【摘要】 飞机环控系统目前面临的主要问题之一是大气中颗粒物的危害,一方面影响环控系统的供气品质;另一方面会堵塞、磨损环控系统中的元器件。本文基于气固两相流动数值模拟方法,对飞机环控系统中颗粒物的动力特性进行了研究。通过与飞机环控系统中几条主管路颗粒沉降率的已有实测数据进行对比,验证了离散相模型对颗粒沉降模拟的有效性。在此基础上,对颗粒沉降特性影响因素进行了研究,发现:不同粒径的颗粒物沿管高度方向的速度分布基本一致,但浓度分布却差异显著;颗粒浓度对沉降率基本无影响;不同气流速度下,所获得的固相速度分布型式基本一致,属于极值分布的类型;管长影响出口颗粒浓度分布,管道越长,出口截面上颗粒分布越集中于管底;方管与圆管相比,管线上沉降了更多的颗粒。更多还原

【Abstract】 In terms of airplane environmental control system, the harm of particulates in the atmosphere is a significant problem to be solved. On the one hand, the gas supply quality will be polluted by particulates. On the other hand, the components of environmental control system will be blocked or wore by particulates. In this paper, the dynamic characteristics of particulates in environmental control system are investigated based on the numerical simulation of the gas-solid two phase flow. The validation of the numerical simulation of sedimentation based on discrete phase model is guaranteed through the comparison with existed experimental data of sedimentation rate in the main pipeline of the environmental control system. The factors related to sedimentation properties of particulates are investigated. It shows the velocity distributions along the direction of pipe height are consistent for particulates with different diameters, but the concentration distributions are significantly different. The sedimentation rate is not affected by concentration of particulates. The velocity distribution of particulates is similar accelerated by different velocity of airflow, which accords with the type of extreme value distribution. The concentration of solid-phase is more distributed at the bottom if the pipe length is longer. Compared with circular pipe, more particles are deposited along the pipeline in the square pipe.更多还原