Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling最新文献

{"title":"Thermal Performance of Double-Sided, Partial Height Strip Fin Arrays in a High Aspect Ratio, Rectangular Channel","authors":"Nathaniel J. Tracy, L. Wright, Je-Chin Han","doi":"10.1115/gt2021-59774","DOIUrl":"https://doi.org/10.1115/gt2021-59774","url":null,"abstract":"\u0000 Friction loss and heat transfer enhancement measurements were obtained for double-sided, partial height, strip fin arrays within a high aspect ratio (AR = 8), rectangular channel. Fins were arranged in a staggered array configuration with channel height to fin thickness ratio H/W = 9.6, spanwise spacing distance to fin thickness ratio S/W = 8.0, and streamwise spacing distance to fin length ratio X/L = 1.0. Shortened strip fins of equal length are positioned directly opposite of each other on the upper and lower channel surfaces with three gap size to channel height ratios considered G/H = 0.2, 0.3, and 0.4. The thermal performance of each fin configuration is determined from the measured pressure drop across the array and regionally averaged heat transfer coefficients at flow Reynolds numbers ranging from Re = 20,000–80,000. The partial height strip fin results are compared to baseline cases of strip fins spanning the full height of the channel and the smooth channel without roughness elements. Linear correlations of friction loss and power correlations of the heat transfer enhancement and thermal performance are provided as functions of flow Reynolds numbers for all cases. Strip fins spanning the full height of the channel provide the greatest heat transfer enhancement of all cases but introducing a gap size can significantly reduce friction losses. Full height strip fins provide the greatest thermal performance for Reynolds numbers ranging from Re = 20,000–30,000, and partial height strip fins with the gap size of G/H = 0.3 provide the greatest thermal performance for flow Reynolds numbers ranging from Re = 40,000–80,000.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126941142","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 Investigations on the Aerothermal Performance and Film Cooling Effectiveness of Turbine Vane Endwall at Inlet Swirl Conditions","authors":"Zhiyuan Li, Kai Zhang, Zhigang Li, Jun Li","doi":"10.1115/gt2021-59062","DOIUrl":"https://doi.org/10.1115/gt2021-59062","url":null,"abstract":"\u0000 Lean burn premix technology of gas turbines results in that the turbine combustor outlet has strong swirl flow characteristics which directly influences the inlet flow condition of the first turbine vane downstream from combustor and raise the thermal load of endwall. The aerothermal performance and film cooling effectiveness of first turbine vane endwall at different inlet swirl conditions is numerically investigated in this paper. The flow pattern, Nusselt number distribution and film cooling effectiveness of turbine vane endwall at the uniform and three kinds of swirl numbers (0.6, 0.8, 1.0) inflow conditions with clockwise and anticlockwise swirl orientations are analyzed using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST k-ω turbulence model solutions. The obtained results show that the flow field is apparently influenced by inlet swirl conditions. The separation in passage is clearly suppressed at clockwise swirl inflow conditions but anticlockwise make the flow pattern more complex. Inlet swirl can increase the overall Nu on the endwall. Especially in the area upstream of leading edge and area between the first and second row of film holes whose Nu are increased by 4 and 1.5 times compared with uniform inflow, respectively. Not only swirl number but also orientation can affect the film cooling effectiveness distribution of the vane endwall. The better film cooling effectiveness distribution and higher film cooling effectiveness downstream of each film hole row can be achieved at the clockwise swirl inflow conditions by weakening the accumulation of coolant near the suction side of the turbine vane endwall. Compared with uniform inflow, average film cooling effectiveness of endwall between the second row and third row is increased from 0.21 to 0.27 at clockwise SN = 1.0 for the maximum increase. The detailed flow field and aerothermal performance of the turbine vane endwall at different swirl inflow conditions is also discussed and illustrated.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134031227","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":"Correlating Time-Resolved Pressure Measurements With Rim Sealing Effectiveness for Real-Time Turbine Health Monitoring","authors":"Eric Deshong, Benjamin Peters, Reid A. Berdanier, K. Thole, K. Paynabar, N. Gebraeel","doi":"10.1115/gt2021-59586","DOIUrl":"https://doi.org/10.1115/gt2021-59586","url":null,"abstract":"\u0000 Purge flow is bled from the upstream compressor and supplied to the under-platform region to prevent hot main gas path ingress that damages vulnerable under-platform hardware components. A majority of turbine rim seal research has sought to identify methods of improving sealing technologies and understanding the physical mechanisms that drive ingress. While these studies directly support the design and analysis of advanced rim seal geometries and purge flow systems, the studies are limited in their applicability to real-time monitoring required for condition-based operation and maintenance. As operational hours increase for in-service engines, this lack of rim seal performance feedback results in progressive degradation of sealing effectiveness, thereby leading to reduced hardware life.