摘要： The formation of dry ice particles in a jet flow has been studied experimentally. The particles were produced by rapid expansion of liquid carbon dioxide through a nozzle, based on the Joule–Thomson effect. Their size distribution was measured by a laser diffraction method. The experimental results showed that the primary dry ice particles ejected from the nozzle were about 1μm in mass median diameter. However, they grew initially in the jet flow and then became smaller due to sublimation. As a result, a bimodal size distribution was formed at increased distances from the nozzle outlet. The presence of a thermally insulated tube at the outlet of the expansion nozzle enhanced the agglomeration of the particles, whereby agglomerates of about 100μm in mass median diameter were recorded. The agglomeration process is considered to take place by the simultaneous processes of particle deposition and reentrainment; i.e. agglomerated particles are reentrained from the layer of dry ice particles deposited on the tube walls. The agglomerate size decreased with increasing flow velocity, due to the greater detachment force applied to the deposition layer. Therefore, the flow velocity was found to be an important parameter influencing the agglomeration of dry ice particles. [Display omitted] ► Dry ice particles were produced by rapid expansion of liquid carbon dioxide. ► Their size distribution was measured by a laser diffraction method. ► The primary particles ejected from the nozzle were about 1μm in particle diameter. ► They grew initially in the jet flow and then became smaller due to sublimation. ► Agglomerates of about 100μm were produced in a thermally insulated tube. 出版者： Oxford: Elsevier Ltd 出版日期： 2012-06-01 出處： Journal of Aerosol Science, 2012-06, Vol.48, p.1-9 資源來源： Elsevier ScienceDirect Journals Complete - AutoHoldings 版權： 2012 Elsevier Ltd 版權： 2015 INIST-CNRS 識別號： ISSN: 0021-8502 識別號： ISSN: 1879-1964 識別號： EISSN: 1879-1964 識別號： DOI: 10.1016/j.jaerosci.2012.01.007 識別號： CODEN: JALSB7
