高温燃气中单个液滴的蒸发特性.pdf

第42卷 第7期 西 安 交 通 大 学 学 报 VoL 42 №7 2008年7月 JOURNAL OFXI AN JIAOTONG UNIVERSITY Ju1．2008 古 日 同皿 燃气中单个液滴的蒸发特性 孙慧娟，张海滨，白博峰 (西安交通大学动力工程多相流国家重点实验室，710049，西安) 摘要：为分析单个液滴在高温燃气中的运动和蒸发过程，考虑了气一液两相耦合，建立了描述整个 过程的数理模型，并通过计算获得了液滴直径、速度和平均温度的变化规律以及燃气温度和速度的 影响．计算结果显示，较高的燃气温度和速度都能加速蒸发过程．另外发现当燃气温度沿液滴运动 方向降低时，存在一个临界液滴直径，小于该值时，燃气速度越高液滴蒸发时间越短，超过该值时， 燃气速度越高液滴蒸发时间越长．在文中的计算条件下测得该临界值约为100／~rn．所得结果可为 雾化液滴群在高温气流中的蒸发特性研究提供依据． 关键词：高温燃气；液滴；蒸发 中图分类号：TK402 文献标志码：A 文章编号：0253—987X(2OO8)07—0833～05 Evaporation Investigation of Single Droplet in High Temperature Fuel Gas SUN Huij uan，ZHANG Haibin，BAI Bofeng (State Key Laboratory of Multiphase Flow in Power Engineering，Xi an Jiaotong University，Xi an 710049，China) Abstract：To understand the movement and evaporation behavior of single droplet in high tern— perature fuel gas，a mathematical model was proposed by considering the gas-liquid two-phase coupling．The droplet diameter，velocity and average temperature during its evaporating process and the influence of the fuel gas temperature(1 530 K～2 130 K)and velocity(30 m／s一6O m／s) were analyzed．The numerical results show that both higher temperature and higher velocity of fuel gas can accelerate the evaporation of droplet．When the fuel gas temperature decreases con— tinuously along the droplet movement direction，a critical droplet diameter for evaporation exists． The evaporation time shortens with the increasing gas velocity as the droplet diameter gets lower than the critical value．However，the trend is contrary to the droplet diameter beyond that value, In the present condition(the temperature of the fuel gas drops from 2 210 K to 1 090 K along 550 mm le