核动力系统分析中细管簇当量元件阻力OACSTPCD

In order to study the parameter variations of the main pipeline of nuclear power systems un-der 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 de-signed.The standard k-εturbulence 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 ζwith 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 ζof the element,the ζ is negatively correlated with d/D and L,and the smaller the value ofd/D,the shorter the L,the grea-ter the change of central axial velocity as well as turbulent kinetic energy,and the longer the down-stream recovery zone becomes.It has been verified that when Re＞3.0×106 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.