工位空调送风气流数值模拟风口模型的比较

对工位空调送风进行数值模拟时需要引入入口边界条件,即建立风口模型.作为比较,文中选择了两种风口模型,即基本模型和计算机直接模拟风口形成入口边界条件的方法.并通过实验验证对模拟结果进行了分析比较,发现采用计算机直接模拟风口形成入口边界条件的方法具有相对较高的精度,不但在室内气流模拟中得到了较好的结果,而且也对风口内的气流做出比较好的描述.     

百叶风口送风射流的数值模拟

为简化风口入流边界条件的描述,提出用N个简单开口代替不同方向出流的百叶风口,建立了N点风口模型,据此模型对不同出流条件的百叶风口射流进行了数值模拟,并就轴心速度衰减,射流扩展角及断面流速分布等与实验数据进行了对比。结果表明,当N=1或3时,模拟结果令人满意。     

地下主厂房拱顶一端均匀送风的数值研究

采用CFD数值模拟的方法对某水电站地下主厂房拱顶一端送风均匀性进行了研究。对不同的风口形式及风口尺寸下的拱顶一端送风的送风均匀性进行了研究,得出了溪洛渡水电站地下主厂房拱顶一端均匀送风的最佳风口形式和风口尺寸,并与模型实验测得的数值进行了对比,证明CFD技术在此类工程应用上的可靠性。     

换流站阀厅空调气流组织模拟分析

本文基于数值模拟软件Fluent,对不同空调进、回风口位置下的换流站阀厅内部空气流动进行了模拟研究。对比了三种不同气流组织下的发热阀体表面温度场情况,模拟结果显示,上下进风、中间回风的方式能最为有效地降低阀体表面的温度。     

一种新型风口边界条件设置方法的研究

采用CFD方法对圆形喷口单股等温自由射流进行数值模拟研究,提出了一种新的用于风口模拟的盒子分区计算模型。先将计算结果与Elsaadawy(1998)、Hussein(1994)实验数据和经典射流公式进行对比,选定合适的湍流模型,后通过对盒子分区计算模型的结果分析对比,说明该模型的可行性,为复杂风口大空间流场计算提供了一种新的思路。     

矿用防尘安全帽中条缝射流隔尘效果数值模拟

井下作业人员利用带条缝风口安全帽的条缝射流来阻挡粉尘侵袭人的面部,这属于气一固两相流的范畴.本文采用Realizable湍流模型来求解条缝射流气流流场中的速度场,在此基础上,建立气一固两相流动的数学模型来研究采煤区粉尘浓度的分布规律.文章对四种不同风口宽度下的条缝射流进行数值模拟,通过对比分析,得到有利于粉尘隔离的条缝...     

带风口屏蔽门地铁车站自然通风特性的数值模拟

建立了全尺寸几何模型,采用动网格方法模拟了地铁列车运行时引起的非稳态流动,分析了屏蔽门风口、隧道区域、站台楼梯口的气流特性及活塞风井特性。结果表明,带风口屏蔽门的地铁车站可以利用活塞风带走隧道及站台余热,从而降低通风能耗。     

三维n连体模型在地铁工程空气流动数值模拟中的应用北大核心

以地铁车站和区间隧道通风空调与防排烟系统设计对空气流动数值模拟的需求为目标,指出地铁工程空气流动数值模拟存在的问题,提出利用三维n连体模型空气流动数值模拟对一维网络模型进行校验与修正的方法,工程案例计算结果表明,三维n连体模型兼顾了三维模拟的精确性与一维模拟的网络化与高效性,能够适应地铁工程设计阶段的要求,可用于校验与修正一维网络模型。     

入口紊乱参数对室内空气分布的影响研究

文中采用计算机流体动力学（ＣＦＤ）的方法就风口入流参数对通风空调房间内空气流动和分布情况的影响作了数值研究,通过对条缝二维平面射流特性及其作为送风口的空调房间室内空气分布的数值计算结果与有关实验数据对比指出：在相当大的紊流入流参数范围内,最终的室内空气流动及平面射流特性的计算结果变化不大,藉此可以指导对室内空气流动进行数值模拟时的边界条件描述。     

三维n连体模型在地铁工程空气流动数值模拟中的应用

以地铁车站和区间隧道通风空调与防排烟系统设计对空气流动数值模拟的需求为目标,指出地铁工程空气流动数值模拟存在的问题,提出利用三维n连体模型空气流动数值模拟对一维网络模型进行校验与修正的方法,工程案例计算结果表明,三维n连体模型兼顾了三维模拟的精确性与一维模拟的网络化与高效性,能够适应地铁工程设计阶段的要求,可用于校验与修正一维网络模型。     

工位空调送风静压箱及其送风气流性能评价

通过对工位空调末端送风装置不同结构尺寸下多种工况的模拟分析，研究影响其送风性能的主要因素及其影响规律，包括末端装置外形尺寸和送风量等。研究结果表明这种送风装置存在送风不均匀的现象，这有助于解决空调送风的吹风感问题。在工位空调送风装置的设计中，应考虑利用送风的不均匀性来解决吹风感问题。     

地板送风系统末端与空调箱的变风量控制

介绍了地板送风系统各类末端装置的特点,阐述了常用末端和相应空调箱的变风量控制模式.     

