非凝性气体于竖直壁面处冷凝传热压力特性影响机理研究

非凝性气体于竖直壁面处冷凝传热的研究对一体化压水堆汽-气稳压器的瞬态调节以及紧凑型安全壳余热排出进程具有重要影响,当前对含有非凝性气体的蒸汽竖直壁面冷凝传热中压力的影响特性研究较少。基于传热传质比拟方法,采用适用于高压的改进扩散层模型对汽-气竖直壁面冷凝传热的压力影响进行研究。研究发现,基于传热传质比拟方法改进的扩散层模型与已有的实验结果基本一致,适用于较高压力汽-气竖直壁面冷凝传热系数的预测;总压的增加对存在非凝性气体的冷凝传热具有促进作用,这种促进作用随总压的增加逐渐减弱;在一定压力范围内(0.1~7.0 MPa),存在压力分界点pc,在压力影响分界点以下的低压力区域(0.1 MPa~pc)为压力影响敏感区,在压力影响分界点以上的高压力区(pc~7.0 MPa)为非敏感区。同时,本文还对非凝性气体的种类和含量对蒸汽在竖直壁面处冷凝传热过程的影响进行了分析,从气体扩散系数方面进一步分析了造成影响差异的原因。

Research on Pressure Influence Characteristic of Steam Condensation in Presence of Non-condensable Gas on Vertical Wall

Pressure influence characteristic of the steam condensation in presence of non-condensable gas on vertical wall is important in the transient regulation of the gas-steam pressurizer in the integrated pressurized water reactor and the progress of the residual heat removing in the compact containment,and it is quite rare in the public researches. Based on the mass and heat analogy method,the improved diffusion layer model suitable for high pressure was developed to access to the pressure influence characteristic of the steam condensation in presence of non-condensable gas on vertical wall.It is indicated that compared with the experiment result,the improved model can get good applicability and accuracy in the low and moderate pressure region.The increase of the total pressure enhances the condensation heat transfer,and this enhanced trend decreases with the increase of total pressure.In the low and moderate pressure region (0.1-7.0 MPa), there is a demarcation point (p c )of the total pressure corresponding to the influence on the condensation heat transfer.It is the pressure sensitive region (0.1 MPa-p c )when the total pressure is less than the demarcation point,and the high pressure region (p c-7.0 MPa)that total pressure is higher than the demarcation point is the pressure un-sensitive region.At the same time,the variety of non-condensable gas and the concen-tration of non-condensable gas play an important role in the heat transfer process of steam condensation on vertical wall and these effects are investigated in the paper.The diffusion coefficient of non-condensable gas is further analyzed to explain the difference caused by non-condensable gas.