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Статті в журналах з теми "Heat Transfer, Cooling, Gas Turbine, Finite Element Anaylsis"
1
Dariusz Jakubek. "Numerical Simulation of Temperature Distribution in the Gas Turbine Blade." Communications - Scientific letters of the University of Zilina 23, no. 3 (July 1, 2021): B227—B236. http://dx.doi.org/10.26552/com.c.2021.3.b227-b236.
Повний текст джерелаАнотація:
This paper concentrates on temperature distribution in the gas turbine blade equipped by the cooling holes system on transient heat transfer. The present study requires the specification of internal and external boundary conditions. The calculations had been done using both Crank-Nicolson algorithm, explicit and implicit methods, in which different heat transfer coefficients on internal cooling surfaces of the holes were applied. The value of coefficients has a direct and crucial impact on the final result. The heat transfer coefficient of cooling the working surface of the of heat pipes was 1600 W/(m2K). It was found that there were no significant differences of temperature distribution in comparison of results from explicit method in the Ansys analysis, Crank-Nicolson algorithm and implicit method in Matlab. The simulation is based on Finite Element Method, which uses the Crank Nicolson algorithm.
2
Wang, M., Di Zhu, Ning Song Qu, and C. Y. Zhang. "Preparation of Turbulated Cooling Hole for Gas Turbine Blade Using Electrochemical Machining." Key Engineering Materials 329 (January 2007): 699–704. http://dx.doi.org/10.4028/www.scientific.net/kem.329.699.
Повний текст джерелаАнотація:
With the development of high performance of gas turbine engine, there is a tendency to design the ribs in the cooling hole in order to improve the heat transfer and cooling efficiency in a cooling passage. This paper focuses on a machining method of the burbulated cooling hole. The cooling hole is formed by electrochemical machining (ECM) process using a shaped electrode. The ribs on the hole wall form using ECM after the shaped electrode is lowed into the bottom of the straight hole machined in advance. The experimental results indicate that machining efficiency increases obviously. Various parameters affecting the forming of the cooling hole, such as voltages, electrolyte concentrations, and the material of the workpiece, are discussed in detail. Furthermore, the flow field and temperature field of the different type of cooling hole are analyzed using computational fluid dynamics (CFD) model and finite element method. Result shows that the heat transfer coefficient in rib channels could enhances significantly
3
Talya, Shashishekara S., J. N. Rajadas, and A. Chattopadhyay. "Multidisciplinary design optimization of film-cooled gas turbine blades." Mathematical Problems in Engineering 5, no. 2 (1999): 97–119. http://dx.doi.org/10.1155/s1024123x99001015.
Повний текст джерелаАнотація:
Design optimization of a gas turbine blade geometry for effective film cooling toreduce the blade temperature has been done using a multiobjective optimization formulation. Three optimization formulations have been used. In the first, the average blade temperature is chosen as the objective function to be minimized. An upper bound constraint has been imposed on the maximum blade temperature. In the second, the maximum blade temperature is chosen as the objective function to be minimized with an upper bound constraint on the average blade temperature. In the third formulation, the blade average and maximum temperatures are chosen as objective functions. Shape optimization is performed using geometric parameters associated with film cooling and blade external shape. A quasi-three-dimensional Navier–Stokes solver for turbomachinery flows is used to solve for the flow field external to the blade with appropriate modifications to incorporate the effect of film cooling. The heat transfer analysis for temperature distribution within the blade is performed by solving the heat diffusion equation using the finite element method. The multiobjective Kreisselmeier–Steinhauser function approach has been used in conjunction with an approximate analysis technique for optimization. The results obtained using both formulations are compared with reference geometry. All three formulations yield significant reductions in blade temperature with the multiobjective formulation yielding largest reduction in blade temperature.
4
Ali, Asif, Lorenzo Cocchi, Alessio Picchi, and Bruno Facchini. "Measurement of Internal Heat Transfer Distribution of Highly-Loaded Gas Turbine Blade by Combined Experimental/Numerical Method." E3S Web of Conferences 197 (2020): 10007. http://dx.doi.org/10.1051/e3sconf/202019710007.
