Through-Flow Analysis of Air-Cooled Gas Turbines

2012 ◽  
Author(s):  
Milan V. Petrovic ◽  
Alexander Wiedermann
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Flow Analysis ◽  
Solution Procedure ◽  
Distribution Model ◽  
Air Cooling ◽  
Test Cases ◽  
Pressure Losses ◽  
Through Flow ◽  
And Performance

This paper describes the development of a new through-flow method for the analysis of axial multistage turbines with cooling by air from compressor bleed. The method is based on a stream function approach and a finite element solution procedure. It includes a high-fidelity loss and deviation model with improved correlations. A radial distribution model of losses and a new spanwise mixing model are applied to simulate 3D flow effects. The calibration of the models is performed by calculation of a number of test cases with different configurations, with the aim of achieving high accuracy and optimum robustness for each of the test cases considered. Various types of cooling air injection were encompassed: film cooling, trailing edge injection and disc/endwall coolant flow. There are two effects of air cooling: (i) increase in mass flow downstream of the injection surface and (ii) reduction of the gas total temperature connected with total pressure losses. For both of these effects, the appropriate 2D models were developed and applied. The code was applied to flow analysis and performance prediction of a newly developed industrial gas turbine. Comparison of the predicted results and measured test data for a number of parameters showed good agreement. The results of the validation confirmed that this method based on calibrated correlations can be considered a reliable tool for flow analysis and parameter variation during the design phase.

Through-Flow Analysis of Air-Cooled Gas Turbines

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Milan V. Petrovic ◽  
Alexander Wiedermann
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Flow Analysis ◽  
Solution Procedure ◽  
Distribution Model ◽  
Air Cooling ◽  
Test Cases ◽  
Pressure Losses ◽  
Through Flow ◽  
And Performance

This paper describes the development of a new through-flow method for the analysis of axial multistage turbines with cooling by air from compressor bleed. The method is based on a stream function approach and a finite element solution procedure. It includes a high-fidelity loss and deviation model with improved correlations. A radial distribution model of losses and a new spanwise mixing model are applied to simulate 3D flow effects. The calibration of the models is performed by calculation of a number of test cases with different configurations, with the aim of achieving high accuracy and optimum robustness for each of the test cases considered. Various types of cooling air injection were encompassed: film cooling, trailing edge injection, and disk/endwall coolant flow. There are two effects of air cooling: (i) increase in mass flow downstream of the injection surface and (ii) reduction of the gas total temperature connected with total pressure losses. For both of these effects, the appropriate 2D models were developed and applied. The code was applied to flow analysis and performance prediction of a newly developed industrial gas turbine. Comparison of the predicted results and measured test data for a number of parameters showed good agreement. The results of the validation confirmed that this method based on calibrated correlations can be considered a reliable tool for flow analysis and parameter variation during the design phase.

Development and Validation of a New Universal Through Flow Method for Axial Compressors

2009 ◽  
Author(s):  
Milan V. Petrovic ◽  
Alexander Wiedermann ◽  
Milan B. Banjac
Keyword(s):  
Flow Analysis ◽  
Solution Procedure ◽  
Operating Conditions ◽  
Distribution Model ◽  
Test Cases ◽  
Flow Method ◽  
Through Flow ◽  
Wide Range ◽  
Flow Effects ◽  
And Performance

This paper describes the development of a new through flow method for the analysis of axial multistage compressors. The method is based on a stream function approach and a finite element solution procedure. It includes a high-fidelity loss and deviation model with improved correlations and endwall boundary layer calculation. A radial distribution model of losses and a new spanwise mixing model are applied to simulate 3D flow effects. The calibration of the models is made by calculation a number of test cases with different configurations with the aim of achieving high accuracy and optimum robustness for each of the test cases considered. The code was applied to flow analysis and performance prediction of a newly developed gas turbine compressor. Comparison of the predicted results and measured test data for the overall compressor performance and a number of parameters under different operating conditions showed good agreement. The results of the validation confirm that this method based on calibrated correlations can be applied as a reliable tool for flow analysis and parameter variation during the design phase for a wide range of compressor configurations.

