管束通道内沸腾两相流特性的研究

Investigation on flow patterns and transition characteristics in a tube-bundle channel

以R113为工质,采用高速动态分析仪对垂直管束通道内的沸腾两相流型及其转变特性进行了实验研究。对管束狭窄通道内沸腾两相流型进行划分,并与圆管内的两相流型进行比较,在此基础上对通道几何形状及物理参数对管束通道内沸腾两相流型及其转变特性的影响进行分析,为进一步对管束通道内流型判定、沸腾换热及阻力压降的研究奠定了基础。

Tube-bundle channels have been widely used in condenser-evaporator and other industrial heat-exchange equipments. The characteristics of two-phase flow patterns and their transitions for refrigerant R-113 through a vertical tube-bundle channel are experimentally investigated using high-speed camera. Experiments show that there are four main flow patterns in the tube-bundle channel, which are bubbly flow, bubbly-churn flow,churn flow and annular flow. And in the same cross-section of tube- bundle channels, it is shown that there might be different flow patterns in different sub- channels. The flow pattern transitions exhibit unsynchronized in different sub- channels. On the basis of experimental research, the flow pattern map is drawn and analyses are made on the comparison of differences between boiling flow patterns in a circular tube and those in a tube-bundle channel.