竖直光管管外含空气蒸汽冷凝特性研究
发布时间：2018-07-13 12:23
【摘要】：为保证安全壳在LOCA、MSLB等极限事故工况下的完整性，新一代核反应堆广泛采用了非能动安全壳冷却系统。对于基于双层混凝土安全壳的非能动安全壳冷却系统，位于安全壳内的冷凝器是其最关键的设备之一，其传热能力决定着非能动安全壳冷却系统的性能。在蒸汽冷凝过程中，安全壳内大量不凝性气体的存在会导致传热严重恶化，所以必须对含不凝性气体的蒸汽冷凝传热问题开展相关的研究工作。 本文对竖直光管管外含空气蒸汽冷凝的传热特性进行了实验研究和数值模拟研究，实验研究分析了混合气体压力、壁面过冷度、空气含量对蒸汽在竖直管管外冷凝传热性能的影响规律，给出了含空气蒸汽的冷凝传热过程中的经验关联式。试验结果表明，仅考虑单一因素对冷凝的影响时，管外冷凝传热系数随混合气体压力的升高而增大；随空气质量分数的升高，管外冷凝传热系数成指数的规律递减；管外冷凝传热系数与壁面过冷度的0.6次方成反比关系。本文得到的管外冷凝传热系数经验关联式与实验值的最大偏差在±10%以内，与现有的经验关联式相比，该关联式具有更广的适用范围。 利用计算流体力学（CFD）软件通过UDF编程在控制方程中加载源项的方法实现了对含空气蒸汽冷凝的数值模拟研究。通过将3个压力工况下的9组数值计算结果与试验值对比，得到冷凝传热系数的最大相对误差为28.59%，平均温度的最大误差为3.75℃，平均压力及空气质量分数的相对误差都在1%以内，说明本文的模拟方法具有一定的精度。数值模拟结果表明，在本文实验条件下，潜热换热是冷凝传热的主导因素；潜热换热系数及显热换热系数都随着空气含量的升高而减小；局部潜热换热系数沿传热管高度方向从下至上呈递减趋势，，而局部显热换热系数则呈现相反变化。在此基础上，应用本文模拟方法对TOSQON试验进行模拟，模拟结果和实验结果的相对误差在10%以内，证明本文模拟方法及冷凝传热系数经验关联式在其他实验条件下也有很好的适用性。
[Abstract]:In order to ensure the integrity of containment under limited accident conditions such as LOCAN MSLB, the new generation of nuclear reactors have widely used inactive containment cooling system. For the non-active containment cooling system based on double-layer concrete containment, the condenser located in the containment is one of its most important equipments, and its heat transfer ability determines the performance of the non-active containment cooling system. In the process of steam condensation, the existence of a large number of non-condensable gases in containment will lead to a serious deterioration of heat transfer, so it is necessary to carry out relevant research work on the condensation heat transfer of steam containing non-condensable gases. In this paper, the heat transfer characteristics of air vapor condensing outside vertical smooth tube are studied experimentally and numerically. The pressure of mixed gas and the undercooling degree of wall are analyzed experimentally. The effect of air content on the condensing heat transfer performance of steam outside the vertical tube is studied. The empirical correlation of condensing heat transfer with air vapor is given. The experimental results show that the external condensation heat transfer coefficient increases with the increase of the pressure of the mixed gas, and decreases exponentially with the increase of air mass fraction when considering the effect of a single factor on the condensation. The condensation heat transfer coefficient outside the tube is inversely proportional to the 0.6 power of the wall undercooling degree. The maximum deviation between the empirical correlation and the experimental value of the external condensation heat transfer coefficient obtained in this paper is less than 卤10%. Compared with the existing empirical correlation, the correlation has a wider range of application. The numerical simulation of vapor condensation with air was carried out by means of the method of loading source term into the governing equation by UDF programming with computational fluid dynamics (CFD) software. The maximum relative error of condensation heat transfer coefficient is 28.599.The maximum error of average temperature is 3.75 鈩
本文编号：2119356
[Abstract]:In order to ensure the integrity of containment under limited accident conditions such as LOCAN MSLB, the new generation of nuclear reactors have widely used inactive containment cooling system. For the non-active containment cooling system based on double-layer concrete containment, the condenser located in the containment is one of its most important equipments, and its heat transfer ability determines the performance of the non-active containment cooling system. In the process of steam condensation, the existence of a large number of non-condensable gases in containment will lead to a serious deterioration of heat transfer, so it is necessary to carry out relevant research work on the condensation heat transfer of steam containing non-condensable gases. In this paper, the heat transfer characteristics of air vapor condensing outside vertical smooth tube are studied experimentally and numerically. The pressure of mixed gas and the undercooling degree of wall are analyzed experimentally. The effect of air content on the condensing heat transfer performance of steam outside the vertical tube is studied. The empirical correlation of condensing heat transfer with air vapor is given. The experimental results show that the external condensation heat transfer coefficient increases with the increase of the pressure of the mixed gas, and decreases exponentially with the increase of air mass fraction when considering the effect of a single factor on the condensation. The condensation heat transfer coefficient outside the tube is inversely proportional to the 0.6 power of the wall undercooling degree. The maximum deviation between the empirical correlation and the experimental value of the external condensation heat transfer coefficient obtained in this paper is less than 卤10%. Compared with the existing empirical correlation, the correlation has a wider range of application. The numerical simulation of vapor condensation with air was carried out by means of the method of loading source term into the governing equation by UDF programming with computational fluid dynamics (CFD) software. The maximum relative error of condensation heat transfer coefficient is 28.599.The maximum error of average temperature is 3.75 鈩
本文编号：2119356
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