热压通风条件下建筑室内湿空气流动特性研究

发布时间：2018-07-24 15:59

【摘要】：在我国南方湿热地区,城市建设与经济都呈高速发展,城市人口众多,高层建筑如雨后春笋般拔地而起,夏季空调除湿降温需求巨大;深入理解建筑室内热湿迁移机理是如何选择合适的楼层居住和办公以及正确调节室内热湿环境的关键。计算机数值模拟方法具有研究周期较短、信息丰富等诸多优势,本文主要利用计算流体动力学方法来探讨热压自然通风条件下建筑室内空气湿环境流动特性。本文首先建立了封闭建筑室内自然对流层流物理模型,数值分析了室内挡板位置、挡板长度和热瑞利数对自然对流下室内热湿传递的影响,结果表明在局部传热传湿系统中,随着垂直挡板长度的减少,对流发挥着越来越重要的作用。低瑞利数情况下,挡板位置和长度对整个传热传质系统影响较小;随着瑞利数的增加,热湿传递速率对垂直挡板位置不敏感。垂直挡板在抑制热湿传递起主导地位。水平挡板位置在传热传质抑制中也起着重要的作用。接着采用模型实验和数值模拟的方法研究了室内垂直挡板长度和位置及室内外温差对室内壁面温度分布的影响,研究表明分层结构与室内垂直挡板位置关联度很小;更长的垂直挡板更有效的干扰流场流动,对室内对流换热影响更大。室内外温差越大,自然通风作用的效果就越加明显。实验结果与数值模拟结果基本一致。然后又分析探讨了热压自然通风下多层建筑单开口室内挡板长度和位置对室内热湿传递的影响,得出垂直挡板越远离开口,室内湿空气对流作用越强。提高热湿传递率,垂直挡板位置是最重要的因素。垂直挡板位于室内中平面时,室内湿空气对流作用效果最差。不同楼层,垂直挡板长度对室内相对湿度影响不同,在中间层,垂直挡板长度对相对湿度影响很小。垂直挡板在中平面附近时,第一、二层室内相对湿度都存在最小值。而对于水平挡板,挡板越靠近顶部,每层热传递速率受挡板长度的影响越小。对于第一、二层,随着水平挡板长度(LH0.75)的增加,挡板的存在几乎不影响湿传递速率。而对于第三层,在水平挡板位置Dy≤0.4时,更短的水平挡板能够增强室内湿空气扩散作用;相对湿度分布对水平挡板位置不敏感。最后计算探讨了高层建筑非封闭室内挡板长度和位置及开口策略对热压通风下室内热湿传递的影响,研究发现无论挡板长度和位置如何,楼层越高,室内湿空气对流作用愈剧烈;无论在某一楼层,更长的垂直挡板对室内对流换热影响较大。随着楼层的升高,相对湿度受垂直挡板长度的直接影响越小;垂直挡板下,较高楼层,相邻楼层之间室内相对湿度相差不大;当建筑楼层低于六层时,垂直挡板位于中平面附近时,传质的效果最差。相对湿度对垂直挡板位置不敏感。当室内存在较短的水平挡板时,传质效果最好;随着楼层的升高,相对湿度分布受水平挡板长度和位置的直接影响越大;对低于六层的建筑而言,更长的水平挡板对室内湿空气对流作用影响较大而挡板位置几乎不影响室内湿传递速率;而当建筑楼层数不小于六层时,挡板越靠近底部,室内相对湿度分布受外界湿空气直接影响的区域越小。采用双开口通风方式,室内湿空气对流换热效果更佳,此外随着楼层的增加,双开口方式下室内对流换热效果更明显;对于楼层数低于七层的建筑,采用双开口通风方式时,室内外水分传递增强,相反当建筑楼层数不小于七层时,采用单开口通风方式,室内外水分传递增强;当建筑楼层高于六层时,随着楼层的增加,水平挡板下,开口方式对湿传递速率的影响减小。南方湿热地区自然通风建筑热湿环境流动机理研究为理解室内热湿耦合自然对流奠定了基础,提出室内装饰物、家具、隔墙等障碍物的恰当布置以及选择合适的楼层居住和办公,为建筑通风环境的优化设计提供了帮助和指导,给人们选择楼层和室内安装提供了一定的参考依据。探讨了热压自然通风作用下热湿耦合传递机制,探索利用自然通风来保持建筑室内适宜的热湿环境。
[Abstract]:In the hot and hot areas in the south of China, the urban construction and economy are developing rapidly, the urban population is large and the high-rise buildings are springing up like bamboo shoots after the rain. The demand of air conditioning dehumidification and cooling in summer is huge. It is the key to understand the mechanism of heat and humidity migration in the building indoor and how to choose the proper floor and office and to adjust the indoor heat and humidity environment correctly. The computer numerical simulation method has many advantages such as short period of study and abundant information. This paper mainly uses computational fluid dynamics to explore the flow characteristics of indoor air wet environment under the condition of hot press and natural ventilation. Firstly, the physical model of indoor flow laminar flow in a closed building is established, and the indoor baffle is numerically analyzed. The effect of the position, the length of the baffle and the number of thermal Rayleigh on the heat and moisture transfer in the indoor heat convection shows that in the local heat transfer system, with the decrease of the length of the vertical baffle, the convection plays a more and more important role. Under the condition of low Rayleigh number, the position and length of the baffle have little influence on the whole heat and mass transfer system. The heat and humidity transfer rate is not sensitive to the position of the vertical baffle. The vertical baffle plays a dominant role in inhibiting the heat and humidity transfer. The position of the horizontal baffle also plays an important role in the heat and mass transfer suppression. Then the model experiment and numerical simulation are used to study the length and position of the indoor vertical baffle and the temperature difference between indoor and outdoor on the interior wall temperature. The influence of the degree distribution shows that the degree of correlation between the stratified structure and the position of the indoor vertical baffle is very small; the longer vertical baffles are more effective to interfere with the flow of the flow field and have greater influence on the convection heat transfer in the room. The greater the indoor and outdoor temperature difference is, the effect of the natural ventilation is more obvious. The experimental results are basically consistent with the numerical simulation results. And then the analysis is also analyzed. The influence of the length and position of the single opening interior baffle on the heat and moisture transfer in the interior of the multi storey building under the hot pressure and natural ventilation is