Distortion Evaluation of Natural Circulation Characteristic Curves Based on Scaled-down Methodology
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摘要: 基于多级双向比例分析(H2TS)比例模化方法,设计建造了原型、1/2高度比与1/4高度比的模型实验装置,开展了不同加热功率下的自然循环实验,对自然循环特性曲线在降高度比例模化中的失真进行了分析,实验结果表明:自然循环流量、雷诺数、格拉晓夫数、修正格拉晓夫数等表征自然循环主要特征的参数在降高度比例模化后,能够保持自然循环流量-加热功率、雷诺数-格拉晓夫数及雷诺数-修正格拉晓夫数等特征关系曲线不严重失真,原型与模型间的拟合曲线能够形成一对一映射。自然循环特性曲线在降高度比例模化过程中能够较准确复现原型规律,自然循环降高度比例模化实验数据在模拟原型中自然循环特性曲线时的可靠性得到有效验证。Abstract: Based on H2TS (Hierarchical, Two-Tiered Scaling) scaled-down method, three groups of experimental facilities, namely prototype, 1/2 model and 1/4 model, were designed and built. Natural circulation experiments on different heating power were carried out. The distortion of natural circulation characteristic curves in the drop-height scaled-down method was analyzed. The experimental results show that the parameters representing the main characteristics of natural circulation, such as natural circulation flow rate, Reynolds number, Grazoff number and modified Grazoff number, can keep the characteristic curves of natural circulation flow rate-heating power, Reynolds number-Grazoff number and Reynolds number-modified Grazoff number from being seriously distorted after being scaled down, and the fitting curves between the prototype and the model can form a one-to-one mapping. The characteristic curves of natural circulation can accurately reproduce the prototype law in the process of drop-height scaling. The reliability of drop-height scaling experiment simulating the natural circulation characteristic curves in the prototype is effectively verified.
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Key words:
- Natural circulation /
- Characteristic curves /
- Scaling simulation /
- H2TS /
- Distortion evaluation
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表 1 等压、同物性模拟准则
Table 1. Scaling Criteria for Isobaric and Homogeneity Simulation
序号 准则 注释 1 $ {\displaystyle \Pi _{\text{R}}} = \dfrac{{g\Delta {\rho _0}L_{{\text{hc}}}^0}}{{{\rho _0}{u_0}^2}} $ Richardson数,表征浮升力与惯性力间关系 2 ${\displaystyle \Pi _{ {\text{F} },i} } = \displaystyle \sum\limits_i {\left( {\dfrac{ {\rho _r^ + } }{ {\rho _i^ + } } } \right)} {\left( {\dfrac{ { {A_r} } }{ { {A_i} } } } \right)^2}{\left( {\dfrac{ {fl} }{ {D_{\rm{e}}} } + k} \right)_i}$ 阻力系数,表征回路的摩擦和形阻 3 $ {\displaystyle \Pi _{{\text{H}},i}} = \dfrac{{{\xi _i}{q_{\text{s}}}l_{{\text{hc}}}^0}}{{{\rho _0}{h_0}{u_0}{a_i}}} $ 热源数,表征热源加热功率对回路焓升的影响 4 $ {\displaystyle \Pi _{{\text{C}},i}} = \dfrac{{{\rho _{\text{s}}}C{v_{\text{s}}}\Delta {T_0}{a_{{\text{s}},i}}}}{{{\rho _0}\Delta {h_{{\text{fg}}}}{a_i}}} $ 热容数,表征结构的热容量对回路焓升的影响 表 2 实验装置主要结构参数
Table 2. Main Structural Parameters of Experimental Facilities
装置 参数 原型 1/2模型 1/4模型 热源 有效加热段高度/mm 3660 1830 915 热源总高度/mm 4634 2804 1889 子通道当量直径/mm 11.8 电加热管规格/mm Φ21×2 承压壳规格/mm Φ255×32.5 热阱 筒体高度/mm 12815 6411 3208 筒体规格/mm Φ114.3×8 传热管高度/m 10605 5282 2611 传热管规格/mm Φ19×2 传热管数目/根 2 一回路管道 冷热芯形位差/m 16 8 4 冷管直径/mm 17.0 冷管长度/m 6 3 1.5 热管直径/mm 18.0 热管长度/m 4.9 2.45 1.225 -
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