Steady-state Performance Simulation and Operation Diagnosis of a 2-spool Separate Flow Type Turbofan Engine

2스풀 분리 배기 방식 엔진의 정상상태 성능모사 및 작동 진단

Abstract

There is a growing interest in engine diagnostic technology for gas turbine engines. An engine simulation program, precisely simulating the engine performance, is required in order to apply it to the engine diagnosis technology for engine health monitoring. In particular, the simulation program can predict not only design point performance but also off-design point and partial load performance in accurate. So the engine simulation program for the 2-spool separate flow type turbofan engine was developed and the JT9D-7R4G engine of PW(Pratt & Whitney) was analyzed. The steady-sate performance analysis is conducted at both design and off-design points in flight path and the differences between analysis results of takeoff and cruise conditions are compared. The effect of Reynold's correction method was analyzed as a scaling method of the engine component performance. The simulation results was compared with NPSS.

가스터빈 엔진에 대한 엔진 진단기술에 대한 관심이 높아지고 있으며, 엔진 건전성 진단기술에 적용 가능한 정확한 엔진 성능모사 프로그램의 중요성은 점점 더 커지고 있다. 이를 위한 엔진 성능모사는 설계점 해석으로부터 시작하여 탈설계점 성능모사, 부분부하 성능모사를 정확하게 수행해야 할 필요가 있다. 이에 따라 본 연구에서는 2-스풀 분리 배기 방식 터보팬 엔진에 대한 엔진 시뮬레이션 프로그램을 개발하고 PW(Pratt & Whitney)사의 JT9D-7R4G 엔진을 해석하였다. 각 비행영역에서의 설계점과 탈설계점에서의 정상상태 성능모사를 수행하고, 최대이륙조건 설계점과 순항상태 설계점의 해석결과의 차이를 비교하였다. 또한 구성품 성능선도 축척법 중 하나인 Reynold's Correction의 효과를 분석하였다. 개발된 프로그램의 결과와 NPSS의 결과를 비교하여 프로그램을 검증하였다.

Fig. 1 JT9D Engine

Fig. 2 Rough JT9D Engine Schematic[5]

Fig. 3 Program Flow Chart

Fig. 4 Acceptance Flight Test Profile[8]

Fig. 6 Total pressure at each station for Cases 111 and 211

Fig. 7 Total temperature at each station for Cases 111 and 211

Fig. 8 Mass flow rate at each station for Cases 121 and 221

Fig. 9 Total pressure at each station for Cases 121 and 221

Fig. 10 Total temperature at each station for Cases 121 and 221

Fig. 11 Mass flow rate at each station for Cases 121 and 122

Fig. 12 Total pressure at each station for Cases 121 and 122

Fig. 13 Total temperature at each station for Cases 121 and 122

Fig. 14 Engine inlet air mass flow rate to time

Fig. 15 Bypass-Ratio to time

Fig. 16 High spool speed to time

Fig. 17 Thrust to time

Table 1 Estimation Variables for Off-design Calculation

Table 2 Flight Operating Condition Used in Calculation

Table 3 Nomenclature of the Flight Operating Conditions used in the Calculation

Fig. 5 Mass flow rate at each station for Cases 111 and 211

Table 4 Mass Flow Rate, Total Pressure, and Total Temperature using Ground Design Point

Table 5 Mass Flow Rate, Total Pressure, Total Temperature Error using Cruise Design Point

Table 6 Mass Flow Rate, Total Pressure, Total Tem-perature Error Using Reynold’s Correction

Table 7 Comparison of thrust calculated