A Fully Integrated Approach to Component Zooming Using Computational Fluid Dynamics

2004 ◽  
Vol 128 (3) ◽  
pp. 579-584 ◽  
Author(s):  
Vassilios Pachidis ◽  
Pericles Pilidis ◽  
Fabien Talhouarn ◽  
Anestis Kalfas ◽  
Ioannis Templalexis
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Gas Turbine ◽  
Engine Performance ◽  
Integrated Approach ◽  
High Fidelity ◽  
Performance Simulation ◽  
Fully Integrated ◽  
Engine Component ◽  
Simulation Strategy

Background . This study focuses on a simulation strategy that will allow the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to be transferred to an engine system analysis carried out at a lower level of resolution. This work will enable component-level, complex physical processes to be captured and analyzed in the context of the whole engine performance, at an affordable computing resource and time. Approach. The technique described in this paper utilizes an object-oriented, zero-dimensional (0D) gas turbine modeling and performance simulation system and a high-fidelity, three-dimensional (3D) computational fluid dynamics (CFD) component model. The work investigates relative changes in the simulated engine performance after coupling the 3D CFD component to the 0D engine analysis system. For the purposes of this preliminary investigation, the high-fidelity component communicates with the lower fidelity cycle via an iterative, semi-manual process for the determination of the correct operating point. This technique has the potential to become fully automated, can be applied to all engine components, and does not involve the generation of a component characteristic map. Results. This paper demonstrates the potentials of the “fully integrated” approach to component zooming by using a 3D CFD intake model of a high bypass ratio turbofan as a case study. The CFD model is based on the geometry of the intake of the CFM56-5B2 engine. The high-fidelity model can fully define the characteristic of the intake at several operating condition and is subsequently used in the 0D cycle analysis to provide a more accurate, physics-based estimate of intake performance (i.e., pressure recovery) and hence, engine performance, replacing the default, empirical values. A detailed comparison between the baseline engine performance (empirical pressure recovery) and the engine performance obtained after using the coupled, high-fidelity component is presented in this paper. The analysis carried out by this study demonstrates relative changes in the simulated engine performance larger than 1%. Conclusions. This investigation proves the value of the simulation strategy followed in this paper and completely justifies (i) the extra computational effort required for a more automatic link between the high-fidelity component and the 0D cycle, and (ii) the extra time and effort that is usually required to create and run a 3D CFD engine component, especially in those cases where more accurate, high-fidelity engine performance simulation is required.

A Fully Integrated Approach to Component Zooming Using Computational Fluid Dynamics

2005 ◽  
Author(s):  
Vassilios Pachidis ◽  
Pericles Pilidis ◽  
Fabien Talhouarn ◽  
Anestis Kalfas ◽  
Ioannis Templalexis
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Gas Turbine ◽  
System Analysis ◽  
Engine Performance ◽  
Integrated Approach ◽  
Pressure Recovery ◽  
High Fidelity ◽  
Fully Integrated ◽  
Characteristic Map

This study focuses on a simulation strategy that will allow the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to be transferred to an engine system analysis carried out at a lower level of resolution. This work will enable component-level, complex physical processes to be captured and analyzed in the context of the whole engine performance, at an affordable computing resource and time. The technique described in this paper utilizes an object-oriented, zero-dimensional (0-D) gas turbine modeling and performance simulation system and a high-fidelity, three-dimensional (3-D) computational fluid dynamics (CFD) component model. The work investigates relative changes in the simulated engine performance after coupling the 3-D CFD component to the 0-D engine analysis system. For the purposes of this preliminary investigation, the high-fidelity component communicates with the lower fidelity cycle via an iterative, semi-manual process for the determination of the correct operating point. This technique has the potential to become fully automated, can be applied to all engine components and does not involve the generation of a component characteristic map. This paper demonstrates the potentials of the ‘fully integrated’ approach to component zooming by using a 3-D CFD intake model of a high by-pass ratio (HBR) turbofan as a case study. The CFD model is based on the geometry of the intake of the CFM56-5B2 engine. The high-fidelity model can fully define the characteristic of the intake at several operating condition and is subsequently used in the 0-D cycle analysis to provide a more accurate, physics-based estimate of intake performance (i.e. pressure recovery) and hence, engine performance, replacing the default, empirical values. A detailed comparison between the baseline engine performance (empirical pressure recovery) and the engine performance obtained after using the coupled, high-fidelity component is presented in this paper. The analysis carried out by this study, demonstrates relative changes in the simulated engine performance larger than 1%.

