Myoungcheol Kang

A Study on Transient Performance Characteristics of the Canard Rotor Wing Type Unmanned Aerial Vehicle Propulsion System During Flight Mode Transition

A propulsion system of the CRW (Canard rotor wing) type UAV (unmanned aerial vehicle) was composed of the turbojet engine, exhaust nozzles (including some tip jet nozzles and a main nozzle), and the duct system (including straight ducts, curved ducts, and master valve). The CRW-type UAV has three different flight modes, such as the rotary wing mode for takeoff and landing, the high-speed forward flight mode with the fixed wing, and the transition flight mode between the previously mentioned two flight modes. In order to evaluate transient performance characteristics of the CRW-type UAV propulsion system during flight mode transition, the propulsion system was modeled using SIMULINK®, which is a user-friendly graphical-user-interface-(GUI) type dynamic analysis tool provided by MATLAB, in this study. The transition flight mode between the rotary wing mode and the fixed wing mode was simulated by considering area variation of the master valve and the main exhaust nozzle. In order to verify acceptability of the main turbojet engine model, performance simulation results using SIMULINK were compared to results using the commercial program GSP. Through this simulation, proper operation of the master valve and the variable area main nozzle can be found for safe flight transition. Therefore, performance characteristics were investigated depending on various angle positions of the master valve.

Intelligent performance diagnostics of a gas turbine engine using user‐friendly interface neural networks

In this study, in order to facilitate application of the NNs as well as to provide user‐friendly conditions, a performance diagnostic computer code using MATLAB® was newly proposed. As a result, not only more precise and prompt analysis results can be obtained due to use of the toolbox in MATLAB® on diagnosis and numerical analysis, but also the graphical user interface platform can be realized. The proposed engine diagnostics system is able to train the BPN with each fault pattern and then construct the total training network by assembling the trained BPNs. The database for network learning and test was constructed using a gas turbine performance simulation program. In order to investigate reliability on construction of the database for diagnostic results, an analysis is performed with five combination cases of 40 fault patterns. Finally, a diagnostic application example for the PT6A‐62 turboprop engine is performed using the trained network with the database, which represents the best diagnostic results among test sets.

Study on Component Map Generation and Performance Simulation of 2-spool Separate Flow Type Turbofan Engine Using SIMULINK

․ MyoungCheol Kang** ㆍ Gwanglim Park***ABSTRACT In this work, a steady-state performance modeling and off-design performance analysis of the 2-spool separate-flow turbofan engine named (BR715-56) which is a power plant for the narrow body commercial aircraft is carried out for engine performance behaviors investigation and condition monitoring using a commercial code MATLAB/SIMULINK. Firstly, th e engine component maps of fan, high pressure compressor, high pressure turbine and low pressur e turbine are generated from similar component maps using the scaling method, and then the off-design performance simulation model is constructed by the mass flow matching and the work matching between components. The model is developed using SIMULINK, which has advantages of easy steady-s tare and dynamic modelling and user friendly interface function. It is found that the off-desi gn performance analysis results using the proposed model are well agreed with the performance analysis results by GASTURB at various operating conditions.초 록 본 연구에서는 중형 항공기의 추진 기관인 2 스풀 분리-배기 형식 터보팬 엔진 (BR715-56)의 성능 해석을 수행하기 위하여 상용코드인 MATLAB/SIMULINK를 이용하여 성능모델을 구성하였으며 유량 및 일 조합에 새로운 조합 서브시스템 블록을 새로이 개발하였다. 성능 모사는 먼저 팬, 고압압축기, 고압터빈, 저압터빈 구성품 성능 맵들을 축척방법을 이용하여 유사성능 맵들로 부터 생성하였고, 다음은 탈설계점 성능 해석을 할 수 있도록 구성품들 간 유량과 일 조합이 이루어 질수 있도록 하였다. 제안된 SIMULINK 성능모델은 정상 및 동적 모사와 사용자 편의의 장점을 가지고 있으며, 다양한 작동 조건들에서 개발된 프로그램을 이용한 탈설계점 해석 결과들이 GASTURB에 의한 해석 결과들과 잘 일치함이 확인 되었다.Key Words: Performance Modeling(성능 모델), Sepaerate Flow Type Turbofan Engine(분리 배기형 터보팬 엔진), Off-design Performance(탈설계점 성능), Component Map Generation(구성품성능 맵 생성)

