Fanno Design of Blow-Off Lines in Heavy Duty Gas Turbine

2013 ◽  
Author(s):  
Marco Cioffi ◽  
Enrico Puppo ◽  
Andrea Silingardi
Keyword(s):  
Gas Turbines ◽  
Gas Flow ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Design Procedure ◽  
Flow Equation ◽  
Heavy Duty ◽  
Cross Sectional ◽  
Pipe Length ◽  
Choked Flow

In typical heavy duty gas turbines the multistage axial compressor is provided with anti-surge pipelines equipped with on-off valves (blow-off lines), to avoid dangerous flow instabilities during start-ups and shut-downs. Blow-off lines show some very peculiar phenomena and somewhat challenging fluid dynamics, which require a deeper regard. In this paper the blow-off lines in axial gas turbines are analyzed by adopting an adiabatic quasi-unidimensional model of the gas flow through a pipe with a constant cross-sectional area and involving geometrical singularities (Fanno flow). The determination of the Fanno limit, on the basis of the flow equation and the second principle of thermodynamics, shows the existence of a critical pipe length which is a function of the pipe parameters and the initial conditions: for a length greater than this maximum one, the model requires a mass-flow reduction. In addition, in the presence of a regulating valve, so-called multi-choked flow can arise. The semi-analytical model has been implemented and the results have been compared with a three-dimensional CFD analysis and cross-checked with available field data, showing a good agreement. The Fanno model has been applied for the analysis of some of the actual machines in the Ansaldo Energia fleet under different working conditions. The Fanno tool will be part of the design procedure of new machines. In addition it will define related experimental activities.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

Three-Dimensional Time-Resolved Flow Field in the First and Last Turbine Stage of a Heavy Duty Gas Turbine: Part II — Interpretation of Blade Pressure Fluctuations

2000 ◽  
Author(s):  
Martin von Hoyningen-Huene ◽  
Wolfram Frank ◽  
Alexander R. Jung
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Potential Interaction ◽  
Heavy Duty ◽  
Turbine Stage ◽  
Count Ratio ◽  
Heavy Duty Gas Turbine

Unsteady stator-rotor interaction in gas turbines has been investigated experimentally and numerically for some years now. Most investigations determine the pressure fluctuations in the flow field as well as on the blades. So far, little attention has been paid to a detailed analysis of the blade pressure fluctuations. For further progress in turbine design, however, it is mandatory to better understand the underlying mechanisms. Therefore, computed space–time maps of static pressure are presented on both the stator vanes and the rotor blades for two test cases, viz the first and the last turbine stage of a modern heavy duty gas turbine. These pressure fluctuation charts are used to explain the interaction of potential interaction, wake-blade interaction, deterministic pressure fluctuations, and acoustic waveswith the instantaneous surface pressure on vanes and blades. Part I of this two-part paper refers to the same computations, focusing on the unsteady secondary now field in these stages. The investigations have been performed with the flow solver ITSM3D which allows for efficient simulations that simulate the real blade count ratio. Accounting for the true blade count ratio is essential to obtain the correct frequencies and amplitudes of the fluctuations.

Multiobjective Hydraulic Cylinder Design

1988 ◽  
Vol 110 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Nestor F. Michelena ◽  
Alice M. Agogino
Keyword(s):  
Stress Ratio ◽  
Pressure Ratio ◽  
Circumferential Stress ◽  
Three Dimensional ◽  
Design Procedure ◽  
Hydraulic Cylinder ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Conflicting Objectives ◽  
Monotonicity Analysis

Monotonicity analysis is used to solve a three-objective optimization problem in which a hydraulic cylinder is to be designed. With the additional application of the Karush-Kuhn-Tucker optimality conditions a reduced symbolic design chart is obtained which is then utilized to obtain parametric numerical results. Two- and three-dimensional parametric Pareto-optimal plots are obtained for the three conflicting objectives: (1) cross-sectional area, (2) circumferential stress ratio and (3) pressure ratio. The analysis and design procedure strengthens and extends the results suggested by previous works.