Fully Coupled Through-Flow Method for Industrial Gas Turbine Analysis

2015 ◽  
Author(s):  
Milan V. Petrovic ◽  
Alexander Wiedermann
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Gas Turbines ◽  
Solution Procedure ◽  
Coupled Method ◽  
Flow Models ◽  
Through Flow ◽  
Path Computations ◽  
Industrial Gas Turbine ◽  
Fully Coupled

A fully coupled method for calculation of the entire flow in single- and twin-shaft industrial gas turbines is described. It is based on individual through-flow methods for axial compressors and air-cooled gas turbines developed by the authors that are coupled using simple combustion and cooling flow models connecting compressor and turbine flow paths. The through-flow computation for the analysis of cooled axial multistage turbines is fed by air from the compressor bleeds, which are part of the through-flow model of the compressor. The through-flow methods are based on a stream function approach and a finite element solution procedure. They include high-fidelity loss and deviation models with improved correlations. Advanced radial mixing and endwall boundary layer models are applied to simulate 3D flow effects. For air-cooled turbine analysis, various types of cooling air injection were adopted: film cooling, trailing edge injection and disc/endwall coolant flow. Compressor and turbine flow path computations were extensively validated individually and previously published by the authors. The coupled method was applied to operation analysis and performance prediction of a newly developed industrial gas turbine in single- and twin-shaft configurations. In the latter case, the matching point of the compressor and high-pressure turbine has to be determined iteratively as a function of the compressor speed line, firing temperature, cooling and bleed-off characteristics, which may be important for strong part-load behavior. This process is explained in the paper. Predicted gas turbine operation points are compared with experimental test data. It is demonstrated that the new method presented is an essential tool for overall gas turbine design and matching of the gas turbine components based on test rig experience. In addition, it is useful for diagnosis and supports the root-cause analysis of misbehaving field engines.

Through-Flow Modeling of Single- and Two-Shaft Gas Turbines at Wide Operating Range

2018 ◽  
Author(s):  
Alexander Wiedermann ◽  
Milan V. Petrovic
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Thermodynamic Cycle ◽  
Solution Procedure ◽  
Operating Conditions ◽  
Coupled Analysis ◽  
Ambient Conditions ◽  
Gas Treatment ◽  
Through Flow ◽  
End Wall

A program suite of coupled analysis tools for all components of industrial gas turbines developed by the authors was applied to off-design operation of single- and two-shaft gas turbines. The through-flow methods are based on a stream function approach and a finite element solution procedure. They include high-fidelity loss and deviation models with improved correlations. Advanced radial mixing and end-wall boundary layer models were applied to simulate 3D flow effects. For air-cooled turbine analysis, various types of cooling air injection were encompassed: film cooling, trailing edge injection and disc/end-wall coolant flow. Several improvements and extensions of the meridional solvers involved were employed. For axial compressor analysis, the original perfect gas treatment was replaced with the same real gas library that had already been implemented for flow computations in air-cooled expansion turbines and combustion modules. Ambient conditions with wet inflow of the compressor can now be taken into account. Compared to the previous model, better closure of the thermodynamic cycle can be achieved with the new approach. The meridional flow solver applied to the cooled turbine was upgraded and has become more stable for transonic outlet Mach numbers. With regard to the cooling flow supply, the codes offer greater freedom at the compressor extraction and turbine injection stations, allowing more realistic modeling of the secondary flow bifurcation. Off-design operating conditions and sensitivity studies for both single- and two-shaft gas turbines covering the entire range of interest are presented and are compared with experimental rig-engine data where available.

