AP1000内置换料水箱热工水力特性研究

发布时间：2018-05-28 22:47

本文选题：内置换料水箱 + 非能动余热排出热交换器　；参考：《华北电力大学(北京)》2017年博士论文

【摘要】：三代先进压水堆AP1000引入了非能动余热排出系统(PRHRs),内置换料水箱(IRWST)是非能动余热排出系统的关键设备之一,非能动余热排出热交换器(PRHR HX)、自动降压系统1-3级喷洒器(ADS sparger)均浸没在内置换料水箱中,事故工况下,非能动余热排出热交换器、自动降压系统喷洒器等设备启动,非能动地将一回路余热排出至二次侧热阱内置换料水箱,为反应堆提供应急冷却,其安全、高效运行对于保证反应堆事故余热排出工况下,反应堆有效降温、降压具有重要作用。本研究以AP1000为主要参考对象,搭建分离效应整体缩比IRWSTPRHR HXADS实验台架,研究反应堆内置换料水箱及其关键部件PRHR HX管壁加热式传热、ADS高温蒸汽喷放式冷凝过程中的热工水力学特性,获得IRWST内整体三维温度场、三维速度场分布及局部传热系数,从而揭示关键进程传热、传质机理,进而把握内置换料水箱内流体整体、局部的传热、流动特性。对于PRHR HX特殊形状的C型管束传热研究,基于IRWSTPRHR HX分离效应缩比实验,分别对PRHR HX竖直段、上部水平段、下部水平段在单相自然对流阶段、两相沸腾阶段传热特性进行了深入分析,且基于实验数据验证了各类传统半经验传热关联式对PRHR HX C型管束不同传热区域的适用性。另外,实验结果表明,在余热排出进程中PRHR HX持续加热作用下,IRWST热分层现象十分明显,对应热分层数(Str数)接近1。对此,本研究创新性地在PRHR HX二次侧管束区新装不同数量的导流板以减弱IRWST内热分层程度,并基于实验数据评价该新型导流板设计方案对IRWST对流传热特性、三维温度速度分布,PRHR HX整体、局部传热效果的影响。实验结果表明,PRHR HX二次侧新增导流板方案使得IRWST内的热分层程度降低30%以上,有利于内置换料水箱在更长时间内对反应堆一回路进行降温、降压,保证长期冷却效果。对于AP1000自动降压系统喷洒器复杂结构多孔喷放条件下的高温高压蒸汽直接接触式冷凝(DCC)现象,本研究基于IRWSTADS喷洒器分离效应缩比实验,研究了内置换料水箱内整体循环特性、温度分布以及自动降压系统蒸汽喷放条件下的传热特性。本研究创新性地采用喷放简化“集总蒸汽冷凝区”模型,对复杂结构、多喷孔条件下ADS原型缩比喷洒器喷放冷凝传热系数进行评估计算,实验结果表明,在IRWST内流体相对大过冷度条件下,蒸汽喷放传热系数范围约为0.6-2.9 MW/(m2·℃)。另外,为减弱ADS喷洒器喷放条件下IRWST内的热分层现象,本研究创新地提出了ADS喷头优化方案,通过调整ADS喷洒器在IRWST内的高度位置,改变IRWST内整体流动、温度分布,并采用热分层准则数理查德森数(Ri数)与热分层数(Str数)预测、评价IRWST内的热分层的形成条件、热分层程度。实验结果表明,ADS喷头位置优化方案能够有效降低IRWST内的热分层程度,有利于长期冷却阶段核电厂的长期、安全、稳定运行。本实验研究对AP1000内置换料水箱热工水力特性进行了详细、深入的研究,实验数据可为中国自主化堆芯、系统一体化分析软件COSINE(Core and System INtegrated Engine for design and analysis)提供实验验证并进行特殊传热模型评估,具有重要的应用价值,实验数据为AP1000工程运行与设计改进提供了重要实验参考。
[Abstract]:The three generation advanced pressurized water reactor (AP1000) has introduced the non active waste heat discharge system (PRHRs), and the built-in feed water tank (IRWST) is one of the key equipment for the non active waste heat discharge system, the non active waste heat discharge heat exchanger (PRHR HX), the 1-3 level spraying device (ADS sparger) of the automatic step-down system are immersed in the built-in redeer tank, and the non dynamic surplus is in the accident condition. Heat discharge heat exchanger and automatic step-down system sprayer are started, and the residual heat of the one loop is discharged to the two side heat trap, which provides emergency cooling for the reactor. It is safe and efficient to reduce the temperature of the reactor effectively to ensure the discharge of the reactor's residual heat. This study is of great importance. AP1000 is the main reference object, and the IRWSTPRHR HXADS experimental platform is built with the separation effect as a whole, and the thermal hydraulic characteristics of the reactor's built-in feed water tank and its key components, PRHR HX tube wall heating, and the thermal hydraulic characteristics during the ADS high temperature steam ejection condensation process, are obtained. The three-dimensional temperature field of the whole body in IRWST, the distribution of the three-dimensional velocity field and the local transmission are obtained. Thermal coefficient, which reveals the heat transfer and mass transfer mechanism of the key process, and then grasps the fluid whole, local heat transfer and flow characteristics in the built-in feed water tank. For the PRHR HX special shape C tube bundle heat transfer, based on the IRWSTPRHR HX separation effect shrinkage experiment, the PRHR HX vertical section, the upper level section and the lower level section are in the single phase natural pair, respectively. In the flow stage, the heat transfer characteristics of the two-phase boiling stage are deeply analyzed. And based on the experimental data, the