijian Cheng, R. Jiang, Zhong-yi Fu, Hui-ren Zhu","doi":"10.1115/GT2018-76088","DOIUrl":"https://doi.org/10.1115/GT2018-76088","url":null,"abstract":"This paper researches on the effects of Reynolds number and mass flow ratio on the film cooling characteristics at high turbulence intensity (Tu = 15%). The experiment adopted an actual three-dimensional twisted vane and presents the film cooling characteristics on full-coverage film surface in a two-passage, linear cascade. The cooling effectiveness and heat transfer coefficient of the vane’s whole surface were obtained by using transient liquid crystal measurement technique. The transient liquid crystal is SPN/R35C1W, whose bandwidth is 2°C. There are fifteen rows of film cooling holes which have different diameter, injection angle and yaw angle. The secondary flow was supplied by two cavities. The front cavity supplied the secondary flow to thirteen rows of film cooling holes that were arranged in the suction surface, the leading edge and the front half of the pressure surface. The rear cavity supplied the secondary flow to the rear half of pressure surface which included two rows of film cooling holes. The investigated parameters are Reynolds number of 1 × 105, 1.3 × 105 and 1.6 × 105 and the mass flow ratio of MFR = 5.5%∼12.5% (6 cases). The data recorded in the experiment was analyzed with MATLAB.\u0000 Results show that the combined effects of mass flow ratio and channel vortex are the maintain reasons that influence the distribution of cooling effectiveness in the contour. Increasing the mass flow ratio can improve the film cooling effectiveness on leading edge and pressure surface, while that presents complex rule on suction surface. Increasing the Reynolds number can improve the heat transfer coefficient at the same mass flow ratio. When increasing the mass flow ratio, the heat transfer coefficient increases on leading edge and pressure surface at Re = 1.6 × 105. However, the decreases at film hole outlet region on the suction side, and not obviously changes at the film hole downstream region.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125806502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Barigozzi, S. Mosconi, A. Perdichizzi, L. Abba, S. Vagnoli
The present paper reports on an experimental investigation carried out at Bergamo University Energy system and turbomachinery laboratory aiming to assess the aerodynamic and heat transfer performance of a high pressure nozzle vane cascade without and with platform cooling. Information collected from solid vane testing was used to design a first platform cooling scheme made of cylindrical holes. The cooling scheme was first aerodynamically tested to quantify its impact on secondary flows and related losses for variable injection condition. Heat transfer performances were then assessed through the measurement of the adiabatic film cooling effectiveness and of the convective heat transfer coefficient. From these data, the Net Heat Flux Reduction (NHFR) parameter was computed to critically assess the cooling scheme. The collected data set is significant for the design process, as it is useful for CFD validation and for the setting up of correlations. In particular, a MFR = 0.7% resulted to be the best injection condition for this geometry, being a compromise between aerodynamic loss augmentation, a good thermal protection inside of the passage and a limited heat load increase to the end wall.
{"title":"Aerodynamic and Heat Transfer Experimental Investigation of Platform Cooling on a HP Nozzle Vane Cascade","authors":"G. Barigozzi, S. Mosconi, A. Perdichizzi, L. Abba, S. Vagnoli","doi":"10.1115/GT2018-75038","DOIUrl":"https://doi.org/10.1115/GT2018-75038","url":null,"abstract":"The present paper reports on an experimental investigation carried out at Bergamo University Energy system and turbomachinery laboratory aiming to assess the aerodynamic and heat transfer performance of a high pressure nozzle vane cascade without and with platform cooling. Information collected from solid vane testing was used to design a first platform cooling scheme made of cylindrical holes. The cooling scheme was first aerodynamically tested to quantify its impact on secondary flows and related losses for variable injection condition. Heat transfer performances were then assessed through the measurement of the adiabatic film cooling effectiveness and of the convective heat transfer coefficient. From these data, the Net Heat Flux Reduction (NHFR) parameter was computed to critically assess the cooling scheme. The collected data set is significant for the design process, as it is useful for CFD validation and for the setting up of correlations. In particular, a MFR = 0.7% resulted to be the best injection condition for this geometry, being a compromise between aerodynamic loss augmentation, a good thermal protection inside of the passage and a limited heat load increase to the end wall.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114174451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Kyrylash, V. Kostiuk, A. Smirnov, D. Tkachenko, Igor Loboda
The paper is devoted to the use of mathematical simulation to investigate the possibilities of ensuring the admissible thermal mode of gas turbine packages equipped with aircraft and marine derivative gas turbine engines. The method proposed for complex heat transfer simulation in the gas turbine packages includes some models. A generalized mathematical model is formed to describe the thermophysical processes taking place in the gas turbine packages. A particular mathematical model of gas turbine engine casing heat transfer and a method to correct the boundary conditions are also developed. These models have been validated with the data collected from the heat transfer measurements in simple objects and from full-scale tests of turbo-compressor units. The proposed method of complex heat transfer simulation has been used to evaluate a temperature state of the gas turbine packages, in particular to ensure the effectiveness of covering the engine casing by thermal insulation.
