A mass transfer model for predicting emission of the volatile organic compounds in wet building materials  

作　　者：ZHANG Tao JIA Li 

机构地区：[1]School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing 100044, China

出　　处：《Chinese Science Bulletin》2008年第17期2701-2705,共5页

基　　金：the National Natural Science Foundation of China (Grant No. 50776006);the 863 Program (Grant No. 2006AA05Z228)

摘　　要：A new mass transfer model is developped to predict the volatile organic compounds (VOCs) from fresh wet building materials. The dry section of wet materials during the process of VOC emission from wet building materials is considered in this new model, differing from the mass transfer-based models in other literatures. The mechanism of effect of saturated vapor pressure on the surface of wet building materials in the process of VOC emission is discussed. The concentration of total volatile organic compounds (TVOC) in the building materials gradually decreases as the emission of VOCs begins, and the vapor pressure of VOCs on the surface of wet building materials decreases in the case of newly wet building materials. To ensure the partial pressure of VOCs on the surface of wet building materials to be saturated vapor pressure, the interface of gas-wet layer is lowered, and a dry layer of no-volatile gases in the material is formed. Compared with the results obtained by VB model, CFD model and the experiment data, the results obtained by the present model agree well with the results obtained by CFD model and the experiment data. The present model is more accurate in predicting emission of VOC from wet building materials than VB model.A new mass transfer model is developped to predict the volatile organic compounds （VOCs） from fresh wet building materials. The dry section of wet materials during the process of VOC emission from wet building materials is considered in this new model, differing from the mass transfer-based models in other literatures. The mechanism of effect of saturated vapor pressure on the surface of wet building materials in the process of VOC emission is discussed. The concentration of total volatile organic compounds （TVOC） in the building materials gradually decreases as the emission of VOCs begins, and the vapor pressure of VOCs on the surface of wet building materials decreases in the case of newly wet building materials. To ensure the partial pressure of VOCs on the surface of wet building materials to be saturated vapor pressure, the interface of gas-wet layer is lowered, and a dry layer of no-volatile gases in the material is formed. Compared with the results obtained by VB model, CFD model and the experiment data, the results obtained by the present model agree well with the results obtained by CFD model and the experiment data. The present model is more accurate in predicting emission of VOC from wet building materials than VB model.

关 键 词：干燥 饱和蒸汽压 易挥发有机物 物质迁移模型 湿建筑材料 

分 类 号：TU5[建筑科学—建筑技术科学]