CFD를 이용한 항공용 마이크로 가스터빈 엔진 시뮬레이션

Abstract

Turbojet-type micro gas turbine engine has been widely adopted for an aero-propulsion system of small-sized aircraft due to its simplicity and prominent thrust-to-weight ratio. The number of applications using micro gas turbine engine continues to grow with the development of various type in aerial vehicles. To adopt an appropriate micro gas turbine engine for a specific aero application, an evaluation of the engine performance is very important. A thermodynamic cycle analysis is an usual method for the gas turbine engine performance evaluation. Establishing the thermodynamic cycle model of turbojet engine is relatively simple and simulation time is the shortest compared to other methods. However, details of engine characteristics would not be captured with the cycle model and the result might be incorrect if analysis condition were apart from component’s operational range. These deficiencies could be compensated by taking the advantage of CFD analysis, which is capable of simulating the details of flow characteristics inside engine components such as stall, choke and shock. These flow phenomena can deteriorate engine performance or can cause severe engine failure. This paper demonstrates performance analysis of micro gas turbine engine using CFD analysis. Major components in a micro gas turbine engine, such as compressor, combustor, turbine and exhaust nozzle, were modeled and linked together to establish entire engine model. Fortran sub-routine was newly developed and embedded to CFD code, which is manipulating the fuel flow into combustor to match compressor and turbine torques. The sub-routine continues to run until it finds matching point of each component at designated rotating speed. Using this CFD model, not only engine cycle performance, but also component performance can be evaluated with a single calculation.