小型空气净化通风系统中风量分配器性能优化

为了实现自控系统根据房间人数调控风量,采用风量分配器分配风量。为优化风量分配器的均匀可调性,本文模拟研究了导流片高度,角度对风量分配的影响,并对其进行了分析。结果表明,当导流片高度为120 mm时,调节导流片角度,风量分配效果最优。     

中小学教学楼机械通风系统设计探讨

中小学教学楼设置机械通风系统有利于改善教室空气品质,为师生创造良好的教学环境。本文比较了机械通风与自然通风的优缺点,对教学楼机械通风系统的空气过滤、风量计算及不同新风系统方案的特点进行了分析探讨,并提出应结合新风系统形式设置普通教室排风系统。     

喷射渗透式纤维空气分布系统孔口送风特性的实验研究

对于3种不同孔口类型的喷射渗透式纤维空气分布系统测试了其在不同风量下的出风速度和射程,并利用射流理论计算了不同工况下的孔口紊流系数。结果表明送风量对同一类型孔口的紊流系数影响不大,3种孔口类型在不同风量下的紊流系数分别为0.068、0.145、0.158。孔口结构对紊流系数有较大影响。同一风量下,18 mm带导流环的孔口送风射程大约是18 mm无导流环孔口送风射程的2倍。     

新风负担室内全部湿负荷的手术室空调系统设计探讨

医院手术部空调系统怎样节能一直是行业关注的话题,由于采用湿度优先的控制方法,传统的一次回风空调系统存在"冷热抵消"的能源浪费现象。论文通过对新风集中处理一次回风空调系统能耗分析,结合新风机组风冷比的概念,提出了变新风量一次回风空调系统。新风采用两档风量,夏季及过渡季节采用高档风量,冬季采用低档风量,且新风机组担负室内全部湿负荷。     

板翘式全热交换器结构优化实验研究

全热交换器入口段结构关系到芯体迎风面的气流分布,对全热交换器性能有重要影响。为进一步提高全热交换器性能,针对一种常见的垂直交叉流板翘式全热交换器,将入口气流垂直于芯体改为入口气流平行于芯体,并在流道内设置导流片,通过实验对导流片的数量和角度的影响进行了研究。结果表明：对比原结构,改变入口气流方向,在低风量下换热效率有所提高;在流道内设置导流片,换热效率进一步提高;增加导流片数量以及增加导流片角度,都会再进一步提高换热效率。     

两种手段提升太阳能新风热利用效率的研究

严寒地区居住建筑面临较为严重的冬季新风不足问题,太阳能新风系统是改善室内空气品质的一种重要手段。研究目的:了解空气流道厚度降低和使用双层玻璃盖板对于提升基础型太阳能新风集热器效率的实际效果。方法:通过搭建太阳能新风集热器实验平台,自制单层、双层玻璃盖板太阳能新风集热器,对比研究空气流道厚度(10mm和30mm)以及不同玻璃盖板层数对集热器效率的影响,并对不同工况下的出口温度和逐时效率进行监测和分析。结果表明:改小集热器空气流道厚度之后平均集热效率上升了10.8%,使用双层玻璃盖板之后平均集热效率上升了7.5%。双层玻璃盖板在低温下能够进一步发挥保温优势,减少了玻璃盖板表面的热损失。结论:减小空气流道厚度,采用双层玻璃盖板具有明显的实际效果,太阳能新风系统具有很好的推广应用潜力。     

氧化沟中导流墙二维水流流态模拟研究

导流墙是氧化沟中改变水流流向的辅助结构,导流墙广泛采用偏心设置,其设置参数多为经验判断。根据Fluent软件进行模拟导流墙处流速分布情况分析,在不同下游长度、偏心距及导流墙半径的条件下,对导流墙的设置进行讨论,得出其优化的设置参数。     

多区域VAV空调系统全年新风分配控制探讨

在多区域VAV空调系统全年新风分配控制方案的制定过程中,需要考虑的因素众多,传统控制方法存在一定的局限其性次。探文讨章传首统先多对区多域区VA域V V空AV调空系调统系全统年新新风风量分需配求控进制行的分局析限,性,最后提出几点有效的优化策略,以期促进VAV空调系统新风分配控制水平的提高。     

