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核级先导式安全阀应用于高温气冷堆一回路压力泄放系统,在安全阀后配置爆破片用于核级先导式安全阀的在线密封性测量。在机组冷试和热试期间发生多次安全阀后爆破片异常爆破事件,经过分析和判断初步认为该问题是由于先导式安全阀在低压阶段的前泄问题引起,为了验证该结论,在现场一回路压力泄放系统管路上进行了现场试验,通过试验数据最终证明爆破片异常爆破的原因是先导式安全阀在低压阶段的前泄问题引起。同时考虑到爆破片异常爆破问题都发生在核级先导式安全阀由维修状态至在线运行状态切换操作窗口期,在试验数据的基础上,对核级先导式安全阀由维修状态向运行状态切换方式提出了优化改进建议及操作方法,通过这一方法可以从根本上解决核级先导式安全阀后爆破片的异常爆破问题,避免了由于核级先导式安全阀后泄漏监测不可用而使机组突破运行限制条件。 相似文献
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分析探讨了爆破片最高标定爆破压力与容器设计压力、最低标定爆破压力与容器最大工作压力、爆破片最大泄放压力与容器最大积聚压力之间的关系,为压力容器设计人员选用爆破片装置提供了重要参考依据。给出了如何根据选用的爆破片来确定容器设计压力或如何根据压力容器设计压力来确定爆破片相关压力参数的一般方法。 相似文献
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爆破片作为一种压力容器的安全泄放装置,是流体压力设备安全技术的重要内容之一。为研究升压速率对爆破片爆破性能的影响规律,采用物理超压调节升压速率的方式搭建了动态超压实验台,并搭配高速摄像系统对泄放动作进行捕捉与分析。以反拱开缝型爆破片为研究对象,研究了不同口径爆破片在静态和不同升压速率下的爆破压力变化情况,以及不同升压速率下爆破片的泄放情况。结果表明:随着升压速率增大,爆破片的爆破压力逐渐升高,两者符合幂函数关系,并定义函数中与静态爆破压力相同时的升压速率为升压速率临界值,作为爆破片动静态工况的判定依据;爆破片泄放口径越大,其升压速率临界值越高,对动态超压工况的适应性越好;随着升压速率增大,爆破片膜片翻转时间先逐渐减小、后趋于稳定,最终翻转时间减少18%。 相似文献
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一、安全阀的功能及主要技术参数
1.功能
核一级氦气安全阀安装在一回路压力泄放系统,主要功能是在反应堆一回路系统达到压力设计限值时,通过安全阀排出部分氦气,防止一回路的压力超过设计限值,保证一回路压力边界的完整性。 相似文献
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安全阀作为一种安全泄放装置,由于其结构简单、紧凑、轻便、调式方便、灵敏可靠,在压力容器上已被大量采用。本文试从安全阀的设计选用、安装和校验三方面,就目前存在的问题进行探讨,并对如何改进提出若干建议。 相似文献
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以卧式结构安全阀为研究对象,采用数值模拟方法,通过对比不同开启高度下阀门流场,研究阀门排量系数变化规律,探究流场马赫数与压力分布情况,研究表明:开启高度影响安全阀最小流动面积和临界流动区域位置,从而影响安全阀排量系数。当最小流道面积为帘面积时,帘面积随开高线性增长,其排量系数线性增长;当最小流道面积为环面积时,环面积随开高非线性增长,其排量系数非线性增长;当最小流道面积为喉部面积时,最小流道面积保持不变,排量系数随开高先继续增大后保持不变。可以根据泄放量需求,适当选择卧式结构安全阀开高。 相似文献
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气瓶安全泄放量计算方法探讨 总被引:1,自引:0,他引:1
基于目前国内外标准中对气瓶安全泄放量的计算存在诸多差异的现状,对国内原气瓶用爆破片标准GB16918--1997、美国压缩气体协会标准CGAS-1.1-2005、美国石油学会标准API521q007中气瓶泄放量的计算方法进行了分析。将CGAS-1.1安全泄放量公式中空气的当量体积排放量推导转化为实际介质的安全泄放质量流量,该成果有助于正确理解和应用CGAS~1.1标准。分析比较认为:CGAS公式计算结果较API相比,爆破片计算面积差别不大,但泄放阀结果明显偏大,API521中对受火引起超压的气瓶泄放面积计算,具有扎实的理论基础,但对因其他原因导致的超压,适用性有待考证。GB16918中气瓶安全泄放量公式采用的是CGAS-1.1中适用于单一压力泄放阀的泄放量公式,因此当泄放装置采用爆破片时,不能采用GB16918进行计算,建议补充完善GB16918中安全泄放相关内容。 相似文献
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《流体机械》2013,(11)
通过流阻试验获得了直径为680mm的三偏心蝶阀在不同开度和速度下的流阻系数。以试验结果为基础验证湍流模型,选择SST模型作为湍流模型,建立获得三偏心蝶阀详细流场的数值模型。利用该数值模型对试验蝶阀在90°、70°、50°开度下的流场和流阻系数进行预测,90°代表全开。试验结果表明,50°开度的流阻系数值约为90°开度流阻系数值的9倍;三偏心蝶阀全开时的流阻系数值约为中线蝶阀全开时流阻系数值的6倍。数值分析表明,全开状态下,三偏心蝶阀阀板处存在的漩涡比中线蝶阀多,可对三偏心蝶阀阀板形状进行优化,以减小流阻系数;随着开度减小,流体的流动产生与阀板关闭方向一致的力矩,帮助阀板关闭。 相似文献
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Jun-Ho Bae Sung-Jin Kim Moon-Saeng Kim Chul Kim 《Journal of Mechanical Science and Technology》2011,25(9):2277-2284
The safety valves used in liquefied natural gas — floating production storage and offloading (LNG-FPSO) ships play an important
role in maintaining a fixed pressure by controlling the release of liquefied natural gas (LNG) from pipes in an LNG piping
system. Therefore, the discharge coefficient is regarded as the most important parameter influencing the valve performance.
