Surrogate model based system identification and control of gas turbine engines

Ekinci, Sinan
The focus of this thesis is on small low-cost turbojet engines where the fuel flow is provided by a gear-type fuel pump rather than a more traditional fuel metering unit. The incorporation of such type of fuel flow actuation devices introduces additional nonlinearities into the modeling and control of the small turbojet engines. As an alternative solution, this thesis presents and applies online/offline parameter estimation and adaptive control methods to such sub-class turbojet engines. For the simulation and analysis, a high-fidelity turbojet engine model including the fuel system is developed. On the other hand, a nonlinear fast engine model is proposed to capture the shaft dynamics of a small turbojet engine equipped with a gear-type fuel pump. The parameters of the fast engine model are estimated using the regression analysis. The same identification procedure is also applied to real engine test data to verify the proposed approach. Next, an online parameter estimation method using the same fast engine model structure is applied to the aero-thermal turbojet engine model. Then, the outputs of the offline and online parameter estimation approaches are compared with each other. Later, the online parameter estimation algorithm is converted to an adaptive controller known as indirect-model reference adaptive control. Last, several control and failure scenarios are applied to the aero-thermal engine model to show its main advantages over the traditional control approaches and also to reveal its further application areas.


Fast engine model for FMU-less small turbojet engines
Ekinci, Sinan; Yavrucuk, İlkay (SAGE Publications, 2020-02-01)
The focus of this paper is on small low-cost turbojet engines equipped with a gear-type fuel pump rather than a more traditional fuel metering unit. The incorporation of such type of fuel flow actuation devices introduce additional nonlinearities into the system and therefore make traditional modeling and system identification methods difficult to apply. In this paper, we propose a nonlinear fast engine model structure that can be used for various applications, including identification, modeling and simulat...
Cooling performance investigation of a two-pass rib-roughened channel
Kavas, İsa; Kurtuluş, Dilek Funda; Yasa, Tolga; Department of Aerospace Engineering (2015)
The performance of the modern aero-engines is highly dependent on the turbine inlet gas temperature. The higher temperature leads to more compact and efficient machines. Additionally, specific fuel consumption of the engine is decreased for the same thrust rating. However, the turbine inlet temperatures of the today’s engines are already beyond the material structural limits. Hence, the turbine section must be cooled down to acceptable levels. Various types of cooling methods are typically applied to the ga...
Bio yakıtla çalışan küçük gaz türbinli motor dönüşümü ve performans karşılaştırması
Akmandor, Sinan İbrahim; Uzol, Oğuz; Karaca, Mehmet(2009)
Since the flow and the combustion processes are continious, the limitations for fuel for gas turbines is much less when compared with other types of engines. Gas turbines enable the use of low calorific value biofuels. Gas turbines can use wide range of fuels from natural gas at cogeneration plants to Kerozene on aircraft engines. Nowadays, increase in the petrol prizes increase tendancy to use bio-fuels in gas turbines for energy generation. Bio-fuels has the potential to contribute a significant portion o...
Experimental and numerical inestigation of an s-duct diffuser designed for a micro turbojet engine powered aircraft
Aslan, Samet; Kurtuluş, Dilek Funda; Department of Aerospace Engineering (2016)
S-duct diffusers are often used for aircraft propulsion systems that convey the intake air to the engine compressor. In this thesis, flow structure at separated entrance conditions in an S-duct diffuser that designed for a micro turbojet engine powered aircraft is investigated using experimental and numerical methods. Flow characteristics such as flow separation, secondary flows, and swirl are investigated to find out the source of distortions and pressure loss at aerodynamics interface plane. Experiments a...
Aerothermodynamics of turbine blade trailing edge cooling
Tunçel, Tuğba; Kahveci, Harika Senem; Department of Aerospace Engineering (2018)
It is known that the thermal efficiency of gas turbines strongly depends on the turbine entry temperature of the working fluid. This has resulted in increased turbine working temperatures, and peak temperatures in advanced gas turbines have been well above maximum allowable metal temperatures for quite some time. For turbine blades to survive while operating beyond these material temperature limits, internal and external cooling techniques have been developed. Due to structural and aerodynamic restrictions,...
Citation Formats
S. Ekinci, “Surrogate model based system identification and control of gas turbine engines,” Ph.D. - Doctoral Program, Middle East Technical University, 2019.