Optimum Design of Internal Strain-Gage Balances: An Example of Three-Dimensional Shape Optimization

1987 ◽  
Vol 109 (2) ◽  
pp. 257-262 ◽  
Author(s):  
J. W. Hou ◽  
S. L. Twu
Keyword(s):  
Shape Optimization ◽  
Strain Gage ◽  
Three Dimensional ◽  
Design Procedure ◽  
Internal Strain ◽  
Main Body ◽  
Cross Sectional ◽  
Dimensional Shape ◽  
The Cross ◽  
Three Dimensional Shape

Internal strain-gage balances are often applied to measure the aerodynamic loads acting on the aircraft model in the wind-tunnel test. The balance system consists essentially of one main body and two shoulders elastically interconnected by multibar cages. Designing the cross-sectional geometry of such a multibar cage balance to improve the accuracy of load measurement is an important task for a balance engineer. The study presents an initial attempt to carry out such a design task in a systematic and automated manner. This is achieved by considering two aspects. One is to establish a mathematical model to analyze the stress distribution in the elastic cage and the other is to adopt a three-dimensional shape optimization scheme to design the cross-sectional geometry of the internal strain-gage balance. The design procedure has been completely automated in a computer program. Numerical examples shows that the proposed numerical scheme performs very well.

scholarly journals Comparative Evaluation of the Effect of Turbine Configuration on the Performance of Heavy-Duty Gas Turbines

1995 ◽  
Author(s):  
Tong Seop Kim ◽  
Sung Tack Ro
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Gas Flow ◽  
System Analysis ◽  
Performance Enhancement ◽  
Special Focus ◽  
Heavy Duty ◽  
Real Component ◽  
Turbine Performance ◽  
Performance Discrepancy

Performance of the heavy-duty gas turbine is analyzed with a special focus on the effect of turbine configuration. A general program is developed to fully represent the real component features by the characteristic models. The program is applied to simulate the performance of current heavy-duty gas turbines and its appropriateness for system analysis is verified. Meanwhile, the component parameters of real engines which describe the technology level are obtained. The effect of turbine parameters on the overall gas turbine performance is comparatively evaluated. A special emphasis is put on the analysis of the effect of number of turbine stages on the gas turbine performance and maximum power. Definite performance discrepancy due to the difference in the number of turbine stages is presented. It is found that number of turbine stages considerably affects the maximum gas flow and thermodynamic performance enhancement of the high-temperature advanced gas turbine is meaningful only when the mechanical constraint is relaxed.

Transient Analysis of Ceramic Vanes for Heavy Duty Gas Turbines

1973 ◽  
Author(s):  
R. T. Schaller ◽  
T. J. Rahaim
Keyword(s):  
Gas Turbines ◽  
Loading Condition ◽  
Transient Analysis ◽  
Thermal Loading ◽  
Thermal Stresses ◽  
Thermal Response ◽  
Inlet Temperature ◽  
Heavy Duty ◽  
Cross Sectional ◽  
Heavy Duty Gas Turbine

A transient analysis of thermal stresses in ceramic stationary vanes is presented. The application of ceramics to gas turbines represents an alternate approach for designers to increase operating temperatures. Highly dense silicon carbide and silicon nitride vanes are analyzed for application in a heavy duty gas turbine. The most severe thermal loading condition for this turbine is imposed on the vanes. The purpose of this paper is to present the effect of ceramic material, vane size, air foil, cross-sectional geometry, and gas inlet temperature on the thermal response of ceramic vanes.

A High-Efficiency Heat Exchanger for Closed Cycle and Heat Recovery Gas Turbines

2010 ◽  
Author(s):  
Luciano Andrea Catalano ◽  
Fabio De Bellis ◽  
Riccardo Amirante ◽  
Matteo Rignanese
Keyword(s):  
Heat Exchanger ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Gas Flow ◽  
High Efficiency ◽  
Small Diameter ◽  
Limiting Factor ◽  
Closed Cycle ◽  
Pipe Length ◽  
Alumina Particles

Designing and manufacturing high-efficiency heat exchangers is usually considered a limiting factor in the development of both heat recovery Joule-Brayton cycles and closed-cycle (external combustion) gas turbine plants. In this work, an innovative heat exchanger is proposed, modeled and partially tested to validate the developed numerical model employed for its design. The heat exchanger is based on an intermediate medium (aluminum oxide Al2O3) flowing in counter-current through an hot stream of gas. In this process, heat can be absorbed from the hot gas, temporarily stored and then similarly released in a second pipe, where a cold stream is warmed up. A flow of alumina particles with very small diameter (of the order of hundreds of micron) can be employed to enhance the heat transfer. Experimental tests demonstrate that simple one-dimensional steady equations, also neglecting conduction in the particles, can be effectively employed to simulate the flow in the vertical part of the pipe, namely to compute the pipe length required to achieve a prescribed heat exchange. On the other side, full three-dimensional Computational Fluid Dynamics (CFD) simulations have been performed to demonstrate that a more thorough gas flow and particle displacement analysis is needed to avoid some geometrical details that may cause a bad distribution of alumina particles, and thus to achieve high thermal efficiency.

