The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
Rudolf Andoga - One of the best experts on this subject based on the ideXlab platform.
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robust control of small turbojet engines
Machines, 2019Co-Authors: Rudolf Andoga, Ladislav Főző, Radovan Kovacs, Karoly Beneda, Tomas Moravec, Michal SchreinerAbstract:Modern turbojet engines mainly use computerized digital engine control systems. This opens the way for application of advanced algorithms aimed at increasing their operational efficiency and safety. The theory of robust control is a set of methods known for good results in complex control tasks, making them ideal candidates for application in the current turbojet engine control units. Different methodologies in the design of robust controllers, utilizing a small turbojet engine with variable Exhaust Nozzle designated as iSTC-21v, were therefore investigated in the article. The resulting controllers were evaluated for efficiency in laboratory conditions. The aim was to find a suitable approach and design method for robust controllers, taking into account the limitations and specifics of a real turbojet engine and its hardware, contrary to most studies which have used only simulated environments. The article shows the most effective approach in the design of robust controllers and the resulting speed controllers for a class of small turbojet engines, which can be applied in a discrete digital control environment.
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linear mathematical model for state space representation of small scale turbojet engine with variable Exhaust Nozzle
Periodica Polytechnica Transportation Engineering, 2017Co-Authors: Karoly Beneda, Rudolf Andoga, Ladislav FőzőAbstract:The goal of this article is to develop a linear mathematical model for a small scale turbojet engine with variable convergent Nozzle, and validate it on existing laboratory hardware owned by the authors’ Departments. Control of gas turbine engines plays an essential role in the safety of aviation. Although its role is constantly expanding, ranging from pilot workload reduction to detailed diagnostics, the basic competence is to regulate the thrust output of the power plant with maximum available accuracy, rapidity, stability, and robustness. The linear quadratic control is one possible solution for the above mentioned criteria. Although civil aircraft engines include fixed Exhaust Nozzle geometry, in military applications the Exhaust Nozzle geometry is also adjustable to reach optimum efficiency due to better matching of individual engine components, etc. In the present article the authors deduce the members of state space governing equations to acquire the basis of the LQ control. The established model is based on the physical laws describing the operational behavior of the engine as well as its complexity should be reduced to an acceptable level where still enough details remain to reflect the nature of the controlled object.
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experimental identification of a small turbojet engine with variable Exhaust Nozzle
International Symposium on Computational Intelligence and Informatics, 2015Co-Authors: M Komjaty, L Fozo, Rudolf AndogaAbstract:The paper deals with mathematical modeling of a small turbojet iSTC-21v with variable Exhaust Nozzle. We evaluate and measure the appropriate parameters that describe the engine modes during changes of the Exhaust Nozzle diameter. The article describes methods of experimental identification (the method of successive integration and the approximation of characteristic response) applied on a system with two inputs and two outputs. For the purpose of mathematical modeling, as well as for models evaluation, real data obtained from a small turbojet engine measurement are used.
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Description of an intelligent small turbo-compressor engine with variable Exhaust Nozzle
2015 IEEE 13th International Symposium on Applied Machine Intelligence and Informatics (SAMI), 2015Co-Authors: Ladislav Főző, J. Kolesár, Rudolf Andoga, Ladislav Madarasz, J. JudičákAbstract:How to use an old turbo-compressor (turboshaft) engine and transfer it into a laboratory system used for design and development of progressive control, diagnostic and modeling algorithms transforming it into an intelligent turbo-compressor engine? The intelligent turbo-compressor engine currently designated as iSTC-21v is a small turbojet engine with a single sided radial compressor, bound combustion chamber, single stage un-cooled turbine and variable Exhaust Nozzle. The engine is equipped with a real-time measurement and intelligent digital control system using two degrees of freedom (fuel supply and Exhaust Nozzle diameter). The article describes transformation of an old TS-20/21 engine into such engine, which is suitable for laboratory use, research in different areas of cybernetics with perspective applications in different areas of technical practice like unmanned aerial vehicles, ground auxiliary energetic units, generators, etc. The article is aimed to be inspirative also for hobby engine builders, scale modelers and people who work with small turbo-compressor engines.
James Bridges - One of the best experts on this subject based on the ideXlab platform.
