Volume 6A: Heat Transfer — Combustors; Film Cooling最新文献

{"title":"Effects of Internal Coolant Crossflow on Film-Cooling Performance of Double-Jet and Cylindrical Holes","authors":"Huaitao Zhu, G. Xie, R. Zhu, B. Sundén","doi":"10.1115/gt2022-82514","DOIUrl":"https://doi.org/10.1115/gt2022-82514","url":null,"abstract":"\u0000 In this paper, the effects of internal coolant crossflow on double-jet holes were simulated and compared with two rows of cylindrical holes under three blowing ratios (M = 0.5, 1.0, and 1.5), with an established and validated turbulence model. The results show that double-jet holes can provide better film cooling performance for the three different blowing ratios compared with cylindrical holes. As the blowing ratio increases, the superiority of double-jet holes becomes more obvious. The introduction of crossflow can significantly enlarge the coolant coverage area of cylindrical holes, and increase the laterally-averaged film cooling effectiveness. For double-jet holes, the internal coolant crossflow also increases the laterally averaged film cooling effectiveness, but the improvement is limited. For the −45° compound angle film hole of double-jet holes, the internal coolant crossflow decreases the normal velocity (momentum), and makes the coolant to attach on the plate. However, for the other hole, the influence is opposite, the normal velocity (momentum) is increased and the coolant is detached from the plate.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126634519","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}

{"title":"Evaluation of Adjoint Optimized Hole - Part II: Parameter Effects on Performance","authors":"Christopher Yoon, D. Gutiérrez, Michael T. Furgeson, D. Bogard","doi":"10.1115/gt2022-82726","DOIUrl":"https://doi.org/10.1115/gt2022-82726","url":null,"abstract":"\u0000 In a previous study from our laboratory, a computational adjoint based optimization method was used to design shaped film cooling holes fed by internal co-flow and cross-flow channels. The associated RANS computations predicted that the holes optimized for use with cross-flow (X-AOpt) and co-flow (Co-AOpt) would increase adiabatic effectiveness significantly compared to a baseline 7-7-7 shaped hole. Experimental validations of these performance predictions are presented in companion paper (Gutierrez et al., 2022). Although the experimental values were significantly lower than the computational predictions, the adiabatic effectiveness for the adjoint optimized holes was measured to be noticeably higher than that for the baseline 7-7-7 shaped hole. Specifically, the X-AOpt hole was 75% higher and the Co-AOpt hole was 30% higher in terms of peak performance when P/D effects were accounted for. In this study, the effects of various key parameters on the performance of the adjoint optimized holes were determined. For these experiments the internal channel velocity ratios ranged from VRc = 0.2 to 0.4, both co-flow and counter-flow conditions were used, and the density ratio ranged from DR = 1.2 to 1.8. These provided a quantification of the performance of the adjoint optimized holes over a wide range of operating conditions encompassing engine relevant conditions. Adiabatic film effectiveness measurements and thermal field measurements are made to understand the performance variations and to compare with 7-7-7 SI (sharp inlet).","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116784060","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}

{"title":"Developing a Scalar Flux Model Solely Based on Mean Flow Quantities for the Film Cooling Jet Flow","authors":"Bo Shi, Xueying Li, Jing Ren","doi":"10.1115/gt2022-82787","DOIUrl":"https://doi.org/10.1115/gt2022-82787","url":null,"abstract":"\u0000 Previous studies showed that the Reynolds-averaged Navier Stokes simulation (RANS) which used gradient diffusion hypothesis (GDH) severely under-predicts the scalar diffusion downstream the film cooling jet flow. Scalar flux models of different types have been developed throughout the years. Of particular interest is the algebraic model, which is easy to implement and has a low computational cost. Well-known algebraic models include the generalized gradient diffusion hypothesis (GGDH) and the high-order generalized gradient diffusion hypothesis (HOGGDH). However, due to the dependence on the Reynolds stress, GGDH and HOGGDH may suffer from a lack of scalar prediction along with RANS, because the Boussinesq core of which will lead to a loss of anisotropy. In a previous study [1], we revealed the mechanism of turbulent scalar transport in the shear layers of the film cooling jet based on the analysis of the flow and scalar field predicted by the large eddy simulation (LES). Upon the mechanism revealed, this paper aims to develop a scalar model that only depend on mean flow quantities, including mean velocity, turbulent kinetic energy and turbulent viscosity. It is our hope that the model can be comparable or surpass the GGDH and HOGGDH concerning the ability of scalar prediction, while not be dependent on the Reynolds stress. Scalar transport equation was solved with the mean flow data provided by the previous LES. The prediction of an inclined cylindrical hole with VR = 0.46 using GGDH, HOGGDH and current model (namely SLR) were compared and analyzed.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"545 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116376930","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}

