ABSTRACT

 

SIMULATION OF JET ENGINES AND THERMOECONOMIC OPTIMIZATION OF A COGENERATION SYSTEM

INCORPORATING J-79 TURBOJET ENGINE

 

 

Narin, Bekir

M.S., Department of Aeronautical Engineering

Supervisor: Prof. Dr. Yalçın A. Göğüş

 

September 2001, 183 pages

 

 

 

In this study, simulation of F110-GE-100 turbofan engine is performed and the code developed for this purpose is adapted for the simulation of J-79 turbojet engine.  This code takes into account the following effects in addition to the usual ones: Dependence of specific heat on temperature and on composition, variation of compressor power requirement and turbine power output due to bleed of cooling air at earlier stages of the compressor, variation of combustion chamber pressure drop with mass flow rate. This model assumed and verifies that changes of efficiencies of rotating components due to off-design operation is equal to each other.  For flying conditions the code is improved to calculate the efficiencies using the performance maps and matching of rotating components.  To determine the unknown engine parameters a tuning procedure is applied by using zero level simulation model of the engine and test bed measurement results. To construct the jet engine component performance maps, some special techniques are used, which utilize the test bed measurement results and general component maps taken from literature.

 

Four different possibilities of utilization of J-79 engines for power production have been studied initially to see the promising ones. One of them, replacing the nozzle with a power turbine, is studied in detail including  thermoeconomic optimization. It appears as feasible to obtain shaft work from J-79 engine for emergency electric generation by reducing the speed and number of stages of the compressor.

 

Keywords: Simulation, Gas Turbines, Zero Level Simulation, Jet Engines, Performance Maps, Tuning of Simulation Parameters, Thermoeconomic Optimization, Cogeneration, Emergency Electric Generation.