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acoustics and thrust of quiet separate flow high bypass ratio Nozzles
AIAA Journal, 2003Co-Authors: Naseem H Saiyed, Kevin L Mikkelsen, James BridgesAbstract:TheNASAGlennResearchCenterrecentlycompletedanexperimentalstudytoreducethejetnoisefrommodern turbofan engines. The study concentrated on Exhaust Nozzle designs for high-bypass-ratio engines. These designs modie ed the core and fan Nozzles individually and simultaneously. In comparison with chevrons, tabs appeared to be an inefe cient method for reducing jet noise. Data trends show that interaction between fan e ow and the core cowl could strongly impact noise and cruise performance irrespective of the mixing device installed. The study demonstrates that modie cations of the core Nozzle are generally more advantageous than of the fan Nozzle. Even greater advantage in noise reduction and associated cruise thrust penalties is demonstrated through simultaneous modie cation of both Nozzles. ThebestNozzledesign had a 0.06% cruisethrustlossand, corrected fortakeoff thrust loss, a 2.7-EPNdB reduction for the effective perceived noise level metric. This design simultaneously employed chevrons on the core and fan Nozzles. Last, e ve Nozzle cone gurations with cruise thrust loss of less than 0.5% and noise reductions of over 2.5 EPNdB are identie ed as candidates for full-scale engine and e ight demonstrations.
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acoustics and trust of separate flow Exhaust Nozzles with mixing devices for high bypass ratio engines
6th Aeroacoustics Conference and Exhibit, 2000Co-Authors: Naseem H Saiyed, Kevin L Mikkelsen, James BridgesAbstract:The NASA Glenn Research Center recently completed an experimental study to reduce the jet noise from modern turbofan engines. The study concentrated on Exhaust Nozzle designs for high-bypass-ratio engines. These designs modified the core and fan Nozzles individually and simultaneously. Several designs provided an ideal jet noise reduction of over 2.5 EPNdB for the effective perceived noise level (EPNL) metric. Noise data, after correcting for takeoff thrust losses, indicated over a 2.0-EPNdB reduction for nine designs. Individually modifying the fan Nozzle did not provide attractive EPNL reductions. Designs in which only the core Nozzle was modified provided greater EPNL reductions. Designs in which core and fan Nozzles were modified simultaneously provided the greatest EPNL reduction. The best Nozzle design had a 2.7-EPNdB reduction (corrected for takeoff thrust loss) with a 0.06-point cruise thrust loss. This design simultaneously employed chevrons on the core and fan Nozzles. In comparison with chevrons, tabs appeared to be an inefficient method for reducing jet noise. Data trends indicate that the sum of the thrust losses from individually modifying core and fan Nozzles did not generally equal the thrust loss from modifying them simultaneously. Flow blockage from tabs did not scale directly with cruise thrust loss and the interaction between fan flow and the core Nozzle seemed to strongly affect noise and cruise performance. Finally, the Nozzle configuration candidates for full-scale engine demonstrations are identified.
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tabs and mixers for re uclng low bypass ratio jet noise
AIAA CEAS Aeroacoustics Conference, 1999Co-Authors: Naseem H Saiyed, James BridgesAbstract:An experiment to determine the effect of tabs on a scale model Exhaust Nozzle system representing low bypass ratio turbo-fan engines was conducted. Both core and Exhaust Nozzle were modified, either alone or simultaneously. Our study looked at noise benefits, both spectrally and on Effective Perceived Noise Level (EPNL) metric, for a range of operating conditions. Tabs provided about 1 EPNdB reduction, relative to simple a Nozzle, when used on the core stream alone and did not provide any reduction when used on the Exhaust Nozzle alone. However, 2 EPNdB benefit was realized with tabs on both core and Exhaust Nozzles simultaneously. These benefits were realized with very little tab-induced high frequency noise generation.
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tabs and mixers for re uclng low bypass ratio jet noise
AIAA CEAS Aeroacoustics Conference, 1999Co-Authors: Naseem H Saiyed, James BridgesAbstract:An experiment to determine the effect of tabs on a scale model Exhaust Nozzle system representing low bypass ratio turbo-fan engines was conducted. Both core and Exhaust Nozzle were modified, either alone or simultaneously. Our study looked at noise benefits, both spectrally and on Effective Perceived Noise Level (EPNL) metric, for a range of operating conditions. Tabs provided about 1 EPNdB reduction, relative to simple a Nozzle, when used on the core stream alone and did not provide any reduction when used on the Exhaust Nozzle alone. However, 2 EPNdB benefit was realized with tabs on both core and Exhaust Nozzles simultaneously. These benefits were realized with very little tab-induced high frequency noise generation.
