Three-Dimensional Numerical Simulation Research On Hydraulic Characteristics Of Labyrinth Throttle

Due to its ability to achieve large pressure drop in a small space,the labyrinth throttle is well used in various types of piping systems in sodium-cold fast reactor to adjust pressure drop.The excessive velocity or cavitation may occur because of unreasonable design.For selection the parameters of labyrinth throttle in design,it is necessary to avoid these problems and evaluate its pressure drop.The most efficient method for evaluating pressure drop is the calculation by the empirical formula.The pressure drop of the labyrinth throttle is affected by various factors such as distance between plates,the height of each plate,the number of plates and mass flow rate of fluid flow through the throttle.There is still no empirical formula for the calculation of the pressure drop of labyrinth throttle.The fitting of formula bases on plenty of data that can be obtained from experiment or numerical simulation.The experimental measurement is expensive and time-consuming while numerical simulation can not only calculate the pressure drop but also predict the flow features and potential hazards.Based on above recognition,numerical models were studied for simulating pressure drop of the labyrinth throttle in this paper,in which standard k-ε was selected as the most reliable model for the pressure drop calculation of labyrinth throttle via the comparison with experimental results.Using the validated numerical modeling,hydraulic characteristics of the labyrinth throttle varying with various factors mentioned above were analyzed.The empirical formulas for the relationship between the pressure drop of labyrinth throttle and the influential factors were fitted by multiple nonlinear regression method.An improved type of labyrinth throttle named"Step labyrinth throttle" was proposed.Relationship between pressure drop of step labyrinth throttle and its influential factors was analyzed as well.