A performance simulation program for the turboprop engine (PT6A-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for more precise performance prediction, development of an EHMS (Engine Health Monitoring System) and the flight simulator.
Characteristics of components including compressors, turbines, the combustor and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. In most cases, these were substituted for what scaled from similar engine components’ characteristics with the scaling law.
The developed program was evaluated with the performance data provided by the engine manufacturer and with analysis results of GASTURB program, which is well known for the performance simulation of gas turbines. Performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption ratio and turbine inlet temperature were discussed to evaluate validity of the developed program at various cases. The first case was the sea level static standard condition and other cases were considered with various altitudes, flight velocities and part loads with the range between idle and 105% rotational speed of the gas generator.
In the transient analysis, the Continuity of Mass Flow Method was utilized under the condition that mass stored between components is ignored and the flow compatibility is satisfied, and the Modified Euler Method was used for integration of the surplus torque.
The transient performance analysis for various fuel schedules was performed. When the fuel step increase was considered, the overshoot of the compressor turbine inlet temperature occurred. However, in case of the fuel ramp increase longer than the fuel step increase, the overshoot of the compressor turbine inlet temperature was effectively reduced.