热扩散管的设计与性能测试

In order to study the effect of volatile components on aerosol characteristics, a thermal denuder (TD) was designed, which is composed of a denuder tube and an adsorption tube. The operation temperature of this TD ranges from 50 ℃ to 350 ℃. Compared with the existing designs in the literatures, the internal temperature measurement position in our design was optimized to improve the accuracy of temperature measurement and control. Furthermore, the two-stage heating method was adopted to improve the stability of internal temperature distribution, and elongate the effective residence time of particles within the analytical tube. The middle connecting flange of the adsorption tube is insulated by heating and glass wool respectively, which can effectively reduce the temperature drop at the outlet of the denuder tube. The TD performance test showed that temperature inside the TD tube is well-distributed and could effectively reduce the volatile components. The transport efficiency of particles larger than 60 nm inside the TD tube showed litte change at differential temperatures, which can be approximately regarded as a constant.