风口侧上置置换通风的热舒适性实验研究

以小型办公室为实验模型,采用了5组对比工况进行了实验,并将实验值与模拟值进行了比较,结果二者吻合较好。分析了侧墙上置风口置换通风的热舒适性。结果表明风口侧上置置换通风在各设计工况下,其负荷承担能力要大于传统置换通风,并且不论是吹风感、吹风温度还是室内头脚垂直温差都满足人体热舒适。这也证实风口上置置换通风与传统置换通风一样,可以在室内形成良好的热力分层现象,并且其能很好地满足人体的热舒适性需求,具有置换通风系统的特性。     

混合热源自然置换通风热力分层高度数值模拟

本文通过数值模拟方法对具有单点热源和单面垂直发热墙体混合工况下的室内自然置换通风热力分层特性进行研究。研究结果显示,在所研究对象的参数变化范围内,室内自然置换通风热力分层高度受有效通风面积的影响,热力分层高度随有效通风面积的增大而升高,反之降低。室内自然置换通风热力分层高度基本不受单点热源和单面垂直发热墙体发热量的影响。     

冬季空调置换通风与热舒适性初探

对置换通风及其热舒适性进行简单的描述.并阐述冬季工况下置换通风与热舒适性的关系,为以后研究冬季空调室内置换通风做下铺垫.     

置换通风与CFD数值模拟

为了降低空调通风系统的能耗,提高通风效率,改善热舒适性,对于建筑在夏季工况下,可采用置换通风方式来满足室内空气品质和热舒适性的要求.通过分析置换通风的运行原理,借助计算流体力学的理论和方法,利用CFD(Fluent)软件,采用了低Re数湍流模型,模拟了夏季工况下的室内温度场和速度场.     

多热源置换通风温度分布及影响因素模拟分析

置换通风是一种新型高效的通风方式。本文运用计算流体力学（CFD）技术对不同工况下的多热源置换通风房间内的温度场及流场进行了数值模拟。分析了热源间距、热气流温度、房间围护结构以及室外温度变化对置换通风系统及人员舒适性的影响。结果表明：热源间距的变化对热源之间室内的垂直温度分布影响较大;热气流温度的变化主要对房间上部区域的温度产生影响;围护结构热损失及室外温度的变化均对室内温度及温度梯度产生较大影响。     

寒冷地区住宅室内不同通风方式模拟与分析

住宅室内存在不同的通风方式,对室内风环境产生不同的影响。研究寒冷地区一梯三户中户住宅室内不同通风方式的特点以及效果,探索不同通风方式对住宅室内风速场、空气品质和热舒适度的影响。引用CFD流体力学的原理,运用Airpak3.0软件对住宅室内自然通风、侧送风、置换通风进行模拟计算,模拟三种通风方式室内风速场、温度场、空气平均年龄、PMV、PPD参数值分布,对比分析不同通风方式下室内风速、温度、空气平均年龄、PMV值,得出采用置换通风的寒冷地区一梯三户中户住宅室内通风利用气流上升,提高了室内新鲜空气,满足室内热舒适环境,创造良好的住宅室内环境,是一种舒适高效的通风方式,为寒冷地区一梯三户中户住宅室内通风设计提供科学指导。     

侧墙上置风口置换通风系统性能的实验研究

对侧墙上置风口置换通风在不同负荷率下进行夏季工况,过渡季节工况,冬季内区工况的系统性能进行实验研究,得出此种通风方式下送风口的速度分布,室内的温度分布,0.1m处的风速等实验数据。通过分析实验数据得出,侧墙上置风口置换通风在满足室内热舒适性的前提下,能够提高房间的负荷承担能力,与混合通风相比能够得出较高的通风效率;另外,阶梯形的风口较普通的送风口能较少地卷吸上区品质差的空气,能更好地满足侧墙上置置换通风的风口特性要求。     