Повний текст джерелаАнотація:
To ensure a passable life span of gas turbine hot gas path components the measurement of metal surface temperature is paramount. Experimental analyses on internally cooled devices are often performed on simplified or scaled up geometries, which reduces the applicability of the results to the actual real hardware. A more reliable estimation of cooling performance could be obtained if the real engine component is directly studied. To achieve this goal, an experimental campaign is performed to investigate the internal heat transfer distribution of an industrial blade, cooled by means of an internal U-shaped channel. During the experiment the blade is heated to a known temperature, then a coolant is introduced through the internal channel to induce a thermal transient, during which the external surface temperature is measured with the help of an infrared camera. Then a transient thermal finite element simulation is performed with the same boundary and inlet conditions of the experiment. Based on the output of the simulation, the internal heat transfer distribution is updated until convergence between simulation output external temperature and the experimental temperature is achieved. In order to start the iterative procedure, a first attempt estimation of the internal heat transfer distribution is obtained with a lumped thermal capacitance model approach. Different experiments were performed with different mass flow rates and the results are compared with available literature data. The obtained results allow to observe detailed heat transfer phenomena, strongly bound to the relevant features of the actual real cooling system.
5
Frąckowiak, Andrzej, and Michał Ciałkowski. "Application of discrete Fourier transform to inverse heat conduction problem regularization." International Journal of Numerical Methods for Heat & Fluid Flow 28, no. 1 (January 2, 2018): 239–53. http://dx.doi.org/10.1108/hff-09-2017-0381.
Повний текст джерелаАнотація:
Purpose This paper aims to present the Cauchy problem for the Laplace’s equation for profiles of gas turbine blades with one and three cooling channels. The distribution of heat transfer coefficient and temperature on the outer boundary of the blade are known. On this basis, the temperature on inner surfaces of the blade (the walls of cooling channels) is determined. Design/methodology/approach Such posed inverse problem was solved using the finite element method in the domain of the discrete Fourier transform (DFT). Findings Calculations indicate that the regularization in the domain of the DFT enables obtaining a stable solution to the inverse problem. In the example under consideration, problems with reconstruction constant temperature, assumed on the outer boundary of the blade, in the vicinity of the trailing and leading edges occurred. Originality/value The application of DFT in connection with regularization is an original achievement presented in this study.
6
Gkoutzamanis, Vasilis G., Justin N. W. Chiu, Guillaume Martin, and Anestis I. Kalfas. "Thermal energy storage in combined cycle power plants: comparing finite volume to finite element methods." E3S Web of Conferences 113 (2019): 01001. http://dx.doi.org/10.1051/e3sconf/201911301001.
Повний текст джерелаАнотація:
The research in thermal energy storage (TES) systems has a long track record. However, there are several technical challenges that need to be overcome, to become omnipresent and reach their full potential. These include performance, physical size, weight and dynamic response. In many cases, it is also necessary to be able to achieve the foregoing at greater and greater scale, in terms of power and energy. One of the applications in which these challenges prevail is in the integration of a thermal energy storage with the gas turbine (GT) compressor inlet conditioning system in a combined cycle power plant. The system is intended to provide either GT cooling or heating, based on the operational strategy of the plant. As a contribution to tackle the preceding, this article describes a series of 3-dimensional (3D) numerical simulations, employing different Computational Fluid Dynamics (CFD) methods, to study the transient effects of inlet temperature and flow rate variation on the performance of an encapsulated TES with phase change materials (PCM). A sensitivity analysis is performed where the heat transfer fluid (HTF) temperature varies from -7°C to 20°C depending on the operating mode of the TES (charging or discharging). The flow rate ranges from 50% to 200% of the nominal inflow rate. Results show that all examined cases lead to instant thermal power above 100kWth. Moreover, increasing the flow rate leads to faster solidification and melting. The increment in each process depends on the driving temperature difference between the encapsulated PCM and the HTF inlet temperature. Lastly, the effect of the inlet temperature has a larger effect as compared to the mass flow rate on the efficiency of the heat transfer of the system.
