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Now showing items 1 - 9 of 9

  • Bond graph modeling of a jet engine with electric starter

    Montazeri-Gh, Morteza   Fashandi, Seyed Alireza Miran  

    Following the technological advances in recent decades, advanced electronic systems linked to the gas turbine industry are increasingly considered by the designers of this field. For this purpose, new airborne systems in conjunction with jet engines are developed, which are incorporated in many challenging design problems such as control law and configuration design. Thus, a comprehensive modeling structure is needed that can bolster the integrity of the system development such as the bond graph approach, which is known as an efficient method for modeling complicated mechatronic systems. In this paper, modeling and simulation of a jet engine dynamic performance and aircraft motion are achieved based on the bond graph approach. At first, the electric starter bond graph model is constructed and physical relationships governing each engine component are obtained. In the aftermath, the modulated energy fields are developed for the jet engine components. Subsequently, the bond graph model of the engine is numerically simulated and experimentally tested and verified for a small jet engine. Finally, bond graph modeling and simulation of integrated engine and aircraft system is presented. The test results indicate the acceptable accuracy of the modeling approach which can be applied for innovative diagnosis and control systems design.
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  • Theoretical and Experimental Study of a Micro Jet Engine Start-Up Behaviour

    Montazeri-Gh, Morteza   Fashandi, Seyed Alireza Miran   Jafari, Soheil  

    Proper functioning of the start-up process in a micro jet engine is of great importance. This is due to the fact that the combustion chamber of such engine is so small and therefore, there is little time for fuel and air mixture to be present in the chamber. Hence, failed starts or repetitive attempts by the electric starter are very likely due to non-formation of the initial combustion. Also, the performance of the turbine start-up, impressively affects the limited life time of the micro jet engine. In this paper, an experimental study on the injection of compressed air during the start-up of a micro jet engine to improve its performance has been conducted. For this purpose, test components' layout and a monitoring system are designed. The allowable pressure of the air injection has been calculated using both the engine dynamic model and experimental tests. The simulation results have also been compared and validated with the experimental test results. Finally, several tests were conducted to study the injection process of the compressed air form which, several results have been deduced including the reduction of maximum exhaust gas temperature (EGT) during the start-up, reduction of the start-up time interval and service lifetime enhancement. The method proposed in this paper is applicable on any micro jet engine with the similar structural form and starting process.
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  • Control Requirements for Future Gas Turbine-Powered Unmanned Drones:JetQuads

    Jafari, Soheil   Fashandi, Seyed Alireza Miran   Nikolaidis, Theoklis  

    The next generation of aerial robots will be utilized extensively in real-world applications for different purposes: Delivery, entertainment, inspection, health and safety, photography, search and rescue operations, fire detection, and use in hazardous and unreachable environments. Thus, dynamic modeling and control of drones will play a vital role in the growth phase of this cutting-edge technology. This paper presents a systematic approach for control mode identification of JetQuads (gas turbine-powered quads) that should be satisfied simultaneously to achieve a safe and optimal operation of the JetQuad. Using bond graphs as a powerful mechatronic tool, a modular model of a JetQuad including the gas turbine, electric starter, and the main body was developed and validated against publicly available data. Two practical scenarios for thrust variation as a function of time were defined to investigate the compatibility and robustness of the JetQuad. The simulation results of these scenarios confirmed the necessity of designing a compatibility control loop, a stability control loop, and physical limitation control loops for the safe and errorless operation of the system. A control structure with its associated control algorithm is also proposed to deal with future challenges in JetQuad control problems.
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  • Modeling and Control of the Starter Motor and Start-Up Phase for Gas Turbines

