通风房间可吸入颗粒物浓度场的数值模拟

利用CFX-10.0软件对通风房间三种不同工况进行了数值模拟,得到实验小室的速度场和浓度场。将模拟计算结果和实验数值进行了对比,较直观地反映了可吸入颗粒物的浓度变化。同时模拟了通风房间污染源的散发过程,并对典型的工况和在不同工况下的流场对浓度场的影响进行了分析。结果表明,CFX-10.0软件计算房间的污染物分布可靠性高,可用于评价室内的空气品质,同时对室内污染的控制策略提供依据。     

晚间通风房间热环境的改善

在实测的基础上,指出晚间通风系统虽然可以在夏季空调房间内保持较低的室内温度,但是室内的热环境有时却不能使人满意,为此可以采用提高室内空气流速的方法加以改善。     

通风房间内污染浓度的预测

对3种预测空调或自然通风房间室内外气相和颗粒相有害物质浓度间演化的典型模型进行了分析，由于各种方法建立的基础和条件不同，讨论并批出它们的适用范围和应用中可能出现的问题，提出了改进意见。     

置换通风气流组织及其影响因素分析研究

利用数值模拟置换通风的气流组织的速度场，温度场，分析了热源的大小以及所处的位置，送回风口相对位置等因素对气流组织的不同影响，为评价这种通风方式的舒适性提供参考依据。     

VLCC修船通风气流组织的研究

从理论上分析了气流组织对通风效果的影响，根据大型原油运输船（ＶＬＣＣ）修船通风的特点，提出了一种新式的气流组织模型及其相应的末端装置，并通过利用示踪气体法测定通风效率，对气流组织作出了定量评价。     

上海地区霾天通风房间室内外粒子浓度的比较

分别在夏、冬两季典型霾过程期间,对上海地区自然通风房间的室内外空气中PM10、PM2.5的逐时变化进行了连续实测和分析。结果表明,霾天无论室内或室外,PM2.5均为颗粒物浓度的主要贡献者。利用实测数据讨论了PM10和PM2.5间的关系和室内外浓度I/O规律。PM2.5/PM10的变化范围在夏、冬两季实测霾过程中分别为0.741~0.984和0.788~0.957。此外,实测结果说明,在霾天气下通过单边自然通风来改善或维持室内空气质量将不会有实质性效果     

通风房间内污染物浓度的预测

对 3种预测空调或自然通风房间室内外气相和颗粒相有害物浓度间演化关系的典型模式进行了分析 ,由于各种方法建立的基础和条件不同 ,讨论并指出它们的适用范围和应用中可能出现的问题 ,提出改进意见     

内区房间通风换气智能控制系统应用

随着我国经济的快速发展,人们生活水平不断提高,人们对于房间的舒适、清洁和健康方面越来越关注.房间内气流速度过快,达不到排放标准时就会造成有害气体产生;当室内风流速太慢又或者太快都会导致新风量超过人们的正常需求.通风换气设备是非常重要的设备.论文研究内区房间通风换气智能控制系统及其应用,给相关工程提供参考.     

置换通风空调房间气流组织的数值模拟

以工程中广泛采用的K ε二方程湍流模式为基础 ,运用计算流体力学的有限差分法对两种置换通风空调房间的三维速度场、温度场和污染物的浓度场进行数值模拟 ,体现这种新型空调送风方式的特点和优点 ,并为置换通风房间的设计和研究提供一定的理论依据。     

Vertical profiles of temperature and contaminant concentration in rooms ventilated by displacement with heat loss through room envelopes

The purpose of this study is to examine the effect of heat loss through walls upon the gradients of temperature and contaminant concentration in room with displacement ventilation. It is known that conduction heat loss is governed by outside temperature, heat load inside the room, supply air temperature and overall heat transfer coefficient of walls. Experiments were conducted to measure the temperature gradient and the ventilation efficiency in the room ventilated by displacement ventilation with various combinations of heat load and temperature difference between supply air and outside air. In order to simulate the change of seasons, the supply air temperature was changed instead of the outside air temperature. The effect of supply air temperature and heat generation inside the room on the temperature gradient and the concentration of tracer gas were investigated through the experiments. As a result, it turned out that the higher the heat generation rate and the lower the supply temperature, the stronger the temperature stratification and the lower the concentration in the lower zone. Additionally, ventilation heat loss turned out to be a good index for assessing the concentration in the lower zone. Temperature differences of around 3 degrees C between supply air temperature and exhaust temperature are at least needed for displacement ventilation under the conditions of the experiment presented in this paper.     