体操训练馆空调系统全年运行模拟分析

针对体操训练馆冬季室内设计温度较高,空调送风量较大的特点,利用模拟分析软件对体操训练馆一次回风定风量系统进行全年模拟分析,预测空调系统全年供冷、供热、通风时间,为确定冷热源运行时间提供设计依据;预测空调系统全年不同新风比工况运行时间,统计不同新风比工况对应外温范围,总结一次回风定风量空调系统全年运行控制策略。     

建筑高度对空调新风负荷影响分析

为分析建筑高度对超高层建筑空调新风负荷的影响,从理论上分析了室外气象参数的竖直变化规律及室外空气比焓的变化规律。以南京市为例,分别分析了100～1 000m不同新风引入高度处连续运行工况和间歇运行工况下单位风量新风负荷。结果表明:随着新风引入高度的增加,夏季新风负荷降幅大于冬季新风负荷增幅,全年单位风量新风负荷呈降低趋势;当新风引入高度为200,500,800,1 000m时,较地面基准新风负荷,连续运行工况下全年累计单位风量新风负荷分别下降了10.3%,22.8%,31.9%,36.2%,间歇工况下全年单位风量新风负荷分别下降了10.5%,23.2%,32.5%,37.1%。     

多层车库风量需求特性与风口布置优化分析

基于国内外现有车库通风量计算理论,并借助CFD方法,分析了多层车库在不同通风量和不同排风口设置位置下的通风气流组织效果,并对部分污染负荷下的风量需求特性进行了分析。结果表明,多层车库的通风量确定可采用单台车所需排气量法进行估算,并推荐采用稀释浓度法进行设计计算;其排风口宜布置于车库顶部以利于污染物有效排除。另外,部分污染负荷下的风量需求比例要高于对应的污染负荷比例。     

Thermal comfort and IAQ assessment of under-floor air distribution system integrated with personalized ventilation in hot and humid climate

The potential for improving occupants’ thermal comfort with personalized ventilation (PV) system combined with under-floor air distribution (UFAD) system was explored through human response study. The hypothesis was that cold draught at feet can be reduced when relatively warm air is supplied by UFAD system and uncomfortable sensation as “warm head” can be reduced by the PV system providing cool and fresh outdoor air at the facial level. A study with 30 human subjects was conducted in a Field Environmental Chamber. The chamber was served by two dedicated systems – a primary air handling unit (AHU) for 100% outdoor air that is supplied through the PV air terminal devices and a secondary AHU for 100% recirculated air that is supplied through UFAD outlets. Responses of the subjects to the PV-UFAD system were collected at various room air and PV air temperature combinations. The analyses of the results obtained reveal improved acceptability of perceived air quality and improved thermal sensation with PV-UFAD in comparison with the reference case of UFAD alone or mixing ventilation with ceiling supply diffuser. The local thermal sensation at the feet was also improved when warmer UFAD supply air temperature was adopted in the PV-UFAD system.     

载人航天器座舱空气龄的数值模拟

建立了一个包含乘员、仪器设备和简单生活设施在内的载人航天器座舱物理模型,采用房间零方程湍流模型模拟了座舱工作区的空气龄分布。送风模式为舱顶两侧45°斜送风,风口布置采用了连续对称布置、间隔对称布置和间隔交错布置3种方案。模拟结果显示,连续对称布置会产生分叉现象,不建议采用;间隔交错布置优于间隔对称布置,并在送风速度为1．1 m／s左右时换气效率最高;在舱壁附近有乘员长期工作的情况下,乘员呼吸区的空气龄偏大,建议采用个性化送风来解决此问题。     

Numerical and experimental study of velocity and temperature characteristics in a ventilated enclosure with underfloor ventilation systems

