为了研究R290制冷剂惰化燃爆特性,采用带搅拌功能和氧浓度在线测定的20L球试验装置,对R290制冷剂进行了极限氧浓度测定.实验测定了丙烷在CO2和N2惰化气氛中的爆炸极限及极限空气浓度LAC,确定丙烷的极限氧浓度LOC;采用三元图爆炸区、丙烷-O2二维图爆炸区和ASTM标准分布图分析了混合气体爆炸区边界的燃爆特征,给出了极限氧浓度的确定方法和边界爆炸压力分布规律.实验结果表明:常温常压下R290的爆炸极限为2.1%~9.6%,CO2惰化气氛中的极限氧浓度为13.3%,对应的丙烷浓度为3.3%;N2惰化气氛中的极限氧浓度为10.8%,对应的丙烷浓度为2.7%.通过对比分析不同CO2和N2浓度下的爆炸区分布特征,表明CO2对丙烷的惰化效果要优于N2,以氮气和二氧化氮体积分数比为1:2测试惰化气氛保护能力,惰化效果介于同浓度单种惰性气体之间.%To study the combustion and explosion characteristics of R290 refrigerant after inerting,the measurement of limit-ing oxygen concentration (LOC)on R290 refrigerant was carried out by using the spherical 20L chamber with the stirring function and on-line measurement of oxygen concentration. The explosion limits and limiting air concentration (LAC)of pro-pane in the inerting atmosphere of CO2 and N2 were measured,and the LOC of propane was determined. The combustion and explosion characteristics in the explosion zone boundary of the gas mixture were analyzed by using the ternary diagram explo-sion zone,propane-oxygen two-dimensional diagram explosion zone and ASTM standard distribution diagram,and the deter-mination method of LOC and the distribution laws of boundary explosion pressure were presented. The results showed that the explosion limits of R290 under normal temperature and pressure was from 2. 1% (v / v)to 9. 6% (v / v),and the LOC in the inerting atmosphere of CO2 was 13. 3%,with the corresponding propane concentration of 3. 3% (v / v). The LOC in the iner-ting atmosphere of N2 was 10. 8%,with the corresponding propane concentration of 2. 7% (v / v). Through comparing and analyzing the distribution characteristics of explosion zone under different concentration of CO2 and N2 ,it showed that the in-erting effect of CO2 for propane was better than N2 . Furthermore,the inerting effect was between the single inert gas with the same concentration when testing the protection capability of inerting atmosphere with the volume fraction ratio of N2 and CO2 as 1:2.
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