applicability of the traditional semi empirical heat transfer correlations for different heat transfer regions of the PRHR HX C tube bundle is verified. In addition, the experimental results show that the IRWST thermal stratification is very obvious in the process of residual heat discharge in the process of residual heat discharge, and the corresponding thermal stratification is very obvious. The number of thermal layers (Str number) is close to 1.. In this study, different number of diversion plates are newly installed in the PRHR HX two side tube bundle to reduce the degree of internal heat stratification in IRWST, and based on the experimental data, the effect of the new guide plate design scheme on the convection heat transfer characteristics of IRWST, the three-dimensional temperature velocity distribution, the whole PRHR HX and the local heat transfer effect are evaluated. The experimental results show that the PRHR HX two side new diversion plate scheme makes the degree of thermal stratification in the IRWST lower than 30%, which is beneficial to the cooling of the reactor first loop for a longer time, the depressurization, and the long-term cooling effect. The high temperature and high temperature of the complex structure of the AP1000 automatic depressurization system spraying device under the porous and porous condition The direct contact condensation (DCC) phenomenon of pressurized steam is studied. Based on the experiment of the separation effect of the IRWSTADS spray, the overall circulation characteristics, the temperature distribution and the heat transfer characteristics under the steam ejection condition of the automatic step-down system are studied. In complex structure, the heat transfer coefficient of ADS prototype shrinkage nozzle is evaluated and calculated under the condition of multiple injection holes. The experimental results show that the heat transfer coefficient range of steam ejection is about 0.6-2.9 MW/ (m2. C) under the condition of relatively large cooling degree in IRWST. In addition, this study is to weaken the thermal stratification phenomenon in IRWST under the spraying conditions of ADS sprinkler. The ADS nozzle optimization scheme was creatively proposed. By adjusting the high position of the ADS sprinkler in IRWST, the overall flow and temperature distribution in the IRWST were changed, and the thermal stratification criterion number (Ri number) and the thermal partition number (Str number) were used to predict the formation conditions of the thermal stratification in IRWST and the degree of thermal stratification. The experimental results showed that the nozzle position of ADS. The optimization scheme can effectively reduce the degree of thermal stratification in the IRWST, which is beneficial to the long-term, safe and stable operation of the nuclear power plant in the long-term cooling stage. The experimental research has carried out a detailed and in-depth study on the thermal hydraulic characteristics of the AP1000 built-in reding water tank. The experimental data can be used as a self main core in China and the system integration analysis software COSINE (Core an). D System INtegrated Engine for design and analysis) provides experimental verification and carries out special heat transfer model evaluation. It has important application value. Experimental data provide important experimental reference for the operation and design improvement of AP1000 engineering.
【学位授予单位】：华北电力大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM623.91

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