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Advanced optimization of gas turbine aero-engine transient performance using linkage-learning genetic algorithm:PartⅡ,optimization in flight mission and controller gains correlation development

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Chinese Journal of Aeronautics 2021年第4期34卷 568-588页

作者： Yinfeng LIU Soheil JAFARI theoklis nikolaidis Aero Engine Test Department of Hunan Aviation Powerplant Research Institute AECCZhuzhou 412002China Centre for Propulsion Engineering School of Aerospace Transport and Manufacturing(SATM)Cranfield UniversityCranfield MK430ALUK

PartⅠhas illustrated the procedures to apply the Linkage Learning Genetic Algorithm(LLGA)in Gas Turbine Engine(GTE)controller gains tuning and generated the optimization results for runway conditions from idle to ***,the total pressure and temperature of the engine inlet vary as the changing of altitude and Mach number,which would lead to the variation in fuel flow supply *** a result,the optimized gains in runway might not be suitable for other flight *** order to maintain the optimal control performance,the GTE controller gains should be adjusted according to the flight *** paper extends the application of the LLGA method to other flight conditions and then simulates a complete flight mission with different gains and weather condition *** this purpose,the control parameters in the Simulink model of the GTE controller are first corrected by the weather condition in ***,a typical flight mission is defined and divided into different flight segments based on the altitude and Mach number *** representative point is selected from each segment as the datum point for optimization *** this step,the LLGA method is used to find the best gains combinations for different flight conditions and the differences in optimization effects for different flight conditions are analyzed *** simulation results show that the optimization effect of the control performance of each flight condition is dependent on the value of(θδ)~(1/2)and the optimal K_(pla)in some flight conditions is approximately equal to p hd times of the Kplavalue in sea level standard ***,the complete flight mission is simulated with different gains and weather condition *** simulation results show that the engine performance has been greatly improved after optimization by LLGA in the transient state and the high altitude *** other steady states,the optimization effect is not

关键词： Aeroengine control Control optimization Flight condition Flight mission simulation GA GTE LLGA Min-Max controller Robustness

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A combined technique of Kalman filter, artificial neural network and fuzzy logic for gas turbines and signal fault isolation

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Chinese Journal of Aeronautics 2021年第2期34卷 124-135页

作者： Simone TOGNI theoklis nikolaidis Suresh SAMPATH Department of Power and Propulsion Cranfield UniversityCranfield MK-43United Kingdom

The target of this paper is the performance-based diagnostics of a gas turbine for the automated early detection of components malfunctions. The paper proposes a new combination of multiple methodologies for the performance-based diagnostics of single and multiple failures on a two-spool engine. The aim of this technique is to combine the strength of each methodology and provide a high success rate for single and multiple failures with the presence of measurement malfunctions. A combination of KF(Kalman Filter), ANN(Artificial Neural Network) and FL(Fuzzy Logic) is used in this research in order to improve the success rate, to increase the flexibility and the number of failures detected and to combine the strength of multiple methods to have a more robust solution. The Kalman filter has in his strength the measurement noise treatment, the artificial neural network the simulation and prediction of reference and deteriorated performance profile and the fuzzy logic the categorization flexibility, which is used to quantify and classify the failures. In the area of GT(Gas Turbine) diagnostics, the multiple failures in combination with measurement issues and the utilization of multiple methods for a 2-spool industrial gas turbine engine has not been investigated *** paper reports the key contribution of each component of the methodology and brief the results in the quantification and classification success rate. The methodology is tested for constant deterioration and increasing noise and for random deterioration. For the random deterioration and nominal noise of 0.4%, in particular, the quantification success rate is above 92.0%, while the classification success rate is above 95.1%. Moreover, the speed of the data processing(1.7 s/sample)proves the suitability of this methodology for online diagnostics.