用示踪气体方法研究通风房间的空气龄

应用示踪气体测量得到了8种强制通风工况下实验小室各各测点处的浓度衰减曲线,并计算出各测点的空气龄,实验结果表明,示踪气体用于强制通风研究时实验可重复性较好,实验结果正确合理,测得的空气龄反映了房间各点空气的新鲜程度,也揭示了室内空气的流动形态。     

温度控制与污染物浓度控制相独立的通风空调系统

为解决传统通风空调系统温度控制与污染物浓度控制需求风量不匹配的问题,提出了一种温度控制与污染物浓度控制相独立的通风空调系统结构和控制方法。通过室内负荷计算及PM2.5浓度计算,对比分析了北京、上海、深圳地区在保证室内温湿度需求时典型办公室内的PM2.5浓度水平。结果表明,该通风空调系统可以同时满足室内温度和PM2.5浓度的控制要求,尤其在室外气候温和且大气污染较重时期对室内环境的保障效果更为明显。以北京地区2018年为例计算,在室内温度相同情况下,采用该通风空调系统室内PM2.5浓度全面达标,而采用传统通风空调系统则有10.3%的时间超标。     

下送风气流组织影响因素的实验研究

通过人体热舒适试验，分析得出下送风气流组织的4个主要因素即送风口形式、送风口到人体的距离、送风速度、送风温度等对人体热舒适的影响，确定了其合理的取值范围，为下送风气流组织的设计提供了参考依据。     

Air distribution in room ventilated by fabric air dispersion system

Several researches about airflow distribution in a room generated by fabric air dispersion system (FADS) were reported, but details about the simulation in computer fluid dynamics (CFD) method were not elaborated. In present work The commercial software FLUENT with standard k−ε$k-\epsilon$ turbulence model is applied to predict air distribution in a room ventilated by FADS in penetration mode, where FADS is described with the porous media model based on the modified Forchheimer equation. And more details about the simulation are given. Flow visualization near the region of FADS is conducted using dry-ice as a smoking material. The distribution of indoor air velocity and temperature and draught rating (DR) around the ankle and neck level are predicted. The simulation well matches the corresponding experimental value and results of earlier work. Results showed that air is radially discharged out in the direction perpendicular to the spatial cambered porous fibre in lower velocity, and evenly distributed along its length direction when air is distributed by FADS in penetration mode. The velocity of indoor air is very low, and the vertical air temperature difference is small (less than 2 K). DR around the ankle and neck is immune to supply air flow rate and location, which is less than the comfort limit of ASHRAE Standard 55-2004. In addition, airflow pattern is greatly impacted by the location and strength of heat load.     

示踪气体浓度衰减法在民用建筑自然通风研究中的应用

用示踪气体浓度衰减法对某会议室的自然通风作了实测研究，分析了影响换气次数的各种因素、示踪气体浓度衰法的有效性及其正确应用。揭示出不同的房间布置及不同的门窗开启民政部对换气次数有很大影响，而示踪气体浓度衰减法是对此进行实验研究的有效手段。     

Numerical simulation of transient flow development in a naturally ventilated room

Numerical simulations were conducted to model the transient flow development in a naturally ventilated space containing a centrally located localized source of heat. The simulations were compared with a series of small-scale laboratory experiments and existing theoretical models. The aim of the work was to benchmark CFD models for time-dependent buoyancy-driven natural ventilation against previously published experimental results and theoretical models. The simulations agree well with experimental results during the initial development of the room stratification. The CFD results accurately predict the maximum depth of the hot buoyant layer at the top of the room as well as the steady-state interface height which separates the warm upper buoyant layer from the cooler air below. The simulations also predict well the time taken for the buoyant upper layer to reach its maximum depth. However, at longer times the results diverge. This may be due to thermal diffusion and mixing at the interface between the upper and lower layers due to the inflow from the floor level vents.     

Numerical evaluation of the particle pollutant homogeneity and mixing time in a ventilated room

With the increase of the computational capability, three-dimensional Lagrangian simulation can now be applied to evaluate the particle pollution evolution in ventilated rooms. The present study deals with the evaluation of 5.0 μm particle dispersion in a prototypical-ventilated room of 10 m³. Two ventilation slots and three different airflow rates have been simulated. Particle trajectories have been calculated using a Lagrangian model. Dispersion of particles has been analyzed for the case of an external pollutant source, a homogeneous particle injection within the room and some puff releases in different locations. Discussion about the best procedure to get useful information about the particle cloud is then presented and illustrated from the simulation results. The definition of two indices based on geometrical and statistical parameters are proposed in order to correctly evaluate the particle cloud homogeneity and mixing time.     

室内空气质量影响因素实验研究

论述了室内空气质量的主要影响因素和《室内空气质量标准》中的相关规定。通过实验分析和对比,指出新风量不能从根本上降低室内污染物浓度,良好的通风换气是提高室内空气质量的有效保证。     

下送风房间热分布系数影响因素的方差分析

提出了用热射流起始无因次高度Ｈ来反映热源起始高度对下送风空调房间热分布系数ａ的影响，利用回归原理得出了ａ随阿基米德数Ａｒｎ、热射流自由度Ｚｒ、机械射流自由度Ｚｊ及热射流起始无因次高度Ｈ变化的准则关系式。用连结向量图法和对实验数据回归公式的Ｆ检验，对影响室内热分布规律的各个因素进行了分析，发现这些因素均为主要影响因素，其影响的相对主次依次为Ａｒｎ，Ｚｒ，Ｈ和Ｚｊ，回归结果具有很强的显著性。