某毛细管辐射与置换通风空调系统的测试

对某安装毛细管辐射与置换通风空调系统的别墅进行了夏季工况测试。从室内温湿度场,置换通风系统效果及能耗几个方面对系统进行了分析,并对系统的经济性运行提出了建议。     

多模式通风净化器的性能模拟

提出了一种具有多种使用模式的通风净化器,在其自然通风和机械通风通道中安装了不同净化效率的空气过滤器。为评估该通风净化器的性能,将不同操作模式下的阻力-流量特性和颗粒过滤性能引入到EnergyPlus中进行建模,模拟了通风净化器的风量和空气过滤效率,并通过实验数据进行了验证。使用该模型对通风净化器在不同气候区典型房间的空气品质和能耗进行模拟,结果显示在满足室内空气品质的前提下,通风净化器较现有高效新风机可降低高效净化模式70%左右的使用时长,单位面积年通风净化能耗降低约30%。     

高大空间膜结构屋顶展厅置换通风空调设计

介绍了上海世博会某膜结构屋顶展厅的置换通风空调设计,采用陈清焰置换通风CFD模拟公式计算了送风量.对室内温度场、速度场进行了模拟及优化,并在运行期间进行了温度实测.结论是本项目可作为陈氏置换通风CFD模拟公式应用于大空间尺度的一个案例.     

某办公室置换通风的两区域模拟

本文建立了研究置换通风气流瞬态情况的两区域模型,用两区域模型对具体建筑进行模拟,分析其模拟结果,与实验结果和CFD模拟结果对比,来说明两区域模型的使用方法。     

侧墙上置送风口置换通风流场及通风效果评价

针对设置侧墙上置送风口置换通风系统的房间,采用CFD软件对室内空气速度场、温度场进行模拟。根据模拟结果,分析贴附射流、冲击射流的发展过程,评价侧墙上置送风口置换通风系统的通风效果。     

Contaminant dispersion with personal displacement ventilation,Part I: Base case study

Personal displacement ventilation (PDV) is a new ventilation concept that combines the positive features of displacement ventilation with those of task conditioning or personalized ventilation. PDV is expected to create a micro-environment around an occupant to control the environment individually. In this study, a base PDV case with a contaminant source at different locations was modeled for contaminant dispersion in a full-scale chamber. Computational fluid dynamics (CFD) was used to simulate the indoor airflow and pollutant transport, and the simulation results were validated against the experimental data. The contaminant concentration field for three different contaminant source locations was analyzed. Based on our results, it seems that this kind of PDV system cannot create the expected “micro-environment” to avoid the disturbance of the outside airflow. Further studies on how to improve the PDV performance are given in the companion paper.     

Effect of Ventilation System on Smoke and Fire Spread in a Public Transport Interchange

In this report, a large eddy simulation (LES) model is used to investigate the conventional types of ventilation system design in the context of a public transport interchange. Various airflow patterns based on two of the most popular ventilation designs (mixing and displacement) are simulated to determine their effect on the fire. The simulation program chosen is the fire dynamics simulator (FDS) published by National Institute of Standards and Technology (NIST). It is found that increased airflow causes the fire temperature to increase by as much as 500 K. Extraction of smoke mixture by fans (exhaust only system) significantly decreases the spread of smoke and fire. Ventilation inlets located at the ground level help to increase the smoke and fire intensity in the occupied zone. Displacement ventilation increases fire intensity and current.     