{"title":"Experimental Study of Film Cooling With Favorable and Adverse Pressure Gradients","authors":"R. Volino, Matthew C. Gillcrist","doi":"10.1115/gt2022-78240","DOIUrl":"https://doi.org/10.1115/gt2022-78240","url":null,"abstract":"\u0000 Film cooling experiments were conducted on a flat wall subject to favorable and adverse pressure gradients with constant acceleration parameter, K. The test wall included a single row of 5 round holes in line with the flow direction and inclined at 35 degrees to the surface. The hole spacing was 3 diameters. The wall opposite the test wall was moveable, and was set to angles with respect to the test wall that produced K values of −0.5 × 10−6, 0, 1 × 10−6, 2 × 10−6, 2.5 × 10−6, and 3 × 10−6. Blowing ratios of 0, 0.5, 1, and 1.5 were tested at each acceleration. The test wall was equipped with constant flux surface heaters, and data were acquired for each flow condition with the wall both heated and unheated. An infrared camera was used to record wall temperature in a region spanning the three center holes and extending 20D downstream of the holes. From these measurements, local film cooling effectiveness and heat transfer coefficients were determined. In the flow, velocity and temperature profiles were acquired using hot-wire anemometry and a traversing thermocouple probe. Particle image velocimetry was used to acquire velocity fields in a plane perpendicular to the flow direction and 10D downstream of the holes. The pressure gradient had a noticeable effect on the flow, with the favorable pressure gradient reducing liftoff and moving the film cooling jets closer to the wall, and reducing turbulence levels in the boundary layer. The adverse pressure gradient had the opposite effect. Near the wall, however, the effects of the pressure gradient on the film cooling effectiveness and heat transfer were more subtle.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132848760","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}

{"title":"Turbine Vane Passage Cooling Experiments With a Close-Coupled Combustor-Turbine Interface Geometry Part 2: Describing the Coolant Coverage","authors":"Kedar P. Nawathe, Aaditya R. Nath, Yong W. Kim, T. Simon","doi":"10.1115/gt2022-82203","DOIUrl":"https://doi.org/10.1115/gt2022-82203","url":null,"abstract":"\u0000 The first stage gas turbine vane surfaces and endwalls require aggressive cooling. This two-part paper introduces a modified design of the combustor-turbine (C-T) interface, the ‘close-coupled interface,’ that is expected to increase cooling performance of vane passage surfaces. While the first part of the paper describes secondary flows and coolant transport in the passage, this part discusses the effects of the new C-T interface geometry on adiabatic cooling effectiveness of the endwall and vane surfaces. Compared to the traditional C-T interface, the coolant requirement is reduced for the same level of cooling effectiveness on all three surfaces for the new C-T interface design, confirming that it is an improvement over the previous design. The endwall crossflow is reduced by combustor coolant injection with the new interface leading to more pitchwise-uniform cooling of the endwall. For the pressure surface, increasing combustor coolant flowrate directly increases phantom cooling effectiveness and spreading of coolant away from the endwall. With the traditional passage vortex seen in the literature replaced by the impingement vortex of the present design, the suction surface receives less phantom cooling than does the pressure surface. However, cooling performance is still improved over that of the previous C-T interface design.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133269932","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}

{"title":"Multi-Parameters Sensitivity Analysis of Overall Cooling Effectiveness on Turbine Blade and Numerical Investigation of Internal Cooling Structures on Heat Transfer","authors":"Runzhou Liu, Haiwang Li, Ruquan You, Z. Tao","doi":"10.1115/gt2022-82372","DOIUrl":"https://doi.org/10.1115/gt2022-82372","url":null,"abstract":"\u0000 Turbine blade overall cooling effectiveness is a conjugate result under the influence of various parameters. In order to analyze the overall cooling effectiveness more accurately, we have to categorize all the influencing parameters. This paper builds a one-dimensional conjugate heat transfer model with four parameters which are adiabatic film cooling effectiveness, heat transfer coefficient ratio between blade external surface (hg) and internal surface (hi), internal coolant warming factor (Tg−Tw,iTg−Tc), Biot number. The effects of different internal cooling structures, film hole inclined angle and blowing ratio on flow and heat transfer characteristic were numerically investigated based on flat-plate film hole model and impingement-effusion model, where 3-D steady RANS method with SST k-ω model was used. V-rib, 45° inclined rib, 90° rib and dimple were adopted to compare with smooth internal channel. The results show that four dimensionless parameters (adiabatic film cooling effectiveness, heat transfer coefficient ratio, warming factor, Biot number) are positively correlated with overall cooling effectiveness. The overall cooling effectiveness is the most sensitive to adiabatic film cooling effectiveness, followed by warming factor. This indicates that the adiabatic film cooling effectiveness is the worthiest to improve. The numerical results show that the ribs and dimple structures have little influence on the distribution of adiabatic film cooling effectiveness and Biot number on the mainstream side. The 45° rib presents higher overall cooling effectiveness.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125440758","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}

