A Modular Code for Real Time Dynamic Simulation of Gas Turbines in Simulink

Abstract

A high-fidelity real-time simulation code based on a lumped, nonlinear representation of gas turbine components is presented. The code is a general-purpose simulation software environment useful for setting up and testing control equipments. The mathematical model and the numerical procedure are specially developed in order to efficiently solve the set of algebraic and ordinary differential equations that describe the dynamic behavior of gas turbine engines. For high-fidelity purposes, the mathematical model takes into account the actual composition of the working gases and the variation of the specific heats with the temperature, including a stage-by-stage model of the air-cooled expansion. The paper presents the model and the adopted solver procedure. The code, developed in Matlab-Simulink using an object-oriented approach, is flexible and can be easily adapted to any kind of plant configuration. Simulation tests of the transients after load rejection have been carried out for a single-shaft heavy-duty gas turbine and a double-shaft aero-derivative industrial engine. Time plots of the main variables that describe the gas turbine dynamic behavior are shown and the results regarding the computational time per time step are discussed.

Development and Validation of a Civil Aircraft Engine Simulation Model for Advanced Controller Design

“…An accurate representation of this element is important since the total percentage of engine inlet mass extracted before the combustor may be up to 25% for a high technology aero or industrial engine [36,42], and cooling flow will represent a significant proportion of this (see figure 6.20). Cooling is often modelled simply as a percentage of the engine's massflow, however the current simulation uses a relation that, although partly empirical (the calculation of high speed fluid dynamics is too big an undertaking for the current simulation), is also based on radius of the cooling air extraction vent and the ratio of the air source pressure (the high pressure compressor) to that of the sink (the high pressure turbine) [8,27] -…”

“…The type of model presented here, called an "aerothermal transient performance model" [42] or "aero-thermodynamic model" [8] avoids iteration by arranging the equations to follow the direction of the gas path, and introducing storage volumes between components to account for the unsteady balance of mass at fan and compressor discharge, combustion chamber, between the turbines, and between the turbines and nozzle [8]. This is the most accurate of the many non-iterative models used for modeling engine performance transient parameters [42].…”

“…This loss is also offset by a superior execution time. The size of the volumes (plena) included between the turbomachinery is important [42], as they have their own time constant [8] and this will affect the maximum permissible time step.…”

“…This method avoids iterative calculations by arranging the component equations to follow the direction of the gas path and introducing storage volumes between components to account for the unsteady balance of mass at compressor discharge, combustion chamber and between the turbines [8].…”

Prediction of Jet Engine Parameters for Control Design Using Genetic Programming

“…Larrowe and Spencer did a first attempt of using a model operating in real time to develop control hardware using a simulation rather than an actual engine [7]. As simulation became an important tool on the design of control systems, some programs such as Matlab/Simulink became very popular for modelling and simulating dynamic systems [8] [9].…”