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Research on Design of Multistage Orifice Plate for Steam Master Tube in Nuclear Power Plant
DOI: 10.12677/nst.2024.122009, PDF, HTML, XML, 下载: 101  浏览: 186

Abstract: In order to alleviate the serious vibration and loud noise of the conventional island main steam tube in a nuclear power plant, this paper has done the preliminary structural design of multistage orifice plate for hydrophobic use by using the method of zero-dimensional theoretical calculation, then through the scale modeling design multistage orifice plate test piece to test the performance of the validation, so as to guide the final design of the multistage orifice plate. The conclusions are as follows: When the zero-dimensional theoretical formula is used to design multistage orifice plate, the error is little (±3%). During the performance verification of the test piece, the critical flow phenomenon appears at the first-stage orifice. According to the deviation between the critical flow rate and the designed flow rate, the first-stage orifice is properly corrected, and the final error is ±1%.

1. 引言

2. 多级孔板理论设计

$\Delta P=2\Delta {P}_{2}=4\Delta {P}_{3}=\cdot \cdot \cdot {2}^{n-1}\Delta {P}_{n}$ (1)

Table 1. Technical parameters of multistage orifice plate

Table 2. Physical parameters of each cavity

$\Delta {P}_{g}=\frac{{W}_{g}^{2}{v}_{g}}{2{A}_{c}^{2}}=\frac{{W}^{2}{x}^{2}{v}_{g}}{2C{D}^{2}{A}_{0}^{2}}$ (2)

${\left(\frac{\Delta {P}_{tp}}{\Delta {P}_{f}}\right)}^{0.5}=\frac{x}{1-x}{\left(\frac{{v}_{g}}{{v}_{f}}\right)}^{0.5}=Y$ (3)

$\frac{\Delta {P}_{tp}}{\Delta {P}_{g}}=1+C\frac{1}{Y}+\frac{1}{{Y}^{2}}$ (4)

$C=k{\left(\frac{{v}_{f}}{{v}_{g}}\right)}^{0.5}+\frac{1}{k}{\left(\frac{{v}_{g}}{{v}_{f}}\right)}^{0.5}$ (5)

$\frac{1}{Y}\ge 1$ 时， $k={\left(\frac{\stackrel{¯}{v}}{{v}_{f}}\right)}^{0.5}$$\frac{1}{Y}<1$ 时， $k={\left(\frac{{v}_{g}}{{v}_{f}}\right)}^{0.25}$

CD为流量系数，与孔板截面比和管道直径有关，计算时可按照相应的图表查询获取 [6] 。采用该理论计算得到的多级孔板各级孔径，见表3

Table 3. Each bore diameter of multistage orifice plate

Table 4. Each minimum thickness of multistage orifice plate

Table 5. Each cavity spacing of multistage orifice plate

3. 多级孔板比例模化

${\left({\pi }_{1}\right)}_{p}={\left(\frac{L}{{D}_{e}}\right)}_{p}$ ${\left({\pi }_{1}\right)}_{m}={\left(\frac{L}{{D}_{e}}\right)}_{m}$

${\left({\pi }_{2}\right)}_{p}={\left(\frac{d}{{D}_{e}}\right)}_{p}$ ${\left({\pi }_{2}\right)}_{m}={\left(\frac{d}{{D}_{e}}\right)}_{m}$

${\left({\pi }_{3}\right)}_{p}={\left(\frac{\epsilon }{{D}_{e}}\right)}_{p}$ ${\left({\pi }_{3}\right)}_{m}={\left(\frac{\epsilon }{{D}_{e}}\right)}_{m}$

Table 6. Each bore diameter of multistage orifice plate test piece

Table 7. Each cavity spacing of multistage orifice plate test piece

4. 多级孔板性能验证

Figure 1. Structure chart of multistage orifice plate test piece

Figure 2. Flow chart of the test system

Table 8. Test data of multistage orifice plate test piece

5. 结论

1) 研究表明，采用零维理论公式的方法对多级节流孔板进行结构设计，误差相对较小，约为±3%。

2) 试验中出现多级孔板试验件一级孔口处达到临界流的现象，出口压力的降低对流量不造成影响，在此基础上根据临界流速及设计流量要求对孔径进行加大处理，最终得到试验流量值与设计流量值误差在±1%。

3) 在多级孔板的最终设计阶段，根据试验求得的临界速度将孔径进一步优化，尽可能地消除了多种因素造成的流量偏差。

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