Experimental Study of Bottom Reflooding in a Narrow Rectangular Channel
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摘要: 为了解矩形窄缝通道在失水事故（LOCA）下底部再淹没过程中的热工水力特性，在不同实验条件下开展再淹没实验研究。矩形窄缝通道由2块因科镍合金焊接而成，本研究根据温度变化曲线分析底部再淹没过程，计算并对比不同实验工况下的骤冷前沿的推进速度（骤冷速度），以及研究实验参数对再淹没过程的影响。实验结果表明，底部再淹没骤冷速度随着系统压力增大、进口流速增大、初始壁面温度降低以及冷却水过冷度的增大而增大。对比分析底部与联合再淹没工况，结果表明流量相同的情况下，底部再淹没的骤冷速度大于联合再淹没。本文研究为板状燃料元件反应堆事故预防以及事故缓解等研究奠定了基础。Abstract: In order to investigate thermal hydraulic characteristics during bottom reflooding when LOCA occurs in a narrow rectangular channel, the reflooding experiments were carried out under different conditions. The narrow rectangular channel was made by welding two Inconel alloy plates. This study analyzes the bottom reflooding process according to the temperature variation curve, calculates and compares the advancing speed of the quench front (quench speed) under different experimental conditions, and studies the influence of experimental parameters on the reflooding process. Experimental results indicated that quench velocity under bottom reflooding is increasing with increased system pressure, increased inlet velocity, reduced initial wall surface temperature and increase in the degree of subcooling of the coolant. A comparative analysis of the bottom and combined reflooding case indicates that quench velocity under bottom reflooding is higher than that during combined reflooding with the same flow rate. This study lays the foundation for the research of accident prevention and mitigation of plate fuel element reactors.
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Key words:
- Narrow rectangular channel /
- LOCA /
- Reflooding /
- Quench speed
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图 4 工况①下TC-3、4、5的测量温度
骤冷温度—再淹没过程中壁面温度开始显著下降的温度；再湿温度—冷却水开始接触壁面的温度[5]
Figure 4. Temperatures of TC-3, 4 and 5 in Case ①
图 5 工况①下实验开始阶段TC-3、4、5温度变化曲线
Figure 5. Temperature Variation Curve of TC-3, 4 and 5 at the Beginning of Experiment in Case ①
图 8 工况①、③、④下TC-4温度变化曲线
Figure 8. Temperature Variation Curve of TC-4 in Case ①, ③ and ④
图 10 工况①、⑤下夹带水箱内水体积变化曲线
Figure 10. Variation Curve of Water Volume in Entrained Water Tank in Cases ① and ⑤
图 11 工况①、⑥、⑦下TC-4温度变化情况
Figure 11. Temperature Variation Curve of TC-4 in Cases ①, ⑥ and ⑦
图 12 TC-4在工况④、⑧、⑨、⑩下温度变化曲线
Figure 12. Temperature Variation Curve of TC-4 in Cases ④, ⑧, ⑨ and ⑩
表 1 底部再淹没实验工况
Table 1. Experimental Cases of Bottom Reflooding
工况 加热板壁温/
℃压力/
105Pa进口水温/
℃入口流速/
(cm·s−1)① 613.23 1.01 35.77 5.55 ② 522.44 1.01 33.39 5.86 ③ 645.91 1.01 32.48 2.79 ④ 606.01 1.01 34.81 11.72 ⑤ 629.85 1.01 90.66 5.80 ⑥ 603.88 1.96 51.58 5.63 ⑦ 646.15 4.09 70.89 5.62 
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表 2 工况①实验开始阶段TC-3、4、5温度转折时间及温度下降速率
Table 2. Temperature Transition Time and Temperature Drop Rate of TC-3, 4 and 5 at the Beginning of Experiment in Case ①
参数 TC-3 TC-4 TC-5 温度转折时间/s 9.67 15.00 24.33 温度下降速率/(℃·s−1) −0.183 −0.078 −0.026
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表 3 各工况下的骤冷、再湿速度
Table 3. Quench and Rewetting Speed in All Cases
工况 平均温度/℃ 速度/(mm·s−1) 骤冷 再湿 骤冷 再湿 ① 522.58 361.68 1.97 2.01 ② 464.89 314.81 2.34 2.47 ③ 588.36 345.14 1.44 1.25 ④ 525.45 345.27 3.22 3.08 ⑤ 515.71 321.90 1.33 1.28 ⑥ 499.08 359.95 2.75 2.91 ⑦ 515.15 393.35 3.43 3.55
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表 4 联合再淹没工况
Table 4. Combined Reflooding Cases
工况 加热板
壁温/℃进口
水温/℃底部进口流速/
(cm·s−1)顶部进口流速/
(cm·s−1)⑧ 639.47 33.77 3.06 8.66 ⑨ 609.90 34.88 5.76 5.85 ⑩ 607.82 30.72 8.64 3.04
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表 5 联合再淹没骤冷、再湿速度
Table 5. Quench, Rewetting Speed of Combined Reflooding
工况 平均温度/℃ 速度/(mm·s−1) 骤冷 再湿 骤冷 再湿 ④ 525.45 345.27 3.22 3.08 ⑧ 556.16 332.46 1.26 1.22 ⑨ 459.00 309.57 1.99 2.14 ⑩ 513.02 342.86 2.73 2.80
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