An Approach to Maintenance Cost Estimation for Aircraft Engines

This study presents a detailed analysis of aircraft engine maintenance cost based on the relationships between engine performance and geometric parameters. Estimating engine maintenance cost is very complicated and depends upon empirical work based on know-how and huge database to develop the industrial cost estimation program. Engine maintenance costs are basically influenced by the shop visit rates (SVR), the workscope of each shop visit, the shop visit pattern and the manhours and materials used in each shop visit. To estimate these values for a specific engine model, there is a need to develop the empirical correlations of engine maintenance. For this study, an engine performance and maintenance database was created. The engine performance data for each major component were simulated by an engine performance code, TURBOMATCH developed at Cranfield University, U.K., at static sea-level condition and geometric data were collected from open literature. Also, engine maintenance cost data for some current engines were collected and used. Some trend line equations based on the database were developed for the estimation of shop-visit interval, work-scope, Man-Hours, material cost and Life Limited Part cost. Comparisons of the results between trend equations and original data were carried out. The results show that this approach can give a more reasonable and detailed estimation of engine maintenance cost than older empirical methods.Copyright

Fuzzy Approaches for Searching Optimal Component Matching Point in Gas Turbine Performance Simulation

In performance simulation of gas turbine, some iteration processes for searching the operating point, which should be matched through gas path components, would be needed. Therefore if the engine is very complicated, the efficiency of convergence is getting lower due to increasing the number of routines and iterations for matching procedure. Furthermore, there may be some problems in numerical calculation such as the tendency of divergence, instability, and increase of calculation time. In the traditional matching methods, after some variable parameters are initially assumed and then calculated, the calculation is iterated to converge within an appropriate error range by expressing the new variables with the previous calculation error function. Even though these traditional methods show comparatively reasonable results in performance simulation, there may be some unsatisfied results in particular cases. Moreover, in this case it can be more difficult in more precise calculation due to simplification by using various assumptions. Therefore in order to search the optimal matching point in performance simulation of gas turbine efficiently and quickly, the fuzzy approaches were applied. In performance simulation using the fuzzy logic, it was found that more effective engine operating points were found and calculation time was considerably reduced less than the traditional methods. Furthermore, MATLAB was used to apply the fuzzy logic easily as well as to make user-friendly circumstance in performance analysis.

Fuel system design of the smart UAV considering operational reliability

Purpose – To set‐up a specific design procedure for the smart unmanned aerial vehicle (UAV) fuel supply system which has been developed by Korean Aerospace Research Institute, and to design it preliminarily with the fuel system requirement and target reliabilities.Design/methodology/approach – The fuel system layout and fuel tank were determined through consideration of total fuel volume, fuel flow rate, reliability, weight, centre of gravity, etc. In sizing of components such as booster pumps, jet pumps, piping system, vent subsystem, refuelling and defuelling subsystem, engine fuel flow requirement, pressure loss, component failure rate, weight and centre of gravity were considered. Finally, the reliability analysis of the preliminary designed fuel system was carried out.Findings – According to the reliability analysis and weight estimation results, it was confirmed that the proposed fuel system agreed well with the design specifications and target reliabilities required by the vehicle system.Research l...

