University of Liège Turbomachinery group

Transcription

1 University of Liège Turbomachinery group Olivier LEONARD, Professor Tel : +32 (0) Institut de Mécanique et Génie civil (B52) Fax : +32 (0) Chemin des chevreuils 1 O.Leonard@ulg.ac.be B-4000 Liège Belgium http :// 1 Brief description of the group The Turbomachinery group is part of the Department of Aerospace and Mechanical Engineering which involves 23 professors and about 130 researchers. The staff of the Turbomachinery group involves 1 professor, 4 research engineers and 1 technician. The group is devoted to teaching in the fields of turbomachinery (compressors, gas and steam turbines, hydraulic machines) and aerospace propulsion (turbojets and rocket engines). Its research activities are organized along 3 major axis : The numerical simulation of flows in turbomachines for design purpose, with the development of a throughflow finite-volume computer code and a multi-stage, blade row per blade row, finite-volume mean-line code. The development of optimization techniques using genetic algorithms with application to the optimal design and operation of pumps, heat pipes, fans or blowers, The development of methods for measurements validation, health monitoring and model-based adaptive control of gas turbine engines. The staff of the Turbomachinery Group involves 1 professor, 5 research engineers and 1 technician : Olivier ADAM (o.adam@ulg.ac.be) Sébastien BORGUET (s.borguet@ulg.ac.be) Wenhai DU (wenhai.du@gmail.com) Vincent KELNER (v.kelner@ulg.ac.be) Olivier LEONARD (o.leonard@ulg.ac.be) Jean-Philippe THOMAS (jp.thomas@ulg.ac.be) Richard LABENDA (R.Labenda@ulg.ac.be) PhD Student Assistant - PhD Student PhD Student PhD Student Professor PhD Student Technician The group is devoted to teaching in the fields of turbomachinery (compressors, gas and steam turbines, hydraulic machines) and aerospace propulsion (turbojets and rocket engines). Its research activities are organized along 3 major axis :

2 The numerical simulation of flows in turbomachines for design purpose, with the development of a throughflow finite-volume computer code and a multi-stage, blade row per blade row, finite-volume mean-line code. The development of optimization techniques using genetic algorithms with application to the optimal design and operation of pumps, heat pipes, fans or blowers, The development of methods for measurements validation, health monitoring and model-based adaptive control of gas turbine engines. The Turbomachinery group has developed relationships with the von Karman Institute, CENAERO, ONERA, Ecole Centrale de Lyon, National Technical University of Athens, Chalmers, Snecma, Techspace Aero, Fluorem, Rutten s.a. and others. Before heading the group, Olivier LEONARD carried out the main part of his research activities at the von Karman Institute, within the Turbomachinery Department. Commercial codes such as FLUENT, FINE/TURBO and ECOSIMPRO are used within the group for flow simulations. A test bench for hydraulic pumps and a small jet engine equipped with data acquisition, fuel control and variable nozzle area are available for the research activities.

3 2 Health Monitoring and Model-Based Control of Gas Turbine Engines The first objective of this project is to develop and validate parametric and adaptive models for the health monitoring of gas turbine engines, so as to enable condition-based maintenance. The identification of the health parameters of the engines is based on measurements taken on the process and includes their validation. It makes it possible to follow the evolution with respect to time (a possible degradation) of the condition of the engine. The adaptation of the non linear model and the estimation of the health of the engine are based on the use of Kalman filters, modified to take into account the nonlinear character of the operation of the gas turbine engines and to allow the detection of erroneous measurements. The most recent versions of the developed algorithms are based on dynamic models and can benefit from the transients followed by the engines. These tools can also provide an estimate of non measurable variables which are fundamental for control such as maximum temperature or surge margin. The second objective of the project is to use these adaptive models and the diagnosis strategy to carry out actions of control and adaptation of the gas turbine operation which would take into account its real, modified or degraded condition. Partners : National Technical University of Athens, Chalmers, Techspace Aero Recent related publications : Robust Validation of Measurements on Jet Engines, P. Dewallef, O. Léonard, European Journal of Mechanical and Environmental Engineering, Vol 46, No 4, 2001 On-Line Validation of Measurements on Jet Engines Using Automatic Learning Methods, P. Dewallef, O. Léonard, Proceedings of the XV International Symposium on Airbreathing Engines, Bangalore, 2001 On-Line Measurement Validation and Performance Monitoring Using Robust Kalman Filtering Techniques, P. Dewallef, O. Léonard, Proceedings of the 5th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, Prague, 2003 On-Line Performance Monitoring and Engine Diagnostic Using Robust Kalman Filtering Techniques, P. Dewallef, O. Léonard, ASME Paper GT , 2003 On-Line Aircraft Engine Diagnostic Using a Soft-Constrained Kalman Filter, P. Dewallef, O. Léonard, K. Mathioudakis, ASME Paper GT , 2004 On-Line Transient Engine Diagnostic in a Kalman Filtering Framework, S. Borguet, P. Dewallef, O. Léonard, ASME Paper GT , 2005 Application of the Kalman Filter to Health Monitoring of Gas Turbine Engines - A Sequential Approach to Robust Diagnosis, P. Dewallef, PhD Thesis, ISSN , D/2005/0480/44, Combining Classification Techniques With Kalman Filters for Aircraft Engine Diagnostics, P. Dewallef, O. Léonard, K. Mathioudakis, Journal of Engineering for Gas Turbines and Power, Vol 128, No 2, pp , 2006 A Way to Deal with Model-Plant Mismatch for a Reliable Diagnosis in Transient Operation, S. Borguet, P. Dewallef, O. Léonard, ASME Paper GT , 2006

