Analysis of Disturbance Resisting Ability of Dual-Loop Natural Circulation System under Asymmetrical Conditions
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摘要: 自然循环铅冷快堆热交换器服役在高温、高压差、高密度和高腐蚀的恶劣环境下,易诱发传热管破裂和堵流事故,导致反应堆非对称热负荷或非对称阻力运行,对反应堆的安全稳定运行具有重要影响。本文以铅冷双环路自然循环系统为研究对象,采用无量纲分析方法,推导双环路系统自然循环流量理论解;分别开展不同负荷差或阻力差下自然循环系统扰动特性分析,采用拟合逼近的方法建立表征自然循环抗扰动能力的特征参数,并获得最佳抗扰动区间。研究结果表明,当系统引入一定的热负荷扰动和阻力扰动后,环路流量变化不大,此时系统抗扰动能力较强。Abstract: Natural circulation lead-cooled fast reactor heat exchangers operate under the harsh environment of high temperature, high pressure difference, high density and high corrosion, which can easily induce heat transfer tube rupture and blockage accidents, resulting in asymmetric thermal load or asymmetric resistance operation of the reactor. It has an important impact on the safe and stable operation of the reactor. This paper takes the lead-cooled dual-loop natural circulation system as the research object, and uses a non-dimensional analysis method to derive the theoretical solution of the natural circulation flow of the dual-loop system; then carries out the disturbance characteristics analysis of the natural circulation system under different thermal load differences or resistance differences, using the fitting approximation method to establish the natural circulation characteristic parameters that characterize the anti-disturbance ability, and get the best anti-disturbance interval. The research results show that when the system introduces some thermal load and resistance disturbance, the loop flow does not change greatly, and the system has strong anti-disturbance ability.
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Key words:
- Natural circulation /
- Asymmetrical condition /
- Dual-Loop /
- Anti-disturbance ability
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表 1 理论和CFD的稳态自然循环流量结果对比分析
Table 1. Comparative Analysis of Steady-State Natural Circulation Flow Results of Theory and CFD
项目 理论值/(kg·s−1) CFD值/(kg·s−1) 相对误差/% 左侧环路 54.68 55.91 −2.20 右侧环路 54.68 55.98 −2.32 总流量 109.36 111.89 −2.26 表 2 非对称热负荷条件下双环路自然循环系各环路流量计算结果对比分析
Table 2. Comparative Analysis of Flow Calculation Results of Each Loop in Dual-loop Natural Circulation System under Asymmetric Heat Load Conditions
k1 理论计算归一化流量 CFD计算归一化流量 相对误差/% 0.7 ${x_{\rm{1}}}{\rm{ = }}0.5828$ ${x_{\rm{1}}}{\rm{ = 0}}{\rm{.6036}}$ −3.45 ${x_2}{\rm{ = }}0.4072$ ${x_2}{\rm{ = 0}}{\rm{.3964}}$ 2.72 0.6 ${x_{\rm{1}}}{\rm{ = 0}}{\rm{.5398}}$ ${x_{\rm{1}}}{\rm{ = 0}}{\rm{.5492}}$ −1.71 ${x_2}{\rm{ = 0}}{\rm{.4602}}$ ${x_2}{\rm{ = 0}}{\rm{.4508}}$ 2.08 0.5 ${x_{\rm{1}}}{\rm{ = 0}}{\rm{.5000}}$ ${x_{\rm{1}}}{\rm{ = 0}}{\rm{.4996}}$ 0.08 ${x_2}{\rm{ = }}0.5000$ ${x_2}{\rm{ = }}$0.5004 −0.08 表 3 非对称阻力条件下双环路自然循环系各环路流量对比结果
Table 3. Comparative Results of Flow of Each Loop in Dual-loop Natural Circulation System under Asymmetric Resistance Conditions
B 理论计算归一化流量 CFD计算归一化流量 相对误差/% 0.5 ${x_{\rm{1}}}{\rm{ = }}0.4401$ ${x_{\rm{1}}}{\rm{ = }}0.4456$ −1.23 ${x_2}{\rm{ = }}0.5599$ ${x_2}{\rm{ = }}0.5544$ 0.99 1.0 ${x_{\rm{1}}}{\rm{ = }}0.5000$ ${x_{\rm{1}}}{\rm{ = }}0.4996$ 0.08 ${x_2}{\rm{ = }}0.5000$ ${x_2}{\rm{ = }}0.5004$ −0.08 2.5 ${x_{\rm{1}}}{\rm{ = }}0.5842$ ${x_{\rm{1}}}{\rm{ = }}0.5833$ 0.15 ${x_2}{\rm{ = }}0.4158$ ${x_2}{\rm{ = }}0.4167$ −0.22 -
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