A Propeller Model for Steady-State and Transient Performance Prediction of Turboprop and Counter-Rotating Open Rotor Engines

Abstract

This paper describes a methodology used for propeller performance estimation, which was implemented in an in-house modular program for gas turbine performance prediction. A model based on subsonic generic propeller maps and corrected for compressibility effects, under high subsonic speeds, was proposed and implemented. Considering this methodology, it is possible to simulate conventional turboprop architectures and counter-rotating open rotor (CROR) engines in both steady-state and transient operating conditions. Two simulation scenarios are available: variable pitch angle propeller with constant speed; or variable speed propeller with constant pitch angle. The simulations results were compared with test bench data and two gas turbine performance commercial software packages were used to fulfill the model validation for conventional turboprop configurations. Furthermore, a direct drive CROR engine was simulated using a variable inlet guide vanes (VIGV) control strategy during transient operation. The model has shown to be able to provide several information about propeller-based engine performance using few input data, and a comprehensive understanding on steady-state and transient performance behavior was achieved in the obtained results.

Experimental Investigation of the Mechanical and Thermal Behavior of a PT6A-61A Engine Using Mixtures of JETA-1 and Biodiesel

“…In terms of the propeller RPM, these results show that adding biodiesel minimally affects the engine operation [28]. For the reverse condition, the propeller revolutions are between 1900 and 2000 RPM [61]. Since these conditions are the operation limit of the propeller, at transient conditions the variability is minimal.…”