通風空間中室內氣懸街塵移除之動態模擬

Removal Dynamics of Indoor Airborne Road Dust in a Ventilated Airspace

黃美玉(Mei-Yu Huang) ； 廖中明(Chung-Min Liao) ； 張倉榮(Tsang-Jung Chang)

《農業工程學報》 51卷4期 (2005/12) Pp. 1-19

https://doi.org/10.29974/JTAE.200512.0001

摘要

本研究將通風空間內部視為完全混合，推導通風空間中室內氣懸街塵移除機制之動態方程式，其中考慮紊流膠結(turbulent coagulation)、紊流擴散附著(turbulent diffusive deposition)、重力沉降(gravitational sedimentation)及氣流型態等作用，描述室內氣懸街塵之移除動態行為。以台灣北部都市地區之街塵為對象，運用室內氣懸街塵移除動態方程式模擬六組空間系統，其中四組採位移式系統(displacement system)和二組採短循環式系統(short-circuiting system)，並以兩種通風量（210及105立方公分s^(-1)，空氣交換率為1.04及0.52h^(-1)）及兩種微粒產生量（0.1及0.05 g min^(-1)）進行模擬。
模擬結果顯示台灣北部都市地區（古亭測站），氣懸街塵對數常態分布幾何平均粒徑為1.01μm，及幾何標準偏差為2.59。當通風量為210及105 立方公分s^(-1)，微粒產生量為0.1及0.05 g min^(-1)時，位移式及短循環式通風系統之累積氣懸街塵濃度範圍分別為64.28~237.38及94.72~356.00 μg m^(-3)。對應比較得知位移式之累積氣懸街塵濃度較短循環式通風系統低，因此位移式較短循環式通風系統能有效移除氣懸街塵。
本研究同時進行模式靈敏度分析，當氣動直徑為1.01 μm時，考慮三種通風量分別為105、210及315立方公分s^(-1)（空氣交換率為爲0.52、1.04及l.56h^(-1)），對模式參數進行靈敏度分析，分析結果顯示通風量為影響最鉅之參數。當通風量為105、210及315立方公分s^(-1)時，皆顯示紊流膠結對移除影響較大，紊流擴散附著及重力沉降則次之。本研究結果，期能對都會住宅室內空間之環境設計有所貢獻。

關鍵字

街塵 ； 通風 ； 紊流膠結 ； 紊流擴散附著 ； 重力沉降

並列摘要

The main purpose of this research is to derive a dynamic equation for describing the removal mechanisms of airborne road dust from a ventilated airspace. This proposed dynamic equation simultaneously takes into account the removal effects of three dimensionless parameters, turbulent coagulation (TC), turbulent diffusive deposition (TD), gravitational sedimentation (GS), and airflow pattern within a ventilated airspace. One set of road dust collected from urban area situated in northern Taiwan. Four displacement associated with two short-circuiting ventilation system modes were conducted in the modeling simulation. Two airflow rates (210 and 105 cm^3s^(-1), ACH= 1.04 and 0.52 h^(-1) with two road dust generation rates (0.1 and 0.05 g min^(-1)) were employed to perform the modeling simulation of the mass concentration of airborne road dose. Results show that there is no significant variation for particle size distributions of the road dust samples obtained from urban area in northern Taiwan, whereas both followed a lognormal distribution with average geometric mean diameter of 1.01 μm and geometric standard deviation of 2.59. Sensitivity analysis of model parameters reveals that airflow is the dominant parameter in the model. Sensitivity analysis shows that TC is the dominant parameter among TC, TD and GS as the airflow rate is 105, 210 and 315 cm^3s^(-1) (ACH=0.52、1.04 and 1.56 h^(-1)). The results of modeling simulation also demonstrate that cumulative mass concentrations of airborne road dust in displacement and short-circuiting ventilation systems are 64.28~237.38 and 94.72~356.00 μg m^(-3), respectively, under airflow rate of 210 and 105 cm^3s^(-1) with road dust generation rate of 0.1 and 0.05 g min^(-1), indications cumulative mass concentration in displacement system is lower than that in short-circuiting system. Moreover, the cumulative mass concentrations under airflow rate of 210 cm^3s^(-1) are lower than that under 105 cm^3s^(-1), in both displacement and short-circuiting ventilation systems. Results also demonstrate that the removal efficiency of displacement ventilation system is higher than that of short-circuiting one. Results obtained from this research are expected to offer designers a control strategy for removal of indoor concentrations of airborne road dust from a ventilated airspace.

並列關鍵字

Road dust ； Ventilation ； Turbulent coagulation ； Turbulent diffusive deposition ； Gravitational sedimentation