A fully automated system for testing the flammability limits of vapor and gases was established according to ASTM E681-04 and ANSI/ASHRAE Standard 34-2007. The measurement system consists of a vacuum unit
a mixing chamber
a humidity control
a combustion chamber and the control software. The deviation between the absolute ratio by volume and the setting value is less than ±0.1%
and the uncertainty of the mixed ratio is below 0.5%. The reliability of the system was verified by comparing experimental data of several common refrigerants. The flammability limits of dimethyl ether/HFC125 mixtures were determined. The results show that the flammability range of the mixture decreases with the increase of HFC125
and there is a critical explosion suppression point at a volume ratio of 4.6(HFC125):1. However
the inert effect of HFC125 with lower content is not obvious. The test result is of great value for the application of dimethyl ether as a green refrigerant.
BI Shengshan, CHEN Qiang, WU Jiangtao, et al. Thermodynamic analysis of the refrigerant mixture R1270/R227ea/DME[J]. Journal of North China Electric Power University, 2009,36(3):6-9.
HE Maogang, LI Tiechen, LIU Zhigang. Experimental study on the refrigerators with refrigerant dimethyl ether [J]. Journal of Xi'an Jiaotong University, 2004, 38(3):221-225.
CHEN Xin, BI Shengshan, WU Jiangtao. The explosion limit of dimethyl ether, methane and their mixtures[J]. Journal of Engineering Thermophysics, 2009,30(8):1267-1270.
JU Biao, HE Maogang, LIU Zhigang. Theoretical and experimental studies on explosion limits of flammable mixed refrigerants [J]. Journal of Engineering Thermophysics, 2000,21(6):680-682.
LIU Zhigang, WU Jiangtao, CHU Yingjie. Thermodynamic analysis of the refrigerant mixture HFC32/HFC125/HFC152a [J]. Journal of Xi'an Jiaotong University, 2005,39(1):1-5.
KONDO S, TAKIZAWA K, TAKAHASHI A, et al. A study on flammability limits of fuel mixtures [J]. Journal of Hazardous Materials, 2008,155(3):440-448.
KONDO S, TAKIZAWA K, TAKAHASHI A, et al. Flammability limits of multi-fluorinated compounds[J]. Fire Safety Journal, 2006,41(1):46-56.
GROSSHANDLER W L, DONNELLY M K, WOMELDORF C. Flammability measurements of difluoromethane [J]. Journal of Heat Transfer, 2000,122(1):92-98.
KONDO S, TAKIZAWA K, TAKAHASHI A, et al. Extended Le Chatelier's formula and nitrogen dilution effect on the flammability limits [J]. Fire Safety Journal, 2006,41(5):406-417.
KONDO S, TAKIZAWA K, TAKAHASHI A, et al. Extended Le Chatelier's formula for carbon dioxide dilution effect on flammability limits [J]. Journal of Hazardous Materials, 2006,138(1):1-8.
DIETLEN S, HIERONYMUS H, PLEWINSKY B, et al. Explosion behavior of the ‘non-flammable' CFC substitute 1,1,1,2-tetrafluoroethane(R134a)[J]. Chemical Engineering of and Processing, 1995,34(3): 141-149.
SAND J R, ANDRJESKI D L. Combustibility of chlorodifluoromethane [J]. ASHRAE Journal, 1982,24(5):38-40.