4 external disturbances v k u k command parameters v k estimated external disturbances engine to monitor engine performance simulation model x k estimated state variables w k estimated health parameters observed measurements y k - y k estimated measurements residuals r k % of deviation from nominal value FAN capacity FAN efficiency LPC capacity LPC efficiency HPC capacity HPC efficiency % of deviation from nominal value time [s] HPT capacity HPT efficiency LPT capacity LPT efficiency Nozzle area

5 On Inverse Problems in Turbine Engine Parameter Estimation, M. Henriksson, S. Borguet, T. Grönstedt, O. Léonard, ASME Paper GT , 2007 A Sensor-Fault-Tolerant Diagnosis Tool Based on a Quadratic Programming Approach, S. Borguet, O. Léonard, ASME Paper GT , 2007 An Adaptive Estimation Algorithm for Aircraft Engine Performance Monitoring, O. Léonard, P. Dewallef, S. Borguet, submitted to the AIAA Journal of Propulsion and Power, 2007 Coupling Principal Component Analysis and Kalman Filter Algorithms for On-line Aircraft Engine Diagnostics, S. Borguet and O. Léonard, Proceedings of the XVIII International Symposium on Airbreathing Engines, Beijing, 2007 A Quadratic Programming Framework for Constrained and Robust Jet Engine Health Monitoring, S. Borguet, O. Léonard, Proceedings of the 2nd European Conference on Aerospace Sciences, Brussels, 2007 A Study on Observability and Sensor Selection for Efficient Jet Engine Health Monitoring, Sébastien Borguet and Olivier Léonard, to be presented at the ISROMAC-12, Honolulu, 2008 A Generalised Likelihood Ratio Test for Adaptive Engine Health Monitoring, Sébastien Borguet and Olivier Léonard, ASME Paper GT , 2008

6 3 Optimization using genetic algorithms The purpose of this project is to develop robust metaheuristic methods for solving optimization, design or process control problems which utilizes simultaneously binary, discrete and continuous parameters. This situation results in a great number of configurations to be considered, which must satisfy a important number of constraints. Moreover real world problems lead to the optimzation of several but contradictory objectives. This project brings a response to this type of problems, by combining the advantages of genetic algorithms and nonlinear mathematical programming. The genetic algorithms allow a broad and systematic exploration of the design space, the various possible solutions being subjected to a Darwinian natural selection process. The nonlinear programming brings the efficiency of a local and fast exploration around a promising configuration. The resulting optimization tool can be coupled to any metamodel of the application to be optimized (data bases, response surfaces, neural networks, analytical models, parametric models...). The multiplicity of the objectives is addressed following the Pareto approach. Up to now these optimization tools were applied to several problems such as the optimal sizing of lubrication pumps for turbojets, the optimization of pump scheduling, the design and the operation of blowers and the optimization of heat pipes geometries. Partners : Partners : CENAERO, Fluorem, Euro Heat Pipes, Techspace Aero, Valeo Recent related publications : Application of Genetic Algorithms to Lubrication Pumps Stacking Design, V. Kelner, O. Léonard, Journal of Computational and Applied Mathematics, Vol 168/1-2 pp , 2003 Optimal Pump Scheduling for Water Supply Using Genetic Algorithms, V. Kelner and O. Léonard, Proceedings of the 5th International Conference on Evolutionary Computing for Industrial Applications - EUROGEN 03, Barcelona, 2003 An Hybrid Optimization Technique Coupling Evolutionary and Local Search Algorithms, V. Kelner, F. Capitanescu, O. Léonard, and L. Wehenkel, Proceedings of the 3rd International Conference on Advanced Computational Methods in Engineering - ACOMEN 05, Ghent, 2005 Multi Objective of a Fan Blade by Coupling a Genetic Algorithm and a Parametric Flow Solver, V. Kelner, G. Grondin, O. Léonard, and P. Ferrand, Proceedings of the 6th International Conference on Evolutionary Computing for Industrial Applications - EUROGEN 05, Munich, 2005 Robust Design of a Fan Blade by Coupling Multi Objective Genetic Optimization and Flow Parameterization, V. Kelner, G. Grondin, O. Léonard, P. Ferrand, Proceedings of the International Congress on Fluid Dynamics Applications in Ground Transportation, Lyon, 2005 Geometric Optimization of Grooved Heat Pipes by a Genetic Algorithm Technique, C. Goffaux, S. Pierret, S. Rossomme, V. Kelner, S. Van Oost and L. Barremaecker, Proceedings of the 6th International Conference on Heat Pipes, Heat Pumps and Refrigerators, Minsk, 2005

