中文摘要：

采用APl000稳压器电加热元件开展大长径比管束沸腾换热特性实验研究。实验热流密度范围为30-270kW／m^2，以去离子水为工质，在常压下进行实验。实验结果表明：管程高度与热流密度对换热系数均有影响，沸腾换热性能与管壁表面附近流型有一定对应关系。分析了不同热流密度下壁温的沿程变化，拟合了局部沸腾换热系数随热流密度及管程高度的关联式。

英文摘要：

The experimental study on heat transfer characteristics of bundle of tubes with big length-diameter ratio was conducted with electrical heating tubes of AP1000 pressurizer. The heat flux range of experimental conditions was 30-270 kW/m^2. The working fluid was deionized water and the experiment was performed under atmospheric pressure. The results show that both of the height of the tube and heat flux had effects on heat transfer coefficient. There is a correspondence relationship between heat transfer performance and boiling phenomenon. The change of wall temperature with the heat flux was analyzed. The correlation of heat transfer coefficient was gained by fitting methods based on experimental results.