Rotodynamic Modeling of an Actively Controlled Magnetic Bearing Gas Turbine Engine

1998 ◽  
Vol 120 (3) ◽  
pp. 621-625 ◽  
Author(s):  
B. M. Antkowiak ◽  
F. C. Nelson
Keyword(s):  
Finite Element ◽  
Gas Turbine ◽  
Closed Loop ◽  
Gas Turbine Engine ◽  
Magnetic Bearing ◽  
The State ◽  
Turbine Engine ◽  
Influence Matrix ◽  
Bode Plots ◽  
Rotor Dynamic

This paper summarizes the development of a finite element rotordynamic solution used in a closed loop simulation for a magnetic bearing rotor system in a gas, turbine engine. A magnetic bearing controlled rotor is analyzed, and the state dynamics matrix [A], the shaft control influence matrix [B], and the sensor matrix [C] are constructed. Bode plots of the state-space transfer function are also constructed and compared to the results of the rotor dynamic model.

scholarly journals Rotordynamic Modeling of an Actively Controlled Magnetic Bearing Gas Turbine Engine

1997 ◽  
Author(s):  
B. M. Antkowiak ◽  
F. C. Nelson
Keyword(s):  
Finite Element ◽  
Gas Turbine ◽  
Closed Loop ◽  
Gas Turbine Engine ◽  
Magnetic Bearing ◽  
The State ◽  
Turbine Engine ◽  
Influence Matrix ◽  
Bode Plots ◽  
Rotor Dynamic

This paper summarizes the development of a finite element rotordynamic solution used in a closed loop simulation for a magnetic bearing rotor system in a gas turbine engine. A magnetic bearing controlled rotor is analyzed, and the state dynamics matrix [A], the shaft control influence matrix [B], and the sensor matrix [C] are constructed. Bode plots of the state-space transfer function are also constructed and compared to the results of the rotor dynamic model.

Optimal State-Space Control of a Gas Turbine Engine

1992 ◽  
Vol 114 (4) ◽  
pp. 763-767 ◽  
Author(s):  
J. W. Watts ◽  
T. E. Dwan ◽  
C. G. Brockus
Keyword(s):  
State Space ◽  
Gas Turbine ◽  
State Space Model ◽  
Gas Turbine Engine ◽  
The State ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Analog Control ◽  
Linear State ◽  
High Level

An analog fuel control for a gas turbine engine was compared with several state-space derived fuel controls. A single-spool, simple cycle gas turbine engine was modeled using ACSL (high level simulation language based on FORTRAN). The model included an analog fuel control representative of existing commercial fuel controls. The ACSL model was stripped of nonessential states to produce an eight-state linear state-space model of the engine. The A, B, and C matrices, derived from rated operating conditions, were used to obtain feedback control gains by the following methods: (1) state feedback; (2) LQR theory; (3) Bellman method; and (4) polygonal search. An off-load transient followed by an on-load transient was run for each of these fuel controls. The transient curves obtained were used to compare the state-space fuel controls with the analog fuel control. The state-space fuel controls did better than the analog control.

An Optimal Automated Zone Allocation Approach for Risk Assessment of Gas Turbine Engine Components

2013 ◽  
Author(s):  
Jonathan P. Moody ◽  
Michael P. Enright ◽  
Wuwei Liang
Keyword(s):  
Risk Assessment ◽  
Finite Element ◽  
Finite Elements ◽  
Fracture Risk ◽  
Gas Turbine ◽  
Optimal Allocation ◽  
Federal Aviation Administration ◽  
High Energy ◽  
Gas Turbine Engine ◽  
Turbine Engine

High-energy rotating components of gas turbine engines may contain rare material anomalies that can lead to uncontained engine failures. The Federal Aviation Administration and the aircraft engine industry have been developing enhanced life management methods to address the rare but significant threats posed by these anomalies. One of the outcomes of this effort has been a zone-based risk assessment methodology in which component fracture risk is estimated using groupings of elements called zones that are associated with 2D finite element (FE) stress and temperature models. Previous papers have presented processes for creation of zones either manually or via an automatic algorithm in which zones are assigned to each finite element in a component model. These processes may require significant human time and computer time. The focus of this paper is on the optimal allocation of multiple finite elements to zones that minimizes the total number of zones required to compute the fracture risk of a component. An algorithm is described that uses a relatively coarse response surface method to estimate the conditional risk value at each node in a finite element model. Zones are initially defined for each finite element in the model, and the algorithm identifies and merges zones based on minimizing the influence on component risk. The process continues until all of the zones have been merged into a single zone. The zone sequence is applied in reverse order to identify the minimum number of zones that satisfies component target risk or convergence threshold constraints. This solution provides the optimal allocation of finite elements to zones. The algorithm is demonstrated for a representative gas turbine engine component. The approach significantly improves the computational efficiency of the zone-based risk analysis process.

