摘要
本文建立了建材有机挥发性化合物(VOCs)通用散发模型,并给出了其分析解。通过此分析解可以计算出VOCs扩散传质速率和扩散量,以及建筑材料内VOCs瞬时浓度分布。通过分析发现:(1)无量纲扩散量只是Bi_m(传质毕渥数)、Fo_m(传质付立叶数)、和 K(分离常数)的函数;(2) Bi_m/K存在临界值;当Bi_m/K大于此临界值时,与内部扩散传质质阻相比外部对流传质质阻可以忽略。文章对该简化进行了误差分析,给出了保证相对误差为5％的FO_m与Bi_m/K临界值的拟合关系式,并通过实例进行了验证。
A new generally applicable model for calculating the surface emissions of VOCs (Volatile Organic Compounds) from the building material and the VOC instantaneous distributions in the materials is developed. Different from the mass transfer based models in the literature, it doesn't neglect the mass transfer resistance through the air phase boundary layer. The results by using the presented model are validated with the experiments in the literature. By normalizing the model, the factors of influencing the surface emissions of VOCs from building material are clarified and the influences are quantitatively analyzed. It is found that the dimensionless emission rate of VOCs is just the function of Bim (the Biot number for mass transfer)/K (the partition coefficient) and Fom (the Fourier number for mass transfer), which summarizes the general surface emission characteristics of VOCs from building materials and provides the basis for fitting experimental data to formulate empirical correlations of VOC emissions. Based upon the model and the analysis, the applicable condition of the famous Little model is presented.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2003年第4期685-687,共3页
Journal of Engineering Thermophysics
基金
清华大学一流大学建设基金(No.200007005)
关键词
传质毕渥数
传质模型
传质付立叶数
分离常数
有机挥发性化合物
the Biot number for mass transfer
mass transfer model
the Fourier number for mass transfer
partition coefficient
Volatile organic compounds