{"title":"Mathematical Simulation of the Gas Turbine Packages Thermal State","authors":"O. Kyrylash, V. Kostiuk, A. Smirnov, D. Tkachenko, Igor Loboda","doi":"10.1115/GT2018-77194","DOIUrl":"https://doi.org/10.1115/GT2018-77194","url":null,"abstract":"The paper is devoted to the use of mathematical simulation to investigate the possibilities of ensuring the admissible thermal mode of gas turbine packages equipped with aircraft and marine derivative gas turbine engines. The method proposed for complex heat transfer simulation in the gas turbine packages includes some models. A generalized mathematical model is formed to describe the thermophysical processes taking place in the gas turbine packages. A particular mathematical model of gas turbine engine casing heat transfer and a method to correct the boundary conditions are also developed. These models have been validated with the data collected from the heat transfer measurements in simple objects and from full-scale tests of turbo-compressor units. The proposed method of complex heat transfer simulation has been used to evaluate a temperature state of the gas turbine packages, in particular to ensure the effectiveness of covering the engine casing by thermal insulation.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128147616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuewen Jiang, Niharika Gurram, E. Romero, P. Ireland, L. Mare
Slot film cooling is a popular choice for trailing edge cooling in high pressure (HP) turbine blades because it can provide more uniform film coverage compared to discrete film cooling holes. The slot geometry consists of a cut back in the blade pressure side connected through rectangular openings to the internal coolant feed passage. The numerical simulation of this kind of film cooling flows is challenging due to the presence of flow interactions like step flow separation, coolant-mainstream mixing and heat transfer. The geometry under consideration is a cutback surface at the trailing edge of a constant cross-section aerofoil. The cutback surface is divided into three sections separated by narrow lands. The experiments are conducted in a high speed cascade in Oxford Osney Thermo-Fluids Laboratory at Reynolds and Mach number distributions representative of engine conditions. The capability of CFD methods to capture these flow phenomena is investigated in this paper. The isentropic Mach number and film effectiveness are compared between CFD and pressure sensitive paint (PSP) data. Compared to steady k–ω SST method, Scale Adaptive Simulation (SAS) can agree better with the measurement. Furthermore, the profiles of kinetic energy, production and shear stress obtained by the steady and SAS methods are compared to identify the main source of inaccuracy in RANS simulations. The SAS method is better to capture the unsteady coolant-hot gas mixing and vortex shedding at the slot lip. The cross flow is found to affect the film significantly as it triggers flow separation near the lands and reduces the effectiveness. The film is non-symmetric with respect to the half-span plane and different flow features are present in each slot. The effect of mass flow ratio (MFR) on flow pattern and coolant distribution is also studied. The profiles of velocity, kinetic energy and production of turbulent energy are compared among the slots in detail. The MFR not only affects the magnitude but also changes the sign of production.
