| 热压自然通风室内污染物浓度演变特性 |
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| 引用本文： | 庄加玮,刁永发,张俪安,沈恒根. 热压自然通风室内污染物浓度演变特性[J]. 西南交通大学学报, 2021, 56(1): 47-55. DOI: 10.3969/j.issn.0258-2724.20190582 |
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| 作者姓名： | 庄加玮 刁永发 张俪安 沈恒根 |
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| 基金项目： | 国家重点研发计划（2018YFC0705300） |
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| 摘 要： | 为探究热压自然通风向稳态发展过程室内气态污染物的迁移规律,对不同高度处污染物浓度演化进行了分析.首先结合预测热分层瞬时变化的非均匀三层模型,针对室内不同的下层污染物混合特性,建立了均匀混合和纯置换两种热压自然通风室内污染物输送模型;其次,采用4阶龙格-库塔(Runge-Kutta)方法迭代求解,得到了通风过程室内污染物...
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| 关 键 词： | 热压自然通风 瞬时流动 热分层 污染物输送模型 浓度变化 |
| 收稿时间： | 2019-06-24 |
Evolution Characteristics of Indoor Pollutant Concentration in Buoyancy-Driven Natural Ventilation |
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| ZHUANG Jiawei,DIAO Yongfa,ZHANG Li’an,SHEN Henggen. Evolution Characteristics of Indoor Pollutant Concentration in Buoyancy-Driven Natural Ventilation[J]. Journal of Southwest Jiaotong University, 2021, 56(1): 47-55. DOI: 10.3969/j.issn.0258-2724.20190582 |
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| Authors: | ZHUANG Jiawei DIAO Yongfa ZHANG Li’an SHEN Henggen |
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| Abstract: | Evolution of pollutant concentration at different heights was analyzed to explore the evolution rule of indoor gaseous pollutants during a period from buoyacy-driven natural ventilation to steady state. Firstly, according to the non-uniform three-layer model used to examine the transient flows driven by buoyancy force, two theoretical models that correspond to homogeneous mix and pure displacement were developed for the different mixing characteristics of the inoor lower-layer pollutants. Then, the fourth-order Runge-Kutta method was adopted to find a iterative solution, and the height and concentration variation characteristics of the indoor pollutants during the ventilation process were obtained. Finally, the effects of the effective ventilation area and buoyancy combination coefficient on pollutant concentration was discussed. The results show that, the thermal stratification interface with zero vertical velocity greatly differs from the fresh air layer interface, and the height difference between thermal stratification interfaces will have a larger peak value and a shorter time to reach steady state when the dimensionless effective ventilation area becomes larger. The greater buoyancy combination coefficient is, the greater the height difference between thermal stratification interfaces at any time is, which becomes more obvious with the increase of the dimensionless effective ventilation area. The mixing characteristics of lower-layer pollutants affect the stratification and time evolution, but do not change the concentration distribution in steady state, and the upper layer has the highest pollutant concentration for both models. For the pure-displacement model, the pollutant concentration of the original layer decreases until it reaches stability, and the lower-layer pollutant concentration remains constant, while that of the upper layer increases sharply in the initial stage before decaying. Meanwhile, the average pollutant concentration of the upper and lower layers both slowly decay to a stable value for the homogeneous mix model. Furthermore, a larger dimensionless effective ventilation area can result in a faster decay of the dimensionless pollutant on the pollutant concentration can be almost ignored. |
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