Blade Excitation in Pulse-Charged Mixed-Flow Turbocharger Turbines

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Stephan M. Senn ◽  
Martin Seiler ◽  
Ottmar Schaefer
Keyword(s):  
Three Dimensional ◽  
Numerical Approach ◽  
Forced Response ◽  
Computational Fluid Mechanics ◽  
Response Analysis ◽  
Mixed Flow ◽  
Design And Optimization ◽  
Modeling Approach ◽  
Measured Stress ◽  
Turbine Design

In this article, a fully three-dimensional computational modeling approach in the time and frequency domain is presented, which allows to accurately predicting fluid-structure interactions in pulse-charged mixed-flow turbocharger turbines. As part of the approach, a transient computational fluid mechanics analysis is performed based on the compressible inviscid Euler equations covering an entire engine cycle. The resulting harmonic orders of aerodynamic excitation are imposed in a forced response analysis of the respective eigenvector to determine effective stress amplitudes. The modeling approach is validated with experimental results based on various mixed-flow turbine designs. It is shown that the numerical results accurately predict the measured stress levels. The numerical approach can be used in the turbine design and optimization process. Aerodynamic excitation forces are the main reason for high cycle fatigue in turbocharger turbines and therefore a fundamental understanding is of key importance.

Blade Excitation in Pulse-Charged Mixed-Flow Turbocharger Turbines

2009 ◽  
Author(s):  
Stephan M. Senn ◽  
Martin Seiler ◽  
Ottmar Schaefer
Keyword(s):  
Three Dimensional ◽  
Numerical Approach ◽  
Forced Response ◽  
Computational Fluid Mechanics ◽  
Response Analysis ◽  
Mixed Flow ◽  
Design And Optimization ◽  
Modeling Approach ◽  
Measured Stress ◽  
Turbine Design

In this article, a fully three-dimensional computational modeling approach in the time and frequency domain is presented which allows to accurately predicting fluid-structure interactions (FSI) in pulse-charged mixed-flow turbocharger turbines. As part of the approach, a transient computational fluid mechanics analysis is performed based on the compressible inviscid Euler equations covering an entire engine cycle. The resulting harmonic orders of aerodynamic excitation are imposed in a forced response analysis of the respective eigenvector to determine effective stress amplitudes. The modeling approach is validated with experimental results based on various mixed-flow turbine designs. It is shown that the numerical results accurately predict the measured stress levels. The numerical approach can be used in the turbine design and optimization process. Aerodynamic excitation forces are the main reason for high cycle fatigue in turbocharger turbines and therefore, a fundamental understanding is of key importance.

Detection of Cracks in Mistuned Bladed Disks Using Reduced-Order Models and Vibration Data

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Chulwoo Jung ◽  
Akira Saito ◽  
Bogdan I. Epureanu
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Equations Of Motion ◽  
Computational Cost ◽  
Three Dimensional ◽  
Cost Savings ◽  
Forced Response ◽  
Response Analysis ◽  
Reduced Order Models ◽  
Reduced Order

A novel methodology to detect the presence of a crack and to predict the nonlinear forced response of mistuned turbine engine rotors with a cracked blade and mistuning is developed. The combined effects of the crack and mistuning are modeled. First, a hybrid-interface method based on component mode synthesis is employed to develop reduced-order models (ROMs) of the tuned system with a cracked blade. Constraint modes are added to model the displacements due to the intermittent contact between the crack surfaces. The degrees of freedom (DOFs) on the crack surfaces are retained as active DOFs so that the physical forces due to the contact/interaction (in the three-dimensional space) can be accurately modeled. Next, the presence of mistuning in the tuned system with a cracked blade is modeled. Component mode mistuning is used to account for mistuning present in the uncracked blades while the cracked blade is considered as a reference (with no mistuning). Next, the resulting (reduced-order) nonlinear equations of motion are solved by applying an alternating frequency/time-domain method. Using these efficient ROMs in a forced response analysis, it is found that the new modeling approach provides significant computational cost savings, while ensuring good accuracy relative to full-order finite element analyses. Furthermore, the effects of the cracked blade on the mistuned system are investigated and used to detect statistically the presence of a crack and to identify which blade of a full bladed disk is cracked. In particular, it is shown that cracks can be distinguished from mistuning.