Influence of air supply parameters on indoor air diffusion

This paper presents the field distributions of air velocity, temperature, contaminant concentration, and thermal comfort in an office with displacement ventilation for different air supply parameters such as the effective area, shape, and dimension of the diffuser and the turbulence intensity, flow rate, and temperature of the air supplied. The research is conducted numerically by using an airflow computer program based on a low-Reynolds-number k-ε model of turbulence. It can be concluded that the effective area, shape, and dimension of the diffuser and the turbulence intensity of the air supplied have little effect on the room air diffusion except at floor level. The influence of the flow rate and temperature of the air supplied is very significant on the air diffusion as well as on the thermal comfort and indoor air quality.     

空调排风直接回用的实践探讨

介绍了空调排风直接回用的设计思路.建筑物内各类空间对空气质量要求不同,将较高标准区域的空调排风直接应用于较低标准区域(如附属用房),可以提高附属用房的舒适度,不需再配置其他空调设备.结合实际工程,介绍了空调排风直接回用系统的设计方法.     

空气源热水型空调系统的应用

本文介绍并分析了空调冷凝热回收和回路控制方法及热水器的设计结构和应用。     

VRV空调新风系统设计

介绍了VRV空调常见的新风处理方式。结合h-d图，分析了不同的新风处理方式对应的气流组织形式，指出选择新风处理设备时应使新风处理过程的热湿比与实际要求一致。     

工位空调送风气流微环境评价

模拟了三种送风速度下送风气流在人体活动区形成的速度场、温度场及PMV的分布，结果表明人员活动区存在送风不均匀和温度分层现象，有助于解决吹风感；PMV值在 1和-1之间，可以满足人体热舒适要求。     

The biofiltration of indoor air: implications for air quality

An alternative method of maintaining indoor air quality may be through the biofiltration of air recirculating within the structure rather than the traditional approach of ventilation. This approach is currently being investigated. Prior to its acceptance for dealing with volatile organic compounds (VOCs) and CO2, efforts were made to determine whether the incorporation of this amount of biomass into the indoor space can have an (negative) impact on indoor air quality. A relatively large ecologically complex biofilter composed of a ca. 10 m2 bioscrubber, 30 m2 of plantings and a 3,500 litre aquarium were established in a 160 m2 'airtight' room in a recently constructed office building in downtown Toronto. This space maintained ca. 0.2 air changes per hour (ACH) compared to the 15 to 20 ACH (with a 30% refresh rate) of other spaces in the same building. Air quality parameters of concern were total VOCs (TVOCs), formaldehyde and aerial spore counts. TVOC and formaldehyde levels in the biofilter room were the same or significantly less than other spaces in the building despite a much slower refresh rate. Aerial spore levels were slightly higher than other indoor spaces but were well within reported values for 'healthy' indoor spaces. Levels appeared to be dependent on horticultural management practices within the space. Most genera of fungal spores present were common indoors and the other genera were associated with living or dead plant material or soil. From these results, the incorporation of a large amount of biomass associated with indoor biofilters does not in itself lower indoor air quality.     

Flow impact of an air conditioner to portable air cleaning

In order to reduce indoor pollutant exposure, people become increasingly interested in portable air cleaning devices, which can be positioned with flexibility. Such purification devices usually discharge cleaned air with strong momentum, which can interrupt indoor airflow created by air-conditioning units. If a well-organized air circulation to a portable air cleaner is not achieved, indoor air purification cannot be fully ensured. This study has used both measurement and computational fluid dynamics (CFD) modeling to investigate the flow interaction between an air conditioner and a portable air cleaner to purify indoor gaseous pollutants. A workshop environment conditioned by an air conditioner and cleaned by a portable air cleaner was mimicked in an environmental chamber to obtain data for validation of a CFD program. Then CFD was applied to evaluate factors that may affect air purification including: positioning of the air conditioner and air cleaner, air conditioner diffuser types, air-conditioning cooling or heating running mode, and location of pollutant sources. The study finds the simulation results are in good agreement with the corresponding experimental data. The positioning coordination of an air conditioner and an air cleaner, and selection of air conditioner diffuser types shall assure a good air circulation cycle to the air cleaner to improve air purification efficacy. In addition to the cleaner effectiveness, it is also recommended to evaluate an air cleaning device in terms of the absolute pollutant concentration, if the portable air cleaner is under the interaction of an air conditioner and the local performance data are interested.     

舒适性空调空气过滤器效率计算方法

给出了舒适性空调空气过滤器效率的设计计算公式,分析了公式中各量的取值范围,以商场和办公室为例计算出了空气过滤器效率,并分析了计算结果。