Experimental Study on Pressure Losses in Circular Orifices With Inlet Cross Flow

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Daniel Feseker ◽  
Mats Kinell ◽  
Matthias Neef
Keyword(s):  
Experimental Study ◽  
Film Cooling ◽  
Gas Turbines ◽  
Discharge Coefficient ◽  
Pressure Ratio ◽  
Cross Flow ◽  
Pressure Losses ◽  
Wide Range ◽  
Cooling Hole ◽  
Secondary Air

The ability to understand and predict the pressure losses of orifices is important in order to improve the air flow within the secondary air system. This experimental study investigates the behavior of the discharge coefficient for circular orifices with inlet cross flow which is a common flow case in gas turbines. Examples of this are at the inlet of a film cooling hole or the feeding of air to a blade through an orifice in a rotor disk. Measurements were conducted for a total number of 38 orifices, covering a wide range of length-to-diameter ratios, including short and long orifices with varying inlet geometries. Up to five different chamfer-to-diameter and radius-to-diameter ratios were tested per orifice length. Furthermore, the static pressure ratio across the orifice was varied between 1.05 and 1.6 for all examined orifices. The results of this comprehensive investigation demonstrate the beneficial influence of rounded inlet geometries and the ability to decrease pressure losses, which is especially true for higher cross flow ratios where the reduction of the pressure loss in comparison to sharp-edged holes can be as high as 54%. With some exceptions, the chamfered orifices show a similar behavior as the rounded ones but with generally lower discharge coefficients. Nevertheless, a chamfered inlet yields lower pressure losses than a sharp-edged inlet. The obtained experimental data were used to develop two correlations for the discharge coefficient as a function of geometrical as well as flow properties.

Aeroderivative Mechanical Drive Gas Turbines: The Design of Intermediate Pressure Turbines

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Alberto Scotti Del Greco ◽  
Vittorio Michelassi ◽  
Stefano Francini ◽  
Daniele Di Benedetto ◽  
Mahendran Manoharan
Keyword(s):  
Gas Turbines ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Secondary Flows ◽  
Power Turbine ◽  
Through Flow ◽  
Booster Compressor ◽  
Flow Curvature ◽  
Emission Limits ◽  
And Performance

Gas turbines engine designers are leaning toward aircraft engine architectures due to their footprint, weight, and performance advantages. Such engines need some modifications to both the combustion system, to comply with emission limits, and turbine rotational speed. Aeroderivative engines maintain the same legacy aircraft engine architecture and replace the fan and booster with a higher speed compressor booster driven by a single-stage intermediate turbine. A multistage free power turbine (FPT) sits on a separate shaft to drive compressors for liquefied natural gas (LNG) applications or generators. The intermediate-power turbine (IPT) design is important for the engine performance as it drives the booster compressor and sets the inlet boundary conditions to the downstream power turbine. This paper describes the experience of Baker Hughes, a GE company (BHGE) in the design of the intermediate turbine that sits in between a GE legacy aircraft engine core exhaust and the downstream power turbine. This paper focuses on the flow path of the turbine center frame (TCF)/intermediate turbine and the associated design, as well as on the 3D steady and unsteady computational fluid dynamics (CFD)-assisted design of the IPT stage to control secondary flows in presence of through flow curvature induced by the upstream TCF.

scholarly journals Internal Aerodynamics and Heat Transfer Problems Associated to Film Cooling of Gas Turbines

1979 ◽  
Author(s):  
Emile Le Grivès ◽  
J.-J. Nicolas ◽  
Jeanne Génot
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Flow Distribution ◽  
Transfer Coefficients ◽  
Pressure Losses ◽  
Effects Of Rotation ◽  
Transient Thermal ◽  
Turbine Airfoils ◽  
Transfer Problems

Heat transfer and aerodynamic processes within coolant ducts and film emission holes of high temperature gas turbine components have been investigated at ONERA by means of specially devised test rigs affording an adequate similitude of geometrical or aerothermal parameters. Results obtained in tests at steady or transient thermal regime are reported for several points of interest concerning internal coolant circuits: • Heat transfer through multihole parts of turbine airfoils • Aerodynamics of flows within perforated ducts, with special attention to coolant mass flow distribution, to pressure losses and heat transfer coefficients in small or scaled up turbine blade models • Heat transfer over a perforated wall, with mass transfer of the coolant flow through holes of various patterns and pitch-to-diameter ratio. Experimental data are discussed in regard to desired accuracy for the analysis of heat transfer in air-cooled gas turbines, except for the effects of rotation.

