Analytical Methods And Experimental Research On Micro Coaxial Rotor's Aerodynamic Performance

Micro aerocraft, an aerocraft with bright future, is attracting attention from research institutions and scientific researchers from all over the world. As a special rotor-driven vehicle, Micro Coaxial Rotor is a hot spot in research. In the meantime, low Reynolds characteristics of aerofoil and aerodynamic interference of Micro Coaxial Rotor play an important role in research of flow field mechanism of Micro Coaxial Rotor, and in improvement as well as calculation of aeroperformance. Therefore, analysis of aeroperformance is the key technique in research of Micro Coaxial Rotors.This paper introduces a method for calculating hover aerodynamic performance of a Micro Coaxial Rotor. To begin with, the paper calculates the lift-drag property of aerofoil under low Reynolds number by means of CFD approach; in the next place, we carry out PIV measurement over micro single-rotor and coaxial rotor at established speed and installation angle by means of two-dimensional PIV measurement system. We obtain flow image of the under-blade wash section successfully, and get the rational and effective single rotor wake boundary based on analysis of vector particles and post-processing software.After that, theoretical analysis and calculation of hover performance of the micro Coaxial-rotor was conducted through the revised momentum theory or blade-element theory based on the lift-drag property of aerofoil under low Reynolds number and single rotor wake boundary under appropriate assumptions. We also make empirical verification over the calculation results with equipments that measure Micro Coaxial Rotor hovering function developed by the research group; last but not least, the article sets up three domains in multiple rotation reference coordinate system, stimulates the numerical model of 3-D flow field under hovering Micro Coaxial Rotor, and makes comparison of pressure intensity of the flow field on and under the hovering Micro Coaxial Rotor in different space and speed. CFD verification is carried out over theoretical results, which proves to be identical with empirical results.Corroboration of theoretical result, empirical results and CFD results demonstrate that the analysis of aerodynamic characteristic of Micro Coaxial Rotor is accurate and reliable, and the conclusions arrived at are meaningful.