Impact of Turbine Center Frame Wakes on Downstream Rows in Heavy-Duty Low-Pressure Turbine

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Sara Biagiotti ◽  
Juri Bellucci ◽  
Michele Marconcini ◽  
Andrea Arnone ◽  
Gino Baldi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Low Pressure ◽  
Numerical Approach ◽  
Forced Response ◽  
Operating Conditions ◽  
Response Analysis ◽  
Test Case ◽  
Low Pressure Turbine ◽  
Harmonic Content ◽  
The Impact

Abstract In this work, the effects of turbine center frame (TCF) wakes on the aeromechanical behavior of the downstream low-pressure turbine (LPT) blades are numerically investigated and compared with the experimental data. A small industrial gas turbine has been selected as a test case, composed of a TCF followed by the two low-pressure stages and a turbine rear frame (TRF) before the exhaust plenum. Full annulus unsteady computations of the whole low-pressure module have been performed. Two operating conditions, full (100%) and partial (50%) load, have been investigated with the aim of highlighting the impact of TCF wakes convection and diffusion through the downstream rows. Attention was paid to the harmonic content of rotors’ blades. The results show a slower decay of the wakes through the downstream rows in off-design conditions compared with the design point. The analysis of the rotors’ frequency spectrum reveals that moving from design to off-design conditions, the effect of the TCF does not change significantly. The harmonic contribution of all turbine components has been extracted, highlighting the effect of statoric parts on the last LPT blade. The TCF harmonic content remains the most relevant from an aeromechanic point of view as per experimental evidence, and it is considered for an forced response analysis (FRA) on the last LPT blade itself. Finally, aerodynamic and aeromechanic predictions have been compared with the experimental data to validate the numerical approach. Some general design solutions aimed at mitigating the TCF wakes impact are discussed.

Study of Hot Streak Effects in a Counter-Rotating Turbine

2001 ◽  
Author(s):  
L. C. Ji ◽  
J. Z. Xu ◽  
J. Chen
Keyword(s):  
High Pressure ◽  
Heat Load ◽  
Three Dimensional ◽  
High Pressure Turbine ◽  
Design And Optimization ◽  
Low Pressure Turbine ◽  
Second Stage ◽  
Euler Solver ◽  
Hot Streak ◽  
Turbine Design

Based on its convection nature, some influences of the hot streak on a 1+1 (with inter-blade vane) counter-rotating turbine are studied by using a three-dimensional (3D) unsteady Euler solver. Emphasis is laid on the hot streak effect to the blade heat load and the clocking effects between hot streak and blade rows. One temperature distortion magnitude, two spanwise and four tangential positions, four clocking locations between vanes of first and second stage are examined. Results show that the effect of the hot streak on a counter-rotating turbine is nearly the same as a conventional turbine. However, clocking between the hot streak and the vane of the high pressure turbine (HPT) exerts significant influences on the heat load of the whole HPT stage. Also, clocking between the HPT vane and the vane of the low pressure turbine (LPT) affects the heat load of the LPT greatly. These effects cannot be captured with the steady flow assumption. So time accurate simulation about the hot streak/blade interaction must be used as a basis for the turbine design and optimization.

scholarly journals Thermo-acoustic cross-talk between cans in a can-annular combustor

2017 ◽  
Vol 9 (4) ◽  
pp. 452-469 ◽  
Author(s):  
Federica Farisco ◽  
Lukasz Panek ◽  
Jim BW Kok
Keyword(s):  
Cross Talk ◽  
Three Dimensional ◽  
Forced Response ◽  
Eddy Simulation ◽  
Acoustic Interaction ◽  
Annular Combustor ◽  
Engine Failure ◽  
Acoustic Instabilities ◽  
Turbine Design ◽  
2D And 3D

Thermo-acoustic instabilities in gas turbine engines are studied to avoid engine failure. Compared to the engines with annular combustors, the can-annular combustor design should be less vulnerable to acoustic burner-to-burner interaction, since the burners are acoustically coupled only by the turbine stator stage and the plenum. However, non-negligible cross-talk between neighboring cans has been observed in measurements in such machines. This study is focused on the analysis of the acoustic interaction between the cans. Simplified two-dimensional (2D) and three-dimensional (3D) equivalent systems representing the corresponding engine alike turbine design are investigated. Thermo-acoustic instabilities are reproduced using a forced response approach. Compressible large eddy simulation based on the open source computational fluid dynamics OpenFOAM framework is used applying accurate boundary conditions for the flow and the acoustics. A study of the reflection coefficient and of the transfer function between the cans has been performed. Comparisons between 2D and 3D equivalent configurations have been evaluated.

scholarly journals Application of Network Analysis to Flow Systems with Alternating Wave Channels: Part B. (Superimposed Drag-Pressure Flows in Extrusion)

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1900
Author(s):  
Christian Marschik ◽  
Wolfgang Roland ◽  
Marius Dörner ◽  
Sarah Schaufler ◽  
Volker Schöppner ◽  
...  
Keyword(s):  
High Performance ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Wave Dispersion ◽  
Pressure Profile ◽  
Design And Optimization ◽  
Single Screw ◽  
Modeling Approach ◽  
Single Screw Extrusion ◽  
Pressure Flows