{"title":"CFD Investigation of the Flow of Trailing Edge Cooling Slots","authors":"Yuewen Jiang, Niharika Gurram, E. Romero, P. Ireland, L. Mare","doi":"10.1115/GT2018-75906","DOIUrl":"https://doi.org/10.1115/GT2018-75906","url":null,"abstract":"Slot film cooling is a popular choice for trailing edge cooling in high pressure (HP) turbine blades because it can provide more uniform film coverage compared to discrete film cooling holes. The slot geometry consists of a cut back in the blade pressure side connected through rectangular openings to the internal coolant feed passage. The numerical simulation of this kind of film cooling flows is challenging due to the presence of flow interactions like step flow separation, coolant-mainstream mixing and heat transfer.\u0000 The geometry under consideration is a cutback surface at the trailing edge of a constant cross-section aerofoil. The cutback surface is divided into three sections separated by narrow lands. The experiments are conducted in a high speed cascade in Oxford Osney Thermo-Fluids Laboratory at Reynolds and Mach number distributions representative of engine conditions. The capability of CFD methods to capture these flow phenomena is investigated in this paper. The isentropic Mach number and film effectiveness are compared between CFD and pressure sensitive paint (PSP) data. Compared to steady k–ω SST method, Scale Adaptive Simulation (SAS) can agree better with the measurement. Furthermore, the profiles of kinetic energy, production and shear stress obtained by the steady and SAS methods are compared to identify the main source of inaccuracy in RANS simulations. The SAS method is better to capture the unsteady coolant-hot gas mixing and vortex shedding at the slot lip.\u0000 The cross flow is found to affect the film significantly as it triggers flow separation near the lands and reduces the effectiveness. The film is non-symmetric with respect to the half-span plane and different flow features are present in each slot. The effect of mass flow ratio (MFR) on flow pattern and coolant distribution is also studied. The profiles of velocity, kinetic energy and production of turbulent energy are compared among the slots in detail. The MFR not only affects the magnitude but also changes the sign of production.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128886293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Film cooling holes are a well-established cooling technique used in gas turbines to keep component metal temperatures in an acceptable range. A streamwise-oriented film cooling hole creates a symmetric counter-rotating vortex pair (CRVP) due to the jet interaction with the crossflow. As the orientation of the film cooling hole is incrementally misaligned with the streamwise direction (known as a compound angle), one of the vortices in the CRVP gains strength at the expense of the other until there is a single streamwise vortex that dominates the flowfield. This vortex diffuses the coolant jet and impinges hot gas onto the surface, which can augment heat transfer coefficients in a region uncovered by coolant. Although this has been well studied for cylindrical holes, there is less understanding about the nature of this phenomenon for shaped holes, which are intended to diffuse coolant laterally to minimize flowfield interaction. In the present study, particle image velocimetry (PIV) was used to measure the flowfield of compound angled shaped film cooling holes at several downstream planes normal to the streamwise direction. Five compound angled 7-7-7 holes were tested, from a streamwise oriented hole (0° compound angle) to a 60° compound angle hole, in increments of 15°. All cases were tested at a density ratio of 1.0 and blowing ratios ranging from 1.0 to 4.0. Experimental data shows that the circulation increases as compound angle increases because the flowfield transitions from a CRVP to a single streamwise vortex. For large compound angles, the streamwise vortex lifts the core of the jet off of the surface, isolating the coolant from the endwall. Measurements also indicate hole-to-hole interaction downstream for cases with high blowing ratio and large compound angle. Flowfield results are compared with adiabatic effectiveness results from a companion study in order to explain hole-to-hole interaction trends.
{"title":"Flowfield of a Shaped Film Cooling Hole Over a Range of Compound Angles","authors":"Shane Haydt, S. Lynch","doi":"10.1115/GT2018-75728","DOIUrl":"https://doi.org/10.1115/GT2018-75728","url":null,"abstract":"Film cooling holes are a well-established cooling technique used in gas turbines to keep component metal temperatures in an acceptable range. A streamwise-oriented film cooling hole creates a symmetric counter-rotating vortex pair (CRVP) due to the jet interaction with the crossflow. As the orientation of the film cooling hole is incrementally misaligned with the streamwise direction (known as a compound angle), one of the vortices in the CRVP gains strength at the expense of the other until there is a single streamwise vortex that dominates the flowfield. This vortex diffuses the coolant jet and impinges hot gas onto the surface, which can augment heat transfer coefficients in a region uncovered by coolant. Although this has been well studied for cylindrical holes, there is less understanding about the nature of this phenomenon for shaped holes, which are intended to diffuse coolant laterally to minimize flowfield interaction. In the present study, particle image velocimetry (PIV) was used to measure the flowfield of compound angled shaped film cooling holes at several downstream planes normal to the streamwise direction. Five compound angled 7-7-7 holes were tested, from a streamwise oriented hole (0° compound angle) to a 60° compound angle hole, in increments of 15°. All cases were tested at a density ratio of 1.0 and blowing ratios ranging from 1.0 to 4.0. Experimental data shows that the circulation increases as compound angle increases because the flowfield transitions from a CRVP to a single streamwise vortex. For large compound angles, the streamwise vortex lifts the core of the jet off of the surface, isolating the coolant from the endwall. Measurements also indicate hole-to-hole interaction downstream for cases with high blowing ratio and large compound angle. Flowfield results are compared with adiabatic effectiveness results from a companion study in order to explain hole-to-hole interaction trends.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"355 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124052494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Impingement jet cooling is a promising cooling method in modern dry low emission combustor because of its high local heat transfer coefficient. This paper investigates the recent research progress on impingement jet cooling in combustor liner. Firstly, the different flow characteristics in the different impingement jet flow regions are described. Then, the factors influencing impingement jet cooling are discussed, including flow factor and geometry factor. The researches in a large range of flow parameters, including Reynolds number, Mach number and temperature ratio, are reported. The researches in different geometry parameters, such as nozzle geometry, nozzle-to-nozzle spacing, nozzle-to-target distance and inclined angle, are presented. Next, the crossflow effect in array impingement jet is considered. Due to the crossflow decreases the heat transfer performance, varieties of structures which can restrict the crossflow and improve the channel flow are introduced. Finally, the methods to enhance the impingement jet cooling are presented. These methods focus on retrofitting the nozzle and target surface. The combination of impingement jet cooling with other methods, such as effusion cooling, rib roughened surface, is important development direction in combustor liner in the future.