7
Nielsen, Annette E., Christoph W. Moll, and Stephan Staudacher. "Modeling and Validation of the Thermal Effects on Gas Turbine Transients." Journal of Engineering for Gas Turbines and Power 127, no. 3 (June 24, 2005): 564–72. http://dx.doi.org/10.1115/1.1850495.
Повний текст джерелаАнотація:
Secondary effects, such as heat transfer from fluid to engine structure and the resulting changes in tip and seal clearances affect component performance and stability. A tip clearance model to be used in transient synthesis codes has been developed. The tip clearance model is derived as a state space structure. The model parameters have been identified from thermomechanical finite element models. The model calculates symmetric rotor tip clearance changes in the turbomachinery and symmetric seal clearance changes in the secondary air system for engine transients within the entire flight envelope. The resulting changes in efficiency, capacity, and cooling airflows are fed into the performance program. Corrections for tip clearance changes on the component characteristics are derived from rig tests. The effect of seal clearance changes on the secondary air system is derived using sophisticated air system models. The clearance model is validated against FE thermomechanical models. The modeling method of modifying the component characteristics is verified comparing engine simulation and test data, which show good agreement. Based on a representative transient maneuver typical transient overshoots in fuel flow and turbine gas temperature and changes in component stability margins can be shown. With the use of this model in the performance synthesis the transient engine performance can be predicted more accurate than currently in the engine development program.
8
Trynov, A. V., and D. G. Sivykh. "DEVELOPMENT OF MEASURES TO INCREASE RELIABILITY TURBOCHARGER BEARING UNIT AUTOTRACTOR DIESEL ENGINE." Internal Combustion Engines, no. 1 (September 7, 2022): 12–21. http://dx.doi.org/10.20998/0419-8719.2022.1.02.
Повний текст джерелаАнотація:
To increase the reliability of small turbochargers, in particular the bearing unit, it is proposed to use in the automatic mode of local cooling of the bearing with compressed air. The design of the turbocharger with the central case which houses the bearing and to which engine oil from the engine lubrication system is brought under excess pressure is considered. This design is the most common among turbochargers of tractor engines. Forced engine modes can be critical for the bearing, accompanied by fluctuations in the exhaust gas temperature, for example, due to an uncontrolled increase in cyclic supply, a sharp increase in load. Such modes lead to an increase in temperature deformations of the turbine wheel, rotor, reduce the reliability of the turbocharger. Heat dissipation from the rotor through the bearing assembly into the lubrication system is insufficient, additional short-term local cooling is required. The study simulated heat transfer processes in the bearing assembly of a small turbocharger using the developed mathematical model based on the finite element method. To clarify the model, namely the boundary conditions of the thermal conductivity problem, a series of non-motorized experiments with a locally cooled bearing were performed. In the course of non-motorized experiments, the algorithm of the automatic control system operation was worked out, some of its structural elements were selected and tested in practice. Conducted non-motorized experiments and the results of mathematical modeling confirmed the effectiveness of using the system of automatic local cooling of the bearing assembly. These measures increase the reliability of small turbochargers.
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Radhakrishnan, Kanmaniraja, and Jun Su Park. "Thermal Analysis and Creep Lifetime Prediction Based on the Effectiveness of Thermal Barrier Coating on a Gas Turbine Combustor Liner Using Coupled CFD and FEM Simulation." Energies 14, no. 13 (June 24, 2021): 3817. http://dx.doi.org/10.3390/en14133817.