A Partially Integrated Approach to Component Zooming Using Computational Fluid Dynamics

2005 ◽  
Author(s):  
Vassilios Pachidis ◽  
Pericles Pilidis ◽  
Geoffrey Guindeuil ◽  
Anestis Kalfas ◽  
Ioannis Templalexis
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Gas Turbine ◽  
Engine Performance ◽  
Integrated Approach ◽  
Operating Conditions ◽  
Pressure Recovery ◽  
High Fidelity ◽  
Cfd Model ◽  
Characteristic Map

This study focuses on a simulation strategy that will allow the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to be transferred to an engine system analysis carried out at a lower level of resolution. This work will enable component-level, complex physical processes to be captured and analyzed in the context of the whole engine performance, at an affordable computing resource and time. The technique described in this paper utilizes an object-oriented, zero-dimensional (0-D) gas turbine modeling and performance simulation system and a high-fidelity, three-dimensional (3-D) computational fluid dynamics (CFD) component model. The technique is called ‘partially integrated’ zooming, in that there is no automatic link between the 0-D engine cycle and the 3-D CFD model. It can be applied to all engine components and involves the generation of a component characteristic map via an iterative execution of the 0-D cycle and the 3-D CFD model. This work investigates relative changes in the simulated engine performance after integrating the CFD-generated component map into the 0-D engine analysis. This paper attempts to demonstrate the ‘partially integrated’ approach to component zooming by using a 3-D CFD intake model of a high by-pass ratio (HBR) turbofan as a case study. The CFD model is based on the geometry of the intake of the CFM56-5B2 engine. The CFD-generated performance map can fully define the characteristic of the intake at several operating conditions and is subsequently used to provide a more accurate, physics-based estimate of intake performance (i.e. pressure recovery) and hence, engine performance, replacing the default, empirical values within the 0-D cycle model. A detailed comparison between the baseline engine performance (empirical pressure recovery) and the engine performance obtained after using the CFD-generated map is presented in this paper. The analysis carried out by this study, demonstrates relative changes in the simulated engine performance larger than 1%.

Military Engine Response to Compressor Inlet Stratified Pressure Distortion by an Integrated CFD Analysis

2006 ◽  
Author(s):  
Leonardo Melloni ◽  
Petros Kotsiopoulos ◽  
Anthony Jackson ◽  
Vassilios Pachidis ◽  
Pericles Pilidis
Keyword(s):  
Engine Performance ◽  
Low Pressure ◽  
Operating Conditions ◽  
High Fidelity ◽  
Inlet Flow ◽  
Performance Simulation ◽  
Simulation Strategy ◽  
Compressor Inlet ◽  
And Performance ◽  
Pressure Compressor

Especially in aircraft applications, the inlet flow is quite often non uniform resulting in severe changes in compressor performance and hence, engine performance. The magnitude of this phenomenon can be amplified in military engines due to the complex shape of intake ducts and the extreme flight conditions. The usual approach to engine performance simulation is based on non-dimensional maps for compressors and turbines and assumes uniform flow characteristics throughout the engine. In the context of the whole engine performance, component-level, complex physical processes, such as compressor inlet flow distortion, can not be captured and analyzed. This work adopts a simulation strategy that allows the performance characteristics of an engine component, resolved from a detailed, high-fidelity analysis, to be transferred to an engine system analysis carried out at a lower level of fidelity. The methodology described in this paper utilizes an object-oriented, zero-dimensional gas turbine modeling and performance simulation system and a high-fidelity, three-dimensional, computational fluid dynamics (CFD), low-pressure compressor model. The CFD model is based on the overall geometry and performance of the low-pressure compressor of a modern, two-spool, low by-pass ratio (LBR) military turbofan engine and is subjected to both clean and distorted inlet flows. The analysis involves the generation of two characteristic maps for the first stage of the LP compressor from CFD simulations that account for a range of operating conditions and power settings with a uniform and a distorted inlet flow. The same simulation strategy could be adopted for other engine components such as the intake or the high-pressure compressor and for different magnitudes and types of distortion (i.e. radial, circumferential). By integrating the CFD-generated maps, into the 0-D engine analysis system, this paper presents a relative comparison between the ‘uniform-inlet’ engine performance (baseline compressor stage map) and the engine performance obtained after using the map accounting for a typical extent of stratified inlet distortion. The analysis carried out by this study, demonstrates relative changes in the simulated engine performance larger than 1%.