{"title":"A Review of Impingement Jet Cooling in Combustor Liner","authors":"Rong-rong Xie, Hao Wang, Baopeng Xu, Wei Wang","doi":"10.1115/GT2018-76335","DOIUrl":"https://doi.org/10.1115/GT2018-76335","url":null,"abstract":"Impingement jet cooling is a promising cooling method in modern dry low emission combustor because of its high local heat transfer coefficient. This paper investigates the recent research progress on impingement jet cooling in combustor liner. Firstly, the different flow characteristics in the different impingement jet flow regions are described. Then, the factors influencing impingement jet cooling are discussed, including flow factor and geometry factor. The researches in a large range of flow parameters, including Reynolds number, Mach number and temperature ratio, are reported. The researches in different geometry parameters, such as nozzle geometry, nozzle-to-nozzle spacing, nozzle-to-target distance and inclined angle, are presented. Next, the crossflow effect in array impingement jet is considered. Due to the crossflow decreases the heat transfer performance, varieties of structures which can restrict the crossflow and improve the channel flow are introduced. Finally, the methods to enhance the impingement jet cooling are presented. These methods focus on retrofitting the nozzle and target surface. The combination of impingement jet cooling with other methods, such as effusion cooling, rib roughened surface, is important development direction in combustor liner in the future.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114230960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years computational fluid dynamics (CFD) is substantially employed in the design process of gas turbines. To increase the performance of the turbines an efficient cooling system design is essential. This is largely dependent on the accuracy of the predicted temperature at the exit of the combustor. Lack of accuracy of the predicted temperature at the combustor-turbine interface results in using large safety factors which affect the performance negatively. It is believed that the RANS methods are incapable of predicting the mixing process in highly swirling flows in the combustors. In this study the flow in a none-reactive model combustor simulator is investigated numerically using RANS, SAS and LES turbulence models in ANSYS CFX code. The model combustor consists of three swirling mixers through which the hot air passes. The cold air that goes through many small effusion holes of the outer and inner liners mixes up with the swirling hot air. The computational domain however consists only of one sector and periodic boundary condition is applied in the circumferential direction. The numerical results are compared with the experimental results that are provided by the University of Florence as part of the European FACTOR project. It is confirmed that the RANS or URANS methods are not capable of reproducing the experimental results.