A Development of EMAS (Easy Maintenance Assistance Solution) for Industrial Gas Turbine Engine

The solution was developed for the maintenance decision support of combined cycle power plant gas turbine. The developed solution provides the calculated result of optimal overhaul interval through the following modules: Overhaul Interval Prediction, Real Time Performance Monitoring, Model-Based Diagnostics, Performance Trend Analysis, Compressor Washing Period Management, and Blade Path Temperature Analysis. Model-Based Diagnostics module analyzed the differences between the data of MHI501G gas turbine performance model and the online measurement. Gas turbine performance model can be modified by the type of gas turbine of each combined cycle power plant. Compressor washing management module suggests the optimal point of balancing between the compressor performance and the maintenance cost. The predicted results of compressor washing period and overhaul period are able to support the operators in combined cycle power plant to make a proper decision of maintenance task. The developed solution was applied to MHI501G gas turbine and is, in present, on the process of field test at GUNSAN combined cycle power plant, South Korea.Copyright

Feasibility Assessment for ORC Generation System Development Using Low Temperature Geothermal Water

Since around 70°C of geothermal water exists in Seokmo-do of Republic of Korea, this study is to assess the feasibility of electricity generation by utilizing ORC system, and the pertinent economic impact.It is generally believed that economic feasibility can be secured only when the source of geothermal water is above 100°C in order to generate electricity by operating ORC system.However, there was an exceptional case that ORC system was commercialized by Pratt-Whitney for around 70 °C of geothermal water in the hot springs of Chena, Alaska.The annual average temperature in the hot springs of Chena, Alaska is approximately 1°C whereas that of Seokmo-do is around 11°C, which makes 10°C of annual average temperature difference in operational environment between the two. Thus, the 2 phases of absorption refrigerating machine is considered for the ORC generation system.With establishing ORC system in consideration of operational environment, the feasibility of the development of ORC system in Seokmo-do is assessed by performance analysis and economic feasibility.As a result of the assessment, it is identified that the economic feasibility can be secured if the price of electricity is over

Study on Condition Monitoring of 2-Spool Turbofan Engine Using Non-Linear GPA(Gas Path Analysis) Method and Genetic Algorithms

0.42/kWh same as that of photovoltaic generation as an incentive of the RPS program granted by the Korean government.Copyright

A Study on Transient Performance Characteristics of the CRW Type UAV Propulsion System During Flight Mode Transition

․ MyoungCheol Kang** ․ Gwanglim Park***ABSTRACT Recently, the advanced condition monitoring methods such as t he model-based method and the artificial intelligent method have been applied to maximize the availability as well as to minimize the maintenance cost of the aircraft gas turbines. Among them the non-linear GPA(Gas Path Analysis) method and the GA(Genetic Algorithms) have lots of advantages t o diagnose the engines compared to other advanced condition monitoring methods such as the linear GPA, fuzzy logic and neural networks. Therefore this work applies both the non-linear GPA a nd the GA to diagnose AE3007 turbofan engine for an aircraft, and in case of having sensor noise and bias it is confirmed that the GA is better than the GPA through the comparison of two methods.초 록 항공기 가스터빈의 운용율을 극대화 하고 정비 비용을 최소화하기 위해 최근 모델기반방법이나 인공지능방법을 이용한 첨단상태진단기법들을 적용하고 있다. 이 진단 방법들 중 비선형 GPA방법과 유전자 알고리즘을 이용한 엔진 진단방법들이 선형 GPA, 퍼지 로직 및 신경망 이론 등의 타 방법들에 비해 장점을 가지고 있는 것으로 알려졌다. 이에 본 연구에서는 항공기용 AE3007H 터보팬엔진의 상태 진단에 비선형 GPA기법과 유전자 알고리즘을 적용한 후 비교를 통해 센서 노이즈와 바이어스가 있는 경우 유전자 알고리즘이 보다 우수한 진단 기법임을 확인하였다. Key Words: Engine Condition Monitoring(엔진상태진단), Non Linear GPA(비선형가스경로기법), Genetic Algorithms(유전자알고리즘), 2-Spool Turbofan Engine(2 스풀 터보팬엔진)