Direct Coupling of a Two-Dimensional Fan Model in a Turbofan Engine Performance Simulation

2016 ◽  
Author(s):  
Ioannis Templalexis ◽  
Alexios Alexiou ◽  
Vassilios Pachidis ◽  
Ioannis Roumeliotis ◽  
Nikolaos Aretakis
Keyword(s):  
Three Dimensional ◽  
Engine Performance ◽  
System Level ◽  
Design Parameters ◽  
High Fidelity ◽  
Two Dimensional ◽  
Performance Simulation ◽  
Cfd Models ◽  
Component Design ◽  
Complex Phenomena

Coupling of high fidelity component calculations with overall engine performance simulations (zooming) can provide more accurate physics and geometry based estimates of component performance. Such a simulation strategy offers the ability to study complex phenomena and their effects on engine performance and enables component design changes to be studied at engine system level. Additionally, component interaction effects can be better captured. Overall, this approach can reduce the need for testing and the engine development time and cost. Different coupling methods and tools have been proposed and developed over the years ranging from integrating the results of the high fidelity code through conventional performance component maps to fully-integrated three-dimensional CFD models. The present paper deals with the direct integration of an in-house two-dimensional (through flow) streamline curvature code (SOCRATES) in a commercial engine performance simulation environment (PROOSIS) with the aim to establish the necessary coupling methodology that will allow future advanced studies to be performed (e.g. engine condition diagnosis, design optimization, mission analysis, distorted flow). A notional two-shaft turbofan model typical for light business jets and trainer aircraft is initially created using components with conventional map-defined performance. Next, a derivative model is produced where the fan component is replaced with one that integrates the high fidelity code. For both cases, an operating line is simulated at sea-level static take-off conditions and their performances are compared. Finally, the versatility of the approach is further demonstrated through a parametric study of various fan design parameters for a better thermodynamic matching with the driving turbine at design point operation.

scholarly journals Assessing the Sensitivity of Stall-Regulated Wind Turbine Power to Blade Design Using High-Fidelity Computational Fluid Dynamics

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Andrea G. Sanvito ◽  
Giacomo Persico ◽  
M. Sergio Campobasso
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Field Testing ◽  
Turbine Rotor ◽  
Operating Conditions ◽  
High Fidelity ◽  
Blade Design ◽  
Computationally Efficient ◽  
Wind Speeds ◽  
Wide Range

Abstract This study provides a novel contribution toward the establishment of a new high-fidelity simulation-based design methodology for stall-regulated horizontal axis wind turbines. The aerodynamic design of these machines is complex, due to the difficulty of reliably predicting stall onset and poststall characteristics. Low-fidelity design methods, widely used in industry, are computationally efficient, but are often affected by significant uncertainty. Conversely, Navier–Stokes computational fluid dynamics (CFD) can reduce such uncertainty, resulting in lower development costs by reducing the need of field testing of designs not fit for purpose. Here, the compressible CFD research code COSA is used to assess the performance of two alternative designs of a 13-m stall-regulated rotor over a wide range of operating conditions. Validation of the numerical methodology is based on thorough comparisons of novel simulations and measured data of the National Renewable Energy Laboratory (NREL) phase VI turbine rotor, and one of the two industrial rotor designs. An excellent agreement is found in all cases. All simulations of the two industrial rotors are time-dependent, to capture the unsteadiness associated with stall which occurs at most wind speeds. The two designs are cross-compared, with emphasis on the different stall patterns resulting from particular design choices. The key novelty of this work is the CFD-based assessment of the correlation among turbine power, blade aerodynamics, and blade design variables (airfoil geometry, blade planform, and twist) over most operational wind speeds.

Training Future Gas Turbine Performance Engineers

2007 ◽  
Author(s):  
V. Pachidis ◽  
P. Pilidis ◽  
I. Li
Keyword(s):  
Gas Turbine ◽  
Thermal Power ◽  
Engine Performance ◽  
Gas Turbine Engine ◽  
Performance Simulation ◽  
Turbine Engine ◽  
Turbine Performance ◽  
Auxiliary Power ◽  
Engine Testing ◽  
The Uk

The performance analysis of modern gas turbine engine systems has led industry to the development of sophisticated gas turbine performance simulation tools and the utilization of skilled operators who must possess the ability to balance environmental, performance and economic requirements. Academic institutions, in their training of potential gas turbine performance engineers have to be able to meet these new challenges, at least at a postgraduate level. This paper describes in detail the “Gas Turbine Performance Simulation” module of the “Thermal Power” MSc course at Cranfield University in the UK, and particularly its practical content. This covers a laboratory test of a small Auxiliary Power Unit (APU) gas turbine engine, the simulation of the ‘clean’ engine performance using a sophisticated gas turbine performance simulation tool, as well as the simulation of the degraded performance of the engine. Through this exercise students are expected to gain a basic understanding of compressor and turbine operation, gain experience in gas turbine engine testing and test data collection and assessment, develop a clear, analytical approach to gas turbine performance simulation issues, improve their technical communication skills and finally gain experience in writing a proper technical report.

