Computer Modeling of Low Reynolds Number Propeller Performance at an Incidence
College
College of Engineering & Technology (Batten)
Department
Mechanical & Aerospace Engineering
Graduate Level
Doctoral
Graduate Program/Concentration
Aerospace Engineering
Presentation Type
No Preference
Abstract
There is an increasingly high popularity of Urban Air Mobility (UAM) concepts. These concepts are varying from small size person carrying vehicles to the cargo operations from urban areas or military applications. Among the various size and configurations of these concepts many of them being developed as prototypes are utilizing the propellers produced for RC models. In this research, a propulsion model for small unmanned aerial vehicle (SUAV) is presented. Main challenges of the propeller performance prediction for these types of vehicles are the quantification of low Reynolds number effects (Re = 20,000-100,000). From the previous investigation, there observed a considerable disagreement of the normal force and torque coefficients of these propellers to the wind-tunnel experiments with low to high incidence angles. Therefore, a revisited version of the blade element momentum theory (BEMT) with correction factors such as tip loss, rotational effects are proposed for a better correlation to the experiment data for blades APC 11 x 7 propellers. The fundamental difference in BEMT and the wind tunnel testing comes from the motor in the system which creates aerodynamic forces and affects the force and moment measurement. Compensation of these effects are being investigated by taking motor only test data and fitted to the same regression model. Finally, a dynamic inflow model is implemented for a more accurate inflow solution at the propeller disk. Initial solutions are demonstrated at high advance ratio forward flight to low advance ratio transition conditions for VTOL operations.
Keywords
Urban air Mobility, VTOL, propeller performance, BEMT, Dynamic inflow, SUAV, Low reynolds propeller
Computer Modeling of Low Reynolds Number Propeller Performance at an Incidence
There is an increasingly high popularity of Urban Air Mobility (UAM) concepts. These concepts are varying from small size person carrying vehicles to the cargo operations from urban areas or military applications. Among the various size and configurations of these concepts many of them being developed as prototypes are utilizing the propellers produced for RC models. In this research, a propulsion model for small unmanned aerial vehicle (SUAV) is presented. Main challenges of the propeller performance prediction for these types of vehicles are the quantification of low Reynolds number effects (Re = 20,000-100,000). From the previous investigation, there observed a considerable disagreement of the normal force and torque coefficients of these propellers to the wind-tunnel experiments with low to high incidence angles. Therefore, a revisited version of the blade element momentum theory (BEMT) with correction factors such as tip loss, rotational effects are proposed for a better correlation to the experiment data for blades APC 11 x 7 propellers. The fundamental difference in BEMT and the wind tunnel testing comes from the motor in the system which creates aerodynamic forces and affects the force and moment measurement. Compensation of these effects are being investigated by taking motor only test data and fitted to the same regression model. Finally, a dynamic inflow model is implemented for a more accurate inflow solution at the propeller disk. Initial solutions are demonstrated at high advance ratio forward flight to low advance ratio transition conditions for VTOL operations.