Development and Validation of a Three-Dimensional Multiphase Flow Computational Fluid Dynamics Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Computational Fluid Dynamics Analysis

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines, this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach, resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach, including cavitation and air entrainment for high-speed turbomachinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty-type gas turbine journal bearings.

An Immersed Particle Heat Exchanger for Externally Fired and Heat Recovery Gas Turbines

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Luciano Andrea Catalano ◽  
Fabio De Bellis ◽  
Riccardo Amirante ◽  
Matteo Rignanese
Keyword(s):  
Heat Exchanger ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Gas Flow ◽  
High Efficiency ◽  
Small Diameter ◽  
Experimental Tests ◽  
Limiting Factor ◽  
Pipe Length ◽  
Alumina Particles

Designing and manufacturing high-efficiency heat exchangers is usually considered a limiting factor in the development of gas turbines employing either heat recovery Joule–Brayton cycles or external combustion. In this work, an innovative heat exchanger is proposed, modeled, and partially tested to validate the developed numerical model employed for its design. The heat exchanger is based on an intermediate medium (aluminum oxide Al2O3) flowing in countercurrent through an hot stream of gas. In this process, heat can be absorbed from the hot gas, temporarily stored, and then similarly released in a second pipe, where a cold stream is warmed up. A flow of alumina particles with very small diameter (of the order of hundreds of microns) can be employed to enhance the heat transfer. Experimental tests demonstrate that simple one-dimensional steady equations, also neglecting conduction in the particles, can be effectively employed to simulate the flow in the vertical part of the pipe, namely, to compute the pipe length required to achieve a prescribed heat exchange. On the other side, full three-dimensional computational fluid dynamics simulations have been performed to demonstrate that a more thorough gas flow and particle displacement analysis is needed to avoid a bad distribution of alumina particles and, thus, to achieve high thermal efficiency.

Adiabatic One-Dimensional Flow of a Perfect Gas through a Rotating Tube of Uniform Cross Section

1954 ◽  
Vol 4 (4) ◽  
pp. 373-399 ◽  
Author(s):  
K. Kestin ◽  
S. K. Zaremba
Keyword(s):  
Differential Equation ◽  
Gas Turbines ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Velocity Variation ◽  
Perfect Gas ◽  
Cross Sectional ◽  
One Dimensional ◽  
Linear Differential ◽  
Entrance Velocity

SummaryThe paper contains an analysis of the flow of a perfect gas with constant specific heats through a rotating channel of constant cross-sectional area, as used in certain helicopter propulsion systems and wind-driven gas turbines. The analysis is restricted to the adiabatic one-dimensional treatment, the Coriolis accelerations acting across a section being disregarded.The equations of motion and energy are deduced and, together with the equation of continuity, reduced to an ordinary non-linear differential equation of the first order, involving a dimensionless form of velocity and distance.The patterns of the integral curves of the differential equation are discussed and sketched by examining their asymptotic behaviour as well as that in the neighbourhood of singular points. It is shown that there exists a critical value of the angular velocity below which the flow remains subsonic in the pipe, if the entrance velocity is subsonic; it may, however, become sonic at the exit of the pipe. For supercritical angular velocities the flow may become sonic or supersonic in the pipe if the entrance velocity attains a given “ correct” but subsonic value. A method of examining for the possibility of shock formation is indicated.The initial conditions for the differential equation are deduced for the design and for the performance problem, two new flow functions being introduced and tabulated to facilitate practical calculations. Formulae are also deduced for the calculation of the pressure and Mach number variation from the previously calculated velocity variation along the pipe.Finally an approximate solution in closed terms is given for the case of small entrance velocities.

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