基于DEM的直升机沙盲加速计算方法  

Accelerated computational method of helicopter brownout based on DEM

作　　者：谭剑锋[1] 韩水 王畅[2] 于领军 TAN Jianfeng;HAN Shui;WANG Chang;YU Lingjun(School of Mechanical and Power Engineering,Nanjing Tech University,Nanjing 211816,China;Rotor Aerodynamics Key Laboratory,China Aerodynamics Research and Development Center,Mianyang 621000,China;Department of Aeronautical Mechanical Engineering,Army Aviation Institute,Beijing 101123,China)

机构地区：[1]南京工业大学机械与动力工程学院,南京211816 [2]中国空气动力研究与发展中心旋翼空气动力学重点实验室,绵阳621000 [3]陆军航空兵学院航空机械工程系,北京101123

出　　处：《北京航空航天大学学报》2023年第6期1352-1361,共10页Journal of Beijing University of Aeronautics and Astronautics

基　　金：国家自然科学基金(12172165);江苏省自然科学基金(BK20211259);旋翼空气动力学重点实验室基金(RAL20200302);江苏省高校“青蓝工程”优秀青年骨干教师项目。

摘　　要：直升机沙盲数值模拟是研究沙盲演化特性的重要手段,而沙盲由众多动力学特性复杂的沙粒构成,这导致沙盲数值模拟复杂且计算量庞大。基于离散单元法(DEM)和沙粒动力学方程,将沙粒映射至背景网格实现加速计算,并将背景网格分裂为多子区再次加速计算,构建背景网格映射-分裂加速计算模型,且耦合沙粒接触碰撞模型、沙粒-流场耦合模型、旋翼/地面气动干扰模型,提出基于DEM的直升机沙盲加速计算方法。通过与美国陆军EH-60L着陆-起飞沙盲测试结果对比表明:所提方法能准确捕捉着陆-起飞状态的直升机沙盲,且相比于沙盲直接模拟方法,所提方法计算量显著减小。直接模拟方法的计算量随沙粒数量抛物线增加,而所提方法计算量随沙粒数量线性增加。当沙粒数量大于1×10^(7)时,相比于仅背景网格映射模型加速方法,所提方法计算量减小70.29%。Numerical simulation of helicopter brownout is a major analysis method to investigate the evolution characteristics of helicopter brownout.However,the sand cloud is composed by many sand particles with complex characteristics resulting in a large computational cost.Based on a discrete element method(DEM)and dynamic equations of sand particles,a background grid mapping-splitting model is proposed,where sand particles are mapped in background grids to accelerate the numerical simulation and the background grids are divided into several zones to reaccelerate the numerical simulation.Coupling the model with contact model of particle-particle interaction,model of particle-fluid interaction,model of rotor/ground unsteady flow,an accelerated computational method of helicopter brownout based on DEM is established,and is compared with the flight test of US Army EH-60L brownout in an approaching flight.The results show that the present numerical method has ability to accurately capture the process of helicopter brownout.Compared to the numerical simulation with direct method,the present computational cost is significantly reduced.Additionally,the computational cost of the direct method increases as a parabola,whereas that of the present method is a linear growth.The computational cost of the present method is reduced by 70.29% when compared with the just background mapping method for a 1×10^(7) particles case.

关 键 词：沙盲 离散单元法 映射-分裂模型 加速方法 直升机 

分 类 号：V221.52[航空宇航科学与技术—飞行器设计] TB553[理学—物理]