DEVELOPMENT OF MODELING AND SIMULATION TOOLS FOR ANALYSIS OF DUCTED FAN AIRCRAFT

Open Access
Author:
Tobias, Eric Luke
Graduate Program:
Aerospace Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
August 13, 2008
Committee Members:
  • Joseph Francis Horn, Thesis Advisor
Keywords:
  • fan
  • control
  • shrouded
  • ducted
  • modeling
  • simulation
  • rotor
  • aircraft
Abstract:
A generic simulation model was developed for stability / control analysis and real-time simulation of ducted fan aircraft. The simulation environment was produced concurrently in MATLAB for rapid model development, as well as in FLIGHTLAB for comparison and validation. The generic simulation model features a modified inflow model for ducted rotors, a basic model of control vane forces and moments, and empirical correction factors to account for duct thrust augmentation, duct pitching moment, and flow turning effects. Two empirical flow turning efficiency factors, one applied before the plane of the rotor, and the other from freestream to far-wake flow, were investigated. A range of flow turning values of 0.20 to 0.90 were successfully implemented. A model of duct pitching moment was developed in which the duct thrust offset normalized by the rotor radius is given as a function of airspeed. Wind tunnel data and literature from several sources have been analyzed and compared in order to refine the pitching moment model and tune the empirical factors. Validation of the simulation model is provided through correlation studies with experimental data of a 29-inch ducted fan UAV. Steady-state, trim, and maneuver results obtained using both the generic simulation model and FLIGHTLAB model are presented and discussed.