水平管降膜换热器性能规律研究进展

Recent Advances in the Performance Rules of Falling Film Heat Exchanger over Horizontal Tubes

水平管降膜换热器具有热质传递效率高、阻力小、结构简单等优点,被广泛应用于化工等传统领域及能源利用的节能减排领域。降膜换热器内部发生复杂的流动及传热传质相互耦合过程。介绍了实验及模拟研究手段的进展,综述了不同操作参数(气体温度、流向及流量,溶液流量、温度及浓度,内部媒介流量及温度等)与结构参数(管径、管间距等)对水平管降膜管间流型、液膜厚度与润湿性等流动特性的影响规律,以及对蒸发传热特性、吸收传热传质特性等换热器性能的影响规律,包括整体性能和局部微细特征,为水平管降膜换热器的性能优化提供理论支撑。指出在不同气流特征以及多因素相互作用下多维度的局部流动与传热传质性能的耦合影响规律以及强化换热手段会是水平管降膜换热器未来研究的重点方向。

The falling film heat exchanger over horizontal tubes has the advantages of high heat and mass transfer efficiency,low resistance,simple structure and so on.It is widely used in traditional fields such as chemical industry and field of energy conservation and emission reduction of energy utilization.Complex coupling flow and heat and mass transfer processes are occured in falling film heat exchanger.The progress of experimental and numerical simulation research methods was reviewed.The multiple influences of different operating parameters(such as gas temperature,gas flow direction,gas flow rate,solution flow rate,solution temperature,solution concentration,internal media flow rate and temperature)and structural parameters(such as tube diameter and tube spacing)on flow characteristics of falling film over horizontal tubes were reviewed,such as intertube flow pattern,liquid film thickness and wettability,etc.And the influence rules on the performance of heat exchangers such as evaporative heat transfer characteristics and absorptive heat and mass transfer characteristics were reviewed,including the overall performance and local fine characteristics,which provided theoretical support for improving the performance optimization of falling film heat exchangers over horizontal tubes.It was pointed out that the coupling effects of multi-dimensional local flow and heat and mass transfer performance under different gas flow characteristics and multi-factor interaction as well as strengthening heat transfer means will be theresearch direction of falling film heat exchangers over horizontal tube in the future.