{"title":"Numerical Investigation of Fluid Flow Parameters in a Combustor Simulator","authors":"D. G. Barhaghi, Lars Hedlund","doi":"10.1115/GT2018-75018","DOIUrl":"https://doi.org/10.1115/GT2018-75018","url":null,"abstract":"In recent years computational fluid dynamics (CFD) is substantially employed in the design process of gas turbines. To increase the performance of the turbines an efficient cooling system design is essential. This is largely dependent on the accuracy of the predicted temperature at the exit of the combustor. Lack of accuracy of the predicted temperature at the combustor-turbine interface results in using large safety factors which affect the performance negatively.\u0000 It is believed that the RANS methods are incapable of predicting the mixing process in highly swirling flows in the combustors. In this study the flow in a none-reactive model combustor simulator is investigated numerically using RANS, SAS and LES turbulence models in ANSYS CFX code. The model combustor consists of three swirling mixers through which the hot air passes. The cold air that goes through many small effusion holes of the outer and inner liners mixes up with the swirling hot air. The computational domain however consists only of one sector and periodic boundary condition is applied in the circumferential direction.\u0000 The numerical results are compared with the experimental results that are provided by the University of Florence as part of the European FACTOR project. It is confirmed that the RANS or URANS methods are not capable of reproducing the experimental results.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"200 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121674613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heat transfer of the counter-inclined cylindrical and laid-back holes with and without impingement on the turbine vane leading edge model are investigated in this paper. To obtain the film cooling effectiveness and heat transfer coefficient, transient temperature measurement technique on complete surface based on double thermochromic liquid crystals is used in this research. A semi-cylinder model is used to model the vane leading edge which is arranged with two rows of holes. Four test models are measured under four blowing ratios including cylindrical film holes with and without impingement tube structure, laid-back film holes with and without impingement tube structure. This is the second part of a two-part paper, the first part paper GT2018-76061 focuses on film cooling effectiveness and this study will focus on heat transfer. Contours of surface heat transfer coefficient and laterally averaged result are presented in this paper. The result shows that the heat transfer coefficient on the surface of the leading edge is enhanced with the increase of blowing ratio for same structure. The shape of the high heat transfer coefficient region gradually inclines to span-wise direction as the blowing ratio increases. Heat transfer coefficient in the region where the jet core flows through is relatively lower, while in the jet edge region the heat transfer coefficient is relatively higher. Compared with cylindrical hole, laid-back holes give higher heat transfer coefficient. Meanwhile, the introduction of impingement also makes heat transfer coefficient higher compared with cross flow air intake. It is found that the heat transfer of the combination of laid-back hole and impingement tube can be very high under large blowing ratio which should get attention in the design process.
{"title":"Investigation on the Leading Edge Film Cooling of Counter-Inclined Cylindrical and Laid-Back Holes With and Without Impingement: Part II — Heat Transfer Coefficient","authors":"Rui-dong Wang, Cun-liang Liu, Hai-yong Liu, Hui-ren Zhu, Qi-ling Guo, Chao Gao","doi":"10.1115/GT2018-76066","DOIUrl":"https://doi.org/10.1115/GT2018-76066","url":null,"abstract":"Heat transfer of the counter-inclined cylindrical and laid-back holes with and without impingement on the turbine vane leading edge model are investigated in this paper. To obtain the film cooling effectiveness and heat transfer coefficient, transient temperature measurement technique on complete surface based on double thermochromic liquid crystals is used in this research. A semi-cylinder model is used to model the vane leading edge which is arranged with two rows of holes. Four test models are measured under four blowing ratios including cylindrical film holes with and without impingement tube structure, laid-back film holes with and without impingement tube structure. This is the second part of a two-part paper, the first part paper GT2018-76061 focuses on film cooling effectiveness and this study will focus on heat transfer. Contours of surface heat transfer coefficient and laterally averaged result are presented in this paper. The result shows that the heat transfer coefficient on the surface of the leading edge is enhanced with the increase of blowing ratio for same structure. The shape of the high heat transfer coefficient region gradually inclines to span-wise direction as the blowing ratio increases. Heat transfer coefficient in the region where the jet core flows through is relatively lower, while in the jet edge region the heat transfer coefficient is relatively higher. Compared with cylindrical hole, laid-back holes give higher heat transfer coefficient. Meanwhile, the introduction of impingement also makes heat transfer coefficient higher compared with cross flow air intake. It is found that the heat transfer of the combination of laid-back hole and impingement tube can be very high under large blowing ratio which should get attention in the design process.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130363302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kevin J. DeMarco, Brian T. Bohan, M. Polanka, J. L. Rutledge, P. Akbari
The Ultra Compact Combustor (UCC) aims to increase the thrust-to-weight ratio of an aircraft gas turbine engine by decreasing the size, and thus weight, of the engine’s combustor. The configuration of the UCC as a primary combustor enables a unique cooling scheme to be employed for the Hybrid Guide Vane (HGV). A previous effort conducted a Computational Fluid Dynamics (CFD) analysis that evaluated whether it would be possible to cool this vane by drawing in freestream flow at the stagnation region of the airfoil. Based on this study, a cooling scheme was designed and modified with internal supports to make additive manufacturing possible. The vane was evaluated using CFD comparing the results with those of a solid vane and hollow vane without cooling holes as a validation and demonstration of the design. Furthermore, the effects of the internal support structure were deemed beneficial to surface cooling when evaluated through comparisons of internal pressure distribution and overall effectiveness.