discussed. It is concluded that the more the vertical baffle is far away from the opening, the stronger the convection in the indoor wet air is stronger. The most important factor is to increase the transfer rate of the heat and humidity, and the position of the vertical baffle is the most important factor. The effect of the vertical baffle length on the relative humidity is different in different floors. In the middle layer, the length of the vertical baffle has little influence on the relative humidity. When the vertical baffle is near the middle plane, the relative humidity of the first, second layers has the minimum value. For the horizontal baffle, the closer the baffle is to the top, the heat transfer rate of each layer is blocked. The less influence of plate length. For the first, second layer, with the increase of the horizontal baffle length (LH0.75), the existence of the baffle almost does not affect the wet transfer rate. For the third layer, the shorter horizontal baffle can enhance the indoor wet air diffusion when the horizontal baffle position is Dy less than 0.4; the relative humidity distribution is not sensitive to the horizontal baffle position. The effect of the length and position of the non enclosed interior baffle and the opening strategy on the heat and humidity transmission under the hot pressure ventilation is discussed in the post calculation. It is found that the higher the floor length and the position, the more the floor is, the more severe the indoor wet air convection is, and the longer the vertical baffle has a great influence on the convection heat transfer in a certain floor. With the rise of the floor, the direct influence of the relative humidity on the length of the vertical baffle is smaller; the relative humidity between the vertical baffles, the higher floors and the adjacent floors is not very different; when the building floor is below the six floor, the effect of the mass transfer is the worst when the vertical baffle is near the middle plane. When there is a short horizontal baffle, the mass transfer effect is the best; with the rise of the floor, the distribution of relative humidity is more directly affected by the length and position of the horizontal baffle; for buildings below six layers, the longer horizontal baffles have greater influence on the indoor wet air convection and the position of the baffle almost does not affect the indoor wet transfer rate; When the number of the building is not less than six layers, the closer the baffle is to the bottom, the smaller the area of the indoor relative humidity is directly affected by the external wet air. With the double opening ventilation, the indoor wet air convection heat transfer is better. In addition, with the increase of the floor, the indoor convection heat transfer effect is more obvious under the double opening mode; the number of floors is lower than the floor number of lower than seven floors. On the contrary, when the number of building floors is not less than seven layers, the water transfer between indoor and outdoor is enhanced when the number of building floors is not less than seven layers. When the building floor is higher than the six layer, the influence of the opening mode on the wet transfer rate decreases with the increase of the floor floor and the horizontal baffle. The research on the heat and wet environment flow mechanism of natural ventilation buildings in the area has laid the foundation for understanding the indoor heat and humidity coupling natural convection, and put forward the proper arrangement of indoor ornaments, furniture, partition wall and other obstacles, and the selection of proper floor residence and office. It provides help and guidance for the optimization design of the ventilation environment of the building, and gives people the choice of floor and room. The internal installation provides a certain reference basis. The mechanism of heat and humidity coupling transfer under the action of hot press and natural ventilation is discussed, and natural ventilation is explored to maintain the suitable heat and humidity environment in the building.
【学位授予单位】：湖南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU831.1

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