{"title":"Numerical Investigation of Laidback Fan-Shaped Film Cooling Holes With Large Eddy Simulation","authors":"Lianfeng Yang, F. Satta, D. Barsi, P. Zunino, Y. Luan","doi":"10.1115/gt2022-83961","DOIUrl":"https://doi.org/10.1115/gt2022-83961","url":null,"abstract":"\u0000 Due to the high demand for the output power and thermal efficiency, the turbine inlet temperature is extremely high which has significantly exceeded the melting point of the blade material. Therefore, the turbine blade cooling system plays a pivotal role in the entire engine. As for the external cooling, film cooling technology has been widely used in the modern advanced design of gas turbines in order to enhance the cooling performance and reducing the cooling air usage. According to the public literature, conventional cylindrical film cooling hole has been studied by many researchers, whereas the laidback fan-shaped film cooling hole, as a cutting-edge technology, is relative novel, advantageous and still under investigation. Thus, large eddy simulation (LES) method was implemented to study the flow field and the thermal performance of shaped film holes at turbulence intensity Tu = 0.5%, density ratio DR = 1.5, blowing ratio M = 0.5–3.0 and momentum flux ratio I = 0.17–6.00. The adiabatic film cooling effectiveness with LES shows a good agreement with the experimental data. A comparison was conducted between the conventional cylindrical film hole and the laidback fan-shaped film hole in the range of M = 0.5–1.5. The results show that shaped film hole obtains better cooling effectiveness with sufficient spread in spanwise direction as the blowing ratio increases, and M = 1.5 can provide a relative better performance for shaped film hole. As for the details of the flow field, the counter-rotating vortex pair (CRVP) and anti-CRVP structures are found in the simulation. Time-averaged Reynolds shear stresses and turbulence viscosity exhibit strong anisotropic properties near the bottom surface. The analyses may help to understand the characteristics of the laidback fan-shaped film cooling and guide the cooling design of the turbine blade.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129163291","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}

{"title":"Effusion Cooling: Influence of Pressure Drop","authors":"Michael Bonds, B. Wahls, S. Ekkad, N. Rudrapatna, R. Dudebout, RyanM . Meyer","doi":"10.1115/gt2022-82067","DOIUrl":"https://doi.org/10.1115/gt2022-82067","url":null,"abstract":"\u0000 Combustor liners are exposed to significant thermal gradients with hot combustion gases on one side and compressor directed cooling air on the other side. To maintain effective life of the liners, development of effective methods to cool gas turbine combustor liners are a necessity. Effusion cooling uses uniformly spaced holes distributed throughout the surface of the combustor liner to introduce convective and film cooling to form a protective layer of coolant along the liner wall and hence reduce the impact of the combustion gases. This experimental study investigates the overall cooling effectiveness of effusion cooling under realistic crossflow coolant operating conditions. The primary factors influencing the coolant mass flow that passed through the liner into the hot main flow was hole geometry, coolant and main flow speed, and pressure drop. For this study, 4 different effusion cooling liners with increasing levels of hole density were studied. Each hole had a length to diameter ratio (L/D) of 5.8. Non-dimensionalized hole to hole spacing in the streamwise (x/D) and spanwise (y/D) direction was equal and included spacings 7.9, 11.2, 15.8, and 22.5. These configurations were tested at uniform hot side and cold side flow speeds of 7 m/s and 15 m/s with both co-flow and counter-flow coolant directions. Pressure drop through the plate was set to 2% and 4% for 7 m/s flow speed and 4% for the 15 m/s condition. Infrared Thermography (IRT) was utilized to capture hot side and cold side liner steady state temperatures. Overall, co-flow conditions resulted in higher coolant mass flow passing through the liner while counter-flow conditions increased performance. The highest hole density configuration had a 20.3% average increase in performance over the next best performing liner geometry. In addition, the highest percentage of air passed through the effusion plate liners at the lower flow rate conditions with a 4% pressure drop. Based upon the experiments done, it was clear that while multiple factors influenced the overall cooling performance of combustor liners, a higher pressure drop consistently resulted in increased performance while higher flow speed resulted in reduced overall cooling performance.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127337697","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}