Due to progress in the development of screw designs over recent decades, numerous high-performance screws have become commercially available in single-screw extrusion. While some of these advanced designs have been studied intensively, others have received comparatively less attention. We developed and validated a semi-numerical network-theory-based modeling approach to predicting flows of shear-thinning polymer melts in wave-dispersion screws. In the first part (Part A), we systematically reduced the complexity of the flow analysis by omitting the influence of the screw rotation on the conveying behavior of the wave zone. In this part (Part B), we extended the original theory by considering the drag flow imposed by the screw. Two- and three-dimensional melt-conveying models were combined to predict locally the conveying characteristics of the wave channels in a discretized flow network. Extensive experiments were performed on a laboratory single-screw extruder, using various barrel designs and wave-dispersion screws. The predictions of our semi-numerical modeling approach for the axial pressure profile along the wave-dispersion zone accurately reproduce the experimental data. Removing the need for time-consuming numerical simulations, this modeling approach enables fast analyses of the conveying behavior of wave-dispersion zones, thereby offering a useful tool for design and optimization studies and process troubleshooting.

Detection of Cracks in Mistuned Bladed Disks Using Reduced Order Models and Vibration Data

2011 ◽  
Author(s):  
Chulwoo Jung ◽  
Akira Saito ◽  
Bogdan I. Epureanu
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Equations Of Motion ◽  
Computational Cost ◽  
Three Dimensional ◽  
Cost Savings ◽  
Forced Response ◽  
Response Analysis ◽  
Reduced Order Models ◽  
Reduced Order

A novel methodology to detect the presence of a crack and to predict the nonlinear forced response of mistuned turbine engine rotors with a cracked blade and mistuning is developed. The combined effects of the crack and mistuning are modeled. First, a hybrid-interface method based on component mode synthesis is employed to develop reduced order models (ROMs) of the tuned system with a cracked blade. Constraint modes are added to model the displacements due to the intermittent contact between the crack surfaces. The degrees of freedom (DOFs) on the crack surfaces are retained as active DOFs so that the physical forces due to the contact/interaction (in the three-dimensional space) can be accurately modeled. Next, the presence of mistuning in the tuned system with a cracked blade is modeled. Component mode mistuning is used to account for mistuning present in the un-cracked blades while the cracked blade is considered as a reference (with no mistuning). Next, the resulting (reducedorder) nonlinear equations of motion are solved by applying an alternating frequency/time-domain method. Using these efficient ROMs in a forced response analysis, it is found that the new modeling approach provides significant computational cost savings, while ensuring good accuracy relative to full-order finite element analyses. Furthermore, the effects of the cracked blade on the mistuned system are investigated, and used to detect statistically the presence of a crack and to identify which blade of a full bladed disk is cracked. In particular, it is shown that cracks can be distinguished from mistuning.

Modeling and Assessment of the Produced Water Discharges from Offshore Petroleum Platforms

2007 ◽  
Vol 42 (4) ◽  
pp. 303-310 ◽  
Author(s):  
Zhi Chen ◽  
Lin Zhao ◽  
Kenneth Lee ◽  
Charles Hannath
Keyword(s):  
Random Walk ◽  
Produced Water ◽  
Model Development ◽  
Three Dimensional ◽  
Monitoring Program ◽  
Ecological Monitoring ◽  
Numerical Approach ◽  
Ocean Model ◽  
Scale Model ◽  
Water Stream

Abstract There has been a growing interest in assessing the risks to the marine environment from produced water discharges. This study describes the development of a numerical approach, POM-RW, based on an integration of the Princeton Ocean Model (POM) and a Random Walk (RW) simulation of pollutant transport. Specifically, the POM is employed to simulate local ocean currents. It provides three-dimensional hydrodynamic input to a Random Walk model focused on the dispersion of toxic components within the produced water stream on a regional spatial scale. Model development and field validation of the predicted current field and pollutant concentrations were conducted in conjunction with a water quality and ecological monitoring program for an offshore facility located on the Grand Banks of Canada. Results indicate that the POM-RW approach is useful to address environmental risks associated with the produced water discharges.

scholarly journals Radial Turbine Design for Solar Chimney Power Plants

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 674
Author(s):  
Paul Caicedo ◽  
David Wood ◽  
Craig Johansen
Keyword(s):  
Power Plants ◽  
Reference Frames ◽  
Three Dimensional ◽  
Discrete Ordinates ◽  
Large Area ◽  
Solar Chimney ◽  
Cfd Simulations ◽  
Radial Turbine ◽  
Design Changes ◽  
Turbine Design

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.

Sign in / Sign up

Export Citation Format

Share Document