Numerical Simulation On Structure Optimization Of Isolation Drip Tray Of Ultra Low Temperature Valve

With the adjustment of the global energy structure,renewable energy and natural gas will greatly increase the proportion of renewable energy and natural gas in the energy system.As the main control equipment in the LNG transportation system,ultra-low temperature valves are critical to the entire LNG industry chain.This article aims to reduce the accumulation of condensate on the surface of the isolation drip tray.Aiming at the problem of valve failure caused by the surface of the ultra-low temperature valve isolation drip tray,it analyzes the influencing factors of the isolation drip tray icing phenomenon,and proposes an optimization plan for the isolation drip tray structure.The research is divided into two aspects:the contact angle of the surface of the isolated drip pan at the micro level and the inclination angle of the isolated drip tray at the macro level.Based on Young-Laplace and Helmholtz free energy,the optimal contact angle of the condensation process is deduced,and the contact angle is 120° when the critical radius is the smallest;the contact angle is 111° when the critical volume is the smallest;the contact angle is 119°.Theoretical analysis of the influence of contact angle on the energy barrier of phase change,and the conclusion that when the contact angle is 120° the energy barrier of phase change is the lowest in the range from 90° to 180°.Based on the VOF model,the influence of the contact angle on the heat transfer process of condensation is analyzed through numerical simulation.The simulation results show that the amount of condensed water is higher when the contact angle is the range from 110° to 120°,and the amount of condensed water is highest when the contact angle is 120°.The advantages and disadvantages and applicable environment of several mainstream superhydrophobic surface preparation methods are analyzed.The contact angle in the range from 110° to 120° is a hydrophobic surface,which is technically easy to achieve.After considering economic issues and efficiency issues,the industrial methods suitable for surface modification of the isolating drip pan are the template method and the electrochemical deposition method.The study of the tilt angle is divided into two parts:the single-phase-convection heat transfer process and the phase-change convective heat transfer process.The research method is a combination of theoretical research and numerical simulation.The research results show that:in the process of single phase change heat transfer,the inclination angle of the isolation drip plate is gradually changed,the heat exchange area increases,and the heat transfer is increased;in the phase change convective heat transfer process,the inclination angle is gradually changed,and the volume fraction of condensed water increases.,Strengthen the heat exchange effect.Considering the heat transfer performance of the isolation drip pan,the economic efficiency of structural optimization,the technical difficulty of surface modification and the effect of condensate shedding,the most suitable optimization solution for the isolation drip pan is the surface contact angle of 120° and the macro tilt angle of 20°.