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| Resistance of thin tube cluster equivalent element in nuclear power system analysis |
| YANG Congxin1,2, ZHANG Wenlan1,2* |
| 1. School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2. Key Laboratory of Fluid Machinery and Systems of Gansu Province, Lanzhou, Gansu 730050, China |
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Abstract In order to study the parameter variations of the main pipeline of nuclear power systems under different working conditions, it is necessary to select the appropriate resistance element equivalent to replace the flow resistance of the thin tube cluster inside the component. According to the law of fluid flow, an equivalent circular arc resistance element with gradual contraction and expansion was designed. The standard k-ε turbulence model was used to explore the influence of the resistance element on the internal flow of the circular tube. The basic laws of the resistance coefficient ζ with the tapering ratio d/D and the length of the resistance element L were obtained by comparative analysis. Finally, the function was fitted and verified. The results show that the resistance element has relatively little effect on the downstream pipeline, which is suitable for replacing the internal flow resistance of complex components. Excluding the influence of Reynolds number(Re)on the ζ of the element, the ζ is negatively correlated with d/D and L, and the smaller the value of d/D, the shorter the L, the greater the change of central axial velocity as well as turbulent kinetic energy, and the longer the downstream recovery zone becomes. It has been verified that when Re>3×107 and d/D=0.5-0.9, the ζ predicted by the fitted exponential function is more accurate, and the exponential function can simplify the inner tube cluster of a steam generator.
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Received: 30 December 2021
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