Gain Scheduled Control of Gas Turbine Engines: Stability and Verification

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Mehrdad Pakmehr ◽  
Nathan Fitzgerald ◽  
Eric M. Feron ◽  
Jeff S. Shamma ◽  
Alireza Behbahani
Keyword(s):  
Convex Optimization ◽  
Gas Turbine ◽  
Closed Loop ◽  
Gas Turbine Engine ◽  
Loop System ◽  
Linear Matrix ◽  
Closed Loop System ◽  
Turbine Engine ◽  
Gain Scheduled Controller ◽  
Gain Scheduled

A stable gain scheduled controller for a gas turbine engine that drives a variable pitch propeller is developed and described. A stability proof is developed for gain scheduled closed-loop system using global linearization and linear matrix inequality (LMI) techniques. Using convex optimization tools, a single quadratic Lyapunov function is computed for multiple linearizations near equilibrium and nonequilibrium points of the nonlinear closed-loop system. This approach guarantees stability of the closed-loop gas turbine engine system. To verify the stability of the closed-loop system on-line, an optimization problem is proposed, which is solvable using convex optimization tools. Simulation results show that the developed gain scheduled controller is capable to regulate a turboshaft engine for large thrust commands in a stable fashion with proper tracking performance.

Experimental and Numerical Correlation of Impact of Spherical Projectile for Damage Analysis of Aero Engine Component

2016 ◽  
Vol 66 (2) ◽  
pp. 193 ◽  
Author(s):  
Anuradha Nayak Majila ◽  
Rajeev Jain ◽  
Chandru Fernando D. ◽  
S. Ramachandra
Keyword(s):  
Finite Element ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Metallographic Analysis ◽  
Damage Analysis ◽  
Alloy Plate ◽  
Turbine Engine ◽  
Aero Engine ◽  
Engine Components ◽  
The Impact

<p>Studies the impact response of flat Titanium alloy plate against spherical projectile for damage analysis of aero engine components using experimental and finite element techniques. Compressed gas gun has been used to impart speed to spherical projectile at various impact velocities for damage studies. Crater dimensions (diameter and depth) obtained due to impact have been compared with finite element results using commercially available explicit finite element method code LS-DYNA. Strain hardening, high strain rate and thermal softening effect along with damage parameters have been considered using modified Johnson-Cook material model of LS-DYNA. Metallographic analysis has been performed on the indented specimen. This analysis is useful to study failure analysis of gas turbine engine components subjected to domestic object damage of gas turbine engine. </p><p> </p>

scholarly journals Assessment of Mechanical Design Parameters for an Aero Gas Turbine Engine Jet Pipe Casing using Finite Element Analysis

2020 ◽  
Vol 9 (5) ◽  
pp. 1197-1201
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Gas Turbine ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Gas Turbine Engine ◽  
Design Parameters ◽  
Element Analysis ◽  
Engine Operation ◽  
Turbine Engine

Aero Gas Turbine engines power aircrafts for civil transport application as well as for military fighter jets. Jet pipe casing assembly is one of the critical components of such an Aero Gas Turbine engine. The objective of the casing is to carry out the required aerodynamic performance with a simultaneous structural performance. The Jet pipe casing assembly located in the rear end of the engine would, in case of fighter jet, consist of an After Burner also called as reheater which is used for thrust augmentation to meet the critical additional thrust requirement as demanded by the combat environment in the war field. The combustion volume for the After burner operation together with the aerodynamic conditions in terms of pressure, temperature and optimum air velocity is provided by the Jet pipe casing. While meeting the aerodynamic requirements, the casing is also expected to meet the structural requirements. The casing carries a Convergent-Divergent Nozzle in the downstream side (at the rear end) and in the upstream side the casing is attached with a rear mount ring which is an interface between engine and the airframe. The mechanical design parameters involving Strength reserve factors, Fatigue Life, Natural Frequencies along with buckling strength margins are assessed while the Jet pipe casing delivers the aerodynamic outputs during the engine operation. A three dimensional non linear Finite Element analysis of the Jet pipe casing assembly is carried out, considering the up & down stream aerodynamics together with the mechanical boundary conditions in order to assess the Mechanical design parameters.

