伞型结构气化器两相流动和传热数值模拟

摘要

Flow and temperature field in combustion chamber of a newly developed umbrella vaporizer were numerically simulated using generalized finite-rate model, which uses flue gas to impact the submerged umbrella, so as to analyze the influence of flue gas circulating rate on both the flue gas velocity and the temperature field at nozzle outlet. Numerical simulation was also performed to analyze the effect of nozzle height and liquid level on the heat transfer of gas-water two-phase flow using VOF model. Results show that optimal impact effect may be obtained when the flue gas circulating rate is 50% of the total volume generated in combustion and when the liquid level is 75 mm, in which case water drops are adequately entrained by flue gas to fill the vaporizer with enhanced heat transfer by vaporization.%采用通用有限比率模型对一种新型烟气冲击浸于水的伞型结构气化器燃烧室的流场与温度场进行了数值模拟,分析了循环烟气量对燃烧室喷嘴出口烟气速度和温度的影响；采用VOF两相流模型对烟气与水滴气液两相流动的传热进行了数值模拟,分析了喷嘴高度和液面高度对烟气冲击浸于水的伞型结构的两相流动传热的影响.结果表明:当循环烟气量为燃烧产生烟气量的50％、液面高度为75 mm时,冲击效果最佳,水滴被烟气充分卷起并充满气化器,气化传热得到强化.