摘要
基于湿球温度效率法(εc-BF法)建立了蒸发器的稳态分布参数模型.以R407C为工质,运用该模型详细分析了4种不同流程布置的2排管蒸发器的换热和流动特性,并与以R22为工质的蒸发器进行了性能比较.结果表明:采用R407C为工质时,4种流程布置中,无论是随着管内冷媒流量的变化,还是随着蒸发器迎风面风速的变化,逆流换热效果都是最好,总换热量、显热换热量、潜热换热量大约比顺流均高5%～40%,压降比顺流略低,其次是错流,顺流最差.同时在进行流程布置时,重力的影响不可忽略.当工质为液态或两相态时,应尽可能使其自上而下流动,以减小压降,增强换热.在与R22为工质的蒸发器性能比较中,无论是随着管内冷媒流量的变化,还是随着迎风面风速的变化,R407C蒸发器总换热量、显热换热量、潜热换热量比R22均高3%～5%左右,压降低约5%～10%,是其理想的替代产品.
Based on the εc-BF, a steady state distributed paramneters model is put forward in the numerical simulation of refrigerant circuitry in evaporators. Applying this model, the heat transfer and flow characteristics of four different two-rows evaporators are studied. The research indicates that the counter-flow evaporators have a better performance than other arrangements. Gravity effects should not be ignored in the arrangement of refrigerants circuitry .When the refrigerants are in the phase of liquid or in the two phase, they should be arranged to flow from up-portion to down-portion, so as to decrease the drop pressure in the tube and increase the heat transfer rate of the evaporators. The total capacity, sensible capacity and latent capacity of R407C evaporators is 3% - 5% higher than that of R22 evaporators and the pressure drop of R407C evaporators is 5% - 10% lower than that of R22 evaporators. R407C is the perfect refrigerant replacement of R22.
出处
《流体机械》
CSCD
北大核心
2005年第11期66-72,共7页
Fluid Machinery
关键词
蒸发器
R407C
流程布置
数值模拟
evaporators
R407C
refrigerant circuitry
numerical simulation