7 Fig. 1 Otimizing a jet engine lubrication pump stacking Fig. 2 Optimizing the pressure jump and the pressure losses of blower blades

8 4 Throughflow simulations in turbomachines 4.1 High-order throughflow, deterministic and circumferential stresses The objective of this project is to introduce non stationary effects due to the rotorstator interactions into a throughflow model for compressors and turbines. Following the approach of Adamczyk, several averages of the unsteady 3-D Navier-Stokes equations are performed to end up with a steady axisymmetric set of equations. In this final set of equations, different stresses and forces appear. They introduce the (mean) effect of the flow phenomena that have been averaged ; in that sense they are similar to the Reynolds stresses. The inclusion of these deterministic and circumferential stresses in a stationary model makes it possible to predict the radial mixing process observed in experiments and in non stationary simulations, but which are not reproducible in stationary simulations using a mixing plane. This set of equations represent the ultimate throughflow model, provided that one could find a way to model the stresses and forces. This throughflow model differs from classical streamline curvature method as it is directly based on the Navier-Stokes equations solved by finite volume techniques. In a first step, the results of unsteady 3-D simulations were used to evaluate the effects of the different stresses and forces (and their modelization) inside the throughflow environment. In a second step, the circumferential stresses and the blade forces are being modelled using an harmonic approach. Partners : ONERA, Ecole Centrale de Lyon Recent related publications : A Throughflow Analysis Tool Based on the Navier-Stokes Equations, J.-F. Simon, O. Léonard, Proceedings of the 6th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, Lille, 2005 Modeling of 3-D Losses and Deviations in a Throughflow Analysis Tool, J.-F. Simon, O. Léonard, Journal of Thermal Science, Vol 16, No 3, pp , 2007 Contribution to Throughflow Modelling, J.-F. Simon, PhD Thesis, University of Liège, 2007 On the Role of the Deterministic and Circumferential Stresses in Throughflow Calculations, Jean-François Simon and Olivier Léonard, ASME Paper GT , 2008 Investigating Circumferential Non-Uniformities in Throughflow Calculations using an Harmonic Reconstruction, Jean-Philippe Thomas, Jean-François Simon and Olivier Léonard, ASME Paper GT , 2008

9 4.2 Fast quasi-one-dimensional simulations in multistage turbomachines The performances of a gas turbine engine must be analyzed well before the engine is tested on the bench or in flight. This study provides the designer with guidelines for the choice of the many design parameters and for optimizing the final configuration of the jet engine. It also allows to test (in a virtual way) the correct operation of the engine during critical manœuvres. The present project is aimed at providing a quasi-1d modern CFD tool for the numerical modeling of the operation of a compressor and a whole jet engine. Thanks to the progress of the simulation methods and computing power, it is now possible to develop and to use models of jet engines based on the application of the laws of the fluid mechanics to a great number of cells. This approach makes it possible to describe with a high degree of accuracy the exchanges of mass, energy and momentum within the machine, while reducing to the bare minimum the quantity of information of empirical nature. It takes advantage of the high precision and efficiency of the CFD methods for space and time discretization, with CPU times of a few seconds. This quasi-1d tool tool may be applied to the a large number of problems such as water and hail ingestion, bleeds and cooling flows, mechanical and thermal transients, reversed flows and surge, characteristic map extrapolation, building global compressor model from stage/partial results, coupling with cycle calculations and global modeling of a jet engine. Recent related publications : Explicit Thermodynamic Properties Using Radial Basis Functions Neural Networks, O. Adam, O. Léonard, Proceedings of the 2nd SIAM International Conference on Data Mining, Arlington, 2002 A Quasi-One-Dimensional Model for Axial Compressors, O. Adam, O. Léonard, Proceedings of the XVII International Symposium on Airbreathing Engines, Munich, 2005 A Quasi-One-Dimensional Model for Axial Turbines, O. Adam and O. Léonard, Proceedings of the XVIII International Symposium on Airbreathing Engines, Beijing, 2007 A Quasi-One-Dimensional CFD Model for Multistage Turbomachines, O. Léonard and O. Adam, submitted to the Journal of Thermal Sciences

10 Fig. 3 Blade force and circumferential stress distribution in a compressor stage Fig. 4 Comparison of the quasi-1d and experimental results on a 3-stage compressor Fig. 5 Comparison of the quasi-1d and experimental results on a 2-stage cooled turbine