Повний текст джерелаАнотація:
Thermal barrier coating (TBC) plays a vital role in the gas turbine combustor liner (CL) to mitigate the internal heat transfer from combustion gas to the CL and enhance the parent material lifetime of the CL. This present study examined the thermal analysis and creep lifetime prediction based on three different TBC thicknesses, 400, 800, and 1200 μm, coated on the inner CL using the coupled computational fluid dynamics/finite element method. The simulation method was divided into three models to minimize the amount of computational work involved. The Eddy Dissipation Model was used in the first model to simulate premixed methane-air combustion, and the wall temperature of the inner CL was obtained. The conjugate heat transfer simulation on the external cooling flows from the rib turbulator, impingement jet, and cross flow, and the wall temperature of the outer CL was obtained in the second model. The thermal analysis was carried out in the third model using three different TBC thicknesses and incorporating the wall data from the first and second model. The effect of increasing TBC thickness shows that the TBC surface temperature was increased. Thereby, the inner CL metal temperature was decreased due to the TBC thickness as well as the material properties of Yttria Stabilized Zirconia, which has low thermal conductivity and a high thermal expansion coefficient. With the increase in TBC thickness, the average temperature difference between the TBC surface and the inner metal surface increased. In contrast, the average temperature difference between the inner and outer metal surfaces remained nearly constant. The von Mises equivalent stress, based on the material property and thermal expansion coefficient, was determined and used to find the creep lifetime of the CL using the Larson–Miller rupture curve for all TBC thickness cases in order to analyze the thermo-structure. Except in the C-channel, the increasing TBC thickness was found to effectively increase the CL lifespan. Furthermore, the case without TBC was compared with the damaged CL with cracks due to thermal stress, which was prevented by increasing TBC thickness shown in this present study.
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Dixon, Jeffrey A., Antonio Guijarro Valencia, Daniel Coren, Daniel Eastwood, and Christopher Long. "Main Annulus Gas Path Interactions—Turbine Stator Well Heat Transfer." Journal of Turbomachinery 136, no. 2 (September 26, 2013). http://dx.doi.org/10.1115/1.4023622.
Повний текст джерелаАнотація:
This paper summarizes the work of a five year research program into the heat transfer within cavities adjacent to the main annulus of a gas turbine. The work has been a collaboration between several gas turbine manufacturers, also involving a number of universities working together. The principal objective of the study has been to develop and validate computer modeling methods of the cooling flow distribution and heat transfer management, in the environs of multistage turbine disk rims and blade fixings, with a view to maintaining component and subsystem integrity, while achieving optimum engine performance and minimizing emissions. A fully coupled analysis capability has been developed using combinations of commercially available and in-house computational fluid dynamics (CFD) and finite element (FE) thermomechanical modeling codes. The main objective of the methodology is to help decide on optimum cooling configurations for disk temperature, stress, and life considerations. The new capability also gives us an effective means of validating the method by direct use of disk temperature measurements, where otherwise, additional and difficult to obtain parameters, such as reliable heat flux measurements, would be considered necessary for validation of the use of CFD for convective heat transfer. A two-stage turbine test rig has been developed and improved to provide good quality thermal boundary condition data with which to validate the analysis methods. A cooling flow optimization study has also been performed to support a redesign of the turbine stator well cavity to maximize the effectiveness of cooling air supplied to the disk rim region. The benefits of this design change have also been demonstrated on the rig. A brief description of the test rig facility will be provided together with some insights into the successful completion of the test program. Comparisons will be provided of disk rim cooling performance for a range of cooling flows and geometry configurations. The new elements of this work are the presentation of additional test data and validation of the automatically coupled analysis method applied to a partially cooled stator well cavity (i.e., including some local gas ingestion) and also the extension of the cavity cooling design optimization study to other new geometries.
Дисертації з теми "Heat Transfer, Cooling, Gas Turbine, Finite Element Anaylsis"
1
Ali, Asif. "Measurement of Heat Transfer Distrubution of Cooled Real Geometry Using Infrared Theromography." Doctoral thesis, 2020. http://hdl.handle.net/2158/1191845.