\u0000 To address this need for rim seal performance monitoring, the present study utilizes measurements from a one-stage turbine research facility operating with true-scale engine hardware at engine-relevant conditions. Time-resolved pressure measurements collected from the rim seal region are regressed with sealing effectiveness through the use of common machine learning techniques to provide real-time feedback of sealing effectiveness. Two modelling approaches are presented that use a single sensor to predict sealing effectiveness accurately over a range of two turbine operating conditions. Results show that an initial purely data-driven model can be further improved using domain knowledge of relevant turbine operations, which yields sealing effectiveness predictions within three percent of measured values.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130600620","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":"Development and Application of a Concentration Probe for Mixing Flows Tracking in Turbomachinery Applications","authors":"G. Babazzi, T. Bacci, A. Picchi, T. Fondelli, T. Lenzi, B. Facchini, S. Cubeda","doi":"10.1115/gt2021-59634","DOIUrl":"https://doi.org/10.1115/gt2021-59634","url":null,"abstract":"\u0000 Modern gas turbines present important temperature distortions in the core-engine flowpath, mainly in the form of hot and cold streaks imputed to combustor burners and components cooling systems. As they highly influence turbines performance and lifetime, the precise knowledge of the thermal field evolution through the combustor and the high-pressure turbine is fundamental. The majority of past studies investigated streaks migrations directly examining the thermal field, while a limited amount of experimental work employed approaches based on the detection of tracer gases. The latter approach provides a more detailed evaluation of the evolution and mixing of the different flows. However, the slow time response due to the employment of sampling probes and gas analysers make the investigation of a whole measurement plane extremely time consuming. To tackle this issue, in this study a commercial oxygen sensor element and its excitation/detection unit were integrated into a newly developed probe to carry out local tracer gas concentration measurements exploiting the fluorescence behaviour. The probe was provided with a Kiel-like shield, a pressure port and a thermocouple, in order to correct the readings in case of 3D flows with pressure, temperature and velocity gradients. The paper summarizes the probe development and calibration activities, with the characterization of its accuracy for different flow conditions. Finally, two probe applications are described: firstly the probe was used to detect tracer gas concentrations on a jet flow; afterwards it was traversed on the interface plane between a non-reactive, lean combustor simulator and the NGV cascade. The probe has proven to provide accurate and reliable measurements both from a quantitative and qualitative point of view even in highly 3D flow fields typical of gas turbines conditions.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124121109","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":"Investigating Heat Transfer in a Straight Cooling Passage Using Transient Infrared Temperature Data and URANS Conjugate Heat Transfer Analysis","authors":"Louis E. Christensen, Richard Celestina, Spencer J. Sperling, Randall M. Mathison, H. Aksoy, Jong-Shang Liu, Jeremy B. Nickol","doi":"10.1115/gt2021-60381","DOIUrl":"https://doi.org/10.1115/gt2021-60381","url":null,"abstract":"\u0000 Experimental work measuring heat transfer due to internal convection on a smooth straight passage is recreated using unsteady Reynolds averaged Navier-Stokes conjugate heat transfer simulations. The experimental work utilizes 1-dimensional and 3-dimensional conduction models to determine internal heat transfer rates from external surface temperature measurements collected with an infrared camera. The numerical simulations recreated these experiments to verify the conduction model and investigate the differences between the k-ω shear stress transport turbulence model, Reynolds stress turbulence model, and the k-ε turbulence model. It is found that the conduction model can accurately predict the heat transfer in the passage within an average error of 6% but with reduced spatial accuracy. The lower spatial accuracy can be accounted for by utilizing both