{"title":"Computational Analysis of an Additively Manufactured Cooled Ultra Compact Combustor Vane","authors":"Kevin J. DeMarco, Brian T. Bohan, M. Polanka, J. L. Rutledge, P. Akbari","doi":"10.1115/GT2018-75392","DOIUrl":"https://doi.org/10.1115/GT2018-75392","url":null,"abstract":"The Ultra Compact Combustor (UCC) aims to increase the thrust-to-weight ratio of an aircraft gas turbine engine by decreasing the size, and thus weight, of the engine’s combustor. The configuration of the UCC as a primary combustor enables a unique cooling scheme to be employed for the Hybrid Guide Vane (HGV). A previous effort conducted a Computational Fluid Dynamics (CFD) analysis that evaluated whether it would be possible to cool this vane by drawing in freestream flow at the stagnation region of the airfoil. Based on this study, a cooling scheme was designed and modified with internal supports to make additive manufacturing possible. The vane was evaluated using CFD comparing the results with those of a solid vane and hollow vane without cooling holes as a validation and demonstration of the design. Furthermore, the effects of the internal support structure were deemed beneficial to surface cooling when evaluated through comparisons of internal pressure distribution and overall effectiveness.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130372991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nian Wang, Mingjie Zhang, Chao-Cheng Shiau, Je-Chin Han
This study investigates the combined effects of blowing ratio and density ratio on flat plate film cooling effectiveness from two-row of compound angled cylindrical holes. Two arrangements of two-row compound angled cylindrical holes are tested: the first row and second row are oriented in staggered but same compound angled direction (β = +45° for the first row, +45° for the second row); the first row and second row are oriented in inline but opposite direction (β = +45° for the first row, −45° for the second row). Each cooling hole is 4 mm in diameter with an inclined angle 30°. The streamwise distance between the two rows is fixed at 4d and the spanwise pitch between the two holes (p) is 4d, 6d, and 8d, respectively. The experiments are performed at four blowing ratios (M = 0.5, 1.0, 1.5, 2.0) and three density ratios (DR = 1.0, 1.5, 2.0). The free stream turbulence intensity is kept at 6%. Detailed film cooling effectiveness distributions are obtained using the steady state pressure-sensitive paint (PSP) technique. The detailed film cooling effectiveness contours are presented and the spanwise averaged film effectiveness results are compared over the range of flow parameters. Film cooling effectiveness correlations are developed for both inline and staggered compound angled cylindrical holes. The results provide baseline information for the flat plate film cooling analysis with two-row of compound angled cylindrical holes.
{"title":"Film Cooling Effectiveness From Two-Row of Compound Angled Cylindrical Holes Using PSP Technique","authors":"Nian Wang, Mingjie Zhang, Chao-Cheng Shiau, Je-Chin Han","doi":"10.1115/GT2018-75167","DOIUrl":"https://doi.org/10.1115/GT2018-75167","url":null,"abstract":"This study investigates the combined effects of blowing ratio and density ratio on flat plate film cooling effectiveness from two-row of compound angled cylindrical holes. Two arrangements of two-row compound angled cylindrical holes are tested: the first row and second row are oriented in staggered but same compound angled direction (β = +45° for the first row, +45° for the second row); the first row and second row are oriented in inline but opposite direction (β = +45° for the first row, −45° for the second row). Each cooling hole is 4 mm in diameter with an inclined angle 30°. The streamwise distance between the two rows is fixed at 4d and the spanwise pitch between the two holes (p) is 4d, 6d, and 8d, respectively. The experiments are performed at four blowing ratios (M = 0.5, 1.0, 1.5, 2.0) and three density ratios (DR = 1.0, 1.5, 2.0). The free stream turbulence intensity is kept at 6%. Detailed film cooling effectiveness distributions are obtained using the steady state pressure-sensitive paint (PSP) technique. The detailed film cooling effectiveness contours are presented and the spanwise averaged film effectiveness results are compared over the range of flow parameters. Film cooling effectiveness correlations are developed for both inline and staggered compound angled cylindrical holes. The results provide baseline information for the flat plate film cooling analysis with two-row of compound angled cylindrical holes.","PeriodicalId":239866,"journal":{"name":"Volume 5C: Heat Transfer","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124015491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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