{"title":"Numerical Prediction of Heat Transfer Coefficient and Adiabatic Effectiveness on a Nozzle Guide Vane With Representative Combustor Outflow","authors":"S. G. Tomasello, A. Andreini, T. Bacci, B. Facchini, S. Cubeda, L. Andrei","doi":"10.1115/gt2022-82128","DOIUrl":"https://doi.org/10.1115/gt2022-82128","url":null,"abstract":"\u0000 The employment of lean-premix combustors in modern gas turbines allows to reduce NOx emissions by controlling the flame temperature at the expense of highly unsteady and strongly non-uniform flow fields which are necessary to stabilize the flame. This highly complex swirled flow field characterized by evident temperature distortions alters the aerodynamics and heat transfer in the first high pressure turbine stator with potential detrimental consequences on engine life and efficiency. From a numerical point of view, the mutual combustor-turbine interaction has been studied by using standard turbulence modeling approaches, as commonly employed during the design phase, even if more advanced scale-resolving methods have been proven more reliable and benchmarked against various experimental findings.\u0000 From the experimental perspective, film-cooling adiabatic effectiveness and heat transfer coefficient (HTC) measurements on the external surface of the nozzle guide vanes, in the presence of representative combustor outflow characteristics, are not common since the relevant temperature distortions that are present make such kind of measurements really challenging to perform. For this reason, very limited assessment of such approaches regarding this aspect is available in literature.\u0000 In this study, an experimental test case with a combustor simulator and a nozzle cascade, where both adiabatic effectiveness and HTC measurements have been carried out, is investigated by carrying out a systematic computational study, through RANS calculations of the combustor-cascade integrated domain. The film cooling system performance has been predicted by meshing the whole vane internal cooling system, while the heat transfer coefficient is calculated using the conventional two-point method, normally adopted for heat transfer calculations in gas turbines.\u0000 The comparison between numerical predictions and experimental results was exploited to assess the capability of traditional modeling approaches in the characterization of both adiabatic effectiveness and heat transfer coefficient. This evaluation represents an effective means to assess if conventional/industrial approaches can be reliably used, when representative and highly unsteady combustor outflows are considered, or advanced and more time-consuming methods shall be adopted.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127342903","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}

{"title":"Evaluation of Adjoint Optimized Holes - Part I Baseline Performance","authors":"D. Gutiérrez, Christopher Yoon, Michael T. Furgeson, Emma M. Veley, D. Bogard, K. Thole","doi":"10.1115/gt2022-83436","DOIUrl":"https://doi.org/10.1115/gt2022-83436","url":null,"abstract":"\u0000 With the advent of the use of additive manufacturing to build gas turbine components, the design space for new hole geometries is essentially unlimited. Recently, a computational adjoint based optimization method was used to design shaped film cooling holes fed by internal co-flow and cross-flow channels. The associated RANS computations predicted that the holes optimized for use with cross-flow (X-AOpt) and co-flow (Co-AOpt) would significantly increase adiabatic effectiveness. However, only the X-AOpt hole was tested experimentally in this previous study. Though the experimentally measured performance for this hole was much less than computationally predicted, it still had a 75% improved performance compared to the conventional 7-7-7 shaped hole. In the current study, the X-AOpt and Co-AOpt shaped holes were experimentally evaluated using measurements of adiabatic effectiveness and overall cooling effectiveness. Coolant was fed to the holes with an internal co-flow channel. For reference, experiments were also conducted with the baseline 7-7-7 shaped hole, and a 15-15-1 shaped hole (shown in a previous study to be the optimum expansion angles for a shaped hole). Furthermore, overall cooling effectiveness measurements were made with engine scale models to evaluate the performance of additively manufactured (AM) X-AOpt and Co-AOpt holes with a realistic metal build. Results from this study confirmed that the X-AOpt hole had a 75% increase in adiabatic effectiveness compared to the 7-7-7 shaped hole. However, the Co-AOpt hole had only a 30% increase in adiabatic effectiveness, substantially less than had been computationally predicted. Measurements of overall cooling effectiveness for the engine-scale models and the large-scale models followed similar trends.","PeriodicalId":267158,"journal":{"name":"Volume 6A: Heat Transfer — Combustors; Film Cooling","volume":"251 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122924077","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}