Heavy-Duty Gas Turbine Plant Aerothermodynamic Simulation Using Simulink

Abstract

This paper presents a physical simulator for predicting the off-design and dynamic behaviour of a single shaft heavy-duty gas turbine plant, suitable for gas-steam combined cycles.The mathematical model, which is non linear and based on the lumped parameter approach, is described by a set of firstorder differential and algebraic equations. The plant components are described adding to their steady state characteristics the dynamic equations of mass, momentum and energy balances. The state variables are mass flow rates, static pressures, static temperatures of the fluid, wall temperatures and shaft rotational speed.The analysis has been applied to a 65 MW heavy-duty gas turbine plant with two off-board silo-type combustion chambers. To model the compressor, equipped with variable inlet guide vanes, a subdivision into five partial compressors is adopted, in serial arrangement, separated by dynamic blocks. The turbine is described using a one dimensional row by row mathematical model, that takes into account both the air bleed cooling effect and the mass storage among the stages. The simulation model considers also the air bleed transformations from the compressor down to the turbine.Both combustion chambers have been modelled utilising a sequence of several sub-volumes, to simulate primary and secondary zones in presence of three hybrid burners.A code has been cleated in Simulink environment Some dynamic responses of the simulated plant, equipped with a proportional-integral speed regulator, are presented.

Overview and Comparative Analysis of Gas Turbine Models for System Stability Studies

“…Other authors (especially those having a mechanical engineering background) [5], [8]- [10] also utilize physical laws as well as thermodynamic laws in order to derive the equations representing gas turbine dynamics. They model different components of the gas turbine such as ducting, compressors, combustors and air blades [5], [8]- [10].…”

“…They involve utilizing laws governing thermodynamic behavior in the Brayton cycle [1], [2] along with some simplifying assumption to obtain the differential equations representing the dynamic gas turbine behavior. These laws include conservation of mass, conservation of power and conservation of energy [5]- [9].…”

“…They model different components of the gas turbine such as ducting, compressors, combustors and air blades [5], [8]- [10].…”

“…The augmented function is given in (5) at the bottom of the page. It can be clearly seen that it incorporates the effect of the IGV, fuel flow, ambient temperature and rotor speed, where refers to the rated exhaust temperature, refers to the ambient temperature, represents the fuel flow and refers to the rotor speed.…”

Gas Turbine Engine Control Design Using Fuzzy Logic and Neural Networks

“…Simulink provides an easy-to-use, graphical, modeling and simulation development environment for developing time-based simulations in a wide range of applications, and Simulink is capable of code generation using associated tools [17][18][19]. So, a dynamic model for a specific turbojet engine is developed using the MATLAB simulation environment and its Simulink toolbox [1].…”