Повний текст джерелаАнотація:
Over the years, gas turbine industry is continuously exploring different methods to increase the turbine inlet temperature for improving the specific power output and thermal efficiency of gas turbine engines, which leads to thermal loads for the engine components, which are usually managed thanks to the introduction of complex internal cooling systems. For this reason, it is necessary to develop tools able to accurately
and quickly estimate thermal loads on turbine components. Typical experimental methods for assessing the heat transfer characteristics of such systems commonly rely upon scaled-up models investigated at nearly ambient conditions, since the size and operating environment of real engine parts make it extremely difficult to perform direct measurements. By doing so, however, many geometric and flow features of the real cooling system get lost, since the studied geometry is ideal and measurement constraints often require a simplification of the system itself. So there is a need for the development of a non-invasive, non-destructive, transient inverse technique which allows testing of real turbine blades temperature measurements.
A much more reliable evaluation of cooling performance would thus be obtained by studying the real hardware, which requires the development of a suitable technique. As an additional advantage, a similar method could also be employed for in-line inspection of manufactured parts, as to clearly identify faults and defects before the actual installation.
The aim of this work is to present the development and application of a measurement technique that allows to record internal heat transfer features of real components. In order to apply this method, based on similar approaches proposed in previous literature works, the component is initially heated up to a steady temperature, then a thermal transient is induced by injecting cool air in the internal cooling system. During this process, the external temperature evolution is recorded by means of an IR camera. Experimental data are then exploited to run a numerical procedure, based on a series of transient finite-element analyses of the component. Then two different approaches can be followed, which will be refereed as fluid model method and regression method respectively.
In fluid model method at the end of transient, finite element output external surface temperature is compared to the one which is obtained with experiment and the convective internal heat transfer coefficient is iterated continually with a root finding algorithm until the convergence between them is achieved. The coolant temperature will be updated during the transient with the help of a fluid model. This approach works very well for simplified geometries, in which convective internal heat transfer coefficient converges specific value but as we move to more complex geometries it may diverge. The reason is the inability of the fluid model to find accurate coolant temperature at certain regions, so a second approach is introduced for more complex geometries, the regression which is a modification version of the first approach.
In the regression method, the test duration is divided into an appropriate number of steps and for each of them, the heat flux on internal surfaces is iteratively updated to target the measured external temperature distribution at the end of step. Heat flux and internal temperature data for all the time steps are eventually employed in order to evaluate the convective heat transfer coefficient via linear regression. This technique has been successfully tested on a cooled high-pressure vane of a Baker Hughes heavy-duty gas turbine, which was realised thanks to the development of a dedicated test rig at the University of Florence, Italy. The obtained results provide sufficiently detailed heat transfer distributions in addition to allowing to appreciate the effect of different coolant mass flow rates. The methodology is also capable of identifying defects, which is demonstrated by inducing controlled faults in the component.
Тези доповідей конференцій з теми "Heat Transfer, Cooling, Gas Turbine, Finite Element Anaylsis"
1
Suresh, Batchu, Ainapur Brijesh, V. Kesavan, and S. Kishore Kumar. "Heat Transfer and Flow Studies of Different Cooling Configurations for Gas Turbine Rotor Blade." In ASME 2014 Gas Turbine India Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gtindia2014-8214.
Повний текст джерелаАнотація:
Military gas turbine engine operates at turbine entry temperatures (TET) of the order of 2000K. Increase in TET improves thermal efficiency and power output. The gas temperature is far above the allowable metal temperature of turbine components. Hence, there is a need to cool the components such as blades and vanes for safe operation. The blades are cooled by combination of internal convective cooling and external film-cooling. Rib tabulators are widely used in blade cooling passages to enhance heat transfer. In the present study, different rib tabulator configurations have been studied. 1D flow network model of blade cooling passages have been modeled using Flowmaster software. Flowmaster software estimates pressure losses, rotational effects and heat transfer of the coolant flow in the blade passages. Cooling passages are modeled as ducts while film cooling holes, impingement holes, tip holes and ejection holes are modeled as orifices. Experimentally measured heat transfer and pressure loss correlations are used in the analysis. The coolant pressure at inlet and sink pressure at exit of film cooling holes are given as input. The heat load coming on to the blade is also given as input for predicting the coolant temperature rise and blade metal temperature. The thermal analysis is carried out with different shaped rib turbulators such as V and W ribs with broken and continuous pattern. It is observed that thermal performance factor for a broken V rib configuration is better than other configurations. The metal temperature for broken V ribbed configuration is 25°C less compared other configurations. The effect of rotation on the blade temperature is also studied. The convective bulk temperatures and convective heat transfer coefficients obtained from 1D flow network are applied on 2D Finite Element (FE) model to obtain nodal temperature distribution.
