关键词: 涵道共轴双旋翼, 沟槽构型, 桨尖间隙, 悬停效率, 数值模拟

Abstract: This article studied the methods for improving the hovering performance of ducted coaxial rotors under conditions of large blade tip clearance, based on the Reynolds-averaged Navier-Stokes (RANS) equations and multiple ref鄄 erence frame (MRF). Firstly, an aerodynamic performance analysis was conducted on the non-grooved duct under different blade tip clearances. The research results show that an increase in blade tip clearance leads to a de鄄 crease in hovering performance. Secondly, five types of groove configurations including square, circular, V - shaped, trapezoidal, and inverse trapezoidal were designed to analyse their effect on hovering efficiency. The re鄄 sults show that the tip position and the groove configuration are the key factors affecting hovering efficiency. When the tip penetrats deeply into the groove and the blade tip clearance is increased to five times the initial val鄄 ue, the hovering efficiency remained basically stable. The circular groove configuration delivers the best perfor鄄 mance, with its hovering efficiency improved by 11.1% when the blade tip clearance is twice its initial value. This study can provide an effective approach for optimizing the aerodynamic performance of ducted coaxial twin rotors under loose assembly tolerance conditions

Key words: ducted coaxial twin rotors, groove configuration, blade tip clearance, hover efficiency, numerical simulation