A New Finite Element Approach to Biaxial Fatigue Life Prediction in Gas Turbine Engine

2010 ◽  
Author(s):  
Wasim Tarar ◽  
M.-H. Herman Shen
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Gas Turbine ◽  
Life Prediction ◽  
Gas Turbine Engine ◽  
Constitutive Law ◽  
Fatigue Life Prediction ◽  
Turbine Engine ◽  
Number Of Cycles ◽  
Cycles To Failure

High cycle fatigue is the most common cause of failure in gas turbine engines. Different design tools have been developed to predict number of cycles to failure for a component subjected to fatigue loads. An energy-based fatigue life prediction framework was previously developed in recent research for prediction of axial and bending fatigue life at various stress ratios. The framework for the prediction of fatigue life via energy analysis was based on a new constitutive law, which states the following: the amount of energy required to fracture a material is constant. A finite element approach for uniaxial and bending fatigue was developed by authors based on this constitutive law. In this study, the energy expressions that construct the new constitutive law are integrated into minimum potential energy formulation to develop a new QUAD-4 finite element for fatigue life prediction. The newly developed QUAD-4 element is further modified to obtain a plate element. The Plate element can be used to model plates subjected to biaxial fatigue including bending loads. The new QUAD-4 element is benchmarked with previously developed uniaxial tension/compression finite element. The comparison of Finite element method (FEM) results to existing experimental fatigue data, verifies the new finite element development for fatigue life prediction. The final output of this finite element analysis is in the form of number of cycles to failure for each element in ascending or descending order. Therefore, the new finite element framework can predict the number of cycles to failure at each location in gas turbine engine structural components. The new finite element provides a very useful tool for fatigue life prediction in gas turbine engine components. The performance of the fatigue finite element is demonstrated by the fatigue life predictions from Al6061-T6 aluminum and Ti-6Al-4V. Results are compared with experimental results and analytical predictions.

Three-Dimensional Structural Evaluation of a Gas Turbine Engine Rotor

2014 ◽  
Author(s):  
Partha S. Das
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Complex Geometries ◽  
Turbine Engine ◽  
Industrial Gas Turbine ◽  
Engine Rotor ◽  
Engine Rotors ◽  
Critical Locations

Engine rotors are one of the most critical components of a heavy duty industrial gas turbine engine, as it transfers mechanical energy from rotor blades to a generator for the production of electrical energy. In general, these are larger bolted rotors with complex geometries, which make analytical modeling of the rotor to determine its static, transient or dynamic behaviors difficult. For this purpose, powerful numerical analysis approaches, such as, the finite element method, in conjunction with high performance computers are being used to analyze the current rotor systems. The complexity in modeling bolted rotor behavior under various loadings, such as, airfoil, centrifugal and gravity loadings, including engine induced vibration is one of the main challenges of simulating the structural performance of an engine rotor. In addition, the internal structural temperature gradients that can be encountered in the transient state as a result of start-up and shutdown procedures are generally higher than those that occur in the steady-state and hence thermal shock is important factor to be considered relative to ordinary thermal stress. To address these issues, the current paper presents the steady-state & quasi-static analyses (to approximate transient responses) of two full 3-D industrial gas turbine engine rotors, SW501F & GE-7FA rotor, comprising of both compressor & turbine sections together. Full 3-D rotor analysis was carried out, since the 2-D axisymmetric model is inadequate to capture the complex geometries & out of plane behavior of the rotor. Both non-linear steady-state & transient analyses of a full gas turbine engine rotor was performed using the general purpose finite element analysis program ABAQUS. The paper presents in detail the FEA modeling technique, overall behavior of the full rotor under various loadings, as well as, the critical locations in the rotor with respect to its strength and life. The identification of these critical locations is needed to help with the repair of the existing rotors and to improve and extend the operational/service life of these rotors.

Sign in / Sign up

Export Citation Format

Share Document