2
Gritsch, M., A. Schulz, and S. Wittig. "Heat Transfer Coefficient Measurements of Film-Cooling Holes With Expanded Exits." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-028.
Повний текст джерелаАнотація:
Detailed measurements of heat transfer coefficients in the nearfield of three different film-cooling holes are presented. The hole geometries investigated include a cylindrical hole and two holes with a diffuser shaped exit portion (i.e. a fan-shaped and a laidback fanshaped hole). They were tested over a range of blowing ratios M = 0.25…1.75 at an external crossflow Mach number of 0.6 and a coolant-to-mainflow density ratio of 1.85. Additionally, the effect of the internal coolant supply Mach number is addressed. Temperatures of the diabatic surface downstream of the injection location are measured by means of an infrared camera system. They are used as boundary conditions for a finite element analysis to determine surface heat fluxes and heat transfer coefficients. The superposition method is applied to evaluate the overall film-cooling performance of the hole geometries investigated. As compared to the cylindrical hole, both expanded holes show significantly lower heat transfer coefficients downstream of the injection location, particularly at high blowing ratios. The laidback fanshaped hole provides a better lateral spreading of the injected coolant than the fanshaped hole which leads to lower laterally averaged heat transfer coefficients. Coolant passage crossflow Mach number affects the flowfield of the jet being ejected from the hole and, therefore, has an important impact on film-cooling performance.
3
Kaçar, E. Nadir, and L. Berrin Erbay. "Numerical Characterization of a Jet Impingement Cooling System Using Coupled Heat Transfer Analysis." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43371.
Повний текст джерелаАнотація:
In this study jet impingement cooling method is investigated with coupled analysis. Total cooling rate is observed for the specific jet impingement configuration using both finite volume and finite element methods. The specific configuration contains single row of jets of separate four rowed impingement cooling system. This single row is placed at the suction side of vane near trailing edge. For the observation, finite volume analysis is carried out via Fluent program. CFD model, which uses constant hot wall (target surface) temperature, is validated using the test case available in the literature. Constant wall temperature is 1250 K and hot gas of system is at 1500 K with 800 kPa. Moreover, conditions of cooling air are 500 K and 400 kPa. All conditions are determined to simulate specifications of a vane of middle class engine. The coupled solution is performed to calculate realistic heat transfer coefficient (htc) values. It involves concurrent execution of finite element analysis and finite volume analysis for aero-thermal optimization. Iterations are carried out via exchanging heat transfer coefficient values for finite element analysis and metal temperature values for finite volume analysis. At the end of three iterations, 8.1% decrease of htc values is obtained and optimum metal temperature values for the specified cooling configuration are calculated.
4
Baldauf, S., A. Schulz, and S. Wittig. "High Resolution Measurements of Local Heat Transfer Coefficients by Discrete Hole Film Cooling." In ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/99-gt-043.
Повний текст джерелаАнотація:
Local heat transfer coefficients on a flat plate surface downstream a row of cylindrical ejection holes were investigated. The parameters blowing angle, hole pitch, blowing rate, and density ratio were varied in a wide range emphasizing on engine relevant conditions. A high resolution IR-thermography technique was used for measuring surface temperature fields. Local heat transfer coefficients were obtained by a Finite Element analysis. IR-determined surface temperatures and backside temperatures of the cooled testplate measured with thermocouples were applied as boundary conditions in a heat flux computation. The superposition approach was employed to obtain the heat transfer coefficient hr referring to adiabatic wall temperatures in the presence of film cooling. Therefore, heat transfer results with different wall temperature conditions and adiabatic film cooling effectiveness results of identical flow situations (constant density ratios) were combined. Characteristic surface patterns of the locally resolved heat transfer coefficients hf depending on the various parameters were recognized and quantified. The detailed results are used to discuss the specific local heat transfer behavior in the presence of film cooling. They also provide a base of surface data essential for the validation of the heat transfer capabilities of CFD-codes in discrete hole film cooling.