关键词： Artificial neural network Data analytics Data filtering Diagnostics Fuzzy logic Gas turbine Kalman filter Performance-based diagnostics

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Utilisation of turboelectric distribution propulsion in commercial aviation:A review on NASA's TeDP concept

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Chinese Journal of Aeronautics 2021年第11期34卷 48-65页

作者： Mosab ALRASHED theoklis nikolaidis Pericles PILIDIS Soheil JAFARI Turboelectric Engineering Group Cranfield CampusCranfield UniversityBedfordshire MK43 OALUK

Emissions produced by the aviation industry are currently a severe environmental threat;therefore,aviation agencies and governments have set emission targets and formulated plans to restrict emissions within the next *** aircraft technology is being considered to meet these *** importance of these technologies lies in their advancements in terms of aircraft life cycles and environmental *** to these advancements,hybrid electric systems with more than one power source have become promising for the aviation industry,considering that the growth of air traffic is projected to double in the next *** technologies have given future hybrid fans and motor-fan engines potential as alternative power ***,Turboelectric Distributed Propulsion(TeDP)is discussed in terms of power distribution and power *** fundamentals of turbofan and turboshaft engines are presented along with their electricitygeneration *** is discussed from a design viewpoint,with a detailed discussion of different types of hybrid electric and turboelectric *** of proposed TeDP aircraft models and numerical modelling tools used to simulate the performance of TeDP models are ***,innovative turboelectric systems in which electric power savers and mechanical gear changers have been discarded for weight optimisation are presented along with other prospective models,engines,approaches,and *** findings of this review indicate the knowledge gaps in the field of numerical modelling for NASA’s TeDP and its capability to increase the efficiency by up to 24%with a 50%reduction in emissions relative to those of conventional gas turbines.

关键词： Futuristic propulsion systems Hybrid aircraft engines Numerical modelling and simulation Turboelectric distributed propulsion Turboelectric power

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A novel model-based multivariable framework for aircraft gas turbine engine limit protection control

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Chinese Journal of Aeronautics 2021年第12期34卷 57-72页

作者： Shuwei PANG Soheil JAFARI theoklis nikolaidis Qiuhong LI Jiangsu Province Key Laboratory of Aerospace Power System Nanjing University of Aeronautics and AstronauticsNanjing 210016China Propulsion Engineering Center School of AerospaceTransport and ManufacturingCranfield UniversityBedford MK43 OALUK

Control technologies are innovated to satisfy increasingly complicated control demands of gas turbine *** terms of limit protection control,a novel model-based multivariable limit protection control method,which is achieved by adaptive command reconstruction and multiplecontrol loop selection and switch logic,is proposed in this paper to address the problem of balancing smaller thrust loss and safe operations by comparing with widely-used Min-Max *** different combination modes of control loops,which represent the online control loop of last time instant and that of current time instant,is *** command reconstructions are designed for these modes,which is based on static gain conversion of amplitude beyond limits by using an onboard *** double-prediction based control loop selection and switch logic is developed to choose a control loop appropriately by comparing converted amplitude beyond limits regardless of one or more parameters tending to exceed *** proposed method is implemented in a twin-spool turbofan engine to achieve limit protection with direct thrust control,and the loss of thrust is improved by about 30% in comparison with the loss of thrust caused by Min-Max logic when limit protection control is activated,which demonstrates the effectiveness of the proposed method.

关键词： Amplitude conversion Command reconstruction Gas turbine engine Limit protection control Multivariable control Onboard prediction

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Reduced-dimensional MPC controller for direct thrust control

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Chinese Journal of Aeronautics 2022年第4期35卷 66-81页

With the development of the aircraft gas turbine engine, a control system should be able to achieve effective thrust control to gain better operability. The main contribution of this paper is to develop a novel direct thrust control approach based on an improved model predictive control method through a strategy that reduces the dimension of control sequence. It can not only achieve normal direct thrust control tasks but also maximize the thrust level within the safe operation boundaries. Only the action of switching the objective functions is required to achieve the switch of these two thrust control modes while there is no modification to the control structure. Besides,a shorter control sequence is defined for multivariable control by updating only one control variable at every simulation time instant. Therefore, the time requirement for the solving process of the optimal control sequence is reduced. The proposed controller is implemented to a twin-spool *** are conducted in the wide flight envelope, and results show that the average timeconsumption can be reduced up to 65% in comparison with the standard model predictive control,and the thrust can be increased significantly when maximum thrust mode is implemented by using engine limit margins.