the conduction model to predict the magnitude of the heat transfer and the numerical simulations to capture the spatial distribution. No one turbulence model was found to provide consistently superior heat transfer predictions, but rather each model excelled in some scenarios and underperformed in others. Overall, the k-ε model was found to best match the experimental heat transfer calculations with an average error of 5.9% of the total heat transfer, and it takes a more conservative approach as it can over predict the external surface temperatures by approximately 0.4 K. The end goal of this study is to develop a way to derive heat-flux data from infrared measurements on a range of geometries. A simple and well-understood geometry is investigated here to provide a firm foundation for future work.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127194623","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":"Adjoint Based Heat Conduction Optimization of Struts Parameters Within Hollow Blade","authors":"Yougang Ruan, Z. Feng","doi":"10.1115/gt2021-59422","DOIUrl":"https://doi.org/10.1115/gt2021-59422","url":null,"abstract":"\u0000 In gas turbine, the interaction between hot gas mainstream and blade solid region becomes more and more obvious as the turbine inlet temperature increases, thus heat conduction within the blade solid regions should be taken into consideration in optimization design process. In this paper, an adjoint-based optimization method for heat conduction problems in the solid region was built based on ANSYS Fluent and OpenFOAM Solver. The continuous adjoint equation and the corresponding boundary conditions for three typical conduction boundary conditions were derived in detail. To validate the correctness of this method, inverse design problems within the hollow cylinder and hollow blade were calculated, respectively. Inner shape inverse design of the hollow cylinder and the blade thickness inverse design were performed, and the target values were found successfully. Adjoint gradients were compared with finite-difference method or theoretical results. Then a Conjugate Heat Transfer (CHT) calculation was performed using ANSYS Fluent software, and the numerical methods were validated against the experimental results. An optimization of the struts place and thickness within hollow blade for average temperature was performed based on the CHT calculation results. Average temperature within the solid region of the optimized blade decreased 11.1K as compared to the original case.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126367559","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 Investigations Into the Effect of Surface Roughness And Contact Force on Leakage Between Two Rigid Metallic Surfaces","authors":"C. Bricaud, O. Schulz, T. Zierer, V. Peltier, C. Schwitzke, H. Bauer","doi":"10.1115/gt2021-59163","DOIUrl":"https://doi.org/10.1115/gt2021-59163","url":null,"abstract":"\u0000 Current research and development efforts in the field of heavy-duty gas turbines focus on increasing engine efficiencies, lowering combustor emissions and extending inspection intervals. To achieve further improvements in these development fields, it is crucial for gas turbine manufacturers to continuously build up knowledge on leakage air inside different components of gas turbines. Leakage air can by nature be hardly predicted and is usually only estimated indirectly in real engines. Therefore, investigations on representative test rigs remain a fundamental method for quantifying air leakages more accurately.\u0000 This article deals with a specific air leakage, which can occur between two firmly pressed rigid surfaces. One challenge for the engineers is to predict the leakage for new surfaces but also used surfaces with fretting corrosion and wear marks as a function of the contact force. In this perspective, air mass flow measurements were performed in a leakage test rig for different contact geometries, pressure ratios and compression levels between the surfaces. The purpose of the analysis is to determine the potential effect of the roughness, length, curvature and contact forces of the pressed surfaces on the leakage amount. The presented measurement procedure and results contribute to the extension of the leakage characteristic database for generic gas turbine components.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125120771","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":"Assessment of CFD Models for Multiphase Heat Transfer in Different Boiling Regimes","authors":"C. Bianchini, Riccardo Da Soghe, L. Mazzei, G. Caggiano, Maddalena Angelucci","doi":"10.1115/gt2021-59658","DOIUrl":"https://doi.org/10.1115/gt2021-59658","url":null,"abstract":"\u0000 Cryogenic propellant rockets, designed to exploit the high energy densities of liquid hydrogen and liquid oxygen, are equipped with turbopumps that deliver liquid fuel to the engine at high pressure levels. Due to the very low saturation temperature of the cryogenic propellant, it is common during the transient operation to have portion of pump walls that achieve boiling conditions. The effect of boiling on the heat transfer between the solid and the fluid needs to be well characterized in order to correctly predict the pump metal temperature evolution and the necessary amount of propellant.