【摘要】 建立了气、液间传热传质数学模型,对单个热气泡在上升过程中与处于蒸发阶段的水之间的传热、传质规律进行了数值研究,获得了气泡半径、气泡温度、水蒸发速率以及蒸发量随时间的变化规律.研究表明:在水恒温蒸发阶段,由于传热传质的共同作用,气泡半径随着气泡的上升而变小,并逐渐趋于稳定;随着气、液间温度差的增大,气泡半径缩小得越快;在气泡与水开始接触时,水的蒸发速率及气泡内的水蒸汽增量最大;气泡温度在较短时间内急剧下降,并趋于稳定;随着气泡半径的缩小,气泡冷却速率提高;但随着接触时间的继续增加,对气体的冷却效果却无明显作用.更多还原

【Abstract】 A mathematical model has been established for conducting a numerical study on heat and mass transfer between gas and liquid during a single syngas bubble arising from gasifier pool.The dependences of the radius,the temperature of bubble,the evaporation rate and the evaporation quantity of water on time were obtained.The results show that the bubble size decreases and then tends gradually to be constant with the arising of the bubble.With an increase of initial temperature difference between gas and water,the bubble size reduced quickly,when in beginning of contact between bubble and water,the increment of vapor content in bubble and the evaporation rate in water were at their maximum.The temperature of bubble dramatically dropped and then it approached to stabilizing.However,with the bubble radius became further smaller and its quenching rate became quite higher,contact time to be lasted any more has no obviously effect on gas quenching process.更多还原