关键词： Computation time Direct thrust control Gas turbine engine Model predictive control Thrust optimization

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Performance assessment of simple and modified cycle turboshaft gas turbines

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Propulsion and Power Research 2013年第2期2卷 96-106页

作者： Barinyima Nkoi Pericles Pilidis theoklis nikolaidis Deparment of Power and Propulsion School of EngineeringCranfied UniversityCranieldBedfordshire MK430ALUnited Kingdom

This paper focuses on investigations encompassing comparative assessment of gasturbine cycle *** specifically,investigation was caried out of technical performanceof turboshaft engine cycles based on existing simple cycle(SC)and its projected modifiedcycles for civil helicopter ***,thermal efficiency,specific fuel consump-tion,and power output are of paramount importance to the overall performance of gas *** course of carrying out this research,turbomatch software established at CranfieldUniversity based on gas turbine theory was applied to conduct simulation of a simple cycle(baseline)two-spool helicopter turboshaft engine model with free power ***,some modified gas urbine cycle configurations incoporating unconventional components,such as engine cycle with low pressure compressor(LPC)zero-staged,recuperated enginecycle,and intercooled/recuperated(ICR)engine cycle,were also *** doing so,designpoint(DP)and off-design point(OD)performances of the engine models were *** changes in performance parameters of the modified cycle engines over the simplecycle were evaluated and it was found that to a large extent,the modified engine cycles withunconventional components exhibit better performances in terms of thermal efficiency andspecific fuel consumption than the traditional simple cycle *** research made use ofpublic domain open source references.

关键词： Gas turbines Turboshaft Technical performance Intercooled Recuperated Low pressure compressor(LPC)zero-staged Simple cycle Comparative assessment

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Performance of small-scale aero-derivative industrial gas turbines derived from helicopter engines

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Propulsion and Power Research 2013年第4期2卷 243-253页

作者： Barinyima Nkoi Pericles Pilidis theoklis nikolaidis Department of Power and Propulsion School of EngineeringCranfield UniversityCranfieldBedfordshireMK430ALUnited Kingdom

This paper considers comparative assessment of simple and advanced cycle small-scale aero-derivative industrial gas turbines derived from helicopter *** particularly,investigation was made of technical performance of the small-scale aero-derivative engine cycles based on existing and projected cycles for applications in industrial power generation,combined heat and power concept,rotating equipment driving,and/or allied *** investigation was done by carrying out preliminary design and performance simulation of a simple cycle(baseline)two-spool small-scale aero-derivative turboshaft engine model,and some advanced counterpart aero-derivative *** advanced configurations consist of recuperated and intercooled/recuperated engine cycles of same nominal power rating of 1.567 *** baseline model was derived from the conversion of an existing helicopter engine *** doing so,design point and off-design point performances of the engine models were *** comparing their performances,it was observed that to a large extent,the advanced engine cycles showed superior performance in terms of thermal efficiency,and specific fuel *** numerical terms,thermal efficiencies of recuperated engine cycle,and intercooled/recuperated engine cycles,over the simple cycle at DP increased by 13.5%,and 14.5%respectively,whereas specific fuel consumption of these cycles over simple cycle at DP decreased by 12.5%,and 13%*** research relied on open access public literature for data.

关键词： Gas turbine Small-scale aero-derivatives Thermal efficiency Intercooled/Recuperated Simple-cycle Specific-fuel-consumption Performance assessment Helicopter engine

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Fault Location Method for Overhead Feeders with Distributed Generation Units Based on Direct Load Flow Approach

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1135-1146页

作者： Charalampos G.Arsoniadis Vassilis C.nikolaidis Department of Electrical and Computer Engineering Democritus University of ThraceXanthi 67100Greece

This paper proposes a novel fault location method for overhead feeders,which is based on the direct load flow *** method is developed in the phase domain to effec-tively deal with unbalanced network conditions,while it can al-so handle any type of distributed generation(DG)units without requiring equivalent *** utilizing the line series parame-ters and synchronized or unsynchronized voltage and current phasor measurements taken from the sources,the method reli-ably identifies the most probable faulty *** the aid of an index,the exact faulty section among the multiple candi-dates is *** simulation studies for the IEEE 123-bus test feeder demonstrate that the proposed method accu-rately estimates the fault position under numerous short-circuit conditions with varying pre-fault system loading conditions,fault resistances,and measurement *** proposed meth-od is promising for practical applications due to the limited number of required measurement devices as well as the short computation time.