Airflow and temperature distributions in an enclosure with heat sources ventilated by floor supply jets with floor or ceiling air exit vents were investigated using experimental and numerical approaches. These ventilation configurations represent the floor return or the top return underfloor ventilation systems found in real applications. Experiments and numerical simulations were performed on a full-sized environmental chamber. The results reveal that the temperature stratification in the enclosure highly depended on the thermal length scale of the floor supply jets. When the thermal length scale of the supply jet was >1, temperature stratification was minor for all tested heat densities and air distribution methods. Significant vertical temperature gradients occurred when the jet thermal length scale was <1. Changes in air distribution methods also became significant for temperature stratification at small supply jet thermal length scales. Temperature stratification also affected the terminal height of the momentum-dominant region of the vertical buoyant supply jets. The applicability of these results to underfloor ventilation design was also discussed. PRACTICAL IMPLICATIONS: In designing underfloor ventilation systems, supply jet conditions and heat load density have to be considered to avoid thermal discomfort because of excessive temperature stratifications. This study demonstrated, by both numerical simulations and experiments, that thermal length scale can be used as a design indicator to predict thermal stratifications under a floor return and a top return underfloor ventilation setting.     

富华国际会议及展览中心空调设计

结合高大空间特点，介绍了各展厅空调系统设计，包括气流组织的确定、系统的划分及机房的设置。第一展厅外区采用下送下回方式、双层百叶风口，内区采用上送下回方式、旋流风口；第二、三展厅均为内区，采用上送下回方式、旋流风口；共享大厅采用侧送下回方式、球型喷口。水系统采用变水量、两管制系统。介绍了通风、自控设计。     

西大望220KV变电站暖通设计

着重介绍了这一目前国内规模最大的地下变电站的通风和防排烟系统设计。根据工艺设备布置和变电站的地理位置,在上风侧设进风竖井和可移动式进风塔,在下风侧设计排风竖井和排风塔,采用自然井风、机械排风的通风方式;对可能产生有毒气体的CIS室设正常通风和事故风系统,房间上、下部均设排风口。不同于常规变电站的防排烟,电气设备间的消防设计不仅考虑火灾后的排烟,而且考虑人员的安全疏散,排烟风机和各种防火阀既能集中控制,亦可就地控制。该变电站已安全运行一年多。     

彭水地下水电站厂房通风数值模拟及方案比较

利用CFD技术对地下水电站发电机层、水轮机层气流组织进行了数值模拟计算。对不同的风口大小、风口数量、风口布置位置形成的室内速度场、温度场分布进行了分析对比,提出适合于本文实际的送风方案,并对所选方案的不同运行工况进行了数值模拟研究,为设计提供了依据。     

Experimental investigation on air heating and natural ventilation of a solar air collector

Solar air collectors are important components for solar energy utilization in green houses. In this paper, experimental studies were carried out regarding to a solar air collector (SAC), for which the length of air channel is 1500 mm, the width is 500 mm, and a variable air channel gap ranges from 100 to 500 mm. In the experiment, the uniform heat flux along the air channel is effected by three electric heating plates, which play a role as solar radiation. It is found that the temperature distribution of air and the induced natural air-flow rate are highly dependent on heat input, inclination angle, channel gap, etc. Experimental results indicate that the optimum inclination angle for the SAC is 45°, under which a maximum natural ventilation rate can be created. Also found is that there exists an appropriate channel length, about 1 m in this study, beyond which the obtained heat and the natural ventilation rate cannot be increased drastically. Higher the volume of air-flow rate through the SAC, lower the temperature difference between inlet and outlet, consequently, it should be balanced between the air temperature rise and a suitable mechanical air-flow rate in order to obtain maximum heat. Additionally, theoretical analysis based on heat balance equations is testified to agree well with experimental results.     

苏州某地铁车站轨顶排风口设置形式探讨

采用数值模拟方法,分析了地铁隧道内轨行区排风口的设置形式对车站隧道温度的影响,提出了一种新的排风口设置方案,为工程设计提供参考。     

碰撞射流末端送风形式对室内气流的影响

通过CFD模拟研究了碰撞射流系统末端不同送风形式,对各送风形式下室内的速度场和温度场的分析结果表明：典型工况条件下,在送风末端管壁处设置小开口以及百叶会使近地面扩散气流速度明显降低,可以降低冬季工况室内人员产生冷风感的风险。所有送风口形式均有下部空间温度高于上部特征,可实现较高的送风能量利用效率。