Naseem H Saiyed - One of the best experts on this subject based on the ideXlab platform.
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acoustics and thrust of quiet separate flow high bypass ratio Nozzles
AIAA Journal, 2003Co-Authors: Naseem H Saiyed, Kevin L Mikkelsen, James BridgesAbstract:TheNASAGlennResearchCenterrecentlycompletedanexperimentalstudytoreducethejetnoisefrommodern turbofan engines. The study concentrated on Exhaust Nozzle designs for high-bypass-ratio engines. These designs modie ed the core and fan Nozzles individually and simultaneously. In comparison with chevrons, tabs appeared to be an inefe cient method for reducing jet noise. Data trends show that interaction between fan e ow and the core cowl could strongly impact noise and cruise performance irrespective of the mixing device installed. The study demonstrates that modie cations of the core Nozzle are generally more advantageous than of the fan Nozzle. Even greater advantage in noise reduction and associated cruise thrust penalties is demonstrated through simultaneous modie cation of both Nozzles. ThebestNozzledesign had a 0.06% cruisethrustlossand, corrected fortakeoff thrust loss, a 2.7-EPNdB reduction for the effective perceived noise level metric. This design simultaneously employed chevrons on the core and fan Nozzles. Last, e ve Nozzle cone gurations with cruise thrust loss of less than 0.5% and noise reductions of over 2.5 EPNdB are identie ed as candidates for full-scale engine and e ight demonstrations.
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acoustics and trust of separate flow Exhaust Nozzles with mixing devices for high bypass ratio engines
6th Aeroacoustics Conference and Exhibit, 2000Co-Authors: Naseem H Saiyed, Kevin L Mikkelsen, James BridgesAbstract:The NASA Glenn Research Center recently completed an experimental study to reduce the jet noise from modern turbofan engines. The study concentrated on Exhaust Nozzle designs for high-bypass-ratio engines. These designs modified the core and fan Nozzles individually and simultaneously. Several designs provided an ideal jet noise reduction of over 2.5 EPNdB for the effective perceived noise level (EPNL) metric. Noise data, after correcting for takeoff thrust losses, indicated over a 2.0-EPNdB reduction for nine designs. Individually modifying the fan Nozzle did not provide attractive EPNL reductions. Designs in which only the core Nozzle was modified provided greater EPNL reductions. Designs in which core and fan Nozzles were modified simultaneously provided the greatest EPNL reduction. The best Nozzle design had a 2.7-EPNdB reduction (corrected for takeoff thrust loss) with a 0.06-point cruise thrust loss. This design simultaneously employed chevrons on the core and fan Nozzles. In comparison with chevrons, tabs appeared to be an inefficient method for reducing jet noise. Data trends indicate that the sum of the thrust losses from individually modifying core and fan Nozzles did not generally equal the thrust loss from modifying them simultaneously. Flow blockage from tabs did not scale directly with cruise thrust loss and the interaction between fan flow and the core Nozzle seemed to strongly affect noise and cruise performance. Finally, the Nozzle configuration candidates for full-scale engine demonstrations are identified.
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tabs and mixers for re uclng low bypass ratio jet noise
AIAA CEAS Aeroacoustics Conference, 1999Co-Authors: Naseem H Saiyed, James BridgesAbstract:An experiment to determine the effect of tabs on a scale model Exhaust Nozzle system representing low bypass ratio turbo-fan engines was conducted. Both core and Exhaust Nozzle were modified, either alone or simultaneously. Our study looked at noise benefits, both spectrally and on Effective Perceived Noise Level (EPNL) metric, for a range of operating conditions. Tabs provided about 1 EPNdB reduction, relative to simple a Nozzle, when used on the core stream alone and did not provide any reduction when used on the Exhaust Nozzle alone. However, 2 EPNdB benefit was realized with tabs on both core and Exhaust Nozzles simultaneously. These benefits were realized with very little tab-induced high frequency noise generation.