关键词： Fault location distribution system direct load flow distributed generation

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The effect of sex and performance level on pacing in cross-country skiers:Vasaloppet 2004-2017

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Journal of Sport and Health Science 2018年第4期7卷 453-458页

作者： Pantelis Theodoros nikolaidis Elias Villiger Beat Knechtle Exercise Physiology Laboratory Nikaia 18450 Greece Institute of Primary Care University of ZurichZurich 9000Switzerland Medbase St.Gallen Am Vadianplatz St.Gallen 9001Switzerland Corresponding author.E-mail address：beat.knechtle@hispeed.ch

Background： Pacing, defined as percentage changes of speed between successive splits, has been extensively studied in running and cycling endurance sports; however, less information about the trends in change of speed during cross-country （XC） ski racing is available. Therefore, the aim of the present study was to examine the effect of performance （quartiles of race time （Q）, with Q1 the fastest and Q4 the slowest） level on pacing in the Vasaloppet ski race, the largest XC skiing race in the world. Methods： For this purpose, we analyzed female （n = 19,465） and male （n = 164,454） finishers in the Vasaloppet ski race from 2004 to 2017 using a one-way （2 sexes） analysis of variance with repeated measures to examine percentage changes of speed between 2 successive splits. Overall, the race consisted of 8 splits. Results： The race speeds of Q1, Q2, Q3, and Q4 were 13.6 ± 1.8, 10.6 ± 0.5, 9.2 ± 0.3, and 8.1 ±- 0.4 km/h, respectively, among females and 16.7 ± 1.7, 13.1 ± 0.7, 10.9 ± 0.6, and 8.9 ± 0.7 km/h, respectively, among males. The overall pacing strategy of finishers was variable. A small sex × split interaction on speed was observed （η^2= 0.016, p 〈 0.001）, with speed difference between sexes ranging from 14.9% （Split 7） to 27.0% （Split 1） and larger changes in speed between 2 successive splits being shown for females （p 〈 0.001, η^2=0.004）. A large performance × split interaction on speed, with Q1 presenting the smallest changes of speed between splits, was shown for females （η^2= 0.149, p 〈 0.001） and males （η^2 = 0.169,p 〈 0.001）. Conclusion： Male and fast XC skiers are more even pacers. Coaches and athletes should develop tailored sex- and performance-level pacing strategies; for instance, they should advise fast XC skiers to start fast and maintain their speed, rather than starting slowly and trying to make up time by going faster at times during the race.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article

关键词： Endurance exercise Race speed Sex Sport performance Winter sport

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Is there stability in the performance of elite half-marathoners?

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Sports Medicine and Health Science 2022年第2期4卷 101-104页

作者： Mabliny Thuany Beat Knechtle Pantelis Theodoros nikolaidis Thayse Natacha Gomes Faculty of Sports University of PortoPortoPortugal Institute of Primary Care University of ZurichZurichSwitzerland School of Health and Caring Sciences University of West AtticaAthensGreece Department of Physical Education Federal University of SergipeSao CristovaoBrazil

The purpose of this study was to investigate the performance stability of elite half-marathoners of both *** study was composed of 24 elite athletes(12 female and 12 male),ranked among the Senior World TOP20 halfmarathoners,who completed a half-marathon race for at least three consecutive *** was tested using autocorrelations and Kappa *** revealed a significant association,but a decrease in correlation among the years in both *** overall weighted kappa showed lower stability in performance for both sexes(K=0.191 and K=-0.245)than for *** findings suggest that both female and male elite halfmarathoners showed low stability in performance during three *** that,athletes with a better performance tended to present the highest performance *** is recommended that coaches track the developmental trajectories of the athletes to comprised the changes in performance across the years,as to provide environmental characteristics that can influence performance.

关键词： Tracking Endurance Running Elite athletes

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