缩比非能动余热排出热交换器管外过冷池沸腾实验研究

搭建了缩比非能动余热排出热交换器C型管实验模型,利用导热油作为管内加热介质,脱盐水作为管外冷却介质开展了一系列传热实验。根据壁温及脱盐水主流温度判断在加热过程中出现明显的温度分层现象并经历自然对流、过冷池沸腾最终达到饱和池沸腾。对存在过冷池沸腾阶段的几个代表性时刻对应上、下水平及竖直段单元分别进行传热计算并与文献经验公式进行比对,验证了Rohsenow饱和沸腾经验公式和McAdams自然对流经验公式的适用性,针对过冷池沸腾阶段实验热流密度与Rohsenow过冷沸腾公式的偏差,采用多自变量自定义非线性拟合方法得到了更准确的加权公式。

Experimental Study of Scaled-down Passive Residual Heat Removal Heat Exchanger under Tube-external Subcooled Pool Boiling Condition

Scaled-down experimental model was built to study the tube outside subcooled pool boiling heat transfer characteristics of the C-shaped tube. A series of experiments were conducted by using thermal oil and desalted water as heating and cooling fluid. Obvious thermal stratification occurs during heating process and the desalted water goes though natural convection, subcooled pool boiling and finally reaches saturated pool boiling. Subcooled pool boiling heat transfer characteristics of the horizontal and vertical tube at three representative times are calculated, and the applicability of McAdams natural convection correlations and Rohsenow saturated boiling correlation is verified. A new weighted formula is proposed to improve accuracy for subcooled pool boiling by using multiple independent variables nonlinear fitting method.