In order to satisfy the ship’s classification criteria, the discharge coefficient of the safety valve must usually be over
0.8. Despite the importance of a good understanding of the flow phenomena inside the safety valve for the improvement of the
discharge coefficient, the successful design of valves depends on experience and experiments in an industrial field. In this
study, a computational fluid dynamics (CFD) investigation was carried out with ANSYS-CFX software to observe the flow phenomena
inside the valve and to determine the discharge coefficients from changes in the valve lift, which is the distance between
the exit of the nozzle and the lower part of the disc plate. The discharge coefficients obtained were also verified through
comparison with available experimental data. 相似文献
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M.K. Sapra M. Bajaj S.N. Kundu B.S.V.G. Sharma 《Flow Measurement and Instrumentation》2011,22(5):469-474
This paper presents performance characteristics of 100 mm line size cone flow elements having beta ratios of 0.4, 0.5, 0.6, 0.7 and 0.8. A magnetic flow meter is used as a reference standard for flow measurement in vertical test section. A series of experiments have been conducted using water at in-house Flow Calibration Facility (FCF) to cover the Reynolds number ranging from 20,000 to 200,000. The performance characteristics of 100 mm line size cone flow elements with different beta values have been evaluated experimentally. It is found that the discharge coefficient of the cone flow element is nearly independent of the specified range of Reynolds number. Testing of the cone flow element in accordance with new API 5.7 is carried out at flow calibration facility. The testing requirements in the standard explain the conditioning effect of the cone flow element having gate valve disturbance upstream of the cone at various locations. The effect of the upstream velocity profile has been investigated by placing a gate valve upstream of the cone flow element at a distance of 0D and 28D and performing experiments at 25%, 50% and 100% opening of gate valve. The value of the discharge coefficient is not affected when the cone is placed at a distance of 0D and for 100% opening of gate valve. The uncertainty results of the cone testing are discussed. For studying pressure and velocity distributions, cone elements are modeled using computational fluid dynamics (CFD) code PHOENICS. Pressure and velocity profiles for different sizes of cone elements are plotted. From the pressure profile, it can be seen that the pressure recovery downstream of the cone is within a distance of 3D. The velocity profile downstream of the cone signifies the use of flow element as a signal conditioner. For measurement of flow through a 100 mm line, differential pressure across the cone is measured using a Differential Pressure Transmitter (DPT). Experiments were repeated by replacing the cone element for obtaining different β values. 相似文献
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Flowmeters and control valves are important components of flow measurement and control in heating, ventilating, and air conditioning (HVAC) system, which directly or indirectly impact building room comfort and energy costs. Valves as resistance components produce differential pressure which in turn can be used for flow measurement. This paper studies the function among valve opening position, pressure difference and flowrate of a new designed butterfly valve. The flow model of the butterfly valve is established based on the Bernoulli equation, the discharge coefficient C under different valve opening conditions are studied by CFD simulations and verified by experiments. The simulation results show that the discharge coefficient C reached a stable value of 0.67–0.70 as Reynolds number exceeded 5000, and the permanent pressure loss ratio is range from 0.95 to 0.37 corresponding to opening range from 10° to 70°. The correctness of the simulation results of C is verified by experiments, in which C is about 0.60. With the corrected values obtained from experiments, the simulation results are instructive to practice. The new designed butterfly valve flowmeter can be used efficiently in HVAC system, especially in variable air volume (VAV) air conditioning system. And the work of this paper offers a reference for other types of valve flowmeters in fluid control processes. 相似文献
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V型内锥流量传感器使用灵活性研究 总被引:1,自引:0,他引:1
利用数值仿真和实验相结合的研究方法,主要研究V型内锥流量传感器的使用灵活性和安装条件,针对50 mm口径的管道,通过长200 mm的渐扩和渐缩管与100 mm口径等效直径比分别为0.45/0.65/0.85 3种结构类型的样机进行连接,对50mm口径的管道进行常温水流量测量.设计并进行了基线和扩管2类实验,仿真预测结果和实验结论吻合,研究结果表明,在一定的前直管段安装条件下,其流出系数相对误差和附加不确定度满足性能指标要求.研究结果可为V型内锥流量传感器实际安装和使用提供一定的参考. 相似文献