垂直降膜、鼓泡流动特性与传热机理研究进展

Review on vertical falling film and bubbling flows and their heat transfer mechanisms

目前对于煤气化技术中洗涤冷却室内喷淋床的垂直降膜液膜波动特性以及鼓泡床中气体穿越液池过程的流动机理尚不清晰,本研究详细阐述洗涤冷却环进水口方式、液相雷诺数Rel、气相雷诺数Reg、下降管高度和管径等因素对垂直降膜中轴、周向液膜厚度、速度分布以及传热传质特性的影响机理。另外对鼓泡床中气体穿越液池过程的研究现状进行综述,尤其是气液夹带理论、气泡形成理论、气体负浮力射流理论、内构件破泡板的结构以及液相物性对气含率的影响理论和两相及多相流理论等。最后对洗涤冷却室内未来的可行性研究进行展望,为工业上气化工艺的合理实施以及能源利用提供参考性建议。

The liquid film fluctuation characteristics of vertical falling film in spray beds within scrubbing cooling chambers,and the flow mechanism of gas passing through liquid pool in bubbling beds are not well studied for coal gasification.In this review,effects of scrubbing cooling ring inlet mode,liquid Reynolds number Rel,gas Reynolds number Reg,descending pipe height and pipe diameter on distribution of thickness and velocity of axial and circumferential liquid film,and heat and mass transfer are summarized in detail.In addition,research status of gas passing through liquid pool in bubbling beds was reviewed,especially gas-liquid entrainment theory,bubble formation theory,gas negative buoyancy jet theory,the structure of internal component bubble breaking plate,and theory of liquid phase physical property effects on gas holdup,two-phase and multiphase flow theory.Finally,feasibility of future scrubbing cooling chamber studies are prospected,which provides suggestions for rational implementation of industrial gasification processes and energy utilization.