城市住区室外通风与空气负离子浓度评测研究

选取合肥市东南区域典型居住区为研究对象,运用CFD数值模拟和室外实地观测相结合的研究方法,量化模拟了夏冬两季住区室外环境的风速图,并分析了其模拟通风状况;在此基础上得到了住区内不同环境的通风特征,包括建筑布局、空间形态、建筑密度、交通路网、植物绿化等对通风的影响;再根据模拟参数,在住区内选取样点实地观测了不同环境特征下的住区夏冬两季的空气负离子和风速、温度、相对湿度以及空气正离子等数据,探索了住区室外环境中空气负离子浓度与风速、温度、湿度和空气正离子之间的相关关系。同时进一步整理了近4万个有效数据应用于空气负离子和风速的时空分布研究,推导出夏季风速与空气负离子的线性回归方程,并运用偏相关分析,得出城市住区环境中空气负离子与风速呈极显著负相关,给出了线性回归方程Y=-0.001X-0.003。最后结合建筑布局的组合、开敞空间的设计和线性道路的组织等分析了空气负离子和风速的分布规律,用以说明评价住区室外环境通风状况的可行性,为今后城乡规划和建筑设计提供科学依据和设计思路。     

铁路某数据中心控制大厅气流组织设计探讨

根据模拟计算和实验测试结果分析了数据中心控制大厅的气流组织,结果显示在工位置换通风条件下,工作区域的热舒适性、风速和CO2浓度满足规范要求,沿高度方向温度和CO2浓度分布有明显的分层现象。     

置换通风的通风效率及其微热环境评价

讨论了通风有效性与空气分布特性的相关性，分析了混合通风（上送下回）通风效率低于置换通风效率的原因。根据大量的实验资料，分析提出了影响通风效率的若干复合因素，得出了预测置换通风效率的经验式。经综合人体舒适性实验，说明置换通风微热环境能提供居住者整体舒适感，而在肢体下部风感不满意率小于１５％     

Air flow and particle control with different ventilation systems in a classroom

Most ventilation and air conditioning systems are designed without much concern about how settling particles behave in ventilation air flows. For displacement ventilation systems, designers normally assume that all pollutants follow the buoyant air flow into an upper zone, where they are evacuated. This is, however, not always true. Previous studies show that high concentrations of settling respirable particles can be found in the breathing zone, and that the exposure rates can be a health hazard to occupants. The emphasis here is on how ventilation systems should be designed to minimize respirable airborne particles in the breathing zone. The supply and exhaust conditions of the ventilation air flow are shown to play an important role in the control of air quality. Computer simulation programs of computational fluid dynamics (CFD) type are used. Particle concentrations, thermal conditions and modified ventilation system solutions are reported.     

剧场座椅送风气流组织数值模拟

座椅送风是置换通风的一种具体形式,不同于传统置换通风的侧送风形式,我国在这方面设计规范也相应较少,又鉴于座椅送风初投资昂贵,在设计时有必要对其气流组织、舒适性等加以模拟预测。本文采用FLUENT软件对其空调系统的气流组织进行模拟研究,运用座椅送风的简化模型,模拟各种送风形式下的温度场和速度场,对比了各种送风形式的温度、速度、风量等因素,为大空间建筑空调系统优化设计、模拟气流组织提供了方法及理论依据。     

Co‐occupant's exposure to exhaled pollutants with two types of personalized ventilation strategies under mixing and displacement ventilation systems

Personalized ventilation (PV) system in conjunction with total ventilation system can provide cleaner inhaled air for the user. Concerns still exist about whether the normally protecting PV device, on the other hand, facilitates the dispersion of infectious agents generated by its user. In this article, two types of PV systems with upward supplied fresh air, namely a chair‐based PV and one kind of desk‐mounted PV systems, when combined with mixing ventilation (MV) and displacement ventilation (DV) systems, are investigated using simulation method with regard to their impacts on co‐occupant's exposure to the exhaled droplet nuclei generated by the infected PV user. Simulation results of tracer gas and particles with aerodynamic diameter of 1, 5, and 10 μm from exhaled air show that, when only the infected person uses a PV, the different PV air supplying directions present very different impacts on the co‐occupant's intake under DV, while no apparent differences can be observed under MV. The findings demonstrate that better inhaled air quality can always be achieved under DV when the adopted PV system can deliver conditioned fresh air in the same direction with the mainly upward airflow patterns of DV.