Improving Structural Fumigation from Engineering Perspectives
Seven sulfuryl fluoride (SF) and one MB fumigation monitoring experiments were conducted as part of regular fumigations in three flour mills. In addition to fumigant concentrations, the environmental conditions both inside and outside of the fumigated facilities were monitored during the experiments. These results showed variability in the fumigation-related parameters that had substantial impact on the success and effectiveness of each fumigation. A CFD model was constructed based on the flour mill as an analysis tool for prediction of fumigant distribution and leakage during the fumigation process. The data from one of the fumigation experiments was used to validate the CFD model. Given the same environmental conditions and fumigation practices,the model was able to reproduce a fumigant leakage rate (i. e., Haft-Loss Time or HLT) and an achieved dosage value (i. e.,Ct product) similar to those observed during the actual fumigation. Thus,it was considered validated. The validated model was used to perform eleven fumigation simulations under weather conditions of the same time period of different years （1996-2006). Although the simulated fumigations were performed for the same time period, yeartoyear variations in weather conditions caused significantly different HLT predictions. In extreme cases,the HLT prediction can be more than 100% different (from 10.7 to 23.3 hours),yielding a difference in the achieved Ct products by more than 70% (from 476 to 840 g · h/m3). These results implied that fumigators should quantify the effectiveness of temporary structural sealing in order to verify HLT before a fumigation, minimizing fumigant use. An automatic fumigation monitoring and decision support system was developed. The system consists of a purge pump, port selection panel, valve control unit, gas concentration sensor, laptop computer,and decision support program. Although the regulation of dosage rate to maintain the desired gas concentration still has to be manually done by the fumigator, the monitoring and decision support system helps prevent over dosing, reduces error and risk from human mistakes, and increases the successrate of fumigation.
structural fumigation half-Loss time computational fluid dynamics (CFD) flour mill monitoring system
Dirk E.Maier Watcharapol Chayaprasert Klein E.Ileleji
Department of Agricultural and Biological Engineering, Purdue University, 225 South University Stree Department of Agricultural and Biological Engineering, Purdue University, 225 South University Stree
国际会议
成都
英文
545-549
2008-09-21（万方平台首次上网日期，不代表论文的发表时间）