An Improved Streamline Curvature Approach for Off-Design Analysis of Transonic Compressors

2005 ◽  
Author(s):  
H. Khaleghi ◽  
A. M. Tousi ◽  
M. Boromand
Keyword(s):  
Numerical Approach ◽  
Solution Procedure ◽  
Good Combination ◽  
Powerful Method ◽  
Transonic Compressor ◽  
Streamline Curvature ◽  
Through Flow ◽  
Profile Losses ◽  
Suitable Combination ◽  
And Performance

Streamline curvature is still a powerful method in predicting the performance of turbomachines whose results will be more realistic if a good combination of losses and deviation is incorporated in the calculations. A streamline curvature through flow numerical approach is modified to better approximate the flow field and performance of a single stage transonic compressor by incorporating shock and profile losses using previous correlations. Deviation is estimated on the basis of several correlations and results are then compared with the present experimental data. Looking at the effect of above mentioned methods on design and off-design performance of compression system, it is possible to recommend that a suitable combination of these methods be incorporated in the solution procedure.

Experimental Analysis of Dust Separation in the Internal Cooling Air System of Gas Turbines

2002 ◽  
Author(s):  
O. Schneider ◽  
H. J. Dohmen ◽  
A. W. Reichert
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Internal Cooling ◽  
Test Rig ◽  
Air System ◽  
And Performance ◽  
Cooling Air

For further improvements in efficiency and performance a better understanding of the internal cooling air system of gas turbines, which provides the turbine rotor blades with cooling air, is necessary. With the increase of cooling air passing through the internal air system, a greater amount of air borne particles are transported to the film cooling holes at the turbine blade surface. In spite of their small size, these holes are critical for blade cooling. Blockage of only a few holes could have harmful effects on the cooling film surrounding the blade. As a result, a reduced mean time between maintenance or even unexpected operation faults of the gas turbine during operation occurs. With a new test rig, the behaviour of particles in the internal cooling air system could be investigated at realistic flow conditions compared to a modern, real world gas turbine. It is possible to simulate different particle sizes and dust concentrations in the coolant air. A first comparison of design expectations and measurements, showing the behaviour of air borne particles in the internal cooling air system under realistic environmental conditions is given in the paper. Further the design tools for nearly a full internal air system flow path could be validated with this new test rig.

Explicit Inversion of Stodola’s Area-Mach Number Equation

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Joseph Majdalani ◽  
Brian A. Maicke
Keyword(s):  
Mach Number ◽  
Gas Turbines ◽  
Numerical Solutions ◽  
Flow Analysis ◽  
Area Ratio ◽  
Dynamics Simulation ◽  
Computationally Efficient ◽  
Formal Approach ◽  
Specific Heats ◽  
And Performance

Stodola’s area-Mach number relation is one of the most widely used expressions in compressible flow analysis. From academe to aeropropulsion, it has found utility in the design and performance characterization of numerous propulsion systems; these include rockets, gas turbines, microcombustors, and microthrusters. In this study, we derive a closed-form approximation for the inverted and more commonly used solution relating performance directly to the nozzle area ratio. The inverted expression provides a computationally efficient alternative to solutions based on traditional lookup tables or root finding. Here, both subsonic and supersonic Mach numbers are obtained explicitly as a function of the area ratio and the ratio of specific heats. The corresponding recursive formulations enable us to specify the desired solution to any level of precision. In closing, a dual verification is achieved using a computational fluid dynamics simulation of a typical nozzle and through Bosley’s formal approach. The latter is intended to confirm the truncation error entailed in our approximations. In this process, both asymptotic and numerical solutions are compared for the Mach number and temperature distributions throughout the nozzle.

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