5
Dixon, Jeffrey A., Antonio Guijarro Valencia, Daniel Coren, Daniel Eastwood, and Christopher Long. "Main Annulus Gas Path Interactions: Turbine Stator Well Heat Transfer." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68588.
Повний текст джерелаАнотація:
This paper summarises the work of a 5-year research programme into the heat transfer within cavities adjacent to the main annulus of a gas turbine. The work has been a collaboration between several gas turbine manufacturers, also involving a number of universities working together. The principal objective of the study has been to develop and validate computer modelling methods of the cooling flow distribution and heat transfer management, in the environs of multi-stage turbine disc rims and blade fixings, with a view to maintaining component and sub-system integrity, whilst achieving optimum engine performance and minimising emissions. A fully coupled analysis capability has been developed using combinations of commercially available and in-house computational fluid dynamics (CFD) and finite element (FE) thermo-mechanical modelling codes. The main objective of the methodology is to help decide on optimum cooling configurations for disc temperature, stress and life considerations. The new capability also gives us an effective means of validating the method by direct use of disc temperature measurements, where otherwise, additional and difficult to obtain parameters, such as reliable heat flux measurements, would be considered necessary for validation of the use of CFD for convective heat transfer. A two-stage turbine test rig has been developed and improved to provide good quality thermal boundary condition data with which to validate the analysis methods. A cooling flow optimisation study has also been performed to support a re-design of the turbine stator well cavity, to maximise the effectiveness of cooling air supplied to the disc rim region. The benefits of this design change have also been demonstrated on the rig. A brief description of the test rig facility will be provided together with some insights into the successful completion of the test programme. Comparisons will be provided of disc rim cooling performance, for a range of cooling flows and geometry configurations. The new elements of this work are the presentation of additional test data and validation of the automatically coupled analysis method applied to a partially cooled stator well cavity, (i.e. including some local gas ingestion); also the extension of the cavity cooling design optimisation study to other new geometries.
6
Medwell, J. O., W. D. Morris, J. Y. Xia, and C. Taylor. "An Investigation of Convective Heat Transfer in a Rotating Coolant Channel." In ASME 1990 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1990. http://dx.doi.org/10.1115/90-gt-329.
Повний текст джерелаАнотація:
A numerical method is presented for the determination of heat transfer rates in a cylindrical cooling duct within turbine blades which rotate about an axis orthogonal to its own axis of symmetry. The equations of motion and energy are solved in conjunction with the k-ε model of turbulence using the finite element method. The predicted results are compared with experimental data and it is clearly demonstrated that conduction in the solid boundary must be taken into account if satisfactory agreement is to be achieved. Excluding these effects can lead to an over-estimation of the maximum wall temperature by approximately 50%.
7
Cunha, Francisco J. T., and David A. DeAngelis. "Inverse Heat Transfer Engineering Design for Internally Cooled Gas Turbine Airfoils." In ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-312.
Повний текст джерелаАнотація:
In the design and development of modern gas turbine machines for efficient power generation in combined cycle applications, nozzle segments with airfoils and sidewalls need to be effectively cooled to operate in gas temperature environments in the excess of the melting point of the material of construction. Particular attention is given to the thermal evaluation as it affects component design life and performance. In this context, an optimization methodology is prescribed for inverse determination of required coolant heat transfer as a function of hot gas conditions and subjected to constraints associated with allowable metal temperature. A general boundary element method is used in the optimization process to provide a relatively fast and economically feasible design procedure. The optimized set of heat transfer results are converged when the external metal temperatures fall within acceptable limits. Once the magnitude and distribution of required coolant heat transfer coefficients are obtained, the cooling technique can be devised using available or referenced correlations for impingement jets through insert plates, banks of pin fins, turbulators, or just simply forced convection through internal passages. An illustrative example is presented with a Joukowski airfoil using a finite element method as an alternative method of solution for comparison and verification.
