摘要
在现代社会中,随着人们在室内工作和学习时间的逐渐增长,对室内工作环境的要求也逐步提高。置换式通风由于其在热舒适性、室内空气品质和节能方面的优越性正在受到国内外的广泛研究和运用。
通常置换通风送风口在房间下部或落地布置,既占用了房间下部的有效空间,又在某些场合造成风口难以布置。为解决传统下置风口置换通风存在的不足,本课题组曾提出了侧墙上置风口置换通风的送风方式,并开展了具有特殊结构形式的上置风口置换通风的理论与实验研究。研究结果表明:在系统性能方面,该方式比混合通风具有较高的通风效率,比传统置换通风具有较高的空调冷负荷承担力。
本文在课题组所做工作的基础上,针对侧墙上置风口置换通风方式做了进一步的实验研究,以典型办公室房间为实验模型,在不同送风口结构形式下,分别进行了具有夏季室内整定温度的工况、具有过渡季节室内整定温度的工况及具有冬季内区室内整定温度的工况在不同负荷率下的实验,测试了房间非等温送风射流发展的速度场和室内空间的温度场,根据舒适性标准的要求,通过分析各个工况室内的垂直温差以及地面0.1m处的风速,确定了满足舒适性要求的送风参数范围,并利用送风射流无因次速度的变化曲线,分析了组合射流发展规律及其对通风效率的影响,基于送风速度与热源强度的双因素,阐明了耦合作用及室内整定温度对通风效率的影响,并指出了风口结构对通风效率的影响。分析表明:送风射流对其周围空气温度场的影响较弱,通风效率的变化,受控于送风射流与热羽流的耦合作用,阶梯形风口有效地提高了室内通风效率,通风效率随室内整定温度的提高而增大。这些为置换通风系统设计和实际应用提供了有意义的参考。
In the modern society, as the time of people working and learning in indoor gradually increase, the requirements to the indoor working environmental has also gradually increased. Displacement ventilation as its advantages in the aspects of thermal comfort、indoor air quality and energy-saving is of being extensive research and application at domestic and abroad.
Displacement ventilation outlet is usually installed at the lower part of the room or floor layouts, both occupy the effective space of the room lower part, and in some cases caused the layout of the outlet difficult. To solve the shortage of the traditional displacement ventilation, our research group ever devised the displacement ventilation system with high sidewall outlet, and the displacement ventilation with a special structure outlet was conducted in the form of the theoretical and experimental research. The results show that: the system performances higher ventilation efficiency than the traditional mixed-mode ventilation, and has a higher commitment of the cooling load than the traditional displacement ventilation.
Based on the work done by our research group, the writer did further experimental studies on the displacement ventilation system with high sidewall outlet. The experimental model is based on a typical office room, under the different forms of diffuser physical configuration, the writer respectively conducted some conditions with summer indoor set temperature, transition season indoor set temperature and winter set indoor temperature under different load rates. The author tested the velocity distribution of the non-isothermal air jet and the temperature field of the room. According to the requirements of comfort standards, by analyzing the vertical temperature difference and the air speed at the 0.1m ground of all the conditions, determined parameters of the air supply that meet the requirements of comfort. And also using the ventilation jet non-dimensional velocity change curve, analyses the combination jet flow regulation and its influence on the ventilation efficiency, explains the influence of coupling action and indoor set temperature on the ventilation effect based on the two factors of supply air velocity and heat source intensity, and presents the influence of diffuser physical configuration on the ventilation effect .The results of the analysis showed that: the impact of the supply air jet on the air temperature around itself is weaker. The change of the ventilation efficiency is controlled by the coupling action of the supply air jet and the thermal plume. The diffuser with ladder velocity distribution effectively improves the indoor ventilation efficiency, and the ventilation efficiency can also improved with the increasing of indoor set temperature. Thus provides a meaningful reference to the design and practical application of the displacement ventilation system.
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