锯齿形细通道内乙醇流动沸腾特性研究  

Study of the Flow Boiling Characteristics of Alcohol in Serrated Slim Passages

作　　者：常威[1] 张树生[1] 郭雷[1] 

机构地区：[1]山东大学能源与动力工程学院,山东济南250061

出　　处：《热能动力工程》2012年第2期187-191,263-264,共5页Journal of Engineering for Thermal Energy and Power

基　　金：国家重点基础研究发展计划(973计划)基金资助项目(2007CB206900)

摘　　要：采用数值模拟的方法对通道宽度为2 mm的竖直布置的锯齿形细通道内乙醇流动沸腾及传热特性展开研究。通过UDF编程的方法对相界面的传热传质过程进行控制,重点考察了气泡的生长特性及其对系统压差和换热系数的影响。结果表明:锯齿形细通道内起始汽化核心均位于内侧突起点附近,且在漂移区和泡底微层共同作用下,该区域工质平均流速高达主流流速的5～10倍,使得该处的气泡生长速度最快,换热增强。系统压差随加热时间呈上升趋势,并在一定范围内震荡。传热系数随干度增大而下降,并将模拟结果与实验数据进行了对比分析,阐述了流型和通道几何结构对于传热系数的影响。By using a numerical simulation method,studied were the flow boiling and heat transfer characterisitcs of alcohol inside serrated slim passages vertically arranged with a width of 2 mm.The heat and mass transfer process at the phase boundary were controlled by using a UDF(user defined function) programmable method and the bubble growth characteristics and its influence on the system pressure difference and heat exchange coefficient were mainly investigated.The research results show that the initial vaporization nucleation locations inside serrated slim passages tend to be around the inner protrusion points and under the co-action of the drift zone and bubble bottom layer,the mean flow speed of the working medium in the drift zone reaches as high as 5~10 times of the main stream flow speed,making the bubble growth rate in the zone be quickest and intensifying the heat exchange.The system pressure difference will assume an ascending tendency with the heating time duration and fluctuate in a certain range.The heat exchange coefficient will decrease with an increase of the dryness.The simulation results were analyzed and contrasted with the test data and the influence of the flow pattern and passage geometrical structure on the heat exchange coefficient was also expounded.

关 键 词：锯齿形细通道 强化传热 乙醇 数值模拟 

分 类 号：TK124[动力工程及工程热物理—工程热物理]