开启个性送风口下飞机客舱污染物传播规律实验研究

发布时间：2019-03-28 13:44

【摘要】：近年来,随着我国航空业的迅猛发展,飞机因其快捷、安全受到越来越多旅行者的青睐。据统计,每年约有10亿人选择乘坐飞机出行,因此建立健康、舒适的客舱环境不仅是飞机设计单位也是飞机制造商面临的巨大挑战。开启机舱内的个性送风口是调节乘客周围局部热舒适和空气质量的有效途径。建筑内个性通风系统已经存在大量研究,然而针对机舱环境,大部分研究集中于对新型个性送风口的研究,缺少对真实机舱环境现有的传统个性送风口的研究。新型个性送风口真正投入应用还有待大量实验验证其有效性、经济性。所以,针对于目前机舱内使用中的个性送风口仍有待研究。本课题的主要研究内容即为真实客机内开启个性送风口工况下机舱内污染物传播规律的实验研究。本研究以一架真实的MD-82飞机为实验平台,采用地面空调车(GAC)通过飞机内部真实环控系统(ECS)向机舱内部提供调节空气。机舱内部共有5列个性送风口,本研究工况中仅打开靠近走廊的2列并关闭余下3列个性送风口。开启状态下的个性送风口的送风角度、流量保持一致。首先,对舱内整体送风的流动边界,机舱内壁热边界条件进行测量;其次,对个性送风口边界条件进行深入研究,包括几何边界、流动边界;最后,使用示踪气体模拟乘客呼出的污染物(CO2、超细颗粒物等),将污染源分别放置在打开和关闭的个性送风口下,通过测量整舱的示踪气体浓度来研究不同工况下污染物的分布特性。本实验并对实验数据的可靠性进行分析。实验结果表明,个性送风风量只占机舱整体送风量的5%,但是由于个性送风口射流断面面积小,射流风速大,对机舱内整体流场影响剧烈。开启个性送风口后,机舱内的纵向气流明显增强,从而导致污染物向机舱后部传播。并且,距离污染源最近的打开的个性送风口卷吸来自污染源附近被污染的空气,造成污染物随个性送风射流传播。同时,向下的个性送风射流会抑制向上的热羽流,导致污染物向机舱天花板传播趋势减弱。通过比较个性送风口关闭和开启状态下乘客呼吸区处浓度,结果表明,开启个性送风之后,在机舱纵向方向上,污染源后排的乘客呼吸区浓度明显升高;在机舱横向方向上,两列打开的个性送风口可形成“空气幕”,阻碍污染物传播,并有效降低污染源在走廊对侧乘客呼吸区附近污染物浓度。为保证测量结果的准确性,本课题对实验误差进行研究。产生误差的主要因素为定位误差以及热边界变化所产生的系统误差,并分别对这两种误差进行实验研究。实验结果表明,定位误差所造成的测量误差低于10%,热边界变化所产生的系统误差是测量误差的主要来源。热边界温度升高,机舱内自然对流增强,导致机舱内浓度分布发生变化。
[Abstract]:In recent years, with the rapid development of China's aviation industry, aircraft is favored by more and more travelers for its fast and safe. According to statistics, about 1 billion people choose to travel by plane each year, so building a healthy and comfortable cabin environment is not only a great challenge for aircraft designers but also for aircraft manufacturers. Opening the air outlet in the cabin is an effective way to regulate the local thermal comfort and air quality around the passengers. There have been a lot of researches on the individual ventilation system in the building. However, for the engine room environment, most of the studies are focused on the study of the new type of individual air vents and the lack of research on the existing traditional individual air vents in the real cabin environment. A large number of experiments have yet to be carried out to verify the effectiveness and economy of the new type of air outlet. Therefore, for the current engine room in the use of individual air vents still need to be studied. The main research content of this paper is an experimental study on the propagation of pollutants in the cabin of a real airliner under the operating condition of opening individual air vents. In this study, a real MD-82 aircraft was used as the experimental platform. The ground air conditioning vehicle (GAC) was used to provide air conditioning to the engine room through the internal real environmental control system (ECS). There are five individual air vents in the engine room. In this study, only two columns close to the corridor were opened and the remaining three individual air vents were closed. In the open state, the supply angle and flow rate of the individual air outlet remain the same. Firstly, the flow boundary of the whole air supply in the cabin and the thermal boundary condition of the interior wall of the cabin are measured, secondly, the boundary conditions of the individual air outlet, including the geometric boundary and the flow boundary, are studied in depth. Finally, a tracer gas is used to simulate the pollutants emitted by passengers (CO2, ultrafine particles, etc.), and the pollution sources are placed under the individual air vents that are opened and closed, respectively. The distribution characteristics of pollutants in different working conditions were studied by measuring the tracer gas concentration in the whole chamber. In this experiment, the reliability of the experimental data is analyzed. The experimental results show that the individual air supply volume only accounts for 5% of the total air supply volume in the engine room. However, due to the small cross-section area of the jet and the large wind speed of the jet at the individual air outlet, the influence on the overall flow field in the cabin is severe. When the air outlet is opened, the longitudinal air flow in the engine room increases obviously, which causes the pollutant to propagate to the rear of the cabin. Moreover, the opening of the air outlet nearest to the pollution source draws in the polluted air near the source, causing the pollutant to propagate with the individual air jet. At the same time, the downward individual air jet will suppress the upward thermal plume, resulting in the pollutant propagation to the engine room ceiling weakened. The results show that the concentration of passenger breathing area in the rear row of the pollution source increases obviously in the longitudinal direction of the engine room after the individual air outlet is turned on and the concentration of the passenger breathing area is compared under the condition of closing and opening of the air outlet. In the horizontal direction of the engine room, two open individual air vents can form "air curtain", hinder the spread of pollutants, and effectively reduce the pollutant concentration near the passenger breathing area on the opposite side of the corridor. In order to ensure the accuracy of the measurement results, the experiment error is studied in this paper. The main factors causing the errors are the systematic errors caused by the change of the thermal boundary and the positioning errors, and the two errors are studied experimentally. The experimental results show that the measurement error caused by positioning error is less than 10%, and the systematic error caused by thermal boundary change is the main source of measurement error. The increase of the thermal boundary temperature and the enhancement of the natural convection in the cabin result in the change of the concentration distribution in the cabin.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V223.2

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