\u0000 This paper presents an investigation about the capabilities of currently available CFD models for boiling to reproduce correctly the phenomenon under various flow conditions. The analysis, conducted with Ansys Fluent CFD solver, focuses on the Eulerian multiphase approach coupled with the mechanistic nucleate boiling model extended to consider the wall boiling regime transition from the nucleate boiling to the critical heat flux regime (CHF).\u0000 Several test cases are presented to cover the full range of boiling regimes and flow characteristics: the first test focuses on nucleate boiling of sub-cooled water in an upward heated cylindrical pipe, second one deals with 3D boiling water in a rectangular-sectioned duct, the third one considers again nucleate boiling but with a different fluid, namely the R-113 refrigerant, whereas the last investigates the critical heat flux and post dry-out regimes in vertical pipes. Selected tests span over different operating conditions and consider alternative fluids in order to provide a preliminary validation propaedeutic for future investigations focused on more complex applications representative of cryogenic turbopumps.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133626597","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":"Investigation on Flow Mechanism Driving Heat Transfer Enhancement in a Wide Channel With Staggered Square Pin Fins","authors":"Jingtian Duan, Ke Zhang, Jin Xu, J. Lei, Junmei Wu","doi":"10.1115/gt2021-60138","DOIUrl":"https://doi.org/10.1115/gt2021-60138","url":null,"abstract":"\u0000 Particle Image Velocimetry (PIV) was used to measure the flow field of staggered square pin-fin array in a wide rectangle channel (AR = 4). The experiment was conducted at two Reynolds number, 10000 and 20000, based on the hydraulic diameter and bulk velocity of the channel. The distribution of flow field properties was compared with that of Nu to analysis the key flow physics driving heat transfer enhancement in channel with square pin fin. The Nusselt number was achieved through temperature measurement using thermochromic liquid crystal in the same geometry setup. Results were compared with those for circular pin fin to study the effect of geometry on flow physics driving heat transfer enhancement. It was found that the wake length of square pin fin is longer than that of circular pin fin, which indicated flow around square pin fin requires longer distance to develop. Compared to circular pin fin, small scale disturbances in the shear layer of square pin fin show its contribution to local end wall heat transfer enhancement. Large motions benefit end wall heat transfer more effectively at lower Re. Small scale unsteadiness contributes more to heat transfer augment as flow develops or Reynolds number increases while large scale motions get weaker.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134052171","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 the Effect of an Axial Pre-Swirl Nozzle With a Radial Angle in a Pre-Swirl Rotor-Stator System","authors":"G. Zhao, S. Ding, Tian Qiu, Shenghui Zhang","doi":"10.1115/gt2021-60189","DOIUrl":"https://doi.org/10.1115/gt2021-60189","url":null,"abstract":"\u0000 Pre-swirl nozzles are often used in gas turbines to deliver the cooling air to the turbine blades. The static axial nozzles swirl the cooling air in the direction of rotation of the turbine disk, thereby reducing the relative total temperature of the air. Most studies about nozzles focus on its shape, radial location, tangential angle to reduce the pressure loss and increase the temperature drop of the pre-swirl system, but few of them consider the benefit of a radial angle of nozzles. This paper investigated numerically the performance of a pre-swirl system whose pre-swirl nozzles have a radial angle. Six radial angles are selected to study the flow dynamics of a direct-transfer pre-swirl system in terms of the total pressure loss coefficient of the pre-swirl cavity, the discharge coefficient of the receiver holes, and the adiabatic effectiveness. It is shown that the nozzles with radial angles can adjust the tangential velocity and radial velocity and thus can influence the performance of a pre-swirl system. There is a lowerest value of total pressure loss in pre-swirl cavity, that is α = 90°, which can hardly be influenced by the radial angle of nozzle and pressure ratio π. For a specific swirl ratio β∞, there exists an optimal αopt where the discharge coefficient of receiver hole is maximum. Moreover, αopt decreases as pressure ratio π increases. And so is the adiabatic effectiveness Θad.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134276731","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}