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tabs and mixers for re uclng low bypass ratio jet noise
AIAA CEAS Aeroacoustics Conference, 1999Co-Authors: Naseem H Saiyed, James BridgesAbstract:An experiment to determine the effect of tabs on a scale model Exhaust Nozzle system representing low bypass ratio turbo-fan engines was conducted. Both core and Exhaust Nozzle were modified, either alone or simultaneously. Our study looked at noise benefits, both spectrally and on Effective Perceived Noise Level (EPNL) metric, for a range of operating conditions. Tabs provided about 1 EPNdB reduction, relative to simple a Nozzle, when used on the core stream alone and did not provide any reduction when used on the Exhaust Nozzle alone. However, 2 EPNdB benefit was realized with tabs on both core and Exhaust Nozzles simultaneously. These benefits were realized with very little tab-induced high frequency noise generation.
Hongsheng Yan - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigation on electrostatic monitoring technology for civil turbofan engine
JVE International, 2017Co-Authors: Yibing Yin, Jing Cai, Hongfu Zuo, Huijie Mao, Hongsheng YanAbstract:This study analyzes the necessity, development, and principles of aero-engine electrostatic monitoring technology. An electrostatic sensor with specific size is assembled in the Exhaust Nozzle of an RB-211 turbofan engine located near the low-pressure turbine outlet, a stress checking procedure for safety is conducted. Two test program cycles are included in the whole experimental process. Electrostatic signal processing flow is presented, and feature parameters used for analysis are root-mean-square (RMS), activity level (AL), negative event rate (NER), positive event rate (PER), kurtosis, impulse factor, and absolute mean value. Thrust is used to parameterize the working conditions of the turbofan engine. Moreover, data fitting is conducted to determine the relations between feature and performance parameters. Accordingly, lubrication oil leakage fault and fuel-rich combustion condition are detected in two test run cycles, which result in the appearance of abnormal signals. The AL, RMS, and absolute mean values exhibit similar trends with the change in thrust. A positive linear correlation is also observed between the AL and the thrust in the varying thrust test period. The method of blade-casing rubbing fault recognition is discussed. Experiment results show that the electrostatic sensor is very sensitive to large-sized charged particles in the Exhaust emissions
Karoly Beneda - One of the best experts on this subject based on the ideXlab platform.
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robust control of small turbojet engines
Machines, 2019Co-Authors: Rudolf Andoga, Ladislav Főző, Radovan Kovacs, Karoly Beneda, Tomas Moravec, Michal SchreinerAbstract:Modern turbojet engines mainly use computerized digital engine control systems. This opens the way for application of advanced algorithms aimed at increasing their operational efficiency and safety. The theory of robust control is a set of methods known for good results in complex control tasks, making them ideal candidates for application in the current turbojet engine control units. Different methodologies in the design of robust controllers, utilizing a small turbojet engine with variable Exhaust Nozzle designated as iSTC-21v, were therefore investigated in the article. The resulting controllers were evaluated for efficiency in laboratory conditions. The aim was to find a suitable approach and design method for robust controllers, taking into account the limitations and specifics of a real turbojet engine and its hardware, contrary to most studies which have used only simulated environments. The article shows the most effective approach in the design of robust controllers and the resulting speed controllers for a class of small turbojet engines, which can be applied in a discrete digital control environment.
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linear mathematical model for state space representation of small scale turbojet engine with variable Exhaust Nozzle
Periodica Polytechnica Transportation Engineering, 2017Co-Authors: Karoly Beneda, Rudolf Andoga, Ladislav FőzőAbstract:The goal of this article is to develop a linear mathematical model for a small scale turbojet engine with variable convergent Nozzle, and validate it on existing laboratory hardware owned by the authors’ Departments. Control of gas turbine engines plays an essential role in the safety of aviation. Although its role is constantly expanding, ranging from pilot workload reduction to detailed diagnostics, the basic competence is to regulate the thrust output of the power plant with maximum available accuracy, rapidity, stability, and robustness. The linear quadratic control is one possible solution for the above mentioned criteria. Although civil aircraft engines include fixed Exhaust Nozzle geometry, in military applications the Exhaust Nozzle geometry is also adjustable to reach optimum efficiency due to better matching of individual engine components, etc. In the present article the authors deduce the members of state space governing equations to acquire the basis of the LQ control. The established model is based on the physical laws describing the operational behavior of the engine as well as its complexity should be reduced to an acceptable level where still enough details remain to reflect the nature of the controlled object.