通风强度对空调可燃制冷剂泄漏安全性的影响

Effects of Ventilation Intensity on Leakage of Flammable Refrigerants of an Air-conditioning System

氟利昂制冷剂破坏臭氧层引发一系列环境问题,激发人们寻找和研究对臭氧层无破坏作用的新型制冷剂的热潮.HFC-32和丙烷等可燃制冷剂逐渐成为研究热点,但其可燃性及由此带来的安全性问题备受关注.针对这一问题,以丙烷制冷剂为例,采用数值模拟方法,研究了通风强度对建筑物内泄漏可燃制冷剂引起混合气体浓度场分布的影响规律及其对室内空间安全性的影响.通过研究可以得到以下结论,制冷剂在房间内的泄漏扩散过程受通风影响很大,通风强度越强,丙烷气体浓度达到爆炸危险的时间越久,在相同时间内,爆炸风险水平越低;补风作用使得房间内丙烷气体浓度等值线出现不同程度的抖动现象,且抖动的剧烈程度随着补风强度的增加而增加.研究结果对采用可燃性制冷剂的建筑空调系统设计及相关风险控制具有一定的指导意义.

Ozone depleting by Freon refrigerants has caused a series of environmental issues which calls for new refrigerants with no ozone-depleting effect.HFC-32 and propane are two of the high performance flammable refrigerants with widely attention but limited by safety considerations.Risk analysis of indoor space with an air-conditioning system using flammable refrigerant propane was provided,based on numerical simulation study of the influences of ventilation intensity to the concentration distribution of propane inside the room after leakage.Simulation results showed that：（1） Ventilation of inlet air did influence the concentration distribution of propane inside the room significantly;（2）Increasing ventilation intensity slowed down the propane concentration reaching combustion or explosion limit,and thus lower the risk of fire or explosion; （3）Propane concentration distribution inside room showed obvious oscillation phenomena with inlet air exist,and the oscillation phenomena goed more intensive with higher inlet air speed.The results may provide references for the design of building airconditioning system with flammable refrigerant and help to control and lower risk.