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Wang, Zuolan, Peter T. Ireland, and Terry V. Jones. "Detailed Heat Transfer Coefficient Measurements and Thermal Analysis at Engine Conditions of a Pedestal With Fillet Radii." In ASME 1993 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/93-gt-329.
Повний текст джерелаАнотація:
The heat transfer coefficient over the surface of a pedestal with fillet radii has been measured using thermochromic liquid crystals and the transient heat transfer method. The tests were performed at engine representative Reynolds numbers for a geometry typical of those used in turbine blade cooling systems. The heat conduction process that occurs in the engine was subsequently modelled numerically with a finite element discretization of the solid pedestal. The measured heat transfer coefficients were used to derive the exact boundary conditions applicable to the engine. The temperature field within the pedestal, calculated using the correct heat transfer coefficient distribution is compared to that calculated using an area averaged heat transfer coefficient. Metal temperature differences of 90K are predicted across the blade wall.
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Nagabandi, K., S. Mills, X. Zhang, D. J. J. Toal, and A. J. Keane. "Surrogate Based Design Optimisation of Combustor Tile Cooling Feed Holes." In ASME 2017 Gas Turbine India Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gtindia2017-4586.
Повний текст джерелаАнотація:
Gas turbine operating temperatures are projected to continue to increase and this leads to drawing more cooling air to keep the metals below their operational temperatures. This cooling air is chargeable as it has gone through several stages of compressor work. In this paper a surrogate based design optimization approach is used to reduce cooling mass flow on combustor tiles to attain pre-defined maximum metal surface temperatures dictated by different service life requirements. A series of Kriging based surrogate models are constructed using an efficient GPU based particle swarm algorithm. Various mechanical and manufacturing constraints such as hole ligament size, encroachment of holes onto other features like side rails, pedestals, dilution ports and retention pins etc. are built into the models and these models are trained using a number of high fidelity simulations. Furthermore these simulations employ the proprietary Rolls-Royce Finite Element Analysis (FEA) package SCO3 to run thermal analysis predicting surface heat transfer coefficients, fluid temperatures and finally metal surface temperatures. These temperature predictions are compared against the pre-defined surface temperature limits for a given service life and fed back to the surrogate model to run for new hole configuration. This way the loop continues until an optimized hole configuration is attained. Results demonstrate the potential of this optimization technique to improve the life of combustor tile by reducing tile temperature and also to reduce the amount of cooling air required.
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Little, D., J. Wilson, and J. Liburdi. "Extension of Gas Turbine Disc Life by Retrofitting a Supplemental Cooling System." In ASME 1985 International Gas Turbine Conference and Exhibit. American Society of Mechanical Engineers, 1985. http://dx.doi.org/10.1115/85-gt-150.
Повний текст джерелаАнотація:
The turbine disc lives in some industrial gas turbines are limited to much less than 100,000 hours by the formation of high temperature creep cracks when the engine is operated continuously at full load. Turbine users have experienced many costly repairs and even a wreck due to this recurring problem. The problem can be eliminated and the existing uncracked disc lives extended well beyond the 100,000 hour milestone by the retrofit of a supplemental disc cooling system. The engineering work involved in properly identifying the cause and designing the cooling modification, including performance, aerodynamic, cooling network, finite element heat transfer, and stress analysis is explained. The build and test of the prototype cooling air system on a mechanical drive unit is discussed and test results demonstrating the success of the method given. The concept of adding a supplemental disc cooling system to extend the expiring turbine disc lives of many mature frames has been demonstrated to be both practical and economical.