03.2 - Experimental Aerodynamics
EXPERIMENTAL AND NUMERICAL INVESTIGATION ON AERODYNAMIC PERFORMANCE OF A MARS ROTOR SYSTEM
Y. Liu¹, J. Xiao¹, N.A. Benai-dara¹, Z. Chen¹, N. Qin, University of Sheffield, United Kingdom; ¹NUAA, China
Due to the recent advancements in electric propulsion drives and their application on the Mars helicopters, contrarotating propulsion systems have emerged as a promising solution. These systems offer aerodynamic advantages by efficiently recovering a significant portion of the slipstream rotational energy that would otherwise be lost when using conventional screw propeller systems; therefore, it is necessary to determine the most optimal combination of possible propulsion system components for a given mission profile.rnThis paper presents an investigation on the aerodynamic performance of a contra-rotor system at high altitudes through both experimental and numerical methods. All experimental research was conducted at the NanJing University of Aeronautics and Astronautics (NUAA) High-Altitude Research Facility. The High-Altitude Simulator has an inner diameter and height of 800mm and 2000mm, respectively. It can simulate atmospheric density and pressure at an altitude of 30-50 kilometers. Computational research was conducted using a steady RANS CFD code with multiple meshes to investigate the sensitivity of computational modeling to contra-rotors. Based on the experimental results, the collective pitch angle effects and Reynolds number effects on the lift-drag characteristics and efficiency of the single/contra-rotor system are investigated during the hovering process with Reynolds number ranging from 15,000 to 50,000 (using the chord and speed at 75% of the blade radius) and tip speed ranging from 35m/s to 75m/s. The aerodynamic measurement results of coaxial rotor show that the thrust reduction of lower blade under the influence of upper blade is up to 40%.rn