    Jafari, Soheil   Fashandi, Seyed Alireza Miran   Nikolaidis, Theoklis  

    Improving the performance of industrial gas turbines has always been at the focus of attention of researchers and manufacturers. Nowadays, the operating environment of gas turbines has been transformed significantly respect to the very fast growth of renewable electricity generation where gas turbines should provide a safe, reliable, fast, and flexible transient operation to support their renewable partners. So, having a reliable tools to predict the transient behavior of the gas turbine is becoming more and more important. Regarding the response time and flexibility, improving the turbine performance during the start-up phase is an important issue that should be taken into account by the turbine manufacturers. To analyze the turbine performance during the start-up phase and to implement novel ideas so as to improve its performance, modeling, and simulation of an industrial gas turbine during cold start-up phase is investigated this article using an integrated modular approach. During this phase, a complex mechatronic system comprised of an asynchronous AC motor (electric starter), static frequency converter drive, and gas turbine exists. The start-up phase happens in this manner: first, the clutch transfers the torque generated by the electric starter to the gas turbine so that the turbine reaches a specific speed (cranking stage). Next, the turbine spends some time at this speed (purging stage), after which the turbine speed decreases, sparking stage begins, and the turbine enters the warm start-up phase. It is, however, possible that the start-up process fails at an intermediate stage. Such unsuccessful start-ups can be caused by turbine vibrations, the increase in the gradients of exhaust gases, or issues with fuel spray nozzles. If, for any reason, the turbine cannot reach the self-sustained speed and the speed falls below a certain threshold, the clutch engages once again with the turbine shaft and the start-up process is repeated. Consequently, when modeling the start-up phase, we face discontinuities in performance and a system with variable structure owing to the existence of clutch. Modeling the start-up phase, which happens to exist in many different fields including electric and mechanical application, brings about problems in numerical solutions (such as algebraic loop). Accordingly, this study attempts to benefit from the bond graph approach (as a powerful physical modeling approach) to model such a mechatronic system. The results confirm the effectiveness of the proposed approach in detailed performance prediction of the gas turbine in start-up phase.
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  • Application of Bond Graph approach in dynamic modelling of industrial gas turbine

    Montazeri-Gh, Morteza   Fashandi, Seyed Alireza Miran  

    Nowadays, gas turbines play a significant role in industry and power generation units. Therefore, any increase in their performance efficiency, is designers' major concern. Power generation system's principal considerations are performance, weight and reliability. Gas turbine engine is considered as a probable choice for such applications. This research develops and validates a Bond Graph model based on flow of energy and information of a gas turbine engine. Here, modelling of the gas turbine engine is achieved based on the pseudo Bond Graph approach. Subsequently, by coupling the Bond-Graph component models, a unified framework for model representation is presented. Also, to study the effect of changing external load on turbine's performance, an industrial two-shaft gas turbine is simulated under large transient loads based on the previously developed component models. Finally, the commercial gas turbine simulation program (GSP) is used to validate the simulation results. Transient response simulations indicate an acceptable error between the GSP and Bond Graph model outputs.
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  • Modeling and simulation of a two-shaft gas turbine propulsion system containing a frictional plate-type clutch

    Montazeri-Gh, Morteza   Fashandi, Seyed Alireza Miran  

    A marine propulsion system is composed of several sub-systems that operate in a variety of energy fields. The propulsion power of a ship can be provided from a two-shaft gas turbine. In this article, the modeling of a two-shaft gas turbine and its associated sub-systems including gears, flexible couplings and clutch is considered. These components are connected in the form of a virtual marine propulsion system, which is based on the bond-graph approach. When a clutch is used in a propulsion system, discontinuities occur in the describing model, which leads to some challenging problems when performing computer simulations. The two main difficulties are the numerical stiffness and the variable model structure. In this research, the bond-graph method is adapted as the modeling framework in order to allow a constant system structure model that minimizes the stiffness problem. Next, simulation results of a two-shaft gas turbine are presented in the off-design condition and verified with experimental tests. These results demonstrate the acceptable accuracy of computer simulations. Also, the effects of clutch performance on the dynamics of the marine propulsion system are discussed.
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  • Diagnosis Please Certificate of Recognition Awarded to Seyed Alireza Emamian, MD, PhD

    Proto, Anthony V.  

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  • Diagnosis Please Certificate of Recognition Awarded to Seyed Alireza Emamian, MD, PhD

    Proto   Anthony V.  

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  • [IEEE 2017 IEEE 4th International Conference on Knowledge-Based Engineering and Innovation (KBEI) - Tehran, Iran (2017.12.22-2017.12.22)] 2017 IEEE 4th International Conference on Knowledge-Based Engineering and Innovation (KBEI) - Modeling and simulation of JetQuad aerial robot

    Fashandi, Seyed Alireza Miran   Montazeri-gh, Morteza  

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