Model order reduction in aerodynamics: Review and applications

2019 ◽  
Vol 233 (15) ◽  
pp. 5816-5836
Author(s):  
Gonçalo Mendonça ◽  
Frederico Afonso ◽  
Fernando Lau
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Model Reduction ◽  
Adaptive Sampling ◽  
Stokes Equations ◽  
Order Reduction ◽  
High Fidelity ◽  
Least Mean Squares ◽  
Speed Up ◽  
Dynamics Models

The need of the aerospace industry, at national or European level, of faster yet reliable computational fluid dynamics models is the main drive for the application of model reduction techniques. This need is linked to the time cost of high-fidelity models, rendering them inefficient for applications like multi-disciplinary optimization. With the goal of testing and applying model reduction to computational fluid dynamics models applicable to lifting surfaces, a bibliographical research covering reduction of nonlinear, dynamic, or steady models was conducted. This established the prevalence of projection and least mean squares methods, which rely on solutions of the original high-fidelity model and their proper orthogonal decomposition to work. Other complementary techniques such as adaptive sampling, greedy sampling, and hybrid models are also presented and discussed. These projection and least mean squares methods are then tested on simple and documented benchmarks to estimate the error and speed-up of the reduced order models thus generated. Dynamic, steady, nonlinear, and multiparametric problems were reduced, with the simplest version of these methods showing the most promise. These methods were later applied to single parameter problems, namely the lid-driven cavity with incompressible Navier–Stokes equations and varying Reynolds number, and the elliptic airfoil at varying angles of attack for compressible Euler flow. An analysis of the performance of these methods is given at the end of this article, highlighting the computational speed-up obtained with these techniques, and the challenges presented by multiparametric problems and problems showing point singularities in their domain.

scholarly journals Propagation of Input Uncertainty in Presence of Model-Form Uncertainty: A Multifidelity Approach for Computational Fluid Dynamics Applications

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Jian-Xun Wang ◽  
Christopher J. Roy ◽  
Heng Xiao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Parameter Space ◽  
Uncertainty Propagation ◽  
High Fidelity ◽  
Sampling Errors ◽  
Uncertainty Distribution ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Applications

Proper quantification and propagation of uncertainties in computational simulations are of critical importance. This issue is especially challenging for computational fluid dynamics (CFD) applications. A particular obstacle for uncertainty quantifications in CFD problems is the large model discrepancies associated with the CFD models used for uncertainty propagation. Neglecting or improperly representing the model discrepancies leads to inaccurate and distorted uncertainty distribution for the quantities of interest (QoI). High-fidelity models, being accurate yet expensive, can accommodate only a small ensemble of simulations and thus lead to large interpolation errors and/or sampling errors; low-fidelity models can propagate a large ensemble, but can introduce large modeling errors. In this work, we propose a multimodel strategy to account for the influences of model discrepancies in uncertainty propagation and to reduce their impact on the predictions. Specifically, we take advantage of CFD models of multiple fidelities to estimate the model discrepancies associated with the lower-fidelity model in the parameter space. A Gaussian process (GP) is adopted to construct the model discrepancy function, and a Bayesian approach is used to infer the discrepancies and corresponding uncertainties in the regions of the parameter space where the high-fidelity simulations are not performed. Several examples of relevance to CFD applications are performed to demonstrate the merits of the proposed strategy. Simulation results suggest that, by combining low- and high-fidelity models, the proposed approach produces better results than what either model can achieve individually.

Computational Fluid Dynamics Analysis of a Steam Power Plant Low-Pressure Turbine Downward Exhaust Hood

1996 ◽  
Vol 118 (1) ◽  
pp. 214-224 ◽  
Author(s):  
R. H. Tindell ◽  
T. M. Alston ◽  
C. A. Sarro ◽  
G. C. Stegmann ◽  
L. Gray ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Integrated Approach ◽  
Low Pressure ◽  
Operating Conditions ◽  
Exhaust Hood ◽  
Steam Power ◽  
Low Pressure Turbine ◽  
Computational Fluid Dynamics Analysis ◽  
Turbine Exhaust

Computational fluid dynamics (CFD) methods are applied to the analysis of a low-pressure turbine exhaust hood at a typical steam power generating station. A Navier-Stokes solver, capable of modeling all the viscous terms, in a Reynolds-averaged formulation, was used. The work had two major goals. The first was to develop a comprehensive understanding of the complex three-dimensional flow fields that exist in the exhaust hood at representative operating conditions. The second was to evaluate the relative benefits of a flow guide modification to optimize performance at a selected operating condition. Also, the influence of simulated turbine discharge characteristics, relative to uniform hood entrance conditions, was evaluated. The calculations show several interesting and possibly unique results. They support use of an integrated approach to the design